A 36-year-old man is brought in by ambulance after being found down on the sidewalk. It is uncertain how long he was down before being found, and he did not have any forms of identification when he was found. On presentation, the man is found to still be unconscious with a disheveled and unkempt appearance. He is also found to be taking slow, shallow breaths that smell of alcohol. His temperature is 98.8°F (37.1°C), blood pressure is 106/67 mmHg, pulse is 119/min, respirations are 5/min, and oxygen saturation is 87% on room air. His pupils are found to be fixed and contracted, and he has multiple bruises and scars on his body. Which of the following sets of findings would most likely be seen in this patient?
Q502
Four days after undergoing an elective total hip replacement, a 65-year-old woman develops a DVT that embolizes to the lung. Along with tachypnea, tachycardia, and cough, the patient would most likely present with a PaO2 of what?
Q503
A 33-year-old man comes to the physician because of gradually worsening bilateral foot pain for 2 months. The pain used to only occur after long walks and subside with rest. For the past week, the pain has been continuous and associated with burning sensations. He has also had transient painful nodules along the course of the leg veins for 4 months that resolve spontaneously. The patient is wearing an ankle brace for support because of a sprained left ankle that occurred three months ago. His mother was diagnosed with protein C deficiency as a teenager. He has smoked 2 packs of cigarettes daily for 15 years and does not drink alcohol. Vitals signs are within normal limits. Examination shows ulcers on the distal portion of his left great, second, and fifth toes. The feet are cool. Pedal pulses are barely palpable. Ankle-brachial pressure index is 0.3 in the left leg and 0.5 in the right leg. Which of the following interventions is most likely to reduce the risk of amputation in this patient?
Q504
A 67-year-old woman is brought by ambulance from home to the emergency department after she developed weakness of her left arm and left face droop. According to her husband, she has a history of COPD, hypertension, and hyperlipidemia. She takes hydrochlorothiazide, albuterol, and atorvastatin. She is not on oxygen at home. She is an active smoker and has smoked a pack a day for 20 years. Her mother died of a heart attack at age 60 and her father died of prostate cancer at age 55. By the time the ambulance arrived, she was having difficulty speaking. Once in the emergency department, she is no longer responsive. Her blood pressure is 125/85 mm Hg, the temperature is 37.2°C (99°F), the heart rate is 77/min, and her breathing is irregular, and she is taking progressively deeper inspirations interrupted with periods of apnea. Of the following, what is the next best step?
Q505
A 64-year-old woman is brought to the emergency department 1 hour after the onset of acute shortness of breath and chest pain. The chest pain is retrosternal in nature and does not radiate. She feels nauseated but has not vomited. She has type 2 diabetes mellitus, hypertension, and chronic kidney disease. Current medications include insulin, aspirin, metoprolol, and hydrochlorothiazide. She is pale and diaphoretic. Her temperature is 37°C (98°F), pulse is 136/min, and blood pressure is 80/60 mm Hg. Examination shows jugular venous distention and absence of a radial pulse during inspiration. Crackles are heard at the lung bases bilaterally. Cardiac examination shows distant heart sounds. Laboratory studies show:
Hemoglobin 8.3 g/dL
Serum
Glucose 313 mg/dL
Urea nitrogen 130 mg/dL
Creatinine 6.0 mg/dL
Which of the following is the most appropriate next step in management?
Q506
A 35-year-old female comes to the physician because of a 2-year history of progressive fatigue and joint pain. She has a 1-year history of skin problems and a 4-month history of episodic pallor of her fingers. She reports that the skin of her face, neck, and hands is always dry and itchy; there are also numerous “red spots” on her face. She has become more “clumsy” and often drops objects. She has gastroesophageal reflux disease treated with lansoprazole. She does not smoke. She occasionally drinks a beer or a glass of wine. Her temperature is 36.5°C (97.7°F), blood pressure is 154/98 mm Hg, and pulse is 75/min. Examination shows hardening and thickening of the skin of face, neck, and hands. There are small dilated blood vessels around her mouth and on her oral mucosa. Mouth opening is reduced. Active and passive range of motion of the proximal and distal interphalangeal joints is limited. Cardiopulmonary examination shows no abnormalities. Her creatinine is 1.4 mg/dL. The patient is at increased risk for which of the following complications?
