Large bowel distention is more peripheral. Slide 11 Recognizing signs of peritonitis is important. While guarding and rigidity are classical signs, the well described rebound tenderness, I feel, should not be elicited. It is unkind to the patient. Subtle signs of peritoneal irritation like percussion tenderness and localized pain on stretching muscle by bending forward or elevating both lower limbs together, are quite diagnostic.
Investigations are an important part of the workup of a patient.
Anaemia may be seen in cases like a bleeding ulcer, leaking aneurysm and a neoplasm with obstruction or perforation. White cell count will be high in infections. A random sugar and urea and creatinine are screening tests. Serum amylase above twice the upper limit of normal denotes pancreatitis. Several other conditions like perforated duodenal ulcer, intestinal ischaemia, salivary gland inflammation and macro-amylasaemia can also cause an elevation in amylase.