Laboratory Studies
Indicated laboratory tests and findings in toluene toxicity include the following:
-
Arterial blood gas (ABG) measurements – Acidosis, hypoxemia, and hypercarbia
-
Complete blood cell count (CBC) with differential and peripheral blood smear – Anemia, leukocytosis, and abnormalities of blood elements
-
Serum electrolytes – Hypokalemia, hyperchloremia, metabolic acidosis, hypocalcemia, and hypophosphatemia
-
Liver enzymes and bilirubin levels – Hepatotoxicity, which may cause jaundice, hepatitis, and liver failure
-
Serum glucose – Hypoglycemia must be ruled out as a cause of decreased mental status
-
Blood urea nitrogen (BUN) and creatinine levels – May indicate acute kidney injury
-
Urine or serum creatine kinase (CK) and myoglobin measurements – Rhabdomyolysis from toluene-induced muscle damage may contribute to renal failure
-
Urine electrolytes – to identify a type I renal tubular acidosis, if a non-anion gap metabolic acidosis is present
Serum toluene concentrations are available only through specialized laboratories and are not available quickly enough to guide therapy. [18] Blood toluene concentrations of 2.5 mg/L correlate with toxicity. Concentrations of 50 mg/L are probably fatal.
Perform toxicological screens to test for alcohol and cocaine, because alcohol can cause mental status changes similar to those from toluene and can increase serum toluene levels and decrease its metabolism, while cocaine may precipitate cardiac dysrhythmias
Imaging Studies
A chest radiograph may show aspiration pneumonitis or acute lung injury.
In patients with chronic exposure to toluene, a CT scan of the head may show cerebral cortex and cerebellar atrophy with brainstem atrophy in severe cases.
In patients with chronic exposure, an MRI may reveal cerebral cortex, cerebellar, and brainstem atrophy with sulcal widening and ventricular dilation. Increased periventricular white matter and loss of differentiation of gray and white matter may also be observed.
Technetium Tc 99m radionucleotide scan of the liver may show a rare form of hepatotoxicity secondary to toluene exposure. In hepatic reticuloendothelial failure (HREF), a decreased uptake of the radionucleotide suggesting impaired liver function occurs. [4]
Electrocardiography
The ECG is an essential test because toluene-induced dysrhythmias, including torsades de points and ventricular fibrillation, often are responsible for the sudden death associated with poisoning. Most ECG show nonspecific changes to the ST segment and depressed T waves, but patients with QT prolongation are at particular risk for dysrhythmia. [19]
Cardiac monitoring of patients should be continuous during observation so that any dysrhythmias may be detected promptly.
