Internal Medicine

3151 soru

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A 48-year-old man is hospitalized for severe acute pancreatitis. On admission, he was resuscitated with intravenous lactated Ringer solution and provided with adequate analgesia. On day 5 of his hospitalization, he reports persistent abdominal pain. His temperature is $38.3^\circ\text{C}$ ( $100.9^\circ\text{F}$ ), blood pressure is $122/78\text{ mmHg}$ , and pulse is $105/\text{min}$ . Physical examination reveals epigastric tenderness without rebound. Laboratory studies show a leukocyte count of $15,200/\text{mm}^3$ . A contrast-enhanced computed tomography scan of the abdomen demonstrates an enlarged pancreas with $>30\%$ non-enhancing necrotic tissue and surrounding peripancreatic fluid. No gas bubbles are visualized within the necrotic collections. Which of the following is the most appropriate next step in management?

Initiate intravenous imipenem-cilastatin

Initiate intravenous fluconazole

Continue current supportive management

Initiate intravenous piperacillin-tazobactam

Initiate oral ciprofloxacin and metronidazole

Cevabı ve açıklamayı göster

Cevap: Continue current supportive management

Cevap

The correct answer is to continue current supportive management.

The correct approach is to continue current supportive management. This patient has severe acute pancreatitis complicated by pancreatic necrosis. In the first week of severe pancreatitis, patients frequently develop Systemic Inflammatory Response Syndrome (SIRS), manifesting with fever, tachycardia, and leukocytosis. These systemic signs are driven by a massive cytokine release from the inflamed pancreas, not necessarily by a bacterial infection. The contrast-enhanced CT scan confirms sterile necrosis, evidenced by the lack of gas bubbles within the necrotic collections. Current gastroenterology and surgical guidelines recommend against the routine use of prophylactic antibiotics or antifungals in patients with sterile pancreatic necrosis. Antimicrobial prophylaxis does not reduce mortality or the incidence of infected necrosis; instead, it increases the risk of selecting for multidrug-resistant organisms and fungal infections. Therefore, the standard of care remains aggressive supportive management, including fluid resuscitation, pain control, and nutritional support.

Adım Adım Çözüm

Analyze the patient's clinical presentation and imaging findings.

The patient has severe acute pancreatitis with >30% necrosis. He exhibits fever and leukocytosis, but the CT scan shows no gas in the necrotic tissue.

To differentiate between sterile pancreatic necrosis and infected pancreatic necrosis.

Determine the etiology of the fever and leukocytosis.

These findings are secondary to Systemic Inflammatory Response Syndrome (SIRS), which is expected in the first week of severe pancreatitis, rather than an active bacterial infection.

To decide if antimicrobial therapy is clinically indicated.

Apply clinical guidelines for the management of pancreatic necrosis.

Prophylactic antibiotics are contraindicated for sterile necrosis; supportive care is the standard.

To select the most appropriate next step in management.

Anahtar Kavram

Prophylactic antibiotics are not indicated in patients with severe acute pancreatitis and sterile necrosis, even in the presence of Systemic Inflammatory Response Syndrome (SIRS).

Soru 2782Soru →

A $72$ -year-old man is evaluated in the intensive care unit for sudden, severe abdominal pain and bilious vomiting that began $4$ hours ago. He was admitted $2$ days ago for a chronic obstructive pulmonary disease (COPD) exacerbation. His past medical history is significant for COPD, heart failure with preserved ejection fraction, and a laparotomy for a perforated appendix $15$ years ago. Since the pain started, he has not passed flatus or stool. His temperature is $38.9^\circ\text{C}$ ( $102.0^\circ\text{F}$ ), blood pressure is $82/50\text{ mmHg}$ , pulse is $130/\text{min}$ , and respiratory rate is $26/\text{min}$ . The jugular venous pressure is $6\text{ cm H}_2\text{O}$ . Physical examination reveals a markedly distended, rigid abdomen with diffuse tenderness, involuntary guarding, and rebound tenderness. Bowel sounds are absent. Laboratory studies show a leukocyte count of $23,000/\text{mm}^3$ and a serum lactate of $6.8\text{ mmol/L}$ . Arterial blood gas analysis on room air reveals a pH of $7.28$ , $\text{PaCO}_2$ of $30\text{ mmHg}$ , and $\text{HCO}_3^-$ of $14\text{ mEq/L}$ . An upright plain radiograph of the abdomen demonstrates multiple dilated loops of small bowel with air-fluid levels and no free intraperitoneal air. Which of the following is the most appropriate next step in management?

Immediate exploratory laparotomy

Placement of a nasogastric tube and serial abdominal examinations

Transport to the radiology suite for an abdominal computed tomography scan

Administration of intravenous furosemide and noninvasive positive pressure ventilation

Administration of intravenous sodium bicarbonate

Cevabı ve açıklamayı göster

Cevap: Immediate exploratory laparotomy

Cevap

Immediate exploratory laparotomy

The patient has a complete small bowel obstruction, likely secondary to adhesions from his previous appendectomy. While many small bowel obstructions can be managed conservatively with bowel rest and nasogastric decompression, this patient presents with classic signs of bowel strangulation and ischemia. These 'red flag' indicators include fever, severe tachycardia, hypotension, a rigid abdomen with rebound tenderness (peritonitis), marked leukocytosis, and lactic acidosis. When an SBO is complicated by strangulation, the affected bowel segment rapidly becomes necrotic. Therefore, the most appropriate next step is an immediate exploratory laparotomy for bowel resection and source control. Any delay for further imaging or conservative observation significantly increases mortality.

Adım Adım Çözüm

Identify the primary diagnosis from the clinical and radiographic presentation.

The combination of severe abdominal pain, bilious vomiting, lack of flatus, previous laparotomy, and dilated small bowel loops with air-fluid levels on radiograph confirms a small bowel obstruction (SBO).

Recognizing the classic triad of SBO symptoms and imaging findings establishes the baseline pathology.

Assess for complications indicating bowel compromise or strangulation.

The patient exhibits fever (

38.9^\circ\text{C}

), shock (blood pressure

82/50\text{ mmHg}

), a rigid abdomen with rebound tenderness, leukocytosis (

23,000/\text{mm}^3

), and lactic acidosis (

6.8\text{ mmol/L}

Differentiating between simple and complicated/strangulated SBO dictates the entire management pathway.

Determine the appropriate intervention based on the severity of the SBO.

The presence of ischemia and peritonitis requires an immediate exploratory laparotomy.

Strangulated SBO is a surgical emergency. Medical management or delayed imaging will increase the risk of bowel perforation, worsening sepsis, and mortality.

Anahtar Kavram

Management of complicated (strangulated) small bowel obstruction

Soru 2783Soru →

Match each clinical exposure scenario with the most appropriate post-exposure prophylaxis (PEP) regimen.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

The correct matching aligns Hepatitis B exposure in a susceptible host with HBIG plus the HBV vaccine; varicella exposure in a non-immune pregnant woman with VZIG only; high-risk wildlife bites with HRIG plus the rabies vaccine; and meningococcal close contact with oral ciprofloxacin or rifampin chemoprophylaxis.

Appropriate post-exposure prophylaxis prevents progression to active disease by intervening during the incubation period. Naive hosts exposed to Hepatitis B or Rabies require immediate combined active-passive immunization (vaccine + immunoglobulin). Non-immune pregnant women exposed to varicella require passive immunization (VZIG) because live vaccines are contraindicated. Close contacts of meningococcal disease require targeted bacterial chemoprophylaxis (ciprofloxacin, rifampin, or ceftriaxone) to eliminate nasopharyngeal carriage before systemic invasion occurs.

Adım Adım Çözüm

Analyze the specific exposure pathogen and the host's baseline immunity or clinical status.

Identified four distinct risk scenarios: Hepatitis B in an unvaccinated host, Varicella in a pregnant and non-immune host, Rabies from a high-risk wildlife bite, and Neisseria meningitidis from close respiratory contact.

Post-exposure prophylaxis guidelines are highly pathogen-specific and depend heavily on host factors like prior vaccination history and pregnancy status.

