PERITONITIS

PERITONITIS

Peritonitis is inflammation of the peritoneum and can be cate gorised as localised or di ff use, acute or chronic or according to the primary underlying pathology . In the clinical setting, the most useful categorisation of peritonitis is based on whether it is localised or di ff use. Summary box 65.2 Causes of peritoneal inflammation /uni25CF /uni25CF - /uni25CF /uni25CF /uni25CF /uni25CF - Summary box 65.3 Paths to peritoneal infection /uni25CF /uni25CF - /uni25CF /uni25CF /uni25CF

Ascending Right colon mesocolon Fascia in retroperitoneal space Divided re /f_l ection (d) Mesoileum Fascia in retroperitoneal space Peritoneal re /f_l ection Mesenteric principles of gastrointestinal surgery: basic and applied Bacterial, gastrointestinal and non-gastrointestinal Chemical, e.g. bile, barium Allergic, e.g. starch peritonitis Traumatic, e.g. operative handling Ischaemia, e.g. strangulated bowel, vascular occlusion Miscellaneous, e.g. familial Mediterranean fever Gastrointestinal perforation, e.g. perforated ulcer, appendix, diverticulum Transmural translocation (no perforation), e.g. pancreatitis, ischaemic bowel, primary bacterial peritonitis Exogenous contamination, e.g. drains, open surgery, trauma, peritoneal dialysis Female genital tract infection, e.g. pelvic in /f_l ammatory disease Haematogenous spread (rare), e.g. septicaemia

This is where a localised area of the peritoneum has become inflamed. If the parietal peritoneum is involved, the patient complains of pain (somatic pain) in the area a ff ected. Vital signs may be normal, but tachycardia and pyrexia are common. The characteristic signs are involuntary guarding (reflex abdominal wall contraction to reduce further peritoneal irritation) and rebound tenderness (worsening of pain on lifting the examin ing hand o ff the abdominal wall). Collectively these signs and symptoms are termed peritonism and the patient is described as peritonitic (see Chapter 63 ). If inflammation arises under the diaphragm, shoulder tip (‘phrenic’) pain may be felt. This is referred pain to the C5 dermatome. In cases of pelvic peritonitis, e.g. from an inflamed appendix or salpingitis, abdominal signs may be limited; dee seated tenderness may be detected by digital rectal or vagi nal examination. Signs may be limited in obese patients or in patients on immunosuppressive medications. The aim is to diagnose the underlying cause and guide treatment. Diagnosis of the underlying condition is made through a combination of history and physical examina supplemented by laboratory and radiological investigations Laboratory biomarkers will support a diagnosis of acute inflammation, but are rarely diagnostically specific. The inves tigation of choice is computed tomography (CT) scanning. Modalities such as ultrasound can be used but lack specificity except in the case of tubo-ovarian pathology (see Chapter 87 Laparoscopy may be required if the above investigations are inconclusive. The aims of treatment are to remove the underlying cause and to lavage or dilute residual contamination. At surgery the inflamed peritoneum appears reddened, thickened and has a velvety texture. Plaques of yellow/white fibrin may be appar ent, causing loops of intestine (and mesentery) to adhere to themselves and to the parietes. There is a reactionary , serous exudate (rich in leukocytes and plasma proteins) that gradually becomes turbid in appearance. The fluid may transfor frank pus if not evacuated.