Q507
A 16-year-old girl is brought to the physician because of a 6-month history of menstrual cramps, heavy menstrual flow, and fatigue; she has gained 5 kg (11 lb) during this period. Menses occur at regular 30-day intervals and last 8 to 10 days; during her period she uses 7 tampons a day and is unable to participate in any physical activities because of cramping. Previously, since menarche at the age of 11 years, menses had lasted 4 to 5 days with moderate flow. Her last menstrual period was 3 weeks ago. She has limited scleroderma with episodic pallor of the fingertips. She takes no medications. She is 160 cm (5 ft 3 in) tall and weighs 77 kg (170 lb); BMI is 30 kg/m2. Her temperature is 36.5°C (97.7°F), pulse is 56/min, respirations are 16/min, and blood pressure is 100/65 mm Hg. Physical examination shows a puffy face with telangiectasias and thinning of the eyebrows. Deep tendon reflexes are 1+ bilaterally with delayed relaxation. Pelvic examination shows a normal appearing vagina, cervix, uterus, and adnexa. Further evaluation of this patient is most likely to show which of the following findings?
Q508
A 32-year-old man presents with hypertension that has been difficult to control with medications. His symptoms include fatigue, frequent waking at night for voiding, and pins and needles in the legs. His symptoms started 2 years ago. Family history is positive for hypertension in his mother. His blood pressure is 160/100 mm Hg in the right arm and 165/107 mm Hg in the left arm, pulse is 85/min, and temperature is 36.5°C (97.7°F). Physical examination reveals global hyporeflexia and muscular weakness. Lab studies are shown:
Serum sodium 147 mEq/L
Serum creatinine 0.7 mg/dL
Serum potassium 2.3 mEq/L
Serum bicarbonate 34 mEq/L
Plasma renin activity low
Which of the following is the most likely diagnosis?
Q509
A 30-year-old man comes to the clinic with complaints of increased frequency of urination, especially at night, for about a month. He has to wake up at least 5-6 times every night to urinate and this is negatively affecting his sleep. He also complains of increased thirst and generalized weakness. Past medical history is significant for bipolar disorder. He is on lithium which he takes regularly. Blood pressure is 150/90 mm Hg, pulse rate is 80/min, respiratory rate is 16/min, and temperature is 36°C (96.8°F). Physical examination is normal. Laboratory studies show:
Na+: 146 mEq/L
K+: 3.8 mEq/L
Serum calcium: 9.5 mg/dL
Creatinine: 0.9 mg/dL
Urine osmolality: 195 mOsm/kg
Serum osmolality: 305 mOsm/kg
Serum fasting glucose: 90 mg/dL
Which of the following is the best initial test for the diagnosis of his condition?
Q510
A 29-year-old homeless man visits his local walk-in-clinic complaining of shortness of breath, fatigability, malaise, and fever for the past month. His personal history is significant for multiple inpatient psychiatric hospitalizations for a constellation of symptoms that included agitation, diarrhea, dilated pupils, and restless legs. On physical examination, his blood pressure is 126/72 mm Hg, heart rate is 117/min, body temperature is 38.5°C (101.3°F), and saturating 86% on room air. Auscultation reveals a holosystolic murmur that is best heard at the left sternal border and noticeably enhanced during inspiration. What is the underlying pathophysiological mechanism in this patient’s heart condition?
Cardiology US Medical PG Practice Questions and MCQs
Question 501: A 36-year-old man is brought in by ambulance after being found down on the sidewalk. It is uncertain how long he was down before being found, and he did not have any forms of identification when he was found. On presentation, the man is found to still be unconscious with a disheveled and unkempt appearance. He is also found to be taking slow, shallow breaths that smell of alcohol. His temperature is 98.8°F (37.1°C), blood pressure is 106/67 mmHg, pulse is 119/min, respirations are 5/min, and oxygen saturation is 87% on room air. His pupils are found to be fixed and contracted, and he has multiple bruises and scars on his body. Which of the following sets of findings would most likely be seen in this patient?
