Porphyria

Porphyria

Anesthetic relevance	High
Anesthetic management	Avoid prolonged fasting, prioritize post-op pain control, avoid drugs that can trigger an acute crisis
Specialty	Hematology
Signs and symptoms	Abdominal pain, neuropathies, hypertension
Diagnosis	Urine and serum testing for porphyrins
Treatment	Heme and/or glucose injection
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Porphyrias are a group of hereditary diseases that cause interruptions in heme synthesis, resulting in accumulation of porphyrins. These accumulations have adverse affects across organ systems that often make anesthetic management of these patients challenging, requiring special considerations starting in the pre-operative period. Patients with porphyrias can be categorized as having acute or non-acute porphyria, with Acute Intermittent Porphyria (AIP) being the most common type. Acute patients will require alterations in anesthetic management, while non-acute patients can be managed like patients without porphyria.

Anesthetic implications

Preoperative optimization

• Avoid prolonged fasting (>2 hours)
• Encourage clear carbohydrate fluids (i.e. gatorade) up to 2 hours before surgery
• Can also opt for dextrose infusions until surgery

Intraoperative management

• General and regional/neuraxial can be safely used
• Drugs to avoid that can precipitate acute crisis:
  • Barbiturates
  • Etomidate
  • Phenobarbital
  • Ketamine
  • Diazepam
  • Phenytoin

Postoperative management

• Ensure adequate pain control, as excessive pain can be a trigger for acute crisis

Pathophysiology

• Porphyrins are compounds important in the synthesis of heme
• Porphyria occurs when the synthesis of heme is interrupted, resulting in the accumulation of porphyrins

Signs and symptoms

Can be separated into acute vs nonacute, with non-acute primarily only having dermatologic symptoms

Acute:

• Abdominal pain
• Weakness/neuropathies
• Hypertension
• Tachyarrhythmias
• Respiratory arrest secondary to bulbar muscle weakness

Diagnosis

• Urine δ-amino levulinic acid (ALA) and porphobilinogen (PBG) levels

Treatment

Medication

• heme arginate

Prognosis

• Good when acute crisis is recognized and treated appropriately
• Few symptoms, if any, between crises

Epidemiology

• More common in females
• Typically present around ages 15-40