Q: My wife has an enlarged lymph node below the left side of the jaw. No other lymph node enlargement is seen. For the last few years,she has been coughing mildly and some times more in response to weather changes etc. The doctors have diagnosed this as allergic cough. The chest X ray and blood tests repeated six monthly did not indicate anything wrong (especially not TB). AIIMS Delhi has diagnosed this as Psyhco-spasm. There is no loss of weight (her weight has actually increased) or appetite or any other related symptom. Is it possible that the cough and the enlargement of lymph node are related? Can it be taken as a clinical basis for TB? If the cough subsides with anti-biotic medicines (Augmentin) or with anti-allergic medicines (cetrizine), could it still be a case of TB?

A:An enlargement of the submandibular (below the jaw) lymph nodes is usually due to some problem or infection in the mouth. A dental and ENT checkup would exclude any cause for this. Also an isolated lymph node is unlikely to be significant. The size of the lymph node is also important, and a clinical examination is necessary to find the nature of the lymph node. It could be that the cough is due to an ENT problem, in which case the enlarged lymph node may be due to that. A solitary lymph node in the absence of other clinical features requires further evaluation and is unlikely to be due to TB. To exclude TB, a Mantoux test and / or a Quantiferon-TB gold (QFTG) test could be done. A strongly positive Mantoux (>15 mm induration) and a positive QFTG would be supportive of a diagnosis of TB. If clinically relevant, a fine needle aspiration cytology (FNAC) could also be done to find the cause of lymph node enlargement.