Extrapulmonary TB (EPTB) can occur at any age.Young children and HIVpositive adults are particularly susceptible. Up to 25% of TB cases may present with EPTB. Children of less than 2 years of age are at risk of disseminated disease causing miliary TB or TB meningitis. The common forms of extrapulmonary TB associated with HIV are the following: lymphadenopathy, pleural effusion, pericardial disease, miliary TB, and meningitis. Many patients with extrapulmonary TB also have coexistent pulmonary TB.
If a patient has extrapulmonary TB, look for pulmonary TB. If the patient has had a productive cough for more than 2 or 3 weeks, send sputum samples for AFB. If testing AFBs the test is negative, do a CXR.
Definitive diagnosis of extrapulmonary TB is often difficult. Diagnosis may be presumptive, provided you can exclude other conditions. Patients usually present with constitutional features (fever, night sweats, weight loss) and local features related to the site of disease.These local features are similar in adults and children. The degree of certainty of diagnosis depends on the availability of diagnostic tools, e.g. specialized X-rays, ultrasound, biopsy.
Regardless of HIV status, the lymph nodes most commonly involved are the cervical nodes.The usual course of lymph node disease is as follows:
firm, discrete fluctuant nodes skin breakdown, healing with nodes matted together abscesses, ^ scarring chronic sinuses
In severely immunocompromised patients, tuberculous lymphadenopathy may be acute and resemble acute pyogenic lymphadenitis.
In adults, the differential diagnosis of tuberculous lymphadenopathy includes the following: persistent generalized lymphadenopathy (PGL), lymphoma, Kaposi sarcoma, carcinomatous metastases, sarcoid, and drug reactions (e.g. phenytoin).
Lymphoid interstitial pneumonitis (LIP) is often associated with PGL in HIV-infected children. LIP may be confused with TB as chronic respiratory symptoms are very common.The lymphadenopathy with LIP is characteristically generalized, symmetrical, mobile, non-tender, firm and non-fluctuant. Differential diagnoses of focal lymphadenopathy in children include bacterial or pyogenic adenitis and lymphoma (e.g. Burkitt lymphoma).
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