HIV/AIDS (pulmonary manifestations)
Pulmonary manifestations of HIV/AIDS are a major contributor to morbidity and mortality related to the disease. The differential in an HIV patient with a chest complaint is broad. Infectious causes are the most common, however, neoplasms, lymphoma and interstitial pneumonias also play a significant role.
A systematic approach that takes into account the imaging findings, the severity of immunosuppression (i.e. CD4 count) and clinical presentation should narrow the differential.
Among the HIV affected patients, there are some demographic groups with a particular predisposition to certain associated conditions. For example, lymphocytic interstitial pneumonitis (LIP) is considerably more common in paediatric patients. Kaposi sarcoma is seen predominantly in the homosexual male population.
The type and onset of respiratory complaint may narrow the differential diagnosis.
An insidious onset of symptoms is more typical of TB, other mycobacterial or fungal infection. Persistent symptoms that do not respond to therapy raise suspicion of a neoplastic process.
- >200 cells/mm3: all patients with HIV are at an increased risk of bacterial infections and TB. The risk increases further as CD4 count drops.
- <200 cells/mm3: also susceptible to PCP, atypical mycobacteria
- <100 cells/mm3: also susceptible to CMV, disseminated fungal and mycobacterial infections
Imaging appearances of patients with AIDS-related chest conditions are protean and often nonspecific. A pattern based approach is suggested for narrowing the differential diagnosis.
A chest x-ray is generally the initial examination, however, a CT is often warranted for characterisation.
Normal chest x-ray
The chest x-ray is not infrequently normal in an HIV patient presenting with a respiratory complaint. Consider:
- upper respiratory tract infection: common in HIV
- radiographically occult infections such as viral or bacterial bronchiolitis
- imaging patterns that may be difficult to see on plain x-ray, e.g. ground glass opacity with PCP
Focal airspace opacity
Bacterial infection is most likely, of which Strep. pneumoniae is most common. In the severely immunosuppressed, consider also TB. A non-resolving airspace opacity may be due to malignancy.
Multifocal airspace opacity
A multifocal bacterial infection is again most likely.
When the opacities are nodular consider fungal infection, mycobacteria and N. asteroides.
Ground glass opacity
PCP is a common cause of ground glass opacity in the immunocompromised host: although incidence has decreased with the advent of prophylactic therapy and HAART. Look for the typical perihilar distribution. There may be a crazy-paving appearance.
Other infectious differentials includes viral and atypical bacterial infections. In the severely immunocompromied (CD4<100), consider CMV pneumonia.
Non-infectious causes of ground glass opacity include LIP (with thin wall cysts), or NSIP.
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- manifestations of HIV/AIDS
- CNS manifestations
- pulmonary manifestations
- cardiovascular manifestations
- gastrointestinal manifestations
- hepatobiliary manifestations
- genitourinary manifestations
- musculoskeletal manifestations
- AIDS defining illnesses
- HIV associated neoplasms
- immune reconstitution inflammatory syndrome (IRIS)
- AIDS embryopathy