Hamilton et al. for their review regarding rare causes of abdominal pain. 1 I wish to suggest four additional conditions which may cause acute abdominal pain and signs of peritonism.Addison disease may be associated with epigastric pain with vomiting, generalized abdominal rigidity, shock, and elevated lipase in the absence of acute pancreatitis (AP). 2 The diagnosis should be considered where there is a history of weight loss, fatigue, presyncope or salt craving, signs of hyperpigmentation, hypotension refractory to fluid resuscitation, or electrolyte abnormalities of hypoglycaemia, hyponatraemia or hyperkalaemia. Diagnosis is by urgent measure of serum cortisol, though parenteral glucocorticoids should be administered pending results. Delay in treatment or proceeding to exploratory surgery may be life-threatening.Glycogenic hepatopathy is an uncommon complication of poorly controlled type 1 diabetes mellitus. Affected individuals present with right upper quadrant pain, massive hepatomegaly, elevated hepatic transaminases and elevated lactate levels. 3 Affected patients commonly present with diabetic ketoacidosis (DKA), and the presence of lactic acidosis and hepatic transaminitis may lead to surgical exploration for suspected mesenteric ischaemia, or consideration of hypoxic/ischaemic liver injury.Diabetic neuropathy may affect intercostal nerve roots resulting in severe, constant, band-like upper or lower abdominal pain, associated with abdominal rigidity and guarding. 4 Thoracolumbar radiculopathy is characteristically accompanied by unexplained weight loss suggestive of underlying malignancy. Other clues to the diagnosis of radiculopathy include unilateral abdominal wall paresis, and hypoaesthesia or hyperesthesia in multiple adjacent dermatomes.Diabetic ketoacidosis is associated with acute epigastric pain in 48% of adults and 62% of children, and may mimic an acute abdomen. 5 Serum lipase more than 3 times the upper limit of normal occurs in 16%-25% of cases of DKA, without radiological changes of AP in approximately half. Mesenteric ischaemia should be considered where abdominal pain or peritonism persist despite resolution of ketoacidosis.