Vitamins

Vitamin A Toxicity

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Vitamin A Toxicity, Hypervitaminosis A, Vitamin A Poisoning, Vitamin A Overdose

  • See Also
  1. Vitamin A
  2. Vitamin A Deficiency
  • Sources
  1. See Vitamin A
  2. Vitamin A Toxicity Sources
    1. Polar bear liver ingestion
    2. Vitamin A supplement Overdose
    3. Vitamin A Analog Overdose (e.g. Acitretin, isoretinoin)
  • Pharmacokinetics
  • Toxicity
  1. Oral Bioavailability: 80%
  2. Toxic Doses
    1. Adult: Vitamin A >1 Million IU
    2. Child: Vitamin A >300,000 IU
  3. Toxicity within hours to days of large ingestion
  4. Hepatic metabolism
  5. Excreted in feces and urine
  • Findings
  1. Gastrointestinal
    1. Nausea and Vomiting
    2. Hepatotoxicity
  2. Neurologic
    1. Pseudotumor Cerebri (intracranial Hypertension)
    2. Headache
    3. Blurred Vision
    4. Papilledema
  3. Endocrine
    1. Hypercalcemia (chronic ingestion)
  4. Skin (late finding)
    1. Skin Desquamation
    2. Alopecia
  • Labs
  1. See Unknown Ingestion
  2. Comprehensive metabolic panel (including serum Electrolytes, Serum Calcium, Liver Function Tests)
  3. Lumbar Puncture
    1. Indicated in suspected Pseudotumor Cerebri or Altered Level of Consciousness
  • Management
  1. See Unknown Ingestion
  2. Evaluate all ingestions >300,000 IU
  3. Activated Charcoal
    1. Indicated if ingestion in last 1-2 hours and patient able to control airway, Emesis
  4. Supportive care
    1. Hypercalcemia management as needed
    2. Observe symptomatic patients
  5. Intracranial Hypertension
    1. Lumbar Puncture
    2. Acetazolamide
    3. Furosemide
  • References
  1. Tomaszewski (2023) Crit Dec Emerg Med 37(12): 32