Abdominal tuberculosis usually results from spread of TB bacilli via the lymphatics from the chest. TB infection from the abdominal lymph nodes can then spread to the omentum, peritoneum, liver and other abdominal organs. These children present with the general signs of tuberculosis, i.e. fever, lethargy and weight loss. They may also have diarrhoea, abdominal pain and a distended (swollen) abdomen due to ascites or enlarged abdominal lymph nodes.
Mycobacterium bovis may also cause abdominal TB due to drinking unpasteurised milk from a cow with tuberculosis. This causes a primary TB infection of the gut. It also gives a positive Mantoux skin test.