osmolar

This discrepancy (commonly called an osmolar gap) suggests the presence of an unmeasured low molecular-weight solute with osmolar properties.

This revealed an osmolar gap of 106mOsm/kg [H.sub.2]O, and anion gap was calculated to 41 mmol/L (Table 1).

Furthermore, we calculate the urine osmolar gap (UOG) using the following formula:

Arterial gasometry showed systemic metabolic acidosis (pH, 7.08; pCO2 28; HCO3, 7.6; BE-27) with high anion gap and high osmolar gap (40 mEq/L).

Ethylene glycol (EG) overdose (514mg/dL in this case) is consistent with metabolic acidosis, an increased serum anion and osmolar gap, decreased serum calcium, urinary oxalate crystals, and acute renal and respiratory failure (1).

Large amount of methanol ingestion can result in seizures, stupor, coma and sometimes death.3 The diagnosis is based on the presence of severe metabolic acidosis with high anion and osmolar gap and high serum methanol levels.3 Neuroradiological findings in methanol poisoning have occasionally been described in the literature.

Common features suggesting methanol poisoning are a suitable history, increased anion gap and increased osmolar gap (2,3).

(2) Many hospitals are unable to perform EG and MTH measurements in a timely fashion; which in this case, a combination of a metabolic acidosis associated with a high anion gap and osmolar gap is considered the hallmark of toxic alcohol intoxication.

After speaking with the resident, I explained to her that classic methanol toxicity presentation includes a high anion gap metabolic acidosis with an elevated osmolar gap. The measured serum osmolality was 289 mOsm/kg.

In humans, the presence of a toxic compound may be suspected indirectly by the demonstration of an osmolar gap between the measured and calculated plasma osmolality.

The difference between the measured and calculated osmolality is called the osmolar gap and can be clinically useful to assess certain toxicities.

Serum electrolytes and osmolality can be measured, and the anion and osmolar gaps can be calculated.