Internal Medicine

For each patient presenting with renal dysfunction, identify the characteristic microscopic urine sediment finding that would most strongly support the underlying diagnosis.

A 54-year-old man is evaluated in the hospital on hospital day 3 for ongoing management of a severe skin and soft tissue infection of the right lower extremity. He initially presented with high fever, chills, and a rapidly expanding area of erythema and induration. Blood cultures drawn on admission have now returned positive for methicillin-susceptible Staphylococcus aureus (MSSA). His empiric antimicrobial regimen since admission has consisted of intravenous vancomycin and cefepime. The patient's medical record indicates an allergy to penicillin, which he describes as a flat, red rash on his chest that occurred 20 years ago when taking amoxicillin. He explicitly denies any history of facial swelling, hives, or breathing difficulties. He is currently hemodynamically stable, his temperature is 37.4°C (99.3°F), and the erythema has significantly receded. Subsequent blood cultures drawn 48 hours after admission show no growth to date.

Which of the following is the most appropriate pharmacologic intervention at this time?

A 20-year-old woman is brought to the emergency department by her roommate due to confusion, nausea, and ringing in her ears for the past 6 hours. The patient has a history of major depressive disorder and recently went through a difficult breakup. On physical examination, she is diaphoretic and mildly disoriented. Temperature is 38.2°C (100.8°F), blood pressure is 115/75 mm Hg, pulse is 116/min, and respirations are 30/min. Lungs are clear to auscultation.

Laboratory studies show:

Arterial blood gas on room air:

Which of the following best describes this patient's acid-base disturbance?

A $66$-year-old man is brought to the emergency department by his daughter due to a $3$-day history of progressively worsening shortness of breath and a persistent cough. He notes his baseline morning cough has increased in frequency, and his sputum has changed from clear to thick and yellowish-green. His medical history is significant for severe chronic obstructive pulmonary disease (COPD), hypertension, and hypothyroidism (managed with levothyroxine). He has a $45$-pack-year smoking history. His temperature is $37.8^\circ\text{C}$ ($100.0^\circ\text{F}$), pulse is $114/\text{min}$, blood pressure is $145/88\text{ mm Hg}$, respiratory rate is $28/\text{min}$, and oxygen saturation is $86\%$ on room air.

Physical examination reveals a barrel-shaped chest with accessory muscle use. Pulmonary auscultation demonstrates a prolonged expiratory phase, diffuse expiratory wheezes, and scattered rhonchi, but no crackles are heard. The jugular venous pressure is elevated at $10\text{ cm H}_2\text{O}$. Abdominal examination shows a liver edge that is palpable $3\text{ cm}$ below the right costal margin and is mildly tender. Trace bilateral lower extremity pitting edema is present.

Laboratory studies show:
Leukocyte count: $11,500/\text{mm}^3$
Serum sodium: $139\text{ mEq/L}$
Serum potassium: $4.1\text{ mEq/L}$
Serum bicarbonate: $31\text{ mEq/L}$
Blood urea nitrogen: $18\text{ mg/dL}$
Serum creatinine: $0.9\text{ mg/dL}$
Thyroid-stimulating hormone (TSH): $0.2\text{ \mu U/mL}$ (Normal: $0.4-4.0\text{ \mu U/mL}$)
Free T4: $1.2\text{ ng/dL}$ (Normal: $0.9-1.7\text{ ng/dL}$)

Arterial blood gas analysis on room air shows a pH of $7.31$, $\text{PaCO}_2$ of $62\text{ mm Hg}$, and $\text{PaO}_2$ of $54\text{ mm Hg}$.

Chest radiography reveals hyperinflated lung fields, flattened diaphragms, and an enlarged right descending pulmonary artery. There are no pleural effusions or focal alveolar opacities.

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

A thirty-five-year-old female is referred for endocrinologic evaluation due to progressive central weight gain, severe exhaustion, proximal muscle weakness, and easy bruising over the past seven months. Physical examination reveals a blood pressure of $162/98$ mm Hg, marked facial plethora, supraclavicular fat accumulation, and broad, violaceous abdominal striae. Arrange the following interventions in the most appropriate chronological sequence for the complete diagnostic workup and definitive management of this condition. Assume the patient ultimately has pituitary-dependent hypercortisolism, but any causative lesion identified on initial imaging is $< 5$ mm in diameter.

Match each clinical presentation with the most likely corresponding coagulation panel findings.

A 42-year-old man presents to the emergency department with a 3-day history of severe nausea, nonbilious vomiting, and diffuse abdominal pain. He has a history of poorly controlled type 1 diabetes mellitus. His temperature is $37.2^\circ\text{C}$ ($99.0^\circ\text{F}$), blood pressure is $90/60\text{ mm Hg}$, pulse is $118/\text{min}$, and respirations are $26/\text{min}$. Physical examination reveals dry mucous membranes, decreased skin turgor, and a diffusely tender abdomen without rebound or guarding.

