Mothball Withdrawal Encephalopathy—Case Report and Review of Paradichlorobenzene Neurotoxicity

Paradichlorobenzene (PDB) is a common household deodorant and pesticide found in room deodorizers, toilet bowl fresheners, and some mothballs. Although human exposure to the compound is generally limited and harmless, PDB in larger doses can produce neurotoxic effects, including a chemical "high" similar to that seen with inhalants such as toluene. Although rare, frank addiction to PDB has been reported, and, in such cases, has been associated with gait ataxia, tremor, dysarthria, limb weakness, and bradyphrenia, in various combinations. In such cases, the adverse neurologic consequences have been presumed to result from a direct toxic effect of this small, organic molecule. We report a case of chronic mothball ingestion where profound encephalopathy with cognitive, pyramidal, extrapyramidal, and cerebellar features appears to have been largely the result of PDB withdrawal, rather than direct toxicity. This case raises important questions about the mechanism of PDB neurotoxicity and possible treatment options for PDB-addicted patients. We propose that in cases with clear clinical deterioration after abstinence, readministration and gradual taper of PDB might be considered a therapeutic option.

A case of serotonin syndrome and mutism associated with methadone

A patient was seen on the palliative care service at our institution who developed serotonin syndrome and mutism associated with methadone use. Serotonin syndrome is often described as a clinical triad of mental status changes, autonomic hyperactivity, and neuromuscular abnormalities, but not all of these findings are consistently present in all patients with the disorder. The incidence of the serotonin syndrome is thought to mirror the increasing number of proserotonergic agents being used in clinical practice. In 2002, the Toxic Exposure Surveillance System, which receives case descriptions from office-based practices, inpatient settings, and emergency departments, reported 26,733 incidences of exposure to selective serotonin-reuptake inhibitors (SSRIs) that caused significant toxic effects in 7349 persons and resulted in 93 deaths. Serotonin syndrome is not an idiopathic drug reaction; it is a predictable consequence of excess serotonergic agonism of central nervous system (CNS) receptors and peripheral serotonergic receptors. The myriad of symptoms with which serotonin syndrome may present is compounded by the fact that more than 85% of physicians are unaware of serotonin syndrome as a clinical diagnosis. Other SSRIs such as fluoxetine and fluvoxamine have been shown to increase methadone plasma concentrations in dependent patients. Although the exact mechanism is unknown, there are several pathways via which a significant interaction could occur. This would include the effects methadone has on N-methyl-D-aspartate (NMDA) in addition to the impact of methadone on the cytochrome P450 enzyme system. The mainstay of treatment of serotonin syndrome is withdrawal of the offending agent and supportive care. These actions resulted in resolution of our patient's symptoms. Serotonin syndrome is becoming more common, and with the utilization of polypharmacy on many palliative care services should be considered as unifying differential diagnosis in the appropriate setting.

Tacrolimus (FK506)-induced mutism after liver transplant

Tacrolimus (FK506), an immunosuppressant, has been associated with mutism in adults after liver transplant. Speech arrest, agitation, tremor, ataxia, and downward gaze deviation in a 5-year-old female 13 days after orthotopic liver transplant are reported. FK506, which began to be administered 12 days earlier, rose to a level of 44 ng/mL (normal range, 10-20 ng/mL) 1 day before neurologic abnormalities began. FK506 dose