Select the indicated prophylactic modality (active vaccine, passive immune globulin, and/or antimicrobial chemoprophylaxis) for each specific scenario.

Matched Hepatitis B and Rabies with combined vaccine and immunoglobulin regimens; matched Varicella in pregnancy with immunoglobulin alone; and matched Meningococcus with targeted bacterial chemoprophylaxis.

Different pathogens have unique pathogenesis timelines, requiring tailored interventions to successfully abort an active infection.

Anahtar Kavram

Post-exposure prophylaxis (PEP) protocols for common infectious diseases

Tahmini Süre:1m 30s

Soru 2784Soru →

A $62$ -year-old woman is brought to the emergency department by her family due to confusion, severe right upper quadrant abdominal pain, and subjective fevers over the past $24$ hours. Her temperature is $39.4^\circ\text{C}$ ( $102.9^\circ\text{F}$ ), blood pressure is $88/54\text{ mmHg}$ , heart rate is $118/\text{min}$ , and respiratory rate is $22/\text{min}$ . Physical examination reveals marked scleral icterus and severe tenderness to palpation in the right upper quadrant with guarding. She is disoriented to time and place. Laboratory studies are notable for a leukocyte count of $18,500/\mu\text{L}$ , total bilirubin of $6.8\text{ mg/dL}$ , alkaline phosphatase of $450\text{ U/L}$ , and aspartate aminotransferase of $112\text{ U/L}$ .

Arrange the following interventions in the most appropriate chronological sequence for the optimal management of this patient.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence is: initial fluid resuscitation and blood cultures, followed by intravenous antibiotics, diagnostic confirmation with a right upper quadrant ultrasound, emergent biliary decompression via ERCP, and finally, a delayed elective cholecystectomy.

This patient presents with Reynolds pentad (fever, jaundice, right upper quadrant pain, hypotension, and altered mental status), indicating severe acute ascending cholangitis. The optimal algorithmic approach begins with stabilizing the patient's hemodynamics using intravenous fluids while simultaneously obtaining blood cultures. Once cultures are secured, empiric broad-spectrum intravenous antibiotics are immediately initiated. Following initial medical stabilization, a right upper quadrant ultrasound is obtained to rapidly and non-invasively confirm common bile duct dilation. With the diagnosis secured, emergent ERCP is performed for life-saving biliary decompression and stone extraction. Once the patient has fully recovered from the acute systemic inflammatory response (often days to weeks later), an elective laparoscopic cholecystectomy is performed to prevent recurrent complications.

Adım Adım Çözüm

Recognize the clinical presentation of acute severe ascending cholangitis (Reynolds pentad) and prioritize initial resuscitation.

The patient requires immediate intravenous crystalloid fluids to manage hypotension, and blood cultures must be drawn prior to administering antimicrobials.

Septic shock from biliary infection is rapidly fatal; hemodynamic stabilization and proper microbiologic sampling are the foundational first steps.

Administer broad-spectrum intravenous antibiotics.

Systemic antimicrobial therapy begins to control the ascending infection.

Early antibiotic administration in sepsis reduces mortality, but it must strictly follow the collection of blood cultures to avoid sterilizing the samples.

Perform a right upper quadrant ultrasound.

Confirmation of common bile duct dilation and possible visualization of choledocholithiasis.

Before committing a hemodynamically unstable patient to an invasive procedure, a rapid, non-invasive imaging modality must verify the presence of mechanical biliary obstruction.

Perform an emergent endoscopic retrograde cholangiopancreatography (ERCP).

The obstructing gallstone is removed, and biliary flow is restored.

Antibiotics alone cannot cure ascending cholangitis if the biliary tree remains obstructed; emergent decompression is life-saving in severe cases.

Schedule an elective laparoscopic cholecystectomy.

Removal of the primary source of the gallstones.

Cholecystectomy is necessary to prevent future episodes but is contraindicated during the acute phase of severe cholangitis due to prohibitively high surgical mortality.

Anahtar Kavram

The management of severe acute ascending cholangitis (Reynolds pentad) follows a strict sequence: hemodynamic stabilization and cultures, empiric broad-spectrum antibiotics, non-invasive imaging to confirm obstruction, emergent biliary decompression (e.g., ERCP), and delayed elective cholecystectomy.

Soru 2785Soru →

A 24-year-old woman with a history of type 1 diabetes mellitus presents to the emergency department with nausea, vomiting, and profound weakness for the past 24 hours. She has been unable to tolerate oral intake. Her blood pressure is 90/60 mm Hg, pulse is 122/min, and respirations are 28/min and deep. Laboratory studies show:

- Serum glucose: 580 mg/dL
- Arterial blood gas pH: 7.12
- Serum bicarbonate: 11 mEq/L
- Serum potassium: 3.1 mEq/L
- Serum sodium: 132 mEq/L
- Serum creatinine: 1.4 mg/dL

Arrange the following management steps in the most appropriate chronological order of execution.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence is: 1) Administration of 0.9% sodium chloride bolus, 2) Intravenous potassium chloride supplementation, 3) Intravenous regular insulin infusion, 4) Addition of 5% dextrose to intravenous fluids.

The management of diabetic ketoacidosis follows a strict sequential protocol to minimize complications. The very first step is restoring intravascular volume with isotonic saline. Next, before giving any insulin, the physician must check the potassium level. Because this patient's potassium is dangerously low (3.1 mEq/L), potassium must be aggressively replaced first. Once the potassium is ≥ 3.3 mEq/L, an intravenous insulin infusion is started to resolve the acidosis. Finally, as the glucose falls (typically ≤ 200 mg/dL), 5% dextrose must be added to the intravenous fluids to prevent hypoglycemia, allowing the insulin drip to continue running until the anion gap is completely closed.

Adım Adım Çözüm

Assess volume status and initiate fluid resuscitation.

Administration of 0.9% sodium chloride bolus.

The patient is hypotensive, tachycardic, and dehydrated. Rapid volume expansion improves perfusion and renal glucose clearance.

Evaluate serum potassium level before giving insulin.

Intravenous potassium chloride supplementation.

The patient's potassium is 3.1 mEq/L. Insulin drives potassium into cells, so severe hypokalemia (< 3.3 mEq/L) must be corrected first to avoid fatal arrhythmias.

Initiate insulin therapy to treat ketoacidosis.

Intravenous regular insulin infusion.

With potassium levels safely repleted, insulin is given to stop ketogenesis and normalize the anion gap.

Monitor glucose and adjust fluids during insulin therapy.

Addition of 5% dextrose to intravenous fluids.

When glucose drops below 200 mg/dL, dextrose is added to prevent hypoglycemia, as the insulin infusion must continue until the ketoacidosis resolves.

Anahtar Kavram

In diabetic ketoacidosis, normal saline is the first step, followed by ensuring serum potassium is ≥ 3.3 mEq/L before starting insulin, and adding dextrose when glucose reaches ≤ 200 mg/dL.

Soru 2786Soru →

Emergency medical services bring a 68-year-old woman to the emergency department after she collapsed in an airport terminal. She had just disembarked from a 12-hour international flight. On presentation, she is lethargic, diaphoretic, and in severe respiratory distress. Vital signs are temperature 36.8°C (98.2°F), blood pressure 76/44 mmHg, pulse 134/min, and respirations 32/min. Pulse oximetry shows 83% on room air. Physical examination reveals marked jugular venous distention when the head of the bed is elevated. The lungs are clear to auscultation bilaterally. Cardiac examination demonstrates a rapid, regular rhythm, a parasternal heave, and a loud pulmonic component of the second heart sound. The right lower extremity is edematous, warm, and tender from the calf to the mid-thigh. A bedside echocardiogram shows a dilated and hypokinetic right ventricle with bowing of the interventricular septum into the left ventricle. Arterial blood gas analysis on room air reveals a $pH$ of 7.22, $pCO_2$ of 28 mmHg, $pO_2$ of 54 mmHg, and $HCO_3^-$ of 11 mEq/L. Which of the following is the most appropriate next step in management?

