A family of uncommon genetic disorders associated w/abnormalities in heme biosynthesis in the liver
Dysfunctional or lower than normal levels of enzyme → accumulation of precursor proteins
Different symptoms/presentations based on which enzymes deficient → build up of different precursor proteins
AIP is most common of the acute porphyrias
Interestingly, most patients w/the genetic defect don't manifest the disease - indicating that other factors contribute
Risk Factors
90% women
Age 18-45
Attacks triggered by meds (multiple, in particular anti-seizure), starvation/decreased caloric intake (low carbs), smoking, etoh, infections
+ family history
Symptoms
Seizure in 20%
Episodic bouts of otherwise unexplained symptoms related to neuro-toxicity of built up precursor protein; some report chronic baseline pain
Anxiety and insomnia often precursor sx prior to attack
During attack, symptoms include: severe abd pain, constipation, agitation/confusion, nausea, vomiting, fatigue, limb pain, motor and sensory neuropathy
Sometimes purple colored urine
Often history of prior unexplained episodes, leading to concern about malingering or drug seeking
Duration of symptoms (typically < 1-2w) and time between attacks vary
Neurological deficits (e.g. foot or wrist drop) resolve w/time (up to 1y)
Physical Exam Findings
Episodic htn, tachycardia
Generalized muscle weakness
Abdominal pain w/normal exam
Sensory loss and/or motor weakness that follows peripheral nerve pattern
Tests
Often hyponatremia that isn't otherwise explained
Elevated urine porphobilinogen, in particular during an attack