Consider<unk>  in patients with abdominal pain that is unexplained after an initial workup has excluded common causes (appendicitis, cholecystitis, pancreatitis, etc).
Spot urinary porphobilinogen (sendout at most hospitals)
Normal = 0-4mg/day
acute attack, spot urine can be 20-200mg/L
Recurrent attacks in a patient with proven acute<unk>  are usually similar and can be diagnosed on clinical grounds without biochemical reconfirmation.
Hyponatremia has been documented in up to 60% of acute attacks & is attributed to elevated levels of antidiuretic hormone
Normal = 0-4mg/day
acute attack, spot urine can be 20-200mg/L
Porphyria
Abdominal aortic aneurysm
Scurvy
Aortocaval fistula
Rickets
Acute gastroenteritis
Pruritus ani
Aortoenteric fisulta