Immediate transfer to the radiology suite for a computed tomography pulmonary angiogram

Intravenous administration of a loop diuretic

Intravenous infusion of sodium bicarbonate

Intravenous administration of tissue plasminogen activator

Empiric administration of broad-spectrum antimicrobial therapy

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Cevap: Intravenous administration of tissue plasminogen activator

Cevap

Intravenous administration of tissue plasminogen activator is the correct intervention for a hemodynamically unstable patient with a massive pulmonary embolism.

The correct intervention is the administration of a systemic thrombolytic agent, such as tissue plasminogen activator (alteplase). This patient presents with classic signs of a massive (high-risk) pulmonary embolism (PE), defined by the presence of sustained hypotension (systolic blood pressure < 90 mmHg) or shock. The history of prolonged immobilization, deep vein thrombosis symptoms, clear lungs, and right ventricular (RV) strain on echocardiography confirm the diagnosis of obstructive shock. In massive PE, the sudden increase in pulmonary vascular resistance leads to acute RV dilation and failure, which compromises left ventricular filling (evidenced by septal bowing) and systemic cardiac output. Thrombolytic therapy rapidly reduces the clot burden, decreasing pulmonary artery pressure and restoring hemodynamics.

Adım Adım Çözüm

Identify the primary clinical syndrome from the patient's history and physical examination.

The combination of a long flight, sudden collapse, hypotension, tachycardia, jugular venous distention, clear lungs, and unilateral leg swelling strongly points to a massive pulmonary embolism causing obstructive shock.

Recognizing the triad of hypotension, clear lungs, and elevated central venous pressure is essential for diagnosing obstructive shock.

Evaluate the diagnostic findings, particularly the bedside echocardiogram and arterial blood gas.

The echocardiogram confirms acute right ventricular strain (dilated RV, septal bowing). The ABG shows a severe mixed metabolic acidosis (lactic acidosis from shock) and respiratory acidosis (impending failure, as the

pCO_2

is higher than predicted by Winter's formula).

Diagnostic data solidifies the severity of the obstruction and the immediate threat to the patient's life, dictating aggressive intervention.

Determine the most appropriate immediate intervention for high-risk (massive) pulmonary embolism.

Systemic thrombolysis (tissue plasminogen activator) is indicated to rapidly dissolve the clot burden.

In hemodynamically unstable patients, reducing pulmonary vascular resistance is critical to restore right ventricular output and prevent cardiac arrest.

Anahtar Kavram

Management of massive (high-risk) pulmonary embolism with obstructive shock requires immediate restoration of right ventricular output, typically via systemic thrombolytic therapy, bypassing confirmatory CT imaging if the patient is hemodynamically unstable.

Tahmini Süre:1m 15s

Soru 2787Soru →

During a routine follow-up appointment, a 38-year-old female reports a one-month history of progressive muscle weakness and fatigue. Her past medical history is significant for Sjögren syndrome and multiple episodes of calcium phosphate nephrolithiasis. Vital signs show a blood pressure of 118/76 mm Hg and a heart rate of 84/min. Physical examination reveals dry oral mucosa and 4/5 motor strength in the proximal muscles of the upper and lower extremities.

Laboratory evaluation reveals the following:

Test	Result
Serum sodium	139 mEq/L
Serum potassium	2.9 mEq/L
Serum chloride	115 mEq/L
Serum bicarbonate	14 mEq/L
Blood urea nitrogen	12 mg/dL
Serum creatinine	0.9 mg/dL
Urine sodium	48 mEq/L
Urine potassium	22 mEq/L
Urine chloride	45 mEq/L

Based on these findings, what is this patient's calculated urine anion gap in mEq/L?

Cevabı ve açıklamayı göster

Cevap: 25

Cevap

The patient presents with a normal anion gap metabolic acidosis (serum anion gap =

139 - (115 + 14) = 10

mEq/L). To differentiate the etiology of the acidosis, the urine anion gap (UAG) is calculated using the formula

UAG = Urine\ Na^+ + Urine\ K^+ - Urine\ Cl^-

. Substituting the provided urine electrolytes yields

48 + 22 - 45 = 25

mEq/L. A positive UAG indicates that the kidneys are failing to adequately excrete ammonium (

NH_4^+

) to buffer the acid load, pointing toward a renal origin for the acidosis. Specifically, a positive UAG combined with hypokalemia, a history of autoimmune disease (Sjögren syndrome), and recurrent nephrolithiasis is highly characteristic of distal (Type 1) renal tubular acidosis.

Adım Adım Çözüm

Calculate the serum anion gap to classify the metabolic acidosis.

139 - (115 + 14) = 10

mEq/L

Determining the serum anion gap is the first step in evaluating any metabolic acidosis; a value of 10 mEq/L indicates a non-anion gap (hyperchloremic) metabolic acidosis.

Identify the appropriate diagnostic parameter to differentiate the underlying etiology of the non-anion gap metabolic acidosis.

Calculation of the urine anion gap (UAG).

In the setting of a non-anion gap metabolic acidosis, the UAG helps distinguish between renal impaired acid excretion (e.g., renal tubular acidosis) and gastrointestinal bicarbonate loss (e.g., diarrhea).

Calculate the urine anion gap using the provided urine electrolytes.

UAG = Urine\ Na^+ + Urine\ K^+ - Urine\ Cl^-

This formula indirectly estimates unmeasured urinary anions, primarily ammonium (

NH_4^+

), which the kidney secretes to clear excess systemic acid.

Substitute the patient's urine laboratory values into the formula.

48 + 22 - 45 = 25

mEq/L

A positive value indicates inappropriately low renal ammonium excretion in the face of systemic acidosis, which is consistent with this patient's presentation of distal (type 1) renal tubular acidosis.

Anahtar Kavram

The urine anion gap (

UAG = Urine\ Na^+ + Urine\ K^+ - Urine\ Cl^-

) differentiates the etiologies of a normal anion gap metabolic acidosis. A positive UAG implies a renal etiology (e.g., renal tubular acidosis), while a negative UAG points to a gastrointestinal etiology (e.g., severe diarrhea).

Soru 2788Soru →

A $36$ -year-old male software engineer visits the clinic complaining of a $3$ -month history of constant sweating, a $5$ -kg ( $11$ -lb) unintended weight loss, and frequent bowel movements. He also mentions a new onset of dull, constant headaches and occasionally bumping into doorframes on his sides over the past few weeks. His temperature is $37.2^\circ\text{C}$ ( $99.0^\circ\text{F}$ ), blood pressure is $145/85 \text{ mmHg}$ , and pulse is $105/\text{min}$ . Physical examination reveals a mild resting tremor, moist skin, and a diffusely enlarged, non-tender thyroid gland without palpable nodules. Extraocular movements are intact, and there is no proptosis.

Laboratory studies are obtained and reveal the following:

Laboratory Test	Result	Reference Range
Thyroid-stimulating hormone (TSH)	$5.2 \mu\text{U/mL}$	$0.4 - 4.0 \mu\text{U/mL}$
Free thyroxine (T4)	$3.1 \text{ ng/dL}$	$0.9 - 1.7 \text{ ng/dL}$
Free triiodothyronine (T3)	$6.5 \text{ pg/mL}$	$2.0 - 4.4 \text{ pg/mL}$

Which of the following is the most appropriate next step in the evaluation of this patient's condition?

Magnetic resonance imaging of the brain

Measurement of thyroid-stimulating immunoglobulins

Radioactive iodine uptake scan

Measurement of serum thyroglobulin

Ultrasound of the thyroid gland

Cevabı ve açıklamayı göster

Cevap: Magnetic resonance imaging of the brain

Cevap

Magnetic resonance imaging of the brain

This patient presents with clinical signs of hyperthyroidism (weight loss, tachycardia, tremor, goiter) and bitemporal hemianopsia (evidenced by bumping into doorframes on his sides), suggesting a mass compressing the optic chiasm. His laboratory results show elevated free T4 and free T3 with an inappropriately elevated TSH. In primary hyperthyroidism, the TSH should be severely suppressed due to negative feedback. The lack of TSH suppression in the presence of elevated thyroid hormones indicates a central etiology, specifically a TSH-secreting pituitary adenoma. The most appropriate next step to confirm the anatomical presence of this pituitary macroadenoma is magnetic resonance imaging of the brain.