Laboratory studies show the following:
Serum sodium: $142\text{ mEq/L}$
Serum potassium: $3.2\text{ mEq/L}$
Serum chloride: $92\text{ mEq/L}$
Serum bicarbonate: $14\text{ mEq/L}$
Blood glucose: $550\text{ mg/dL}$
Serum blood urea nitrogen: $45\text{ mg/dL}$
Serum creatinine: $1.8\text{ mg/dL}$

Assuming a normal serum anion gap of $12\text{ mEq/L}$ and a normal serum bicarbonate of $24\text{ mEq/L}$, what is this patient's delta-delta ratio ($\Delta\text{AG} / \Delta\text{HCO}_3^-$)?

A 72-year-old woman is brought to the clinic by her daughter due to progressive forgetfulness, irritability, and unsteadiness on her feet over the past 6 months. Her past medical history is significant for hypothyroidism and type 2 diabetes mellitus, which have been managed with levothyroxine and metformin for the last 8 years. Vital signs are within normal limits. Neurological examination reveals a broad-based gait, decreased vibratory sensation in the distal lower extremities bilaterally, and a positive Romberg sign. Deep tendon reflexes are 1+ at the ankles and 2+ at the patellae. Laboratory studies show:

Hemoglobin: 10.2 g/dL
Mean corpuscular volume (MCV): 108 fL
Platelets: 140,000/mm³
Serum vitamin B12: 245 pg/mL (normal: 200-900 pg/mL)
Serum folate: 14 ng/mL (normal: > 4.0 ng/mL)
Thyroid-stimulating hormone (TSH): 2.4 µU/mL

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

A 52-year-old woman comes to the clinic due to a 4-month history of progressively worsening shortness of breath and fatigue. She has a 12-year history of limited cutaneous systemic sclerosis, which has primarily manifested as Raynaud phenomenon, sclerodactyly, and cutaneous telangiectasias. She does not have a cough, fever, orthopnea, or lower extremity swelling. Vital signs are within normal limits. On physical examination, the lungs are clear to auscultation bilaterally. Cardiac examination reveals a prominently loud pulmonic component of the second heart sound (P2) and a right ventricular heave. There are no murmurs or gallops. Pulmonary function testing reveals the following:

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

An 82-year-old woman is brought to the emergency department from a skilled nursing facility due to a 2-day history of worsening confusion and agitation. She has a medical history of moderate Alzheimer dementia, type 2 diabetes mellitus, hypertension, and urge urinary incontinence. Two weeks ago, she was evaluated for worsening incontinence, and oral oxybutynin was added to her regimen. She cannot provide a reliable history, but the facility staff reports no observed coughing, vomiting, diarrhea, or signs of pain during urination. The staff did note that her urine has been cloudy and malodorous for the past 3 days.

Vital signs are temperature $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure $138/84\text{ mmHg}$, pulse $88/\text{min}$, and respiratory rate $16/\text{min}$. Oxygen saturation is $98\%$ on room air. The patient is disoriented to time and place and frequently picks at her clothing. The abdomen is soft, non-tender, and without suprapubic distension. Bilateral costovertebral angle percussion elicits no reaction.

Laboratory evaluation shows a leukocyte count of $8,500/\text{mm}^3$, serum sodium of $138\text{ mEq/L}$, serum creatinine of $1.0\text{ mg/dL}$, and blood glucose of $115\text{ mg/dL}$. Urinalysis obtained via straight catheterization reveals:

Color: Yellow, cloudy
Specific gravity: $1.018$
Leukocyte esterase: Positive
Nitrites: Positive
WBCs: $30\text{-}40/\text{hpf}$
RBCs: $0\text{-}2/\text{hpf}$
Bacteria: Many

A urine culture is sent to the laboratory. Which of the following is the most appropriate next step in management?

A 24-year-old woman is brought to the endocrinology clinic by her sister due to distressing changes in her appearance over the past three months. She has developed thick, dark hair on her chin and chest, and she notes her voice has become noticeably deeper. Her menstrual periods, previously regular, have been absent for four months. She takes no medications. Her blood pressure is 118/76 mmHg and her body mass index is $23 \text{ kg/m}^2$. Physical examination reveals severe hirsutism, cystic acne on her back, temporal hair thinning, and clitoromegaly. A bedside pelvic ultrasound demonstrates multiple small follicles peripherally arranged in both ovaries. Which of the following is the most appropriate next step in management?

