A 72-year-old man with a purpuric rash

Clues from the urinalysis and chest radiography

Our patient’s sedimentation rate is 24 mm/hour. The urinalysis is strongly positive for blood and a moderate amount of protein but negative for leukocyte esterase and nitrite. The urine sediment contains numerous red blood cell casts and 6 to 10 white blood cells per high-power field.

Chest radiography (Figure 2) shows diffuse air-space opacities throughout the right lung and in the upper lobe of the left lung.

Pending return of blood cultures, ceftriaxone (Rocephin) and azithromycin (Zithromax) are started to treat possible community-acquired pneumonia. Vancomycin (Vancocin) is empirically added, given the possibility of prosthetic valve endocarditis. Gram stain on blood cultures shows gram-positive cocci.

Chest CT (Figure 3) reveals diffuse reticular nodular densities associated with ground-glass attenuation in the areas identified on the chest radiograph.

Ground-glass attenuation implies focal or diffuse opacification of the lung that does not obscure the vascular structures, is not associated with air bronchograms, and appears as a “veil” across the lung parenchyma.¹ It can be seen in acute diseases such as infection (including pneumonia from atypical bacteria, viruses, acid-fast bacilli, and Pneumocystis jiroveci), pulmonary hemorrhage of any cause, acute viral, eosinophilic, and interstitial pneumonias, and hypersensitivity pneumonitis. It can also be seen in chronic disease states such as interstitial lung disease, bronchoalveolar carcinoma, alveolar proteinosis, and sarcoidosis.

WHICH TEST WOULD NOT HELP?

2. Which of the following tests is least likely to help in the diagnostic evaluation at this point?

• Transthoracic echocardiography
• Transesophageal echocardiography
• Bronchoscopy
• Cystoscopy

In this case, the least likely to help is cystoscopy.

This patient’s vasculitic-appearing rash, ground-glass pulmonary infiltrates, and impaired renal function with red cell casts suggest a pulmonary-renal syndrome, and with this constellation of features, a systemic vasculitis is very likely. Therefore, the focus of the evaluation should be on any evidence to support a diagnosis of vasculitis, as well as other possible causes.

In a patient with diabetes, an artificial heart valve, and fever, the possibility of infection, especially endocarditis, remains high. Transthoracic echocardiography is warranted, and if it is negative for vegetations, transesophageal echocardiography would be a reasonable next option.

Bronchoscopy is warranted to determine if the infiltrates represent pulmonary hemorrhage, which can be seen in certain types of vasculitic and systemic disorders.

The finding of red cell casts in the urine indicates glomerulonephritis, and therefore the kidneys are the likely source of the urinary red blood cells, making cystoscopy of no utility in this current, acute setting.

Case continued: His condition worsens

Transthoracic echocardiography reveals a well-seated mechanical prosthetic aortic valve, trivial aortic regurgitation, a peak gradient of 23 mm Hg and a mean gradient of 12 mm Hg (normal values for his prosthetic valve), and no valvular vegetations. Transesophageal echocardiography confirms the absence of vegetations.

His oxygen requirement increases, and analysis of arterial blood gases reveals a pH of 7.37, Pco₂ 49 mm Hg (normal range 35–45), Po₂ 102 mm Hg (normal 80–100), and bicarbonate 28 mmol/L while breathing 100% supplemental oxygen by a nonrebreather face mask. He is taken to the medical intensive care unit for intubation and mechanical ventilation. Bronchoscopy performed while he is intubated confirms diffuse alveolar hemorrhage. Pulse intravenous methylprednisolone (Solu-Medrol) therapy is started.

DIFFUSE ALVEOLAR HEMORRHAGE

3. Which of the following is not true about diffuse alveolar hemorrhage?

• Its onset is usually abrupt or of short duration
• It is always associated with hemoptysis
• Radiography most commonly shows new patchy or diffuse alveolar opacities
• Pulmonary function testing shows increased diffusing capacity of the lung for carbon monoxide (Dlco)

Hemoptysis is absent at presentation in as many as 33% of patients.

The onset of diffuse alveolar hemorrhage is usually abrupt or of short duration, with initial symptoms of cough, fever, and dyspnea. Some patients, such as ours, can present with severe acute respiratory distress syndrome requiring mechanical ventilation. Radiography most often shows new patchy alveolar opacities, and CT may reveal a ground-glass appearance. On pulmonary function testing, the Dlco is high, owing to the hemoglobin within the alveoli.