Adım Adım Çözüm

Identify the clinical syndrome

The patient demonstrates classic signs of thyrotoxicosis, including weight loss, tachycardia, heat intolerance, tremor, and goiter.

Recognizing the broad clinical picture is required to interpret the laboratory results effectively.

Interpret the laboratory findings

Elevated free T4 and free T3 confirm thyrotoxicosis, while the TSH is inappropriately elevated.

In primary hyperthyroidism, the TSH should be suppressed via negative feedback. An elevated TSH paired with elevated thyroid hormones indicates secondary (central) hyperthyroidism.

Correlate lab findings with additional clinical clues

The patient's headaches and tendency to bump into doorframes (suggesting bitemporal hemianopsia) point to an intracranial mass compressing the optic chiasm.

This localizes the source of the secondary hyperthyroidism to a pituitary adenoma.

Determine the next diagnostic step

Brain imaging is required.

To confirm the anatomical presence and extent of a TSH-secreting pituitary adenoma, magnetic resonance imaging of the brain is the gold standard.

Anahtar Kavram

Diagnosis of secondary hyperthyroidism caused by a TSH-secreting pituitary adenoma

Soru 2789Soru →

A $76$ -year-old woman is brought to the emergency department by her family due to severe, sudden-onset abdominal pain that started $3$ hours ago. She describes the pain as generalized, constant, and $10/10$ in intensity. She has had one episode of nonbilious emesis. Her medical history is significant for permanent atrial fibrillation, diet-controlled type 2 diabetes mellitus, and hypothyroidism. She admits to running out of her apixaban medication three weeks ago and has not taken it since. She takes levothyroxine daily.

Vital signs:
- Temperature: $37.4^\circ\text{C}$ ( $99.3^\circ\text{F}$ )
- Blood pressure: $105/65\text{ mm Hg}$
- Heart rate: $118/\text{min}$ and irregularly irregular
- Respiratory rate: $26/\text{min}$

Physical examination reveals a soft, non-distended abdomen. There is mild, diffuse tenderness to deep palpation, but no guarding, rigidity, or rebound tenderness. Bowel sounds are diminished.

Laboratory results:
- Leukocytes: $18,500/\text{mm}^3$
- Serum sodium: $138\text{ mEq/L}$
- Serum potassium: $4.2\text{ mEq/L}$
- Serum bicarbonate: $14\text{ mEq/L}$
- Blood urea nitrogen: $28\text{ mg/dL}$
- Serum creatinine: $1.2\text{ mg/dL}$
- Lactic acid: $5.8\text{ mmol/L}$ (normal: $0.5-2.2\text{ mmol/L}$ )
- Thyroid-stimulating hormone (TSH): $0.1\text{ }\mu\text{U/mL}$ (normal: $0.4-4.0\text{ }\mu\text{U/mL}$ )
- Free T4: $1.3\text{ ng/dL}$ (normal: $0.9-1.7\text{ ng/dL}$ )

Arterial blood gas (room air):
- pH: $7.28$
- pCO2: $32\text{ mm Hg}$
- pO2: $88\text{ mm Hg}$

Which of the following is the most appropriate next step in the management of this patient?

Initiate bowel rest, intravenous fluid resuscitation, and serial clinical examinations

Administer empiric intravenous piperacillin-tazobactam and observe

Perform computed tomography angiography of the abdomen

Administer a continuous intravenous infusion of sodium bicarbonate

Increase the patient's maintenance dosage of levothyroxine and monitor heart rate

Cevabı ve açıklamayı göster

Cevap: Perform computed tomography angiography of the abdomen

Cevap

Perform computed tomography angiography of the abdomen

This patient's sudden onset of severe abdominal pain out of proportion to physical examination findings, combined with her history of unanticoagulated atrial fibrillation, is highly suspicious for acute mesenteric ischemia (AMI) due to a superior mesenteric artery embolus. The presence of significant leukocytosis and lactic acidosis further supports tissue hypoperfusion and active bowel ischemia. In patients suspected of having AMI who do not have frank peritonitis (e.g., rigid abdomen, rebound tenderness) or hemodynamic instability, the most appropriate next step is computed tomography (CT) angiography of the abdomen to definitively identify the vascular occlusion before proceeding to surgical or endovascular revascularization.

Adım Adım Çözüm

Identify the primary clinical syndrome from the patient's presentation.

The patient has acute, severe abdominal pain out of proportion to physical examination findings, alongside a history of untreated atrial fibrillation.

Recognizing this classic triad (acute pain, soft abdomen, embolic risk factor) is essential for suspecting acute mesenteric ischemia.

Evaluate the laboratory data for signs of tissue ischemia.

Marked leukocytosis (

18,500/\text{mm}^3

) and lactic acidosis (

5.8\text{ mmol/L}

) with a significant anion gap are present.

These findings confirm systemic toxicity and anaerobic metabolism, strongly supporting acute bowel ischemia rather than a benign process.

Determine the most appropriate diagnostic or therapeutic next step.

Computed tomography (CT) angiography of the abdomen is selected.

In the absence of frank peritonitis or hemodynamic collapse requiring immediate exploratory laparotomy, CT angiography is the gold standard to definitively locate the mesenteric arterial occlusion.

Anahtar Kavram

Diagnosis and initial management of acute mesenteric ischemia

Tahmini Süre:1m 30s

Soru 2790Soru →

A 42-year-old man is evaluated in the hospital on day 3 of admission for community-acquired pneumonia. He initially presented with a productive cough, high fever, and shortness of breath. Chest radiography on admission showed a right lower lobe infiltrate. He was empirically started on intravenous ceftriaxone and azithromycin. Blood and sputum cultures obtained on admission have now grown Streptococcus pneumoniae. Susceptibility testing reveals the isolate is highly susceptible to penicillin (minimum inhibitory concentration < 0.06 mcg/mL), amoxicillin, ceftriaxone, and levofloxacin. Today, his temperature is 37.0 C (98.6 F), blood pressure is 120/78 mm Hg, pulse is 78/min, and respiratory rate is 14/min. His oxygen saturation is 97% on ambient air. He is tolerating a regular diet and reports feeling much better. Which of the following is the most appropriate next step in management?

Continue intravenous ceftriaxone and azithromycin

Transition to oral levofloxacin

Transition to oral amoxicillin

Transition to oral amoxicillin-clavulanate

Transition to oral amoxicillin and azithromycin

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Cevap: Transition to oral amoxicillin

Cevap

Transition to oral amoxicillin

The most appropriate next step in management is transitioning to oral amoxicillin. This patient was admitted with community-acquired pneumonia (CAP) and empirically treated with a standard regimen of a beta-lactam (ceftriaxone) and a macrolide (azithromycin). On hospital day 3, he meets the criteria for clinical stability: he is afebrile, hemodynamically stable, off supplemental oxygen, and able to tolerate oral intake. When clinical stability is achieved, patients should be transitioned from intravenous to oral antibiotics. Furthermore, blood and sputum cultures identified Streptococcus pneumoniae that is highly susceptible to penicillin (MIC < 0.06 mcg/mL). According to principles of antibiotic stewardship, empiric broad-spectrum therapy should be de-escalated to the narrowest effective agent. For penicillin-susceptible S. pneumoniae, high-dose oral amoxicillin is the drug of choice because it provides excellent targeted coverage without unnecessarily disrupting normal gut flora.

Adım Adım Çözüm

Evaluate the patient's clinical stability for an intravenous-to-oral transition.

The patient is afebrile, hemodynamically stable, has normal oxygen saturation on ambient air, and is tolerating a regular diet.

Clinical stability indicates that the patient is ready to step down from intravenous to oral antibiotics, reducing hospital length of stay and risk of catheter-related complications.