A. Decreased bicarbonate and decreased carbon dioxide
B. Normal bicarbonate and normal carbon dioxide
C. Increased bicarbonate and decreased carbon dioxide
D. Increased bicarbonate and increased carbon dioxide (Correct Answer)
E. Decreased bicarbonate and increased carbon dioxide
Explanation: ***Correct: Increased bicarbonate and increased carbon dioxide***
- This patient presents with **opioid overdose** causing severe **respiratory depression** (respirations 5/min, pinpoint pupils, altered mental status)
- The profound **hypoventilation leads to CO2 retention** (respiratory acidosis) with **increased PaCO2**
- While this appears to be an acute presentation, the **disheveled appearance, multiple scars, and chronic substance abuse history** suggest this may be **acute-on-chronic respiratory acidosis**
- In patients with chronic respiratory acidosis (or repeated episodes), the kidneys compensate by **retaining bicarbonate**, leading to **elevated serum HCO3**
- Even in primarily acute settings, some degree of renal compensation begins within hours, and chronic opioid users may have baseline compensated respiratory acidosis
- **Expected findings:** Elevated PaCO2 (>45 mmHg) and elevated HCO3 (>26 mEq/L)
*Incorrect: Decreased bicarbonate and increased carbon dioxide*
- While the increased CO2 is correct for respiratory acidosis, this combination would suggest **concurrent metabolic acidosis** (e.g., lactic acidosis, ketoacidosis)
- Although severe hypoxemia could cause lactic acidosis, the primary pathophysiology here is respiratory depression without clear evidence of severe metabolic derangement
- This pattern would be seen in mixed respiratory acidosis with metabolic acidosis, which is less likely than compensated respiratory acidosis
*Incorrect: Normal bicarbonate and normal carbon dioxide*
- This would indicate **no acid-base disturbance**, which contradicts the severe hypoventilation (5/min) and hypoxemia (87% O2 sat)
- The patient clearly has respiratory failure requiring immediate intervention
*Incorrect: Increased bicarbonate and decreased carbon dioxide*
- This combination indicates **compensated metabolic alkalosis** where respiratory compensation causes CO2 retention (though "decreased" is inconsistent)
- The primary problem here is **respiratory depression causing CO2 retention**, not alkalosis
- Decreased CO2 is the opposite of what occurs in hypoventilation
*Incorrect: Decreased bicarbonate and decreased carbon dioxide*
- This pattern suggests **compensated metabolic acidosis** where the lungs compensate by hyperventilating to blow off CO2
- This patient has **hypoventilation, not hyperventilation**, so CO2 would be increased, not decreased
- This is incompatible with the clinical presentation of respiratory depression
Question 502: Four days after undergoing an elective total hip replacement, a 65-year-old woman develops a DVT that embolizes to the lung. Along with tachypnea, tachycardia, and cough, the patient would most likely present with a PaO2 of what?
A. 120 mmHg
B. 100 mmHg
C. 85 mmHg (Correct Answer)
D. 110 mmHg
E. 60 mmHg
Explanation: ***85 mmHg***
- A pulmonary embolism (PE) causes a **ventilation-perfusion (V/Q) mismatch**, leading to **hypoxemia** and a reduced PaO2.
- While exact values vary, a PaO2 of 85 mmHg indicates **mild to moderate hypoxemia**, which is common in PE, especially with accompanying symptoms like tachypnea and tachycardia.
*120 mmHg*
- This value is significantly **higher than normal (75-100 mmHg)** and would indicate **hyperoxia**, which is inconsistent with acute pulmonary embolism causing respiratory distress.
- A patient with PE would typically have **reduced oxygenation**, not supernormal levels, unless receiving high-flow supplemental oxygen.
*100 mmHg*
- A PaO2 of 100 mmHg is at the **upper end of the normal range** (75-100 mmHg) and would imply **no significant hypoxemia**.
- Given the patient's symptoms of tachypnea, tachycardia, and cough following a DVT with embolization, a normal or high-normal PaO2 is unlikely without aggressive oxygen therapy (which is not stated).
*110 mmHg*
- This value is **above the normal range** and suggests **hyperoxia**, which is contrary to the pathophysiology of a pulmonary embolism.
- A PE impairs gas exchange, leading to a decrease in PaO2, not an increase.
*60 mmHg*
- A PaO2 of 60 mmHg indicates **significant hypoxemia**, which might occur in a severe, large pulmonary embolism or in a patient with underlying lung disease.
- While possible, 85 mmHg represents a more common, moderate hypoxemia seen in PE, especially given the prompt presentation of symptoms.
Question 503: A 33-year-old man comes to the physician because of gradually worsening bilateral foot pain for 2 months. The pain used to only occur after long walks and subside with rest. For the past week, the pain has been continuous and associated with burning sensations. He has also had transient painful nodules along the course of the leg veins for 4 months that resolve spontaneously. The patient is wearing an ankle brace for support because of a sprained left ankle that occurred three months ago. His mother was diagnosed with protein C deficiency as a teenager. He has smoked 2 packs of cigarettes daily for 15 years and does not drink alcohol. Vitals signs are within normal limits. Examination shows ulcers on the distal portion of his left great, second, and fifth toes. The feet are cool. Pedal pulses are barely palpable. Ankle-brachial pressure index is 0.3 in the left leg and 0.5 in the right leg. Which of the following interventions is most likely to reduce the risk of amputation in this patient?
A. Enoxaparin therapy
B. Bypass grafting
C. Simvastatin therapy
D. Smoking cessation (Correct Answer)
E. Removing the ankle brace
Explanation: ***Smoking cessation***
- This patient has **Buerger's disease (Thromboangiitis obliterans)**, indicated by: young age (<45 years), heavy smoking, **superficial thrombophlebitis** (transient painful nodules along leg veins), distal extremity involvement, and severe ischemia with markedly reduced **ankle-brachial pressure indices (ABPIs 0.3 and 0.5)**.
