Left-sided appendicitis

Clinical History

A 58-year-old male patient presented with left iliac fossa pain, low grade temperature and elevated inflammatory markers. A differential diagnosis of diverticulitis, diverticular abscess or locally perforated colonic neoplasm was made and the patient proceeded to cross sectional imaging with computed tomography.

Imaging Findings

A 58-year-old male patient presented with a 2 day history of left iliac fossa pain. On examination, the patient was haemodynamically stable with a low grade temperature of 37.5 degrees. He was tender in the left iliac fossa with guarding but no rigidity. His inflammatory markers were mildly elevated with a white cell count of 12. Laboratory investigations were otherwise unremarkable. Chest X-ray was normal with no evidence of perforation. Plain film of abdomen demonstrated a paucity of bowel gas on the right side of the abdomen but was otherwise unremarkable with no evidence of obstruction or perforation (Fig . 1). A clinical diagnosis of diverticulitis was made and a CT abdomen and pelvis post oral and intravenous contrast was performed to exclude complications or underlying neoplasm. CT demonstrated imaging findings consistent with congenital malrotation of the colon with the large bowel occupying the left side of the abdomen (Fig. 2 a and b). The caecum was positioned in the left flank. The appendix was dilated with associated inflammatory changes in the mesentery (Fig. 3 a and b). Imaging features were consistent with an acute appendicitis. There was no evidence of diverticulitis, perforation or abscess formation. The patient was admitted under the surgical services and proceeded to appendicectomy which confirmed the diagnosis. He made a full and uncomplicated clinical recovery. Other imaging features of malrotation included reversal of the SMV/SMA relationship and abnormal location of the duodenal -jeunal flexure to the right of the vertebral column (Fig. 4a and b).

Discussion

Left sided appendicitis can occur in the context of two congenital bowel abnormalities, situs inversus and malrotation. The imaging findings locally round the appendix are similar to right sided appendicitis, with dilation of the appendix (>6mm) and inflammatory changes in the mesentery with or without the presence of an appendicoloith, local abscess or perforation (1). Malrotation of the bowel is caused by arrest of gut rotation and fixation during embryological development when the developing bowel returns to the abdominal cavity. There is a spectrum of abnormalities including non-rotation (true malrotation), incomplete rotation and reversed rotation (2,3). Most patients (75%) present during the first year of life with symptoms of obstruction or an acute abdomen. The presence of Ladds bands and a short small bowel mesentery put these patients at high risk of volvulus which may occur at any age, but tends to occur earlier in life. The Ladds bands may also cause obstruction. In undiagnosed malrotation, the disruption of normal anatomy may also complicate clinical diagnosis as demonstrated in this case where appendicitis presented as left iliac fossa pain, mimicking acute diverticulits (4,5). Diagnostic cluesof malrotation on plain film of abdomen include abnormal bowel gas distribution with small bowel occupying the right side of the abdomen and colon on the left. The diagnosis can be suggested in children by ultrasound demonstrating inversion of the normal SMV/SMA relationship, however this finding is not entirely sensitive or specific (Fig. 4a). The diagnosis can be confidently made by fluoroscopic barium studies demonstrating small bowel on the right and colon on the left of the abdomen. The duodenal - jejunal flexure lies low and immediately over or to the right of the vertebral column (normal position to the left) (Fig. 4b). Contrast may end abruptly in a characteristic corkscrew pattern at this level due to the presence of mesenteric bands. Malrotation tends to be seen as an incidental finding on computed tomography imaging, but demonstrates similar imaging features (6). There are a number of associated anomalies, including pancreatic aplasia or hypoplasia of the uncinate process of the pancreas most commonly (Fig. 5). There is an increased incidence of gut abnormalities including omphalocaele, gastrochisis, duodenal stenosis and Hirschprung's disease. Asplenia/polysplenia syndromes and inferior vena cava abnormalities are also seen more commonly.

Differential Diagnosis List

Final Diagnosis

Malrotation of colon with acute left sided appendicitis.

URL:	https://www.eurorad.org/case/6518
DOI:	10.1594/EURORAD/CASE.6518
ISSN:	1563-4086