What is Porphyria ? What Are The Porphyrias ?
Acute intermittent porphyria is a particularly
severe form of porphyria which results from a deficiency
of porphobilinogen deaminase. In common with the other
acute porphyrias the clinical course is one of clinical
latency followed by an acute episode following a
precipitating event. The main clinical features of an
attack are gastrointestinal disturbance and
neuropsychiatric disorders. Acute intermittent porphyria
is an autosomal dominant deficiency in porphobilinogen
deaminase. This results in an excessive production of the
haem precursors aminolevulinic acid (ALA) and
porphobilinogen (PBG). Most individuals remain clinically
latent until a precipitating factor triggers an acute
attack. Porphobilinogen deaminase is an enzyme used in
haem synthesis; its deficiency results in acute
What are the "precipitating factors" ?
The most common precipitants are drug ingestion, alcohol
consumption, and endogenous and exogenous steroid
hormonal factors. AIP, VP and HCP may be precipitated by:
drugs, especially barbiturates, and
sulphonamides; enzyme inducing anticonvulsants,
for example carbamazepine, phenytoin,
phenobarbitone, primodone, oral contraceptive
pill; also, diphenylhydantoin, rifampicin,
chlordiazepoxide, griseofulvin and ergots.
fluctuations in female sex hormones
may also precipitate acute porphyrias
Clinical features are similar to those seen
in lead poisoning (abdominal pain, constipation or
vomiting, peripheral neuropathy, confusion or psychosis,
Medications and drugs are often the worst triggers. For a
comprehensive list of contraindicated drugs consult one
of the safe/unsafe drug lists in the Links area of this
page. Here is a list of the most commonly used unsafe
medications: alcohols, barbiturates, sulphonamides,
carbamazepine, phenytoin, rifampicin, pyrazinamide,
chlordiazepoxide, griseofulvin, ergot, imipramine,
meprobamate, lead poisoning
How common is Porphyria ?
Acute intermittent porphyria rarely presents
before puberty. Females are affected slightly more than
males; 1.5 to 2.0:1. The incidence in most parts of the
world is 1.5 per 100,000; rates in Sweden are 1 per
What are the symptoms / clinical features of AIP
Generally, the clinical features of AIP relate
to the autonomic nervous system. There are acute attacks
respiratory failure - bulbar paresis
motor neuropathy in acute
cerebellar signs may develop
hypothalamic dysfunction -
inappropriate ADH secretion
hyponatremia - from inappropriate
ADH, or GI or renal sodium loss
patients with AIP often have
psychiatric disturbances, particularly with
features of delerium - confusion, agitation,
disorientation and hallucinations
syndrome of inappropriate
antidiuretic hormone secretion
severity and frequency of attacks
varies widely between individuals
autonomic neuropathy: abdominal
pain: in 80-90% of cases; diffuse or localised;
often intermittent and spastic, constipation,
vomiting, hypertension, postural hypotension,
peripheral neuropathy, localized pain to a
complete generalised flaccid paralysis
What investigation should be done if
Porphyria is suspected?
biochemistry - hyponatraemia,
hypomagnesaemia and hypovolaemia may occur during
definitive test is porphobilinogen
deaminase in erythrocytes which is decreased by
urine - usually normal colouration
when fresh but becomes brown, red or black on
standing; marked increase in porphobilinogen
(PBG); slightly elevated coproporphyrin and
stool - coproporphyrin and
liver function tests -
increased serum cholesterol, serum
iron and T4
abnormal glucose tolerance
What is the Ehrlich Aldehyde Test ?
Ehrlich's aldehyde test is used to confirm a diagnosis of
acute intermittent porphyria. Ehlich's aldehyde reagent
consists of p-dimethyl amino benzaldehyde in acid
solution. Equal volumes of urine and Ehrlich's reagent
are mixed. If a pink colour is formed this indicates a
raised urinary concentration of either porphobilinogen or
urobilinogen. In cases of raised porphobilinogen, as in
acute intermittent porphyria, the pink precipitate is
observed to be insoluble in chloroform.
Is there a treatment for my Acute Intermittent
Currently, there is no specific treatment. Avoidance of
precipitating factors is advised. Glucose loading and
haematin infusion have some benefit but haematin may
cause transient renal insufficiency and coagulopathy.
Specific symptoms should be treated during an attack.
What does the APF say about all this?
"AIP is a rare disease that is inherited
from one parent. It is almost always latent (i.e. does
not produce illness) in childhood and is usually latent
in most adults throughout life. When the disorder is
active it can cause intermittent attacks of abdominal
pain as well as a variety of other symptoms which range
from mild to life threatening. After the correct
diagnosis of AIP is made, simple precautions can be taken
to prevent attacks. It is important to check all
relatives of porphyria patients for the genetic defect,
so they can take the same precautions and avoid becoming
ill from porphyria. Even relatives who have never had
symptoms should be tested."
So what does all this mean ?
That is an oversimpilization of our disease and
attacks, and it's intended to give you the "medical
mumbo-jumbo that might inmpress your friends or doctors
or emergency technicians. In reality, only YOU can truly
describe this illness as each case presents a variety of
symptoms that magnify in one person, and hide-away and
never to be seen in other people.
You would be doing yourself a great favor by sitting down
during one of your lucid moments and list all the
physical and mental troubles you experience due to
Porphyria. Always keep that for future use. And that is
also the day that you should start a brief journal about
Porphyria. List all your daily activities (difficulties
doing them), medications taken, what were your
limitations, what was your pain scale (and what hurt),
were you hampered from doing chores, miss
work/school/church, etc ... In other words, list
everything about your health and your Porphyria. That
will be a basis for a great Porphyria journal that you
can later share with your doctor, an insurance company,
or the SSA and it's disability board.
Keep in mind the goal of this page is to prevent
Porphyria attacks, especially those "life
threatening attacks". Hopefully you will find useful
information at this site, including the links on this
Facts you probably didn't know...
Type II does not show up in the blood serum.In other
words the PBG-deamanase which in Type I will be
diminished by 50% wil be normal in Type II and Type III.
Type III is known to have some cutaneous elements with
itching and rash of the skin.
Type II has been referred to as "pseudo"
cutaneous.....whatever that is supposed to mean.
14% without the diminished PBG_D do have skin
problems along with the CNS symptoms.