Analyze the culture and susceptibility results to identify the optimal targeted therapy.

Cultures grew Streptococcus pneumoniae that is highly susceptible to penicillin and amoxicillin.

Empiric broad-spectrum therapy must be narrowed to targeted therapy once a causative pathogen and its susceptibilities are identified, in accordance with antibiotic stewardship principles.

Select the most appropriate narrow-spectrum oral antibiotic.

Oral amoxicillin is selected over broader options like fluoroquinolones or combination therapies.

Amoxicillin is the preferred narrow-spectrum oral beta-lactam for fully susceptible S. pneumoniae, avoiding the unnecessary broad-spectrum coverage.

Anahtar Kavram

In patients hospitalized with community-acquired pneumonia who achieve clinical stability and have a confirmed bacterial isolate, empiric broad-spectrum intravenous antibiotics should be de-escalated to narrow-spectrum targeted oral therapy.

Tahmini Süre:1m 0s

Soru 2791Soru →

A 65-year-old man with a history of chronic obstructive pulmonary disease (COPD) and ischemic cardiomyopathy (ejection fraction 40%) is evaluated in the intensive care unit. He was admitted 3 days ago for severe community-acquired pneumonia and was started on empiric intravenous vancomycin and cefepime. Today, his admission sputum cultures finalized, growing *Haemophilus influenzae* that is susceptible to ceftriaxone and ampicillin. Blood cultures remain negative.

Over the last 2 hours, the patient has developed increasing dyspnea, orthopnea, and severe anxiety.
Vital signs are temperature $37.1^\circ C$ ( $98.8^\circ F$ ), blood pressure 165/95 mm Hg, heart rate 115/min, and respiratory rate 28/min.
Physical examination reveals elevated jugular venous pressure, an $S_3$ gallop, and coarse crackles up to the mid-lung fields bilaterally. Mild expiratory wheezes are also audible. There is 2+ pitting edema in both lower extremities.

Arterial blood gas analysis on a 4 L/min nasal cannula reveals:
pH: 7.29
$PaCO_2$ : 30 mm Hg
$PaO_2$ : 64 mm Hg
$HCO_3^-$ : 14 mEq/L

Serum chemistry shows a lactate level of 4.0 mmol/L.

Which of the following are appropriate next steps in the management of this patient? (Select all that apply)

Geçerli olan tümünü seçin

Initiate noninvasive positive pressure ventilation (NPPV)

Transition antibiotic therapy to intravenous ceftriaxone

Administer intravenous methylprednisolone and continuous nebulized albuterol

Perform endotracheal intubation for uncompensated respiratory failure

Continue current therapy with intravenous vancomycin and cefepime

Cevabı ve açıklamayı göster

Cevap: Initiate noninvasive positive pressure ventilation (NPPV); Transition antibiotic therapy to intravenous ceftriaxone

Cevap

The correct steps are to initiate noninvasive positive pressure ventilation (NPPV) and transition antibiotic therapy to intravenous ceftriaxone.

The patient is experiencing acute decompensated heart failure (ADHF), characterized by signs of severe volume overload (elevated JVP,

S_3

gallop, crackles) and hypertensive emergency. Noninvasive positive pressure ventilation (NPPV) is the most appropriate initial respiratory step because it reduces the work of breathing, improves oxygenation, and decreases both cardiac preload and afterload, which is ideal in hypertensive ADHF. Concurrently, the patient's sputum culture results warrant the de-escalation of empiric broad-spectrum antibiotics (vancomycin and cefepime) to a targeted narrow-spectrum agent (ceftriaxone) in strict accordance with antibiotic stewardship principles.

Adım Adım Çözüm

Interpret the physical examination and vital signs in the context of acute dyspnea.

The patient exhibits elevated jugular venous pressure, an

S_3

gallop, and bilateral crackles in the setting of hypertension, which is highly consistent with acute decompensated heart failure (ADHF) and pulmonary edema.

Accurately identifying the primary cause of acute respiratory deterioration (ADHF vs. COPD exacerbation) dictates the immediate life-saving interventions.

Analyze the arterial blood gas using Winter's formula to determine the acid-base status.

The primary disorder is a metabolic acidosis (

HCO_3^-

of 14 mEq/L, elevated lactate). Using Winter's formula: Expected

PaCO_2 = (1.5 \times 14) + 8 = 29 \pm 2

mm Hg. The actual

PaCO_2

is 30 mm Hg, indicating appropriate respiratory compensation.

This confirms the patient is effectively compensating and is not in uncompensated hypercapnic respiratory failure, meaning immediate endotracheal intubation can be deferred in favor of NPPV.

Review culture and sensitivity results to guide ongoing pharmacological management.

The admission sputum culture finalized growing *Haemophilus influenzae* susceptible to ceftriaxone.

Standard antimicrobial stewardship requires prompt de-escalation from empiric broad-spectrum coverage to targeted, narrow-spectrum therapy.

Anahtar Kavram

Management of acute decompensated heart failure (ADHF) involves recognizing volume overload signs and initiating NPPV, while concurrently applying Winter's formula to assess respiratory compensation and adhering to antibiotic stewardship.

Soru 2792Soru →

Paramedics transport a 69-year-old female to the acute care clinic due to a three-day history of escalating respiratory distress. The patient describes a persistent cough yielding frothy white sputum and states she has been sleeping in her recliner to avoid a choking sensation. She has a documented background of essential hypertension, hyperlipidemia, and a 45-pack-year smoking habit. She takes lisinopril and atorvastatin.

Upon initial triage, her core body temperature is 37.0°C (98.6°F), arterial blood pressure measures 168/96 mm Hg, heart rate is 115/min, and respiratory rate is 28/min. Oxygen saturation reads 86% while breathing ambient air.

Clinical assessment reveals elevated jugular venous pressure. Pulmonary auscultation identifies a markedly prolonged expiratory phase accompanied by diffuse, high-pitched wheezing throughout all lung fields; no localized crackles are evident. Cardiac auscultation reveals tachycardia with a distinct protodiastolic gallop (S3). Examination of the lower extremities shows bilateral pitting edema up to the mid-calf.

Arterial blood gas analysis on ambient air:

Parameter	Value	Reference Range
pH	7.46	7.35–7.45
PaCO2	31 mm Hg	35–45 mm Hg
PaO2	54 mm Hg	75–105 mm Hg
HCO3-	21 mEq/L	22–28 mEq/L

A bedside chest radiograph displays enlargement of the upper lobe pulmonary veins, indistinct vascular margins, and blunting of both costophrenic angles. No lobar opacities are present.

Which of the following is the most appropriate initial pharmacologic intervention for this patient?

Inhaled albuterol and systemic glucocorticoids

Intravenous piperacillin-tazobactam

Intravenous furosemide

Intravenous magnesium sulfate

Intravenous sodium bicarbonate

Cevabı ve açıklamayı göster

Cevap: Intravenous furosemide

Cevap

Intravenous furosemide

The correct answer is intravenous furosemide. The patient's clinical presentation—progressive dyspnea, orthopnea, frothy sputum, jugular venous distention, an S3 gallop, and bilateral lower extremity edema—is classic for acute decompensated heart failure (ADHF). The chest radiograph findings of prominent upper lobe vessels (cephalization) and bilateral pleural effusions further support this diagnosis. Although she has a significant smoking history and presents with diffuse wheezing, the wheezing in this context is known as 'cardiac asthma.' It results from peribronchial edema and external compression of the small airways by engorged pulmonary vessels, rather than the intrinsic bronchospasm seen in COPD or asthma exacerbations. The most appropriate initial pharmacologic intervention to rapidly relieve her symptoms and reduce pulmonary congestion is a loop diuretic, such as intravenous furosemide, which decreases intravascular volume and reduces ventricular preload.

Adım Adım Çözüm

Analyze the patient's vital signs, physical examination, and radiographic findings.

The patient exhibits hypertension, tachycardia, hypoxia, jugular venous distention, an S3 gallop, bilateral edema, and radiographic evidence of cephalization and pleural effusions.

