Methanol Poisoning Physiotherapy

Clinical Features of Methanol Poisoning

In this article we will discuss the Clinical Features of Methanol Poisoning.

In this article, we will discuss the Clinical Features of Methanol Poisoning. So, let’s get started.

Clinical Features

The clinical features depend on the amount ingested. The time of onset of symptoms and signs after ingestion us variable and features are late in onset when ethanol is ingested concurrently. Hence, all patients of suspected methanol poisoning should be closely observed for an extended period of time before discharge. The early manifestations are caused by methanol itself; while late features are produced by its toxic metabolites (formaldehyde and formic acid). Shortly after the ingestion, patients usually appear drunk. The clinical features are given below:

1. At Low Concentration (>20 mg/dl)


  • Nausea, vomiting, and abdominal pain
  • Headache, vertigo, dizziness
  • Ethanol-like intoxication

Late (after 24 hours)

  • Seizures
  • Severe metabolic acidosis
  • An increased osmolal gap (>10 mOsm/L)

2. At high concentration (>40 mg/dl)


  • Alteration in consciousness
  • Convulsions
  • Coma
  • Metabolic acidosis
  • An increased osmolal gap (>5 mOsm/L)

Late (after 24 hours)

  • Visual disturbances, e.g. clouding and diminished vision, dancing and flashing spots, fixed or dilated pupils, disc hyperemia and blindness due to retinal injury
  • Coma
  • Severe intoxication may produce myocardial depression, bradycardia, shock, etc.
  • Death may occur.

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