Toluene is an aromatic hydrocarbon found in gasoline, paint thinners, lacquers, and adhesives. Toluene is the inhalant that demonstrates the greatest toxicity when chronically. abused. Although all inhalants can cause neurotoxicity, toluene causes a pattern of cognitive dysfunction that includes apathy, poor attention and concentration, memory loss, visuospatial dysfunction and impaired complex cognition. White matter
dementia occurs. Cognitive deficits may occur after a single abuse of toluene. Cerebellar deficits include gait and leg ataxia, dysarthria, nystagmus, and tremor. Oculomotor abnormalities, deafness, hyposmia have also been reported. CNS demyelination may occur, and multiple sclerosis-like syndromes have been reported. Renal and hepatic toxicity occurs. Renal tubular acidosis may be profound. Patients present with muscle weakness and severe hypokalemia. Rhabdomyolysis and myoglobinuria may also be present. The distal tubule of the nephron is unable to secrete hydrogen ions. There is a resultant metabolic acidosis with respiratory compensation and production of alkaline urine. Hyperchloremia usually accompanies this metabolic disorder. High anion gap acidosis may develop from the accumulation of the acid metabolites, benzoic acid, and hippuric acid. Hippuric acid can be found in the urine if it is ordered.
Three constellation of symptoms are seen in adults who are chronic toluene abusers"
- Muscle weakness syndromes, ranging from generalized weakness to quadriparesis. Severe electrolyte abnormalities (hypokalemia, hypophosphatemia, acidosis)
- GI symptoms-abdominal pain, nausea vomiting, and hematemesis. These symptoms are a side effect of benzoic acid, a toluene metabolite, and gastric irritant
- Neuropsychiatric syndromes-dizziness, syncope, paresthesias, peripheral neuropathy, hallucinations, cerebellar signs, cognitive dysfunction including apathy and memory loss
Resources:
National Inhalant Prevention Coalition 1-800-269-4237 or on the web at http://www.inhalants.org.
I am interested in any questions that you would like answered in "Question of the Week." Please e-mail me with any suggestions at donna.seger@vanderbilt.edu
Donna Seger, M.D.
Medical Director, Middle Tennessee Poison Center