Thank you to Sarah for presenting an interesting case of a man with HIV with fevers, chills, weight loss, and productive cough as well as a headache. We discussed a broad differential for both pulmonary and CNS infections. This case brought up the need to review some of the classic imaging findings for HIV-associated pulmonary infections.
HIV Pulmonary Syndromes and Radiology Findings:
Information and images comes from radiopaedia.org, which is a great radiology website with lots of great info and images!
- Although up to 90% of chest radiographs in patients with PCP are abnormal, appearances are often non-specific. Between 10-15% of patients with PCP have normal chest radiographs and close to 30% have non-specific or inconclusive findings.
- Features which are highly suggestive of PCP in patients with CD4 counts below 200/mm3 include:
- small pneumatocoeles, subpleural blebs
- a fine reticular interstitial pulmonary pattern
- there is often a perihilar distribution
- Pleural effusions are normally not a feature, being seen in less than 5% of cases.
Case courtesy of Dr Behrang Amini , Radiopaedia.org, rID: 35823
Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 9171
High-resolution computed tomography (HRCT) is more sensitive and may be used to exclude PCP in patients with clinical suspicion for PCP but normal or inconclusive chest radiographs.
- Ground-glass pattern
- Considered a principal finding
- Predominantly involving perihilar or mid zones
- There may be a mid, upper or lower zone predilection depending on whether the patient is on prophylactic aerosolised medication
- If they are, then the poorly ventilated upper zones are prone to infection, whereas in those who are not, the lower zones are more frequently involved
- There may be a relative preservation of previously irradiated areas
- May show some peripheral sparing in a considerable number of patients (~40%)
- Reticular Opacities or septal thickening may also be present; a crazy paving pattern may, therefore, be seen when both ground-glass opacities and septal thickening are superimposed on one another
- Varying shape, size, and wall thickness are seen in up to 30% of cases
- Pleural effusions are rare
- Lymphadenopathy is uncommon (10%)
Case courtesy of Dr Behrang Amini , Radiopaedia.org, rID: 35862
Case courtesy of Dr Praveen Jha, Radiopaedia.org, rID: 17273
In general, there are several CT patterns that can be seen:
- Clustered nodular pattern: most prevalent 4
- Solitary pulmonary nodule or mass with or without cavitation
- Scattered nodules
- Peribronchovascular consolidation
The most common CT findings in immunocompetent patients with pulmonary cryptococcosis are pulmonary nodules. The nodules are most often multiple, smaller than 10 mm in diameter, and well-defined with smooth margins. The nodules usually involve less than 10% of the parenchyma and tend to be distributed peripherally in the middle and upper zones. Where there are multiple nodules, they are usually bilateral 2. Associated cavitation may be seen in up to 40% of cases 8. Occasionally, unusual presentation such as large cavities may be seen 13.
Case courtesy of Dr Yale Rosen, Radiopaedia.org, rID: 16218
Also check out this website to scrolls through some classic CT scans:
- Wide variability
- Cavitation is uncommon in primary TB and only seen in 10-30% of cases
- Often can becomes localized and form a caseating granuloma (tuberculoma)
- Pleural effusions are more frequent in adults, seen in 30-40% of cases.
In the majority of cases, post-primary TB within the lungs develops in either: posterior segments of the upper lobe or superior segments of the lower lobes
- Patchy consolidation or poorly defined linear and nodular opacities.
- Far more likely to cavitate than primary infections and are seen in 20-45% of cases.
- In the vast majority of cases, they develop in the posterior segments of the upper lobes (85%)
- Hilar nodal enlargement is seen in only approximately a third of cases
- Lobar consolidation, tuberculoma formation and miliary TB are also recognised patterns of post-primary TB but are less common.
Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org, rID: 8632
Case courtesy of Dr Jeremy Jones, Radiopaedia.org, rID: 13234
Case courtesy of Dr Natalie Yang, Radiopaedia.org, rID: 9095
Case courtesy of Dr Ruslan Esedov, Radiopaedia.org, rID: 8230
- HIV Pulmonary Syndromes: https://www.evernote.com/shard/s509/sh/5c81e647-2082-4647-a0b9-51130ec54a5d/321226bd762ddca8a95b608b39d6b4a5