A $42$-year-old man visits the outpatient physician reporting a $4$-month history of profound tiredness, reduced sexual desire, and frequent morning headaches. Over the last several weeks, he has experienced near-miss accidents while driving because he did not see cars in the adjacent lanes. Vital signs are within normal limits. Laboratory studies reveal:

* Thyroid-stimulating hormone (TSH): $1.1$ mU/L (Normal: $0.5$ - $5.0$ mU/L)
* Free thyroxine (T4): $0.4$ ng/dL (Normal: $0.9$ - $1.7$ ng/dL)

Which of the following is the most likely underlying cause of this patient's presentation?

A $42$-year-old man comes to the clinic complaining of worsening anxiety, excessive sweating, and a $5$-kg ($11$-lb) weight loss over the past three months despite an increased appetite. He has no significant past medical history and takes no medications. Vital signs show a blood pressure of $142/82$ mmHg and a heart rate of $110$/min. Physical examination reveals a restless patient with a fine resting tremor of the hands, warm and diaphoretic skin, and a palpable, diffusely enlarged, non-tender thyroid gland without discrete nodules. No exophthalmos or pretibial myxedema is noted.

Laboratory evaluation reveals the following:

Based on the clinical and laboratory findings, which of the following is the most appropriate next diagnostic step?

A $34$-year-old woman comes to the clinic for a $6$-week follow-up visit. She was diagnosed with Graves disease after presenting with a $4$-kg ($8.8$-lb) weight loss, frequent palpitations, and heat intolerance. At the time of diagnosis, her thyroid-stimulating hormone (TSH) level was $<0.01$ $\mu$ U/mL and her free thyroxine (T4) level was $3.8$ ng/dL. She was initiated on methimazole and propranolol. Today, the patient reports that she feels much better; her palpitations have resolved, she is sleeping well, and her weight has remained stable for the past three weeks. Vital signs are temperature $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure $118/74$ mm Hg, and pulse $72$/min. Physical examination shows a mild, non-tender thyromegaly. She has no tremors. Laboratory evaluation today shows:

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

A 54-year-old man is evaluated in the hospital for decreased urine output. He was admitted 7 days ago for infective endocarditis and has been receiving intravenous vancomycin and gentamicin. Over the past 24 hours, his urine output has dropped to 300 mL. His vital signs are within normal limits and he appears euvolemic on examination. Laboratory studies show the following:

Microscopic urinalysis reveals muddy brown granular casts.

Based on the provided laboratory findings, what is this patient's fractional excretion of sodium ($Fe_{Na}$)? (Express your answer as a percentage)

A 65-year-old man with a history of metastatic prostate cancer presents to the emergency department reporting severe, progressively worsening back pain for the past two weeks. This morning, he developed new-onset bilateral leg weakness and urinary retention. Physical examination reveals 3/5 motor strength in both lower extremities, patellar hyperreflexia, and decreased sensation to pinprick below the umbilicus. Anal sphincter tone is decreased. Arrange the following interventions in the most appropriate chronological sequence for the optimal management of this patient's condition.

Match each rheumatologic autoantibody profile with its most characteristic clinical presentation.

Emergency medical services bring a 68-year-old male resident of a skilled nursing facility to the hospital for evaluation of profound lethargy and confusion. According to the transfer paperwork, the patient has a history of severe chronic obstructive pulmonary disease requiring continuous home oxygen, as well as hypertension and type 2 diabetes mellitus. Over the past four days, he has experienced up to 10 large-volume, watery bowel movements daily following a recent course of oral clindamycin. On arrival, his blood pressure is 98/60 mm Hg, heart rate is 114/min, and respiratory rate is 26/min. Physical examination reveals dry mucous membranes, decreased skin turgor, and diffuse bilateral wheezing.

Laboratory results are as follows:
Serum sodium: 138 mEq/L
Serum potassium: 3.2 mEq/L
Serum chloride: 115 mEq/L
Serum bicarbonate: 12 mEq/L
Blood urea nitrogen: 48 mg/dL
Serum creatinine: 1.8 mg/dL

Arterial blood gas (room air):
pH: 7.12
pCO2: 38 mm Hg
pO2: 58 mm Hg

Which of the following best characterizes this patient's acid-base status?

A 45-year-old woman is found to have a palpable 2.5-cm nodule in the right lobe of her thyroid gland during a routine physical examination. Arrange the following steps in the correct chronological sequence for the standard diagnostic evaluation and management of this patient. Assume that her initial biochemical testing reveals a suppressed TSH level and subsequent imaging demonstrates a non-functioning nodule.

Various parasitic infections require specific antimicrobial agents based on their pathogenesis and the patient's clinical syndrome. For each patient vignette described below, select the most appropriate definitive treatment regimen.