A 32-year-old man presented to his GP complaining of a cough. He had been unwell for four days with fever and shortness of breath. This had started while he was on holiday in the Caribbean. The GP diagnosed a viral URTI.
Over the following six days the patient’s condition worsened and he presented to A&E, where he gave a history of gradually increasing cough without sputum and feeling tight-chested, particularly on exertion. Previously he had been well. He smoked five cigarettes a day.
The patient had a fever of 38.2°C, was tachycardic, tachy-pnoeic and hypoxic. His oxygen saturation (SaO2)was 82 per cent. Crepitations were noted in the base of his left lung. A chest X-ray showed bilateral basal haziness, and an ECG showed sinus tachycardia.
A provisional diagnosis of atypical pneumonia was made. He was admitted and started on IV clarithromycin and fluids.
While he was on the ward it was noticed that his SaO2 had dropped to 55 per cent on mobilising. The patient’s condition deteriorated overnight and he was transferred to the high-dependency unit, where continuous positive airway pressure (CPAP) was started.
Blood gases revealed type-one respiratory failure. Treatment continued for atypical bacterial pneumonia, and IV co-trimoxazole and methylprednisolone were added as presumptive treatment.
A rapid HIV test was performed after a pre-test discussion identified he had had unprotected sexual intercourse with various partners during his holiday. The test was reactive.
Broncho-alveolar lavage was positive on immunofluorescence for Pneumocystis carinii pneumonia (PCP). His CD4 count was 15 cells/µl.
Opportunistic infection
Seventeen per cent of newly diagnosed patients had had a likely HIV-related clinical episode in the preceding 12 months but the diagnosis of HIV has been missed. Oppor-tunistic infections are seen in undiagnosed patients and in those failing HAART therapy.
In 1981, five men diagnosed with PCP in Los Angeles, California, were the first recognised indication of HIV. The causative organism of PCP has been reclassified and renamed as Pneumocystis jiroveci, a fungus which causes pneumonia in patients with CD4 counts of less than 200cells/µl. PCP is unlikely, but not impossible, in patients with CD4 counts of over 200cells/µl.
PCP classically causes fever, dry cough and shortness of breath on exercise. It may also cause night sweats. Chest examination is often unremarkable. X-ray is often normal but may show bilateral bat’s wing perihilar shadowing. Pneumothorax may occur.
The diagnosis is strongly suggested by desaturation on exercise. A positive test is one in which there is desaturation to 90 per cent or less. This is likely to remain present after recovery from an episode of PCP and so is not diagnostic for subsequent episodes.
The diagnosis is confirmed by sputum immunofluorescent staining specific for P jiroveci.
Treatment
Treatment is with co-trimoxazole. Oral therapy as an outpatient may be considered in a patient with pO2 greater than 10kPa. If the pO2 is less than 10kPa then the patient requires admission and IV co-trimoxazole. If the pO2 is below 8kPa, IV corticosteroids should be added.
This patient was started on antiretroviral therapy and was discharged after 15 days. Co-trimoxazole was continued for a total of four weeks and then reduced to a prophylactic dose.
The co-trimoxazole therapy will need to be continued until his CD4 count remains over 200 cells/µl for at least six months. He was also advised not to travel by air for at least six weeks.
Differential diagnoses of PCP include bacterial pneumonia, TB, and rarely toxoplasma, cryptococcus, histoplasmosis and cytomegalovirus. TB must always be excluded in a patient presenting with atypical features including fevers, sweats and weight loss.
The British Association of Sexual Health and HIV has issued guidelines on HIV testing, pre-test discussion, consent and confidentiality, insurance issues, methods to increase testing uptake and methods of giving results.
Dr Price is a specialist registrar, Dr Sullivan is consultant physician, and Dr Jones is a specialist registrar, in the department of genitourinary and HIV medicine, Chelsea and Westminster Hospital, London
Lessons Learnt
- 17 per cent of newly diagnosed HIV patients have had an HIV-related clinical episode in the preceding 12 months.
- Opportunistic infections are seen in patients with advanced but undiagnosed HIV disease.
- PCP causes fever, dry cough and shortness of breath on exercise.
- Diagnosis is confirmed by sputum immunofluorescent staining.
- After an episode of PCP patients should not travel by plane for six weeks.