To establish the primary physiological mechanism causing the severe respiratory distress.

Evaluate the significance of wheezing in the context of the overall clinical picture.

The wheezing is identified as 'cardiac asthma' secondary to peribronchial edema, rather than a primary obstructive lung disease exacerbation.

To distinguish between acute decompensated heart failure and a COPD or asthma exacerbation, as the targeted treatments differ significantly.

Interpret the arterial blood gas (ABG) results.

The ABG demonstrates an elevated pH (7.46) and a low PaCO2 (31 mm Hg), indicating a primary acute respiratory alkalosis driven by hypoxia-induced hyperventilation.

To rule out primary metabolic or respiratory acidosis and ensure appropriate targeted therapy.

Determine the most appropriate initial pharmacologic therapy based on the established diagnosis.

Intravenous furosemide is selected as the primary intervention.

Loop diuretics rapidly reduce intravascular volume and ventricular preload, directly addressing the pulmonary congestion and relieving the respiratory distress in acute decompensated heart failure.

Anahtar Kavram

Acute decompensated heart failure can present with diffuse wheezing (cardiac asthma) due to peribronchial edema; it must be differentiated from COPD exacerbation using clinical signs of volume overload (jugular venous distention, S3 gallop, peripheral edema) to ensure appropriate treatment with loop diuretics.

Soru 2793Soru →

A clinical investigator is reviewing the laboratory records of four distinct patients evaluated for abnormalities in bone and mineral metabolism. Match each patient's serum and urine laboratory profile to the most likely underlying pathophysiologic diagnosis.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Profile 1 matches Primary hyperparathyroidism; Profile 2 matches Familial hypocalciuric hypercalcemia; Profile 3 matches Secondary hyperparathyroidism; Profile 4 matches Primary hypoparathyroidism.

Each laboratory profile uniquely isolates a distinct pathology within the calcium-PTH feedback loop. Profile 1 shows autonomous PTH secretion (Primary hyperparathyroidism). Profile 2 shows an altered calcium-sensing set point (FHH). Profile 3 shows an appropriate physiological response to external deficiency (Secondary hyperparathyroidism). Profile 4 shows primary glandular failure (Primary hypoparathyroidism).

Adım Adım Çözüm

Analyze Profile 1 for directionality of calcium and PTH.

Identified hypercalcemia driven by elevated PTH, with high urine calcium.

Elevated PTH despite hypercalcemia indicates primary hyperparathyroidism. High urine calcium helps rule out FHH.

Examine Profile 2 focusing on urine calcium levels.

Identified hypercalcemia with normal PTH, but very low urine calcium (40 mg/day).

The marked hypocalciuria in the setting of hypercalcemia is pathognomonic for Familial hypocalciuric hypercalcemia (FHH), differentiating it from primary hyperparathyroidism.

Evaluate Profile 3 integrating vitamin D status.

Identified low-normal calcium, low phosphorus, high PTH, and low 25-hydroxyvitamin D.

The parathyroid glands are appropriately responding (high PTH) to the hypocalcemia caused by severe vitamin D deficiency, diagnosing secondary hyperparathyroidism.

Assess Profile 4 for gland functionality.

Identified frank hypocalcemia and hyperphosphatemia with absent/low PTH.

The inability to mount a PTH response to severe hypocalcemia indicates primary gland failure, establishing the diagnosis of primary hypoparathyroidism.

Anahtar Kavram

Interpretation of the calcium-PTH axis and 24-hour urinary calcium excretion to differentiate primary, secondary, and receptor-mediated parathyroid disorders.

Soru 2794Soru →

A 68-year-old renal transplant recipient is brought to the emergency department by his family due to profound confusion and high fever for the past 24 hours. Vital signs show a temperature of 39.2°C (102.6°F), blood pressure of 110/70 mmHg, and heart rate of 115/min. Neurologic examination reveals marked nuchal rigidity, somnolence, and a new left-sided pronator drift. Arrange the following steps in the most appropriate sequential order for the initial management of this patient.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence is: 1) Obtain peripheral blood cultures, 2) Administer empiric intravenous antibiotics and dexamethasone, 3) Obtain a noncontrast CT scan of the head, and 4) Perform a lumbar puncture.

The correct sequence prioritizes the rapid initiation of life-saving antimicrobial therapy while ensuring procedural safety. For any patient with suspected bacterial meningitis, blood cultures must be drawn first to guide targeted therapy later. However, because this patient has indications for a CT scan prior to LP (age > 60, immunocompromised, focal neurologic deficit, altered mental status), empiric antibiotics and dexamethasone must be given immediately after blood cultures and before the CT scan. Delaying antibiotics for neuroimaging is a critical error. Once antibiotics are running, the patient undergoes the CT scan. If the CT shows no mass effect, a lumbar puncture is safely performed.

Adım Adım Çözüm

Identify high-risk features for intracranial pressure (ICP) elevation.

The patient has multiple high-risk features: age > 60, immunocompromised state (renal transplant), altered mental status (somnolence, confusion), and a focal neurologic deficit (left-sided pronator drift).

These features mandate neuroimaging (CT scan) prior to a lumbar puncture (LP) to rule out mass effect and prevent cerebral herniation.

Sequence the immediate therapeutic interventions.

Blood cultures are drawn first, immediately followed by empiric intravenous antibiotics and dexamethasone.

Blood cultures must be obtained prior to antibiotic administration to ensure accurate pathogen identification, but antibiotics cannot be delayed for CT or LP due to the high mortality associated with delayed treatment in bacterial meningitis.

Sequence the diagnostic imaging and procedure.

A noncontrast CT scan of the head is performed, followed by a lumbar puncture.

The CT scan is necessary to confirm it is safe to perform the LP. Once cleared by CT, the LP is performed to analyze the cerebrospinal fluid.

Anahtar Kavram

Management algorithm for suspected bacterial meningitis in patients with indications for neuroimaging prior to lumbar puncture.

Soru 2795Soru →

An $58$ -year-old male with a history of poorly controlled hypertension is evaluated in the emergency department for severe, abrupt-onset chest pain radiating to his upper back. He describes the pain as "tearing" and rates it a $10$ out of $10$ . He appears diaphoretic and in severe distress. Blood pressure is $215/115$ mm Hg in the right arm and $175/90$ mm Hg in the left arm. Heart rate is $115$ /min. Neurologic examination is unremarkable. An electrocardiogram shows sinus tachycardia and voltage criteria for left ventricular hypertrophy. A portable chest radiograph reveals a widened mediastinum.

Arrange the following next steps in patient management in the optimal chronological sequence.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The correct sequence of management is: First, initiate intravenous beta-blockade to reduce heart rate and shear stress. Second, initiate an intravenous vasodilator (like sodium nitroprusside) if blood pressure remains elevated. Third, obtain computed tomography angiography of the aorta for definitive diagnosis. Finally, classify the dissection based on imaging to determine surgical candidacy.

The patient's clinical presentation (tearing back pain, pulse deficit, widened mediastinum, severe hypertension) is highly suspicious for an acute aortic dissection. The primary initial goal is to arrest the progression of the dissecting hematoma by reducing aortic wall shear stress. Shear stress is directly proportional to both blood pressure and the rate of ventricular contraction (dP/dt). Intravenous beta-blockers (e.g., esmolol, labetalol) effectively lower both heart rate and dP/dt and must be given first. Once the heart rate is controlled, if the blood pressure remains above the target systolic of 100-120 mm Hg, an intravenous vasodilator (e.g., sodium nitroprusside) is added. After hemodynamic stabilization is achieved, the patient should undergo computed tomography (CT) angiography to confirm the diagnosis and determine the extent of the dissection. Based on the CT findings, the patient is then appropriately triaged for emergent cardiothoracic surgery (for Type A) or continued medical management (for Type B).

Adım Adım Çözüm

Control heart rate and left ventricular contractility (dP/dt).

Heart rate drops to target (

< 60

/min) and aortic shear stress decreases.

