Urinary porphobilinogen (PBG) is elevated during the acute phase of the
neurologic porphyrias: acute intermittent porphyria (AIP), hereditary
coproporphyria (HCP), and variegate porphyria (VP). Acute attacks may produce
symptoms of cerebral dysfunction and damage (confusion, "psychiatric disease"),
autonomic neuropathy, constipation, urinary retention, tachycardia,
hypertension, and severe (sometimes chronic) abdominal pain. In the acute phase,
these disorders can be life threatening. Between attacks patients have mild
symptoms that may include psychoneuroses. Several studies indicate that
approximately 1 in 300 psychiatric patients have AIP.
The common symptoms of AIP, HCP, and VP mimic many other diseases from acute
appendicitis to acute schizophrenia. Acute episodes usually begin with or
include abdominal discomfort ranging from mild cramping to severe pain that
suggests a need for surgical intervention. These symptoms and outward signs are
common to a variety of medical problems and diagnosis usually depends on timely,
accurate laboratory testing. Frequently, surgical intervention can be avoided if
the laboratory returns an elevated level for urinary PBG.