This is characterised by the presence of a Ghon focus and hilar lymphadenopathy. This develops within 4 weeks of first infection.
There are generally few, if any, symptoms.
There are usually no abnormal chest signs. However, segmental collapse due to bronchial obstruction because of enlarged hilar lymph nodes sometimes occurs.
Rarely, primary tuberculosis is associated with erythema nodosum. Healing then occurs and the tuberculin test becomes positive as a degree of immunity to the tubercle bacillus is developed. The lymphadenopathy resolves and the peripheral lung lesion becomes reduced to a small nodule which may calcify and then be a constant feature on subsequent chest radiographs.
Last reviewed 01/2018