Chest X-Ray: HIV-Associated Infections

The chest radiograph is the primary imaging tool for evaluating respiratory illness in people living with HIV, particularly in high-burden African settings where it guides diagnosis of tuberculosis and opportunistic infection. Radiographic patterns correlate strongly with the degree of immunosuppression (CD4 count), and interpretation must integrate CD4 status, symptom duration and local epidemiology. Serial comparison is essential because HIV-related disease often evolves rapidly and co-infections are common.

Indications

HIV-positive patient with cough, dyspnoea, fever, chest pain or haemoptysis
CD4 count <200 cells/mm3 with respiratory symptoms (higher risk of PCP and disseminated disease)
Suspected pulmonary or disseminated tuberculosis
Suspected Pneumocystis jirovecii pneumonia (subacute dyspnoea, dry cough, hypoxia)
Suspected bacterial pneumonia, Kaposi sarcoma or lymphoma
Screening before or during antiretroviral therapy and to detect immune reconstitution inflammatory syndrome (IRIS)
Assessment of treatment response and detection of complications (effusion, pneumothorax, empyema)

Contraindications & Cautions

No absolute contraindication; benefits outweigh minimal radiation risk
Pregnancy: justify and shield the abdomen; the PA chest dose is very low but ALARA applies
Minimise cumulative dose with repeat imaging by clinically justifying each film
Infection control: TB is airborne - image in ventilated areas and follow isolation and PPE protocols to protect staff and other patients
Mobile radiography for isolated or critically ill ICU patients to limit transport-related transmission

Patient Preparation

Explain the procedure and obtain verbal consent
Remove clothing, jewellery and radio-opaque objects from the chest
Position for a full inspiratory PA erect film where the patient can stand; lateral view adds value for retrocardiac and hilar disease
Supine AP mobile film for immobile/ICU patients, noting positional magnification and altered vascular pattern
Retrieve and display prior films for direct comparison
Record CD4 count, ART status and symptom timeline on the request to aid interpretation

Technique & Parameters

PA erect at ~110-125 kVp with a grid, short exposure to freeze cardiac motion, full inspiration (9-10 posterior ribs)
Lateral view for localisation of infiltrates and detection of small effusions
AP mobile technique (~80-90 kVp) for bedside ICU imaging; annotate as supine/AP
Lateral decubitus film to confirm free-flowing pleural effusion when ultrasound unavailable
Resource-limited adjuncts: thoracic ultrasound for effusion characterisation and drainage guidance; digital or portable CXR systems improve access and comparison
Correlate with sputum Xpert MTB/RIF, urine LAM and CD4 count rather than relying on imaging alone

Systematic Review

Confirm patient identity, projection, rotation, inspiration and penetration adequacy
Assess lung volumes and symmetry
Review lung zones systematically for consolidation, interstitial change, nodules, cavities and miliary pattern
Compare zonal distribution: upper-zone predominance (reactivation TB) vs perihilar (PCP) vs lobar (bacterial)
Evaluate hila and mediastinum for lymphadenopathy and masses
Inspect pleura for effusion, pneumothorax and thickening
Assess heart size, and check for pericardial effusion suggested by an enlarging globular cardiac silhouette (TB pericarditis)
Review bones and soft tissues, and directly compare with prior films for progression or resolution

Key Findings & Significance

Pneumocystis pneumonia: bilateral, symmetric perihilar interstitial or ground-glass opacities, often with sparing of the periphery; may develop cysts/pneumatoceles and spontaneous pneumothorax; can be normal early
Pulmonary TB with preserved CD4: upper-lobe/apical infiltrates and cavitation with possible fibrosis
TB with advanced immunosuppression (CD4 <200): atypical pattern - lower/mid-zone infiltrates, mediastinal/hilar lymphadenopathy, miliary micronodules and pleural or pericardial effusion, cavitation often absent
Miliary TB: innumerable 1-3 mm nodules evenly distributed throughout both lungs
Bacterial pneumonia (Streptococcus pneumoniae common): focal lobar or segmental consolidation with air bronchograms, often at higher CD4
Kaposi sarcoma: bilateral peribronchovascular nodular opacities in a 'flame-shaped' perihilar distribution, effusions and adenopathy
Lymphoma: mediastinal/hilar mass, nodules, effusions
A normal radiograph does not exclude PCP or early disseminated infection

Differential Considerations

Diffuse bilateral interstitial/ground-glass pattern -> PCP vs viral/atypical pneumonia vs pulmonary oedema vs miliary TB
Upper-lobe cavitation -> post-primary TB vs necrotising bacterial pneumonia vs fungal infection (cryptococcus, histoplasma) vs Nocardia
Miliary nodules -> miliary TB vs disseminated fungal infection vs metastatic malignancy
Perihilar/peribronchovascular nodular opacities with effusion -> Kaposi sarcoma vs lymphoma vs pulmonary oedema
Lobar consolidation -> bacterial pneumonia vs TB vs Kaposi consolidation
Mediastinal/hilar adenopathy -> TB vs lymphoma vs Castleman disease vs sarcoidosis
Pleural effusion in HIV -> TB (most common) vs bacterial empyema vs Kaposi vs lymphoma

Pearls & Pitfalls

Always interpret in the context of the CD4 count: lower counts give more atypical, disseminated and lymphadenopathic TB patterns
Symmetric perihilar ground-glass with hypoxia out of proportion to the film strongly suggests PCP - treat empirically and consider CT if available
Spontaneous pneumothorax in an HIV patient is PCP until proven otherwise
A normal or minimally abnormal CXR does not exclude active TB in advanced HIV; use molecular testing and urine LAM
TB pericardial effusion can present as progressive cardiomegaly - look for a globular heart and correlate with echocardiography
Kaposi sarcoma pulmonary lesions are typically accompanied by mucocutaneous lesions and bloody pleural effusions that are cytology-negative
IRIS can cause paradoxical worsening (enlarging nodes, new infiltrates) weeks after starting ART - do not mistake for treatment failure
Beware co-infection: TB plus bacterial pneumonia or PCP can coexist, so a mixed pattern is common

Structured Report

State projection, adequacy and whether prior films were available for comparison
Describe distribution and character of parenchymal disease (zone, pattern, cavitation, nodularity)
Report lymphadenopathy, pleural and pericardial disease, and pneumothorax explicitly
Interpret the pattern in the stated CD4 context and comment on most likely infective aetiology
Note change from previous imaging (progression, resolution, IRIS)
Impression: prioritised differential emphasising TB where relevant, with confidence level
Recommend confirmatory testing (Xpert MTB/RIF, urine LAM, sputum, CT chest, echocardiography) and isolation where TB is suspected

References

WHO Consolidated Guidelines on Tuberculosis and TB/HIV
WHO/UNAIDS guidance on HIV-associated opportunistic infections
ACR Appropriateness Criteria: Acute Respiratory Illness in Immunocompromised Patients
RadioGraphics: Thoracic Manifestations of HIV/AIDS
British HIV Association (BHIVA) opportunistic infection guidelines

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.

Chest X-Ray: HIV-Associated Infections

📋 Indications

⛔ Contraindications & Cautions

🧑‍⚕️ Patient Preparation

⚙️ Technique & Parameters

🔎 Systematic Review

🩻 Key Findings & Significance

🧠 Differential Considerations

💡 Pearls & Pitfalls

📝 Structured Report

📚 References