Anesthesia Considerations 

Porphyria

 

 

 

Considerations

 

• Risk of perioperative porphyric crisis

• The need to avoid certain anesthetic drugs, including: 

  • Barbiturates/etomidate 

  • Ropivacaine (caution in regional anesthesia), lidocaine & bupivacaine are OK  

  • Ketorolac 

  • Anti-seizure medications: phenytoin, barbiturates

• Acute intermittent porphyria (AIP) attacks last days to weeks & are multi-systemic: 

  • Risk of aspiration (bulbar dysfunction)

  • CNS: seizures, peripheral neuropathy, quadriplegia, altered LOC

  • Respiratory: respiratory failure from respiratory muscle weakness

  • Cardiovascular: autonomic instability, tachycardia, hypertension 

  • Electrolyte imbalances: especially hyponatremia but also hypomagnesemia and hypokalemia

  • GI: severe abdominal pain 

  • Psych: anxiety, restlessness, agitation, hallucinations, hysteria, disorientation, delirium, apathy, depression, phobias and altered consciousness, ranging from somnolence to coma

• Chronic effects:

  • Usually symptom-free between attacks 

  • But, some have persistent hypertension & develop kidney disease, chronic pain, depression/anxiety/suicidality 

 

Goals

 

• Minimize risk of aspiration 

• Optimization:

  • Ensure consultation with hematology before procedure 

  • Avoid prolonged fasting

  • Give pre-operative glucose load (e.g., maintain on D10NS IV prior to surgery) 

  • Correct anemia

  • Manage pain & anxiety

• Avoid triggers of porphyric crisis:

  • Drugs: sodium thiopental, etomidate, chlordiazepoxide, ropivacaine, diazepam, steroids, ergots, ketorolac and diclofenac, cephalosporins, sulphonamides

  • Physiologic: fasting/hypoglycemia, anemia, stress, estrogen, progesterone, infection

  • Substance abuse: alcohol, smoking, marijuana, cocaine, ecstasy, amphetamines

• Prepare to treat crisis:

  • Hydration, glucose, electrolyte replacement, analgesia, hematin, cimetidine, somatostatin, plasmapheresis

  • Seizures: use midazolam, propofol 

 

Complications

 

• Aspiration

• Muscle weakness, neuropathy, paraplegia:

  • Postoperative ventilation requirements 

  • Confusion with respect to neuropraxia and complications after regional

• Acute porphyric crisis:

  • Symptoms:

    • CNS: changes, seizures, sensory loss, pain, quadriplegia, upper motor neuron signs, cranial nerve lesions

    • Cardiovascular: autonomic instability (tachycardia, hypertension, hypotension)

    • Respiratory: respiratory paralysis/failure

    • GI: abdominal pain, vomiting, constipation, diarrhea

• Treatment: 

  • Eliminate drug/triggering factor

  • Hydration

  • Glucose 20g/hr infusion (D10W)

  • Hematin 3-4 mg/kg IV over 20 min (specific therapy) 

  • Beta blockers for hypertension/tachycardia

  • Octreotide

  • Analgesia

  • Propofol and midazolam for seizures  

• Seizure attack:

  • Use propofol, benzodiazepenes

  • AVOID phenytoin, barbiturates 

 

Porphyria in pregnancy

 

• No evidence to choose between general anesthesia vs. neuraxial technique

• Epidural definitely OK 

• Propofol/succinylcholine OK for RSI 

• Ergotamine is CONTRAINDICATED!  Use oxytocin, hemabate for postpartum hemorrhage 

 

Some key drugs to avoid

 

• Barbiturates 

• Etomidate

• Ergotamine  

• Antiepileptics (phenytoin) 

• Corticosteroids 

• Hydralazine