- **Complete smoking cessation is the ONLY intervention that halts disease progression** in Buerger's disease and is absolutely essential to prevent amputation. Even minimal tobacco use (including secondhand smoke or nicotine replacement) can perpetuate disease activity.
- This is the **most effective intervention** to prevent limb loss in this patient.
*Enoxaparin therapy*
- Enoxaparin is a **low-molecular-weight heparin** used for anticoagulation in conditions like deep vein thrombosis, pulmonary embolism, or acute coronary syndromes.
- While this patient has thrombotic phenomena (superficial thrombophlebitis, family history of protein C deficiency), Buerger's disease is an **inflammatory arteritis** with thrombosis, not a primary thrombophilic condition. Anticoagulation does not address the underlying inflammatory process or prevent amputation.
*Bypass grafting*
- **Bypass grafting** or revascularization is challenging in Buerger's disease because the disease affects **small and medium-sized vessels distally**, often with inadequate target vessels for grafting.
- While revascularization may be attempted in selected cases, it is **not the primary intervention** and has poor outcomes if smoking continues. Without smoking cessation, the disease will progress and grafts will fail.
*Simvastatin therapy*
- **Simvastatin** is a statin used to lower cholesterol and manage **atherosclerotic disease**.
- Buerger's disease is **not atherosclerotic** in nature; it is an inflammatory vasculitis. While statins may have some anti-inflammatory effects, they do not address the primary pathophysiology and are not effective in preventing amputation in Buerger's disease without smoking cessation.
*Removing the ankle brace*
- The ankle brace is for a **previous sprained ankle** and provides musculoskeletal support.
- While trauma and immobilization could theoretically affect local circulation, the brace is not the cause of his widespread, severe vascular disease. Removing it would not address the underlying **Buerger's disease** or prevent amputation.
Question 504: A 67-year-old woman is brought by ambulance from home to the emergency department after she developed weakness of her left arm and left face droop. According to her husband, she has a history of COPD, hypertension, and hyperlipidemia. She takes hydrochlorothiazide, albuterol, and atorvastatin. She is not on oxygen at home. She is an active smoker and has smoked a pack a day for 20 years. Her mother died of a heart attack at age 60 and her father died of prostate cancer at age 55. By the time the ambulance arrived, she was having difficulty speaking. Once in the emergency department, she is no longer responsive. Her blood pressure is 125/85 mm Hg, the temperature is 37.2°C (99°F), the heart rate is 77/min, and her breathing is irregular, and she is taking progressively deeper inspirations interrupted with periods of apnea. Of the following, what is the next best step?
A. Start tissue plasminogen activator (tPA)
B. Intubate the patient (Correct Answer)
C. Consult a cardiologist
D. Obtain an MRI of brain
E. Obtain non-contrast enhanced CT of brain
Explanation: ***Intubate the patient***
- The patient's **irregular breathing pattern with progressively deeper inspirations interrupted by periods of apnea** (known as **Cheyne-Stokes respiration**) combined with unresponsiveness due to probable acute stroke indicates imminent respiratory failure and the need for **airway protection**.
- **Intubation** secures the airway, ensures adequate ventilation, and prevents aspiration during a neurological emergency.
*Start tissue plasminogen activator (tPA)*
- Although this patient likely has an **acute ischemic stroke**, the first priority is managing the **compromised airway and breathing**.
- **tPA** administration is time-sensitive but requires stabilization of vital signs and exclusion of hemorrhage via neuroimaging, which hasn't occurred yet.
*Consult a cardiologist*
- While the patient has significant **cardiovascular risk factors** (**hypertension, hyperlipidemia, smoking, COPD, family history**), an acute cardiac event is not the immediate concern.
- The pressing issue is **acute neurological deterioration with respiratory compromise**.
*Obtain an MRI of brain*
- An **MRI** offers detailed imaging for stroke but is **time-consuming** and **less accessible** in an emergency compared to CT.
- The patient's critical respiratory status requires immediate intervention before non-urgent diagnostic imaging.
*Obtain non-contrast enhanced CT of brain*
- A **non-contrast CT scan of the brain** is crucial for differentiating between **ischemic** and **hemorrhagic stroke** and guiding treatment, specifically for tPA administration.
- However, ensuring a **patent airway and stable ventilation** takes precedence over imaging in a patient with impending respiratory arrest.
