Toxic leukoencephalopathy is a rare condition that is characterized by progressive damage (-pathy) to white matter (-leuko-) in the brain (-encephalo-), particularly myelin, due to causes such as exposure to substance use, environmental toxins, or chemotherapeutic drugs.
[citation needed] Common initial symptoms include confusion, somnolence, generalized seizures, headaches, and vision impairment.
[1] The intermediate stage includes pyramidal tract and pseudobulbar signs, spastic paresis, myoclonic jerks, and choreoathetoid movements.
The final or terminal stage is characterized by stretching spasms, akinetic mutism, hypotonic paresis, central pyrexia, and death.
[7] Symptoms of leukoencephalopathy caused by overdose of metronidazole medication include dysarthria, gait disturbance, weakness of extremities, and mental confusion.
The most common causes are substance use and chemotherapy; however, the disease has also occurred on the rare occasion as a side effect of certain medications and environmental toxins.
Leukoencephalopathy caused by inhalation of heroin,[13] also known as "chasing the dragon" syndrome,[6] is one of the most studied of these rare occurrences and has even been recognized for over twenty five years.
Cases include a 65-year-old woman who had mistakenly been taking three times the dose of methadone that had been prescribed for pain management, and a young girl intoxicated with pure morphine sulfate tablets.
[citation needed] Metronidazole, an antibiotic used to treat anaerobic and protozoal infections, has been known at high doses to produce neurologic symptoms associated with toxic leukoencephalopathy.
MRI can aid in the detection of injured brain tissue; however, the severity and extent of the damage demonstrated by imaging does not always reflect patient clinical status.
[1] Toxic leukoencephalopathy-related damage to central nervous system (CNS) white matter, typically of the periventricular nucleus, and other structures in the brain is often bilateral and symmetric.
[4][5][8] Depending on the source of toxicity or pharmacological substance and severity of the white matter damage, many patients can have complete clinical recovery.