Acute porphyrias Flashcards
What is acute porphyria?
Group of inherited enzymatic defects of heme synthesis leading to overproduction of heme precursors and intermittent symptomatic attacks
Which drugs can trigger acute porphyrias?
barbituates, ergot (methergen), metoclopramide, steroids
What are non-drug triggers for porphyrias?
dehydration, fasting, stress, infection
What do you want to ascertain from the hx of people with acute porphyria?
Hx of attacks-abdominal pain, vomiting, fever, hallucinations, mental status changes, seizures (AIP)
Drugs they take and specific things that have triggered them
What would you want to ascertain from the physical exam?
Signs of autonomic dysfxn-HTN and increased HR
Assess volume status
Neuro exam-weakness, bulbar involvement, respiratory failure
Abdominal exam often normal
What kinds of labs do you want in these pts?
electrolyes-they can have low Na, low K+, low Calcium.
How can you optimize these patients?
Carb loading suppresses the synthesis of porphyrins-start IV with D10W (or D5LR if hyponatremic)
Can you give RA to pts with porphyria?
yes, but be careful in patients with pre-existing deficits?
Maintenance of anesthesia in porphyria patients-what are you thinking?
expect labile BP (can have autonomic dysfunction).
Disposition/pain in porphyria?
Observe 24 hours for attack
If pt in porphyria crisis, then what?
remove trigger/end surgery, IV hydration with dextrose, hematin 3-4 mg/kg IV (inhibits ALA syntetase), treadt N/V with antiemetics, treat pain with opioids, beta blockers for HTN, tachy, if seizures-MIDAZ NOT PHENYTOIN, monitor electroytes and treat accordingly
Unsafe drugs in pts with porphyria:
barbituates, etomidate, ropivicaine, hydralazine, nifedipine, phenoxybenzamine, pentazocine