Administering a beta-blocker first prevents reflex tachycardia and reduces the force of blood hitting the damaged aortic wall, halting the propagation of the dissection.

Control blood pressure with vasodilators.

Systolic blood pressure drops to target (

100

120

mm Hg).

Vasodilators further lower the pressure within the aorta. They are given only after beta-blockade to prevent compensatory reflex tachycardia from worsening the dissection.

Perform definitive diagnostic imaging.

Confirmation of the intimal flap and extent of the dissection.

Computed tomography angiography is required to map the anatomy, but the patient must be hemodynamically stabilized first to prevent rupture during transport or imaging.

Triage for definitive care based on anatomical classification.

The patient is routed to either emergent surgery or intensive medical management.

Dissections involving the ascending aorta (Type A) require emergent surgical repair, while those confined to the descending aorta (Type B) are typically managed medically.

Anahtar Kavram

In the acute management of suspected aortic dissection, intravenous beta-blockade must be administered before vasodilators to prevent reflex tachycardia and increased aortic wall shear stress. Diagnostic imaging and surgical triage follow immediate pharmacological stabilization.

Soru 2796Soru →

A $45$ -year-old woman is evaluated in the clinic for an $8$ -month history of worsening lethargy, unexplained weight gain, and generalized weakness. She also reports that her menstrual periods have been completely absent for the past year. Her blood pressure is $95/60$ mm Hg and her pulse is $55$ /min. Physical examination reveals pale, dry skin and a noticeable delay in the relaxation phase of her deep tendon reflexes.

Laboratory studies reveal the following:

Test	Result	Reference Range
Thyroid-stimulating hormone (TSH)	$1.8$ $\mu$ U/mL	$0.5$ - $5.0$ $\mu$ U/mL
Free thyroxine (T4)	$0.5$ ng/dL	$0.9$ - $1.7$ ng/dL
Follicle-stimulating hormone (FSH)	$3.2$ mIU/mL	$> 30$ mIU/mL (postmenopausal)

Based on these findings, which of the following is the most appropriate next step in management prior to initiating thyroid replacement therapy?

Measurement of early morning serum cortisol

Measurement of anti-thyroid peroxidase antibodies

Immediate initiation of levothyroxine monotherapy

Ultrasound of the thyroid gland

Radioactive iodine uptake scan

Cevabı ve açıklamayı göster

Cevap: Measurement of early morning serum cortisol

Cevap

Measurement of early morning serum cortisol

The correct answer is measuring early morning serum cortisol. This patient presents with signs of hypothyroidism and amenorrhea. Her laboratory profile—a low free T4 coupled with an inappropriately normal TSH—is diagnostic of central (secondary) hypothyroidism. Furthermore, her low FSH in the setting of prolonged amenorrhea suggests concurrent hypogonadotropic hypogonadism, pointing broadly toward panhypopituitarism (which could be caused by a pituitary adenoma or other sellar pathology). In patients with panhypopituitarism, central adrenal insufficiency is highly likely. Because exogenous thyroid hormone increases the hepatic clearance of cortisol, initiating levothyroxine therapy without first assessing and, if necessary, treating underlying adrenal insufficiency can rapidly precipitate a potentially fatal adrenal crisis. Therefore, evaluating the adrenal axis with an early morning serum cortisol is the mandatory next step.

Adım Adım Çözüm

Interpret the thyroid laboratory panel.

The patient has a low free T4 with an inappropriately normal TSH, indicating central (secondary) hypothyroidism.

In primary hypothyroidism, the low T4 would cause a compensatory elevation in TSH. A normal or low TSH with low T4 confirms a pituitary or hypothalamic failure.

Correlate with additional endocrine findings.

The patient has amenorrhea with an inappropriately low FSH for a postmenopausal-aged woman, indicating concurrent hypogonadotropic hypogonadism.

Multiple pituitary hormone deficiencies suggest panhypopituitarism (e.g., due to a pituitary adenoma).

Identify the required safety protocol for initiating thyroid replacement in panhypopituitarism.

Adrenal axis function must be evaluated (and treated if deficient) prior to starting levothyroxine.

Thyroid hormone increases the metabolic clearance of cortisol. If a patient has concurrent central adrenal insufficiency, starting levothyroxine without glucocorticoid coverage can precipitate a fatal adrenal crisis.

Anahtar Kavram

In patients with suspected central hypothyroidism or panhypopituitarism, central adrenal insufficiency must be ruled out (e.g., via early morning serum cortisol) prior to initiating levothyroxine therapy to avoid precipitating an acute adrenal crisis.

Soru 2797Soru →

A 62-year-old man is brought to the emergency department by ambulance after experiencing sudden-onset, severe epigastric and lower chest pain for the past 90 minutes. He describes the pain as a "heavy weight" and reports associated nausea and profuse sweating. His medical history includes type 2 diabetes mellitus, peripheral arterial disease, and a 40-pack-year smoking history. Current medications include metformin and atorvastatin. On arrival, his temperature is 36.8 °C (98.2 °F), blood pressure is 82/50 mmHg, pulse is 112/min, and respiratory rate is 18/min. Pulse oximetry is 97% on room air. Physical examination reveals clear lungs to auscultation bilaterally. Jugular venous pulsations are visible 10 cm above the sternal angle while the patient is seated at a 45-degree angle. Cardiac auscultation reveals a regular rhythm without murmurs or gallops. The extremities are cool and clammy. An electrocardiogram reveals sinus tachycardia with 3-mm ST-segment elevations in leads II, III, and aVF, as well as 2-mm ST-segment depressions in leads I and aVL. The patient is administered chewable aspirin and ticagrelor. Which of the following is the most appropriate initial step to stabilize this patient's hemodynamics?

Administration of an isotonic saline bolus

Administration of sublingual nitroglycerin

Administration of intravenous furosemide

Administration of intravenous metoprolol

Initiation of an intravenous dobutamine infusion

Cevabı ve açıklamayı göster

Cevap: Administration of an isotonic saline bolus

Cevap

Administration of an isotonic saline bolus

This patient is presenting with an acute inferior ST-segment elevation myocardial infarction (STEMI) complicated by right ventricular myocardial infarction (RVMI). The classic triad of RVMI includes hypotension, clear lungs (no evidence of pulmonary edema), and elevated jugular venous pressure. In RVMI, the right ventricle loses its contractile function and acts largely as a passive conduit. Consequently, the right ventricle becomes highly dependent on elevated venous return (preload) to push blood through the pulmonary circuit and ensure adequate filling of the left ventricle. Therefore, the most appropriate initial step to stabilize hemodynamics in a patient with RVMI is volume expansion with an isotonic saline bolus. This optimizes right ventricular preload and improves systemic cardiac output.

Adım Adım Çözüm

Analyze the electrocardiogram and clinical presentation to determine the anatomical location of the myocardial infarction.

ST-segment elevations in leads II, III, and aVF indicate an acute inferior ST-segment elevation myocardial infarction (STEMI).

Identifying the territory of the infarct is crucial for predicting potential complications, such as right ventricular involvement.

Synthesize the vital signs and physical examination findings to diagnose the specific complication.

The classic triad of hypotension, clear lungs, and elevated jugular venous pressure in the setting of an inferior STEMI confirms right ventricular myocardial infarction (RVMI).

The right coronary artery supplies the inferior wall of the left ventricle and the right ventricle. Obstruction leads to right ventricular failure.

Select the appropriate targeted intervention to address the altered hemodynamics of right ventricular failure.

Choose volume expansion with an isotonic saline bolus to maximize venous return.

The infarcted right ventricle loses contractility and becomes highly dependent on elevated preload to push blood forward into the pulmonary circulation and maintain left ventricular filling.

Anahtar Kavram

Hemodynamic management of Right Ventricular Myocardial Infarction

Soru 2798Soru →

Match each patient's clinical presentation with the most likely corresponding arterial blood gas and basic metabolic panel profile.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Diabetic ketoacidosis matches with the high anion gap metabolic acidosis profile; COPD exacerbation matches with the acute-on-chronic respiratory acidosis profile; panic attack matches with the acute respiratory alkalosis profile; and vomiting matches with the metabolic alkalosis profile.

