SYB Case #3

SYB Case #367-year-old male with leukemia and abdominal distention.

Radiographic finding: PneumatosisGas in the bowel wall

A photograph of the mucosal surface of the necrotic bowel shows numerous air bubbles which have lifted the mucosa away from the muscularis

Primary pneumatosis intestinalis (15% of cases) is a benign idiopathic condition in which multiple thin-walled cysts10-100mm develop in the submucosa or subserosa of the colon.

Secondary form (85% of cases) is associated with obstructive pulmonary disease, as well as with obstructive and necrotic gastrointestinal disease. Linear or curvilinear gas collections seen parallel to the bowel wall1.Necrotic GI disease: Necrotizing enterocolitisMesenteric ischemia-Life threatening emergency 50-75% mortality Caustic ingestions 2.Nonnecrotic GI disease: Obstruction/increased intraluminal pressureInflammation/UlcerationCollagen vascular disease Abdominal trauma. ImmunosuppresionInfection3.Obstructive Pulmonary disease: Rupture of pulmonary blebs in obstructive lung disease may cause air to dissectthrough the retroperitoneum, into the mesentery, and, finally, to the bowel subserosa and submucosa.Mesenteric vascular occlusion leads to ischemic damage of the mucosa, which allows luminal gas and bacteria to invade the bowel wall. Bowel wall thickening and dilation, with or without pneumatosis, are warning signs for ischemia and infarct.

increased pressure proximal to the obstruction forces intraluminal gas into the bowel wallCrohn disease and ulcerative colitis because of a combination of mucosal ulceration, stenotic segments that increase the luminal pressure, and bacterial invasion

Immuno suppresion depletion of Peyer patches, resulting in loss of structural integrity of the bowel wall.8Signs and symptoms include diarrhea, bloody stools, abdominal pain, abdominal distention, and constipation. The physical findings are usually unremarkable.

Prognosis depends on the overall clinical picture.NEC has a mortality rate of about 30%, and as many as 50% of patients may require surgery for perforation.Pneumatosis is an ominous radiographic finding in patients suspected of having bowel ischemiasigns of perforation, peritonitis, or abdominal sepsis.

Mesenteric IschemiaDecreased intestinal blood flow results in ischemia and subsequent reperfusion damage at the cellular level that may progress to the development of mucosal injury, tissue necrosis, and metabolic acidosis.Acute (arterial embolism, thrombosis, vasoconstriction-sepsis/hypovolemia/cocaine, hypercoagulable states)Chronic (long-standing atherosclerotic disease of 2 or more mesenteric vessels, vasculitides, worse during meals)*Relatively normal abdominal examination in the face of severe abdominal pain.10