Clinical History:

A 35-year-old man was driving home from work when he suddenly became short of breath. He pulled his pickup truck into the lot of a local hospital and walked with difficulty into the emergency room. His vital signs showed respirations 30, pulse 102, temperature 37.9 C, and blood pressure 110/60 mm Hg. A chest x-ray showed bilateral patchy infiltrates. A bronchoalvoelar lavage was performed. Although therapy was initiated, he died four days after admission.

Answers:

1. What did pathologic examination of the BAL fluid probably show?

The most likely opportunistic infection with these clinical findings is Pneumocystis carinii (jirovecii), which produces a pneumonia (PCP). BAL is a good method for obtaining diagnostic material for suspected pulmonary infections.

2. How could his acute illness have been prevented?

Pneumocystis carinii (jirovecii) pneumonia (PCP) can be prevented in large measure by two methods: (1) antiretroviral therapy to suppress HIV replication and maintain the immune system, and (2) use of prophylaxis for PCP once the immune system has begun to fail. Although most patients with PCP respond to therapy, some do not. Patients at risk may have repeated bouts of PCP.

3. What are underlying disease processes that can lead to this acute illness?

Without a history of previous immunosuppression, this strongly suggests human immunodeficiency virus (HIV) infection. Persons with primary immunodeficiency (usually children, but sometimes adults) and persons with secondary immunodeficiencies (as from chemotherapy) are at risk. History should be directed toward finding risk factors. The fact that he has an AIDS-defining illness (PCP) suggests a diagnosis of AIDS. From 1 to 5% of patients presenting to an emergency room in large metropolitan cities in the United States are HIV-infected.

4. How would you confirm this?

A history would help. An ELISA test for HIV, confirmed with Western blot, would establish the diagnosis. Remember that AIDS is a reportable disease (to the health department).