Unexplained Fever/Lower Abdominal Pain (Complications)

abdo_22a_n.jpg to abdo_22d_n.jpg: CT of the abdomen in a febrile schoolchild with lower abdominal pain; horizontal slices from the kidneys to the pelvis. abdo_22a_n.jpg: Large right kidney with some dilatation of the pelvis. Figure abdo_22b_n.jpg: Behind and below the right kidney a mass is visible with contrast accumulation in its wall. abdo_22c_n.jpg: The mass has a diameter of 5 by 6 cm and is adjacent to the psoas muscle. abdo_22d_n.jpg: The mass becomes smaller and locular more distally. abdo_22a_n.jpg to abdo_22d_n.jpg: The CT has been performed in this schoolchild because of unexplained fever and lower abdominal pain persisting for a while. The diagnosis is a large perityphlitic abscess due to a perforated appendicitis which has not been recognized at the beginning. The abscess membrane picks up contrast. Some of the intestinal loops containing air (black) and contrast (white) are dilated following a chronic ileus. A CT to exclude a simple acute focal appendicits is inappropriate; on the other hand, in case of suspected complicated appendicitis, such as subacute or chronic perityphlitic abscess, it is very useful. The CT also allows to exclude another cause of abdominal tumor.