Differential Diagnosis Of Pulmonary Tb In Hivinfected Children

Bacterial pneumonia

Bacterial pneumonia is very common in all HIV-infected children and recurrent bacterial pneumonia is a feature of children with AIDS. The commonest cause is Streptococcus pneumoniae and response to treatment is usually satisfactory. Other causes include Haemophilus influenzae, Salmonella, Staphylococcus aureus, Klebsiella pneumoniae and Escherichia coli.The presentation of PTB in infants can be acute, so PTB should be considered when there is a poor clinical response to standard antibiotics and the mother has TB. Pneumonia due to Staphylococcus or Klebsiella may be a problem in HIV-infected children with chronic lung disease.These bacteria can cause cystic changes and cavitation.

Lymphocytic interstitial pneumonitis (LIP)

LIP is a very common cause of lung disease in HIV-infected children over 2 years of age. LIP may be difficult to differentiate from PTB or miliary TB. Clinical features that are commonly associated with LIP include symmetrical, generalized lymphadenopathy (painless and mobile), bilateral chronic non-tender parotid enlargement, and finger clubbing. Diagnosis is clinical as it can only be confirmed by lung biopsy. Typical CXR findings are bilateral diffuse reticulonodular pattern and enlarged mediastinal/hilar lymph nodes. Note that the CXR abnormalities are often unilateral with PTB. However, LIP presents with a broad spectrum of clinical and radiological features. Bacterial pneumonia is a common complication and further confuses the CXR findings.

Bronchiectasis

This is usually a complication of LIP but may also complicate TB.A cough productive of copious purulent and sometimes blood-stained sputum, finger clubbing, and halitosis are typical features.

Pulmonary Kaposi sarcoma

KS can involve the lungs and causes diffuse lung infiltration and lymph node enlargement. Patients may present with a large pleural effusion which is bloody on aspiration. Look for the typical KS lesions elsewhere: on the skin, palate or conjunctiva.

Pneumocystis carinii pneumonia

PCP is a common problem in HIV-infected children and usually presents as an acute, severe pneumonia in infants less than 6 months of age. Compared with TB in infants, PCP is characterized by severe hypoxia. The commonest CXR abnormalities are diffuse interstitial infiltration and hyperinflation. In developing countries, PCP is a very unlikely diagnosis of persistent respiratory disease in children after infancy. In countries where there is antenatal HIV screening and routine cotrimoxazole prophylaxis in HIV-infected infants, PCP is now unusual .

Others

Other conditions to be considered in the differential diagnosis include: fungal pneumonia, e.g. due to Candida or cryptococcus, nocardiosis and pulmonary lymphoma.

The commonest HIV-related lung disease in children that may be confused with TB is LIP.

T^M MANAGEMENT OF CHILD CONTACTS OF INFECTIOUS ADULTS

Children with TB may present to health units when they are ill. However, most national TB control programmes also recommend active contact tracing of children who are household contacts of infectious adults. In order to be effective, this screening must be systematic. If you do not have a systematic, organized process for child contact screening where you work, could you start one?

The scheme below shows how to manage child contacts of infectious adults (with sputum smear-positive PTB). Suspicion that a child contact is HIV-infected may arise because of the following: the child has clinical evidence of HIV infection; the parent (the infectious TB patient) is known, or suspected, to be HIV-positive. If you suspect a child contact is HIV-infected, it is important to counsel the parents before HIV-testing the child.

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