The symptoms of each type of porphyria depend on the concentration of the specific porphyrin or porphyrin precursors (ALA and PBG) that are overproduced. Accumulations of ALA and possibly PBG, as in acute intermittent porphyria affect nerve endings and can cause a variety of neurovisceral symptoms and specific neurologic syndromes. The symptoms involve the nerves to the gastrointestinal tract where severe abdominal pain, often severe enough to be confused with acute appendicitis, can develop and lead to exploratory surgery. There can be emotional and psychiatric problems such as anxiety, insomnia, agitation, confusion, paranoia, depression and hallucinations, although there is little evidence to suggest that porphyria itself is a cause of any of the chronic psychiatric syndromes.
Seizures fortunately are rare, as the anticonvulsant medications commonly used to treat seizures have been known to precipitate acute attacks in some patients. Many forms of peripheral neuropathy may develop involving either the motor system causing weakness, or the sensory system causing funny feelings or loss of sensation in various areas of the body. The autonomic or involuntary nervous system can be affected leading to problems such as high blood pressure, excessive sweating, fast heart rate, and changing bowel and bladder functions including constipation and urinary retention. The serum levels of sodium and magnesium can also be diminished through involvement of the neuroendocrine system. The severity and extent of these symptoms will vary from patient to patient and from day to day, depending in part on internal or endogenous factors such as menstrual hormone cycles along with external or exogenous changes including exposure to stress, drugs, sunlight, alcohol and even fasting. Sometimes these symptoms can be identified soon after birth, but usually they do not become apparent until the patient is a teenager or young adult.
Another very important group of symptoms is related to the fact that the completed porphyrin ring structure has the ability to absorb radiant energy, usually ultraviolet light with a wavelength of about 400nm. For the most part this radiant energy is derived from exposure to bright sunlight. This energy build up within the cells can damage the subcellular structures. Certain of the porphyrins because of their structure are better able to absorb this radiant energy more than others. This process is called photosensitivity or phototoxicity and it can cause many skin abnormalities. Skin changes associated with the chronic porphyrias can include scarring, increased or decreased amounts of hair growth, thickening of the skin of the exposed areas and increased skin fragility. It differs from sunburn in that it is recurrent and usually is not associated with prolonged or intense exposure to sunlight.
Source: This information originally appeared in a booklet written for the Canadian Porphyria Foundation: A Guide to Porphyria (1991) by Dr. Barry A. Tobe, MD, Ph.D, FRCP(C), Toronto, Ontario, Canada. The content has been updated by Dr. Brian M. Gilfix, MDCM, PhD, FRCPC, DABCC, FACB on 22/03/2015.
Last Updated: 22/March/2015