Question 505: A 64-year-old woman is brought to the emergency department 1 hour after the onset of acute shortness of breath and chest pain. The chest pain is retrosternal in nature and does not radiate. She feels nauseated but has not vomited. She has type 2 diabetes mellitus, hypertension, and chronic kidney disease. Current medications include insulin, aspirin, metoprolol, and hydrochlorothiazide. She is pale and diaphoretic. Her temperature is 37°C (98°F), pulse is 136/min, and blood pressure is 80/60 mm Hg. Examination shows jugular venous distention and absence of a radial pulse during inspiration. Crackles are heard at the lung bases bilaterally. Cardiac examination shows distant heart sounds. Laboratory studies show:
Hemoglobin 8.3 g/dL
Serum
Glucose 313 mg/dL
Urea nitrogen 130 mg/dL
Creatinine 6.0 mg/dL
Which of the following is the most appropriate next step in management?
A. Furosemide therapy
B. Pericardiocentesis (Correct Answer)
C. Aspirin therapy
D. Hemodialysis
E. Norepinephrine infusion
Explanation: ***Pericardiocentesis***
* The patient presents with classic signs of **cardiac tamponade**, including **Beck's triad** (hypotension, jugular venous distension, distant heart sounds), **pulsus paradoxus** (absence of radial pulse during inspiration), and acute onset of shortness of breath and chest pain.
* Given her history of **chronic kidney disease** and elevated urea/creatinine levels, uremic pericarditis is a likely cause, leading to significant pericardial effusion and tamponade. **Pericardiocentesis** is the definitive treatment to relieve pressure on the heart.
*Furosemide therapy*
* While **crackles** suggest pulmonary congestion, this patient is severely hypotensive with signs of cardiogenic shock due to tamponade. Administering a diuretic like **furosemide** would further reduce preload, worsening her already compromised cardiac output and hypotension.
* The primary issue is extrinsic compression of the heart by pericardial fluid, not left ventricular failure responsive to diuresis.
*Aspirin therapy*
* The patient's chest pain and other symptoms could potentially point to an acute coronary syndrome, which would warrant **aspirin**. However, her profound hypotension and clear signs of cardiac tamponade (Beck's triad, pulsus paradoxus) make **cardiac tamponade** the more immediate and life-threatening concern.
* Addressing the tamponade takes priority as its hemodynamic compromise is more acute and direct.
*Hemodialysis*
* The patient has severe **acute-on-chronic kidney disease** and likely **uremic pericarditis**. While **hemodialysis** is indicated for uremia, it is not the immediate life-saving intervention for **cardiac tamponade**.
* **Pericardiocentesis** is required first to stabilize her hemodynamics; hemodialysis can be performed afterward to address the underlying uremia.
*Norepinephrine infusion*
* **Norepinephrine** is a powerful vasopressor that would increase systemic vascular resistance and blood pressure. While the patient is hypotensive, the underlying cause is **cardiac tamponade**, which mechanically obstructs cardiac filling and output.
* **Vasopressors** alone will not resolve the mechanical obstruction and may even increase myocardial oxygen demand without increasing cardiac output, potentially worsening the situation. The tamponade must be relieved first.
Question 506: A 35-year-old female comes to the physician because of a 2-year history of progressive fatigue and joint pain. She has a 1-year history of skin problems and a 4-month history of episodic pallor of her fingers. She reports that the skin of her face, neck, and hands is always dry and itchy; there are also numerous “red spots” on her face. She has become more “clumsy” and often drops objects. She has gastroesophageal reflux disease treated with lansoprazole. She does not smoke. She occasionally drinks a beer or a glass of wine. Her temperature is 36.5°C (97.7°F), blood pressure is 154/98 mm Hg, and pulse is 75/min. Examination shows hardening and thickening of the skin of face, neck, and hands. There are small dilated blood vessels around her mouth and on her oral mucosa. Mouth opening is reduced. Active and passive range of motion of the proximal and distal interphalangeal joints is limited. Cardiopulmonary examination shows no abnormalities. Her creatinine is 1.4 mg/dL. The patient is at increased risk for which of the following complications?
A. Digital ulcers (Correct Answer)
B. Scleroderma renal crisis
C. Pulmonary arterial hypertension
D. Gastrointestinal dysmotility
E. Interstitial lung disease
Explanation: ***Digital ulcers***
- The patient exhibits several features of **systemic sclerosis (scleroderma)**, including **active Raynaud phenomenon** (**episodic pallor of fingers**), skin thickening, and telangiectasias (**red spots**). **Digital ulcers are the most immediate complication** given the active vascular symptoms.
- Raynaud phenomenon causes repeated ischemia-reperfusion injury to the digits, and **up to 50% of patients with systemic sclerosis and Raynaud develop digital ulcers**, making this the highest near-term risk among the options.
