Endocrinology
Cardiology
100

A 60-year-old man comes to the physician because of a 6-month history of recurrent episodes of fatigue, palpitations, nausea, and diaphoresis. The episodes have become more frequent over the past 2 weeks and he has missed work several times because of them. His symptoms usually improve after he drinks some juice and rests. He has had a 2-kg (4.5-lb) weight gain in the past 6 months. He has a history of hypertension and asthma. His sister has type 2 diabetes mellitus. His medications include hydrochlorothiazide, aspirin, and a budesonide inhaler. His temperature is 36.3°C (97.3°F), pulse is 92/min and regular, respirations are 20/min, and blood pressure is 118/65 mm Hg. Abdominal examination shows no abnormalities. Serum studies show:

Na+145 mEq/L K+3.9 mEq/L Cl-103 mEq/L Calcium9.2 mg/dL Glucose88 mg/dL


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


A.Oral glucose tolerance test


B.24-hour urine catecholamine test


C.Dexamethasone suppression test

D.72-hour fasting test


E.Corticotropin stimulation test









72-hour fasting test


Symptoms of spontaneous episodic hypoglycemia and symptom resolution upon administration of glucose are two components of the Whipple triad. If hypoglycemia is not present at the time of evaluation, a 72-hour fasting test can be conducted to reproduce hypoglycemic symptoms and reach a definitive diagnosis. Glucose and hypoglycemic studies, including measurement of insulin, C-peptide, proinsulin, and β-hydroxybutyrate, should be obtained at the beginning of the test and then repeated every 6 hours until the serum glucose falls below 60 mg/dL. C-peptide and proinsulin are measures of the endogenous production of insulin and are decreased in hypoglycemia; hypoglycemia with elevated C-peptide and proinsulin levels should raise concern for insulinoma.


100

A 14-year-old boy is brought to the physician because of fever, malaise, and severe right knee joint pain and swelling for 3 days. Five days ago, he had swelling and pain in his left ankle joint which has since resolved. He reports having a sore throat 3 weeks ago while he was camping in the woods, for which he received symptomatic treatment. His immunizations are up-to-date. His temperature is 38.7°C (101.6°F), pulse is 119/min, and blood pressure is 90/60 mm Hg. Examination shows a swollen, tender right knee; range of motion is limited. There are painless 3 to 4-mm nodules over the elbow. Cardiopulmonary examination is normal. His hemoglobin concentration is 12.3 g/dL, leukocyte count is 11,800/mm3, and erythrocyte sedimentation rate is 63 mm/h. Arthrocentesis of the right knee joint yields clear, straw-colored fluid. Analysis of the synovial fluid shows a leukocyte count of 1350/mm3 with 17% neutrophils; no organisms are identified on Gram stain. Which of the following is the most likely diagnosis?


1.Acute rheumatic fever

2.Septic arthritis

3.Infective endocarditis

4.Lyme disease



5.Kawasaki disease


6.Juvenile idiopathic arthritis


A.Acute rheumatic fever

Acute rheumatic fever (ARF) is a delayed inflammatory complication that occurs 1–5 weeks following an untreated group A beta-hemolytic streptococcal infection, particularly pharyngitis. To diagnose ARF, two major or one major plus two minor revised Jones criteria are required. Major criteria include arthritis (migratory polyarthritis primarily involving the large joints), subcutaneous nodules, carditis (pancarditis, including valvulitis), Sydenham chorea (CNS involvement), and erythema marginatum. Minor criteria include polyarthralgia, fever, elevated acute phase reactants (ESR, CRP), and a prolonged PR interval on ECG. This patient meets 2 major and 3 minor criteria, which is sufficient to establish the diagnosis of ARF.



200

A 12-year-old girl is brought to the physician by her mother because of a 2-day history of high fever and swelling of the left ankle and knee. She had a sore throat 3 weeks ago. There is no family history of serious illness. Her immunizations are up-to-date. She developed an episode of breathlessness and generalized rash when she received dicloxacillin for a skin infection 2 years ago. She appears ill. Her temperature is 38.8°C (102.3°F), pulse is 87/min, and blood pressure is 98/62 mm Hg. Examination shows swelling and tenderness of the left ankle and knee; range of motion is limited. Lungs are clear to auscultation. A grade 3/6 holosystolic murmur is heard best at the apex. Abdominal examination shows no abnormalities. Which of the following is the most appropriate pharmacotherapy?

1.Vancomycin

2.Clarithromycin

3.High-dose glucocorticoids

4.Amoxicillin

5.Doxycycline

6.Methotrexate

7.Ciprofloxacin












Clarithromycin

Macrolides such as clarithromycin are the antibiotics of choice for ARF in patients with hypersensitivity to beta-lactam antibiotics. In addition to group A streptococcal eradication therapy, patients with ARF also require symptomatic treatment with NSAIDs for arthritis and fever.

Additionally, an echocardiogram should be performed to evaluate for the presence of rheumatic valvulitis. This patient's apical holosystolic murmur is consistent with mitral regurgitation (likely due to rheumatic valvulitis).