Each clinical vignette provides a classic etiology for one of the four primary acid-base disorders. By interpreting the pH to determine the primary disturbance (acidosis vs. alkalosis), and then analyzing the

\text{PaCO}_2

\text{HCO}_3^-

, and anion gap, the correct laboratory profile can be definitively paired with the patient's presentation.

Adım Adım Çözüm

Analyze the first presentation (type 1 diabetes with vomiting and fruity breath).

Identify the primary acid-base disorder as high anion gap metabolic acidosis (HAGMA) secondary to diabetic ketoacidosis.

Ketone body production consumes bicarbonate (

\text{HCO}_3^-

) and increases the anion gap.

Match HAGMA to the correct lab profile.

Select the profile with pH 7.25,

\text{HCO}_3^-

14 mEq/L, and an anion gap of 24.

The calculated anion gap (

138 - 100 - 14 = 24

) confirms HAGMA, and the

\text{PaCO}_2

of 30 mm Hg reflects appropriate respiratory compensation per Winter's formula (

1.5 \times 14 + 8 \pm 2 = 29 \pm 2

Analyze the second presentation (COPD exacerbation).

Identify the primary disorder as respiratory acidosis with chronic partial metabolic compensation.

Airway obstruction causes

\text{CO}_2

retention, while chronic COPD leads to compensatory renal bicarbonate (

\text{HCO}_3^-

) retention.

Match respiratory acidosis to the correct lab profile.

Select the profile with pH 7.28,

\text{PaCO}_2

70 mm Hg, and

\text{HCO}_3^-

32 mEq/L.

The elevated

\text{PaCO}_2

directly causes the acidosis, and the elevated bicarbonate indicates chronic renal compensation.

Analyze the third presentation (panic attack with hyperventilation).

Identify the primary disorder as acute respiratory alkalosis.

Tachypnea blows off excessive

\text{CO}_2

, rapidly raising the blood pH.

Match acute respiratory alkalosis to the correct lab profile.

Select the profile with pH 7.55,

\text{PaCO}_2

24 mm Hg, and

\text{HCO}_3^-

20 mEq/L.

The low

\text{PaCO}_2

drives the alkalemia, and the small drop in bicarbonate represents acute cellular buffering.

Analyze the fourth presentation (severe recurrent vomiting).

Identify the primary disorder as metabolic alkalosis.

Loss of gastric hydrochloric acid (

\text{HCl}

) directly leads to alkalosis and hypochloremia.

Match metabolic alkalosis to the correct lab profile.

Select the profile with pH 7.52,

\text{PaCO}_2

48 mm Hg,

\text{HCO}_3^-

38 mEq/L, and

\text{Cl}^-

88 mEq/L.

The high bicarbonate defines the alkalosis, hypochloremia (

\text{Cl}^-

88 mEq/L) reflects gastric losses, and the elevated

\text{PaCO}_2

indicates respiratory compensation.

Anahtar Kavram

Diagnosis of primary acid-base disorders by analyzing clinical history, pH, PaCO2, bicarbonate, and anion gap.

Soru 2799Soru →

A 65-year-old man with end-stage renal disease secondary to diabetic nephropathy is brought to the emergency department due to progressive generalized weakness and lethargy. He missed his last two scheduled hemodialysis sessions. His current heart rate is 54/min and blood pressure is 105/60 mm Hg. A stat basic metabolic panel is drawn, and the physician orders continuous cardiac monitoring. Assuming his serum potassium continues to rise untreated, arrange the following electrocardiographic (ECG) changes in the chronological order they are expected to appear.

Öğeleri doğru sıraya koymak için sürükleyin

Cevabı ve açıklamayı göster

Cevap

The expected progression of ECG changes in severe, untreated hyperkalemia begins with peaked T waves, followed by PR prolongation and loss of P waves, then QRS widening, and finally a sine wave pattern.

As serum potassium rises, it predictably alters cardiac electrophysiology. Initial mild hyperkalemia (5.5-6.5 mEq/L) shortens repolarization, producing tall, peaked T waves. Moderate hyperkalemia (6.5-7.5 mEq/L) depolarizes the resting membrane potential, inactivating sodium channels and slowing conduction; this affects atrial tissue first, causing PR prolongation and loss of P waves. Severe hyperkalemia (7.0-8.0 mEq/L) slows ventricular conduction, widening the QRS complex. Critical hyperkalemia (>8.0 mEq/L) causes the QRS to fuse with the T wave, creating a sine wave pattern.

Adım Adım Çözüm

Identify the primary underlying pathophysiological risk for this patient.

The patient has end-stage renal disease and missed dialysis, placing him at extremely high risk for severe hyperkalemia.

Establishing the biochemical abnormality dictates the expected physiological effects on the cardiac conduction system.

Determine the earliest electrocardiographic effect of rising extracellular potassium.

Accelerated phase 3 repolarization leads to the earliest sign: tall, peaked T waves with a narrow base.

Mild hyperkalemia increases the conductance of repolarizing potassium channels.

Sequence the subsequent changes as potassium continues to rise and affects depolarization.

Resting membrane potential becomes less negative, progressively slowing atrial conduction (PR prolongation and loss of P waves) before significantly affecting ventricular conduction (QRS widening).

Atrial tissue is generally more sensitive to the conduction-slowing effects of hyperkalemia than ventricular tissue.

Identify the terminal electrocardiographic pattern.

The final stage is the merging of the severely widened QRS complex with the T wave, forming a sine wave pattern.

This indicates imminent cardiovascular collapse and precedes ventricular fibrillation or asystole.

Anahtar Kavram

Progressive electrocardiographic changes in hyperkalemia

Tahmini Süre:1m 0s

Soru 2800Soru →

Match each chronic liver disease to its classic serologic marker, genetic association, or histopathologic finding.

Soldaki öğeye tıklayın, sonra eşleşen sağdaki öğeye tıklayın

Cevabı ve açıklamayı göster

Cevap

Primary Biliary Cholangitis matches with AMA and intrahepatic duct destruction; Primary Sclerosing Cholangitis matches with ulcerative colitis and biliary stricturing; Autoimmune Hepatitis matches with elevated IgG and ASMA; Hereditary Hemochromatosis matches with HFE gene mutations.

Each liver disease has a distinct pathophysiologic mechanism and diagnostic marker profile that allows for accurate matching. Accurate diagnosis relies on combining serology (e.g., AMA for PBC, ASMA for AIH), genetic testing (HFE for hemochromatosis), and recognizing associated clinical conditions (ulcerative colitis for PSC).

Adım Adım Çözüm

Identify the distinguishing features of Primary Biliary Cholangitis (PBC).

Matches with anti-mitochondrial antibodies (AMA) and intrahepatic duct destruction.

AMA is the hallmark serologic marker for PBC, which selectively damages small intrahepatic ducts.

Identify the clinical associations for Primary Sclerosing Cholangitis (PSC).

Matches with ulcerative colitis, biliary stricturing, and p-ANCA positivity.

PSC is uniquely associated with inflammatory bowel disease and affects both intra- and extrahepatic ducts.

Identify the diagnostic criteria for Autoimmune Hepatitis (AIH).

Matches with elevated IgG levels and anti-smooth muscle or anti-LKM1 antibodies.

These specific autoantibodies and elevated immunoglobulins confirm the hepatocellular autoimmune process.

Identify the genetic basis of Hereditary Hemochromatosis.

Matches with HFE gene mutations and excessive iron absorption.

Hemochromatosis is an inherited disorder leading to toxic iron deposition due to unregulated absorption.

Anahtar Kavram

Autoimmune and genetic liver diseases are differentiated by their specific autoantibody profiles, genetic markers, and patterns of hepatobiliary injury.

Tahmini Süre:1m 30s

ÖncekiSayfa 140 / 158Sonraki

Internal Medicine

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

Sık Yapılan Hatalar

Cevap

Adım Adım Çözüm

Anahtar Kavram

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