- The patient's **reduced mouth opening** and **limited range of motion in interphalangeal joints** are consistent with skin changes and joint involvement in scleroderma, further supporting the diagnosis and vascular complications.
*Scleroderma renal crisis*
- While **hypertension** is present (154/98 mm Hg) and **creatinine is elevated** (1.4 mg/dL), these findings are relatively mild and do not meet criteria for **scleroderma renal crisis**, which typically presents with **acute malignant hypertension** (>180/100 mmHg), rapidly progressive renal failure, microangiopathic hemolytic anemia, and thrombocytopenia.
- Renal crisis tends to occur earlier in the disease course (within first 4-5 years) and is more common with diffuse cutaneous scleroderma and recent corticosteroid use. This patient's presentation suggests limited cutaneous involvement (face, neck, hands - consistent with CREST/limited variant).
*Pulmonary arterial hypertension*
- **Pulmonary arterial hypertension (PAH)** is a serious late complication of systemic sclerosis, particularly in limited cutaneous disease, but there are **no current signs or symptoms** on cardiopulmonary examination.
- While this remains a long-term risk requiring screening, it is not the most immediate complication. PAH typically develops years after disease onset and would present with dyspnea, fatigue, and signs of right heart dysfunction.
*Gastrointestinal dysmotility*
- The patient **already has** **gastroesophageal reflux disease (GERD)**, which is a manifestation of gastrointestinal dysmotility in systemic sclerosis due to esophageal smooth muscle involvement.
- Since the patient already has this complication (not "at risk for" a future complication), this is not the best answer. Further GI complications could occur, but digital ulcers represent a more immediate risk.
*Interstitial lung disease*
- **Interstitial lung disease (ILD)** is a common and severe complication of systemic sclerosis, particularly in the diffuse cutaneous form, and is a leading cause of mortality.
- However, the patient's **cardiopulmonary examination is noted as normal**, which does not suggest active or clinically apparent ILD at this time. While this remains a long-term risk requiring monitoring (with pulmonary function tests and HRCT), it is not the most immediate complication given the active Raynaud phenomenon.
Question 507: A 16-year-old girl is brought to the physician because of a 6-month history of menstrual cramps, heavy menstrual flow, and fatigue; she has gained 5 kg (11 lb) during this period. Menses occur at regular 30-day intervals and last 8 to 10 days; during her period she uses 7 tampons a day and is unable to participate in any physical activities because of cramping. Previously, since menarche at the age of 11 years, menses had lasted 4 to 5 days with moderate flow. Her last menstrual period was 3 weeks ago. She has limited scleroderma with episodic pallor of the fingertips. She takes no medications. She is 160 cm (5 ft 3 in) tall and weighs 77 kg (170 lb); BMI is 30 kg/m2. Her temperature is 36.5°C (97.7°F), pulse is 56/min, respirations are 16/min, and blood pressure is 100/65 mm Hg. Physical examination shows a puffy face with telangiectasias and thinning of the eyebrows. Deep tendon reflexes are 1+ bilaterally with delayed relaxation. Pelvic examination shows a normal appearing vagina, cervix, uterus, and adnexa. Further evaluation of this patient is most likely to show which of the following findings?
A. Elevated TSH (Correct Answer)
B. Elevated androgens
C. Elevated LH:FSH ratio
D. Elevated midnight cortisol
E. Prolonged aPTT
Explanation: ***Elevated TSH***
- The patient's symptoms, including **heavy menstrual flow** (**menorrhagia**), **fatigue**, **weight gain**, **puffy face**, **thinning eyebrows**, **bradycardia**, and **delayed relaxation of deep tendon reflexes**, are highly suggestive of **hypothyroidism**.
- **Elevated TSH** (thyroid-stimulating hormone) is the most sensitive and specific laboratory finding for **primary hypothyroidism**, indicating the thyroid gland is not producing enough thyroid hormones.
*Elevated androgens*
- Elevated androgens are associated with conditions like **polycystic ovary syndrome (PCOS)**, which typically presents with **oligomenorrhea** or **amenorrhea**, not menorrhagia.
- While weight gain can occur in PCOS, other classic features like **hirsutism** or significant **acne** are not mentioned, and the other symptoms point away from this diagnosis.
*Elevated LH:FSH ratio*
- An **elevated LH:FSH ratio** is a characteristic finding in **polycystic ovary syndrome (PCOS)**.
- As with elevated androgens, PCOS is unlikely given the patient's presentation of **heavy, regular periods** and other hypothyroid-consistent symptoms.
*Elevated midnight cortisol*
- Elevated midnight cortisol is indicative of **Cushing's syndrome**, which involves symptoms such as **central obesity**, **moon facies**, **buffalo hump**, **striae**, and **hypertension**.
- While this patient has a puffy face and weight gain, her **hypotension** and other features like **bradycardia** are inconsistent with Cushing's.
*Prolonged aPTT*
- A prolonged aPTT (activated partial thromboplastin time) suggests a **coagulation disorder**, such as **hemophilia** or **von Willebrand disease (vWD)**, which could cause menorrhagia.
- While vWD is a common cause of heavy menstrual bleeding, the array of other systemic symptoms (fatigue, weight gain, bradycardia, puffy face, delayed reflexes) strongly points towards an endocrine cause, specifically hypothyroidism, rather than solely a bleeding disorder.
Question 508: A 32-year-old man presents with hypertension that has been difficult to control with medications. His symptoms include fatigue, frequent waking at night for voiding, and pins and needles in the legs. His symptoms started 2 years ago. Family history is positive for hypertension in his mother. His blood pressure is 160/100 mm Hg in the right arm and 165/107 mm Hg in the left arm, pulse is 85/min, and temperature is 36.5°C (97.7°F). Physical examination reveals global hyporeflexia and muscular weakness. Lab studies are shown:
Serum sodium 147 mEq/L
Serum creatinine 0.7 mg/dL
Serum potassium 2.3 mEq/L
Serum bicarbonate 34 mEq/L
Plasma renin activity low
Which of the following is the most likely diagnosis?
A. Renal artery stenosis
B. Coarctation of aorta
C. Cushing syndrome
D. Primary aldosteronism (Correct Answer)
E. Essential hypertension
Explanation: ***Primary aldosteronism***
- The patient presents with **resistant hypertension**, **hypokalemia** (2.3 mEq/L), **metabolic alkalosis** (bicarbonate 34 mEq/L), and **low plasma renin activity**, which are classic features of primary aldosteronism.
- Symptoms like **fatigue**, **nocturia**, and **paresthesias** (pins and needles) in the legs are consistent with severe hypokalemia, directly resulting from excessive aldosterone secretion.
*Renal artery stenosis*
- This condition typically causes **secondary hypertension** with **elevated renin levels** due to decreased renal perfusion, which contradicts the low plasma renin activity seen in this patient.
- While it can cause hypokalemia because of increased renin-angiotensin-aldosterone system activation, the **primary driver** in this case, based on low renin, points away from renal artery stenosis.
*Coarctation of aorta*
- Characterized by **differential blood pressures** between the upper and lower extremities and sometimes between the arms, and a **systolic murmur** that is often present.
- It does not typically present with severe **hypokalemia** or metabolic alkalosis or the low plasma renin activity observed in this patient.
*Cushing syndrome*
- This syndrome is caused by **excessive cortisol** and can lead to hypertension and hypokalemia, but it is also associated with distinct clinical features like **central obesity**, buffalo hump, moon facies, and proximal muscle weakness, which are not described.
- While it can cause similar electrolyte imbalances, the lack of classic Cushingoid features makes it less likely, and the specific **low plasma renin** points more strongly to aldosterone excess.
*Essential hypertension*
- This is a diagnosis of exclusion, typically presenting without a clear secondary cause and with **normal electrolyte levels**.
- The presence of severe **hypokalemia**, **metabolic alkalosis**, and **low plasma renin activity** indicates a secondary cause, ruling out essential hypertension.
Question 509: A 30-year-old man comes to the clinic with complaints of increased frequency of urination, especially at night, for about a month. He has to wake up at least 5-6 times every night to urinate and this is negatively affecting his sleep. He also complains of increased thirst and generalized weakness. Past medical history is significant for bipolar disorder. He is on lithium which he takes regularly. Blood pressure is 150/90 mm Hg, pulse rate is 80/min, respiratory rate is 16/min, and temperature is 36°C (96.8°F). Physical examination is normal. Laboratory studies show:
Na+: 146 mEq/L
K+: 3.8 mEq/L
Serum calcium: 9.5 mg/dL
Creatinine: 0.9 mg/dL
Urine osmolality: 195 mOsm/kg
Serum osmolality: 305 mOsm/kg
Serum fasting glucose: 90 mg/dL
Which of the following is the best initial test for the diagnosis of his condition?
A. Serum ADH level
B. MRI scan of brain
C. CT thorax
D. Chest X-ray
E. Water deprivation test (Correct Answer)
Explanation: ***Water deprivation test***
- The patient presents with **polyuria**, **polydipsia**, and **nocturia**, along with elevated **serum osmolality** and low **urine osmolality**, indicating a probable diagnosis of **diabetes insipidus**. The **water deprivation test** is the gold standard for differentiating between central and nephrogenic diabetes insipidus by assessing the kidney's response to fluid restriction and subsequently to desmopressin.
- Given the history of **lithium use**, **nephrogenic diabetes insipidus** is a strong possibility, as lithium can impair the kidney's ability to respond to ADH. The water deprivation test will help clarify the type of diabetes insipidus.
*Serum ADH level*
- While **ADH levels** can be informative, they are often difficult to interpret in isolation and can vary based on hydration status; a single measurement might not be diagnostic.
- The diagnosis of diabetes insipidus is primarily clinical and biochemical, with ADH levels used as an adjunct rather than a primary diagnostic test.
*MRI scan of brain*
- An **MRI of the brain** would be considered if **central diabetes insipidus** is highly suspected, as it could identify structural abnormalities of the hypothalamus or pituitary gland.
- However, since the patient is on **lithium**, which commonly causes nephrogenic diabetes insipidus, evaluating renal response to dehydration and possibly ADH is the more immediate and appropriate next step before imaging.
*CT thorax*
- A **CT thorax** is not indicated in the initial workup for diabetes insipidus, as the patient's symptoms are not suggestive of a pulmonary or thoracic etiology.
- This test would be used to investigate conditions like sarcoidosis or lung cancer, which can rarely cause central diabetes insipidus through ADH suppression or ectopic ADH production, but these are not the primary concerns here.
*Chest X-ray*
- A **chest X-ray** is generally not part of the initial diagnostic workup for diabetes insipidus.
- It would only be considered if there were respiratory symptoms or a suspicion of conditions like **sarcoidosis** or **tuberculosis** that could involve the pituitary, but there are no such indications in this patient.
Question 510: A 29-year-old homeless man visits his local walk-in-clinic complaining of shortness of breath, fatigability, malaise, and fever for the past month. His personal history is significant for multiple inpatient psychiatric hospitalizations for a constellation of symptoms that included agitation, diarrhea, dilated pupils, and restless legs. On physical examination, his blood pressure is 126/72 mm Hg, heart rate is 117/min, body temperature is 38.5°C (101.3°F), and saturating 86% on room air. Auscultation reveals a holosystolic murmur that is best heard at the left sternal border and noticeably enhanced during inspiration. What is the underlying pathophysiological mechanism in this patient’s heart condition?
A. Failed delamination
B. Chemical endothelial damage (Correct Answer)
C. Verrucous lesions
D. Myxomatous degeneration
E. Fibrillin 1 (FBN1) mutations
Explanation: ***Chemical endothelial damage***
- The patient's history of recurrent psychiatric hospitalizations with symptoms of agitation, diarrhea, dilated pupils, and restless legs points to **substance abuse**, particularly consistent with IV drug use, a common issue in homeless individuals. This, in conjunction with the signs of infection (fever, malaise, elevated heart rate) and a heart murmur, strongly suggests **infective endocarditis** in an IV drug user.
- **Intravenous drug use** introduces foreign substances and bacteria directly into the bloodstream, causing **chemical endothelial damage** to the heart valves. This damage, particularly to the **tricuspid valve** (indicated by the holosystolic murmur at the left sternal border enhanced by inspiration), provides a nidus for bacterial adherence and vegetation formation, leading to infective endocarditis.
*Failed delamination*
- **Failed delamination** is a developmental anomaly typically associated with **Ebstein's anomaly**, where the tricuspid valve leaflets are displaced into the right ventricle.
- This condition is congenital and usually diagnosed earlier in life, contrasting with the patient's acquired symptoms of infection and drug use.
*Verrucous lesions*
- **Verrucous lesions** on heart valves are characteristic of **nonbacterial thrombotic endocarditis (NBTE)**, also known as marantic endocarditis.
- While NBTE can occur in debilitated patients, it is typically associated with hypercoagulable states or advanced malignancy and does not usually present with the overt signs of infection (fever, malaise) seen in this patient.
*Myxomatous degeneration*
- **Myxomatous degeneration** is the primary pathophysiology behind **mitral valve prolapse**, a common cause of mitral regurgitation.
- While it can cause a murmur, it does not typically lead to the inflammatory and infectious presentation described, nor is it usually associated with IV drug use.
*Fibrillin 1 (FBN1) mutations*
- **Fibrillin 1 (FBN1) mutations** are the genetic basis of **Marfan syndrome**, a connective tissue disorder.
- Marfan syndrome can cause cardiovascular abnormalities, particularly **aortic root dilation** and **mitral valve prolapse**, but it does not directly explain the acute infectious presentation or the association with IV drug use.