300


A 14-year-old boy is brought to the physician for generalized fatigue and mild shortness of breath on exertion for 3 months. He has a history of recurrent patellar dislocations. He is at the 99th percentile for height and at the 30th percentile for weight. His temperature is 37°C (98.6°F), pulse is 99/min, and blood pressure is 140/50 mm Hg. Examination shows scoliosis, a protruding breast bone, thin extremities, and flat feet. Ocular examination shows bilateral upward displacement of the lenses. A grade 3/6 early diastolic murmur is heard along the left sternal border. Further evaluation of this patient is most likely to show which of the following?


A.Paradoxical splitting of S2


B.Pulsus paradoxus


C.Pulsus parvus et tardus


D.Fixed splitting of S2


E.Water hammer pulse


F.Radio-femoral pulse delay


Water hammer pulse


A water hammer pulse is a classic finding on cardiovascular examination in patients with AR. On palpation of a peripheral artery, such as the radial artery, the clinician will feel rapid engorgement of the artery followed by a significant, prompt collapse of the vessel. This is due to the incompetent aortic valve failing to maintain adequate diastolic pressure in the arterial system, which also causes a widened pulse pressure. Other findings of AR include pulse synchronous head nodding (de Musset's sign) and, occasionally, a rumbling, low-pitched mid-diastolic murmur (Austin Flint murmur) that is caused by the regurgitant blood striking the anterior leaflet of the mitral valve, leading to premature closure of the mitral leaflets.

Patients with Marfan syndrome often have aortic disease (e.g., aortic regurgitation) as a consequence of cystic medial degeneration.


400


A 68-year-old man comes to the emergency department because of a 1-week history of difficulty breathing. He has had recurrent palpitations over the past 2 years. During this time, he has also had several episodes of anxiety despite no change in his daily life. He has occasional sharp chest pain localized to the left upper sternal border. He has no abdominal pain or leg swelling. Two years ago, he had streptococcal pharyngitis, which was promptly treated with a 10-day course of penicillin. He has never traveled outside of the country. His temperature is 36.5°C (97.7°F), pulse is 82/min, and blood pressure is 140/85 mm Hg. Physical examination shows a 3/6 holosystolic murmur that is loudest at the apex and radiates to the axilla with a mid-systolic click. Bilateral fine crackles are heard on lung auscultation. Which of the following is the most likely cause of this patient's symptoms?

A.Ectopic production of serotonin


B.Myxomatous valve degeneration


C.Calcific valve degeneration


D.Inflammatory valve degeneration


E.Overproduction of catecholamines








Myxomatous degeneration is caused by the accumulation of dermatan sulfate within the connective tissue of the mitral valve. In developed countries, it is the most common cause of mitral valve degeneration and subsequent mitral valve prolapse. As the disease course progresses, mitral regurgitation can occur. This patient presents with common features of mitral valve prolapse (palpitations, anxiety, chest pain, mid-systolic click). The new-onset dyspnea, holosystolic murmur, and crackles on lung auscultation are consistent with regurgitation of the mitral valve, indicating an advanced disease process.



Heart murmur in ventricular septal defect, mitral regurgitation, and tricuspid regurgitation


500

A 52-year-old woman comes to the physician because of intense retrosternal chest pain for the last 3 days. The pain is worse with breathing or coughing, and improves while sitting upright. She also reports a mild fever and shortness of breath. She was diagnosed with chronic kidney disease secondary to lupus nephritis 12 years ago and has been on hemodialysis since then, but she missed her last two appointments because of international travel. She also underwent a percutaneous coronary intervention 8 months ago for a myocardial infarction. She takes azathioprine after hemodialysis. Her temperature is 37.8°C (100.0°F), pulse is 110/min, and blood pressure is 130/84 mm Hg. The lungs are clear to auscultation bilaterally with normal breath sounds. Cardiac examination reveals a high-pitched scratching that obscures both heart sounds. The remainder of the examination is unremarkable. Cardiac enzyme levels and anti-dsDNA antibodies are within normal limits. An x-ray of the chest shows no abnormalities. An ECG shows Q waves in the anterior leads. Which of the following is the most likely cause of this patient's presentation?

A.Adverse effect of medication


B.Serositis from an immunologic reaction


C.Infarction of myocardial segment

D.Purulent exudate in the pericardial space


E.Elevated serum levels of nitrogenous waste









Elevated serum levels of nitrogenous waste


This patient presents with a history of chronic kidney disease and missed dialysis sessions, which makes uremia the most likely cause of her symptoms. In patients with end-stage renal disease, inadequate clearance of uremic toxins can lead to pericardial inflammation. Pericardial inflammation due to uremia is less likely than other types of pericarditis to manifest with diffuse ST elevations and PR depressions on ECG, possibly because epicardial injury is minimal. Urgent hemodialysis is indicated to remove the accumulated toxins and resolve inflammation.

Some sources distinguish between uremic pericarditis, which occurs before or up to 8 weeks after starting dialysis, and dialysis-associated pericarditis, which can manifest in patients undergoing long-term treatment. Both conditions are caused by inadequate toxin clearance and are managed similarly regardless of when dialysis was initiated.


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