- What is the material in the alveoli?
A foamy proteinaceous exudate fills each alveolus. There is minimal
accompanying inflammation.
- What do you see on GMS (silver) stain in image 8.4?
Numerous cup shaped rather delicate organisms that look a little like RBC's, however notice that the staining is different from RBC's in that in the Pneumocystis carinii (jirovecii) (PCP) the delicate cell wall stains and the center is clear, where the RBC's stain more darkly in the center.
- What is his likely underlying condition?
He probably has AIDS with HIV infection, but additional history and an HIV test are needed.
- If this patient had some other reason for being immunosuppressed, such as being on corticosteroids, receiving chemotherapy for malignancy, or having an undiagnosed lymphoma, how would the biopsy differ most likely?
In PCP infection in AIDS the organism burden is overwhelming, with the alveoli packed with organisms. In immunosuppression due to other causes such as lymphoma, chemotherapy, or steroid use, often there are many fewer organisms present and one has to hunt to find them. However, even in persons with HIV infection, the appearance of PCP may be "atypical" from the usual diffuse involvement, with fewer lesions and fewer organisms. The typical diagnostic procedure is bronchoalveolar lavage (BAL).
- How is this disease treated?
The drug of choice for PCP is trimethoprim-sulfamethoxazole (TMP-SMX). Alternatives include TMP plus dapsone, clindamycin plus primaquine, or atovaquone alone. For more severe cases pentamidine can be used, but it has significant toxicities. Concomitant administration of corticosteroids with anti-pneumocystis drugs improves respiratory function.
Prophylaxis for PCP in persons at risk is very succesful in preventing this disease. The drug of choice is TMP-SMX.
- What advance directives should be considered by this patient?
With AIDS the risk of losing capacity for decision-making is very high, and if the patient with HIV infection develops an opportunistic infection, then AIDS dementia could be just around the corner. So making out an advance directive (AD) is crucial, during the same hospitalization as the PCP diagnosis and treatment.
The patient may want intubation, since there is a good chance for coming off a ventilator, if that therapy becomes necessary. But the doctor can introduce the idea of time-limited trials: give the ventilatory support a week, but no more--or maybe up to two weeks, if there are indications by day 7 that respiratory status is improving and he may get off the ventilator. Or more likely the AD choice of most people with AIDS (or any other grave illness with poor prognosis): if my capacity is already lost and unlikely to ever return, don't put me on a ventilator at all, not even for a time limited trial.
