A 25-year-old man comes to the emergency department with shortness of breath and cough productive of blood-tinged sputum for the past few days. He has not had any fevers, arthralgias, or weight loss. He has never had these symptoms before and is extremely concerned. The patient has no history of recent travel or sick contacts. He smokes half a pack of cigarettes daily, and has had 2 sexual partners in the past 6 months. Temperature is 37.2 C (98.9 F), blood pressure is 120/70 mm Hg, pulse is 102/min, and respirations are 22/min. Lung auscultation reveals patchy bilateral rales. Chest x-ray demonstrates bilateral pulmonary infiltrates. Serum creatinine is 2.6 mg/dL and urinalysis shows dysmorphic red cells. Which of the following is the most likely cause of his current condition?

Question

A 25-year-old man comes to the emergency department with shortness of breath and cough productive of blood-tinged sputum for the past few days.  He has not had any fevers, arthralgias, or weight loss.  He has never had these symptoms before and is extremely concerned.  The patient has no history of recent travel or sick contacts.  He smokes half a pack of cigarettes daily, and has had 2 sexual partners in the past 6 months.  Temperature is 37.2 C (98.9 F), blood pressure is 120/70 mm Hg, pulse is 102/min, and respirations are 22/min.  Lung auscultation reveals patchy bilateral rales.  Chest x-ray demonstrates bilateral pulmonary infiltrates.  Serum creatinine is 2.6 mg/dL and urinalysis shows dysmorphic red cells.  Which of the following is the most likely cause of his current condition?

Quizplus · Accepted Answer

Explanation: This patient's renal and pulmonary findings together suggest a diagnosis of anti-glomerular basement membrane (anti-GBM) disease (previously Goodpasture syndrome), a condition most common in young adult males. Renal findings in anti-GBM disease include nephritic-range proteinuria (eg, <3.5 g/day), acute renal failure, and urinary sediment with dysmorphic red cells and red cell casts. Pulmonary findings include shortness of breath, cough, and hemoptysis caused by pulmonary hemorrhage. Systemic symptoms (fever, weight loss, arthralgias) are uncommon. The underlying cause is formation of antibodies to the alpha-3 chain of type IV collagen, a protein expressed most strongly in the glomerular and alveolar basement membranes. Renal biopsy demonstrating linear IgG deposition along the glomerular basement membrane on immunofluorescence is diagnostic. (Choice B) Pneumocystis pneumonia (PCP) typically affects HIV patients with CD4 counts <200/mm³. Fever, dyspnea, and nonproductive cough are the most characteristic symptoms. Fatigue, weight loss, and chills are also common. PCP does not involve the kidneys. ³ (Choice C) This patient's cough, hemoptysis and dyspnea could represent tuberculosis (TB), but TB tends to also cause systemic symptoms like weight loss, fever, and night sweats. TB infection may involve the kidneys (causing dysuria, hematuria); secondary amyloidosis causing nephrotic range proteinuria is also possible. (Choice D) Pulmonary thromboembolism presents with sudden-onset dyspnea. Cough, hemoptysis, pleuritic chest pain, and fever may also occur. The kidneys would not be involved. (Choice E) Endocarditis could potentially explain this patient's presentation, with nephritic syndrome secondary to immunocomplex deposition and hemoptysis secondary to septic emboli. However, almost all patients have prominent systemic symptoms (fever, chills, dyspnea, sweats, and weakness), along with possible new-onset heart murmur, Osler nodes, Roth spots, Janeway lesions, and splinter hemorrhages. Educational objective: Anti-glomerular basement membrane disease affects the lungs (causing cough, dyspnea, and hemoptysis) and kidneys (causing nephritic range proteinuria, acute renal failure, and dysmorphic red cells/red cell casts on urinalysis). Systemic symptoms are uncommon. Diagnosis is made by renal biopsy showing linear IgG antibodies along the glomerular basement membrane.

A 25-Year-Old Man Comes to the Emergency Department with Shortness of Breath