Makindo Medical Notes

CT scan abdomen is the gold standard and more sensitive than plain films so should be considered where there is a suspected perforation. Findings may be masked in pts who are elderly or chronically immunosuppressed

About

• Perforation of gas and bacteria-containing GI tract at any point from the upper oesophagus to the anus
• Gas will rise and be seen trapped under the diaphragm in erect CXR
• Perforation of hollow viscus also leads to intraluminal spillage

Aetiology

• Perforation of gas containing GI tract at any point from the upper oesophagus to the anus
• It should be a diagnosis considered in all patients with an acute abdomen.
• Bowel contains air and fecal materials
• Free air means overwhelming bacterial peritonitis and sepsis

Free air

Causes

• Oesophagus: Ingested chemical or physical substance causing perforation, oesophageal biopsy or dilation, severe vomiting (Boerhaave Syndrome), oesophageal tumour , Perforating chest trauma
• Gastric: Ulcer disease and chemical erosion. Perforating abdominal trauma
• Small bowel: ischaemic and erosion, Fistula formation (e.g. Crohn's Disease), Perforating abdominal trauma
• Large bowel: Fistula formation (e.g. Crohn's Disease), Toxic Megacolon (e.g. Clostridioides difficile or Ulcerative Colitis), Procedure - polypectomy, Perforating abdominal trauma

Clinical: Findings masked in elderly or chronically immunosuppressed

• Acute onset, severe abdominal pain, worse w/ movement
• May be seen with bowel obstruction, diverticulitis, cancer, or other primary GI pathology
• Generalised abdominal pain. Rigidity, tap tenderness, rebound,
• Hard Rigid board like abdomen, lack of bowel sounds
• Fever, hypotension, tachycardia

Differentials

• Acute pancreatitis
• Myocardial infarction
• Tubo-ovarian pathology
• Ruptured aortic aneurysm.

Investigations

• FBC, U&E, LFTs, Amylase: raised WCC/CRP
• CXR/AXR: Free air under diaphragm. Rigler sign air on both sides of the bowel wall can be seen, due to free intra-abdominal air acting as an additional contrast. Psoas sign loss of the sharp delineation of the psoas muscle border, secondary to fluid in the retroperitoneum.
• A contrast swallow is also useful for confirming any suspected oesophageal perforation.
• CT scan abdomen is the gold standard

Management

• Nil by mouth. ABC, Resuscitation, IV fluids, Antibiotics, Analgesia. ITU.
• Immediate surgical consult: Surgical repair or resection of the mucosal defect as needed - in somewhere the patient is well and perforation contained then conservative care may be appropriate
• Broad spectrum antibiotics to cover polymicrobial infection