Tüm alıştırma soruları

An overweight 45-year-old female is evaluated in an urgent care clinic for severe, right-sided upper abdominal pain that started after eating a large, fatty meal last night. The pain occasionally radiates to her right shoulder. She also complains of nausea. Her current temperature is 38.1°C (100.6°F) and heart rate is 98/min. During the abdominal assessment, the clinician applies deep, firm palpation just below the right rib cage and instructs the patient to take a slow, deep breath. The patient abruptly catches her breath and stops inhaling midway due to a sudden spike in focal pain. Which of the following conditions is most strongly supported by this specific examination maneuver?

A 14-month-old girl is brought to the pediatric clinic by her parents due to delayed walking and bowing of her legs. On physical examination, the child's length and weight are at the 10th percentile for her age. She has mild frontal bossing, a flat nasal bridge, and distinctly blue sclerae. Radiographs of the lower extremities reveal anterior bowing of the tibiae and a healing fracture of the right fibula, which the parents did not realize had occurred. A skin biopsy is performed, and molecular analysis of cultured fibroblasts demonstrates a single missense mutation in the *COL1A1* gene, resulting in a bulky amino acid substituting for a critical glycine residue. The geneticist notes that this specific single-nucleotide substitution causes a much more severe clinical phenotype than if the patient had inherited a complete deletion of one *COL1A1* allele. Which of the following best describes the molecular mechanism responsible for this discrepancy in disease severity?

During a musculoskeletal evaluation, various provocative physical maneuvers are utilized to isolate specific anatomical structures. Match each physical examination maneuver to the specific musculoskeletal pathology it is primarily used to identify.

A clinical pharmacologist is assisting the critical care team with dosing adjustments for patients experiencing severe hemodynamic and metabolic derangements. The relationship between hepatic blood flow ($Q$), intrinsic hepatocellular clearance ($Cl_{int}$), and the fraction of unbound drug ($f_u$) mathematically dictates the disposition of hepatically cleared medications. Carefully evaluate the following patient scenarios and drug properties. Pair each specific clinical scenario with its most accurate primary pharmacokinetic consequence.

A $32$-year-old industrial worker is brought to the emergency department after losing consciousness in a metal plating facility. Coworkers report a chemical spill occurred shortly before he collapsed. On examination, he is comatose with a respiratory rate of $28$/min and a heart rate of $120$/min. His skin appears flushed. A faint "bitter almond" odor is noted on his clothing. Arterial blood gas analysis on room air reveals:

Which of the following describes the primary subcellular mechanism responsible for this patient's profound cellular injury?

A $62$-year-old woman is evaluated in the oncology clinic for progressive shortness of breath and right upper quadrant abdominal fullness over the past three weeks. She has a history of metastatic non-small cell lung cancer (NSCLC) diagnosed $20$ months ago. At the time of initial diagnosis, molecular testing of the lung primary tumor revealed an epidermal growth factor receptor (EGFR) exon $19$ deletion. She was started on osimertinib, with a robust partial response. She has no other significant past medical history and has never smoked. Current vital signs are within normal limits.

Physical examination reveals decreased breath sounds at the right lung base and a palpable, slightly tender liver edge $4$ cm below the right costal margin. Restaging computed tomography (CT) of the chest, abdomen, and pelvis demonstrates enlargement of the primary right lung mass, new right-sided pleural effusion, and multiple new, hypervascular hepatic lesions.

A liquid biopsy (cell-free DNA) is performed and confirms the presence of the original EGFR exon $19$ deletion but is negative for secondary EGFR mutations, including T790M and C797S, as well as MET amplification. Subsequently, an ultrasound-guided core needle biopsy of one of the new hepatic lesions is performed. Histopathologic evaluation of the liver specimen reveals sheets of small cells with scant cytoplasm, finely granular nuclear chromatin, and absent glandular architecture. Immunohistochemical staining is strongly positive for synaptophysin and chromogranin A.

Based on the patient's new clinicopathologic findings, which of the following is the most appropriate next step in management?

A 42-year-old woman is brought to the emergency department by her husband due to progressive confusion, unsteadiness, and hand tremors over the past 3 days. She has a history of bipolar disorder and has been stable on a fixed dose of lithium carbonate for the last three years. Two weeks ago, she was diagnosed with osteoarthritis of the knee and began taking a newly prescribed daily oral medication for joint pain. Her vital signs are temperature $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure $138/85\text{ mmHg}$, pulse $88/\text{min}$, and respiratory rate $14/\text{min}$. Physical examination reveals a coarse resting tremor and marked ataxia. Laboratory studies show a serum lithium concentration of $2.1\text{ mEq/L}$ (therapeutic range: $0.6-1.2\text{ mEq/L}$) and a serum creatinine of $1.4\text{ mg/dL}$ (baseline: $0.8\text{ mg/dL}$). The newly prescribed medication is identified as the likely cause of her current condition. Which of the following pharmacokinetic mechanisms best explains this patient's acute toxicity?

A 45-year-old man with type 1 diabetes mellitus is brought to the emergency department after being found unresponsive by his wife. His capillary blood glucose is 32 mg/dL. He is administered intramuscular glucagon, which promptly restores his consciousness and raises his blood glucose levels by promoting hepatic glycogenolysis. Arrange the following steps of the intracellular signal transduction cascade in the correct chronological order, starting immediately after the medication reaches the hepatocyte.

A 68-year-old man is hospitalized for management of infective endocarditis involving a prosthetic aortic valve. Blood cultures drawn on admission grow methicillin-resistant *Staphylococcus aureus* (MRSA). He is started on intravenous vancomycin, and subsequent trough levels are maintained consistently between $15$ and $20 \mu\text{g/mL}$. The patient's clinical status improves, and repeat blood cultures on day $4$ are sterile. However, on day $18$ of hospitalization, he develops a new fever of $38.9^\circ\text{C}$ ($102.0^\circ\text{F}$) and worsening fatigue. Repeat blood cultures again grow MRSA. Susceptibility testing of the new bacterial isolate reveals a vancomycin minimum inhibitory concentration (MIC) of $4 \mu\text{g/mL}$, compared to an initial MIC of $1 \mu\text{g/mL}$. Which of the following best describes the molecular mechanism responsible for this pathogen's reduced susceptibility to the current therapy?

Match each clinical presentation described below with its primary underlying genetic or molecular pathophysiologic mechanism.

A 55-year-old man with a history of alcohol use disorder and compensated cirrhosis presents to the clinic to discuss an upcoming umbilical hernia repair. He reports no recent bleeding episodes, and a recent screening endoscopy showed small esophageal varices without stigmata of recent bleeding. Vital signs are within normal limits. Laboratory evaluation reveals:

* Hemoglobin: $12.4 \text{ g/dL}$
* Platelets: $85,000/\mu L$
* Prothrombin time (PT): $18 \text{ seconds}$ (Reference: $11-14 \text{ seconds}$)
* INR: $1.7$
* Activated partial thromboplastin time (aPTT): $34 \text{ seconds}$ (Reference: $25-40 \text{ seconds}$)

The surgeon expresses concern regarding the prolonged INR and requests a hematology consultation for preoperative optimization. The hematologist recommends proceeding with the surgery without the prophylactic administration of fresh frozen plasma. Which of the following principles of hemodynamics and coagulation best justifies this recommendation?

A 38-year-old woman is admitted to the intensive care unit with profound hypotension, widespread purpuric skin lesions, and persistent oozing from her intravenous catheter sites following an emergency dilation and curettage for a septic abortion. Laboratory studies reveal a platelet count of $22,000/\text{mm}^3$, a significantly prolonged prothrombin time, a decreased fibrinogen level, and a markedly elevated D-dimer. Arrange the pathophysiologic events underlying this patient's hematologic and hemodynamic collapse in the correct chronological sequence, from the initial trigger to the final clinical manifestation.

A 42-year-old man is brought to the emergency department by his wife due to a 3-week history of recurrent fevers, profound fatigue, night sweats, and new-onset shortness of breath with exertion. One month ago, he was hospitalized for a complicated methicillin-susceptible Staphylococcus aureus (MSSA) skin infection that was treated with a short course of oral antibiotics against medical advice. He appears acutely ill and diaphoretic. His temperature is 39.2°C (102.6°F), blood pressure is 110/50 mmHg, heart rate is 112/min, and respiratory rate is 22/min. Pulse oximetry shows 94% on ambient air. The physician suspects a severe, acute systemic intravascular infection. Which of the following physical examination findings are highly indicative of the most likely diagnosis in this patient? (Select all that apply)

Match each patient's clinical presentation with the most appropriate initial imaging modality.

A $74$-year-old man with a history of nonvalvular atrial fibrillation and hypertension is admitted to the hospital with hemoptysis and a cavitary lung lesion. He is diagnosed with chronic pulmonary histoplasmosis. The infectious disease consultant recommends initiating therapy with oral itraconazole.

The patient's outpatient medications include rivaroxaban $20 \text{ mg}$ once daily and amlodipine $5 \text{ mg}$ once daily.

His baseline laboratory studies on admission show:
- Hemoglobin: $13.8 \text{ g/dL}$
- Serum creatinine: $1.2 \text{ mg/dL}$ (Estimated creatinine clearance: $58 \text{ mL/min}$)

Four days after starting itraconazole, the patient develops acute-onset hematemesis and melena. He becomes hypotensive and tachycardic. Repeat laboratory studies show:
- Hemoglobin: $7.4 \text{ g/dL}$
- Serum creatinine: $1.4 \text{ mg/dL}$

Which of the following best describes the primary mechanism responsible for this patient's acute gastrointestinal hemorrhage?

Review the following clinical presentations and histopathological findings. Match each patient scenario to the precise underlying subcellular mechanism or biochemical hallmark responsible for the described cellular adaptation or injury.

A hematology consultation service is evaluating four patients with undiagnosed bleeding diatheses and suspected hereditary coagulopathies. Pair each patient's clinical presentation and initial laboratory screening with the specific confirmatory diagnostic finding that best establishes the underlying defect.

A 32-year-old man presents to the physical therapy clinic for his initial evaluation following a right knee anterior cruciate ligament (ACL) reconstruction. For the past four weeks, his right lower extremity has been immobilized in a rigid extension brace, and he has been strictly non-weight-bearing. On physical examination, the surgical incisions are well-healed without erythema or discharge. However, the circumference of his right mid-thigh is 4.5 cm less than that of his left mid-thigh. He reports no pain or paresthesias in the limb. Which of the following intracellular processes is primarily responsible for the macroscopic changes observed in this patient's right lower extremity?

A 75-year-old man presents to the outpatient clinic reporting a 3-month history of progressive exertional shortness of breath and occasional lightheadedness when climbing stairs. His vital signs are within normal limits. On physical examination, palpation of the carotid arteries reveals a pulse with a decreased amplitude and a delayed upstroke. Cardiac auscultation reveals a harsh, crescendo-decrescendo systolic murmur heard best at the right second intercostal space with radiation to the carotid arteries. Based on these physical examination findings, which of the following is the most likely diagnosis?

A 58-year-old man is brought to the emergency department due to a persistent nosebleed that began 3 hours ago. He has a history of type 2 diabetes mellitus, hypertension, and end-stage renal disease. The patient reports missing his last three hemodialysis sessions due to a lack of transportation. His blood pressure is 168/92 mmHg, and his heart rate is 94/min. Physical examination shows continuous oozing of blood from both nares despite the application of direct pressure and anterior nasal packing. Laboratory studies reveal the following:

Hemoglobin: 9.2 g/dL
Platelet count: 210,000/mm³
Blood urea nitrogen: 96 mg/dL
Serum creatinine: 7.8 mg/dL
Prothrombin time: 11 seconds
Partial thromboplastin time: 26 seconds

Which of the following best describes the mechanism of action of the most appropriate initial pharmacologic therapy for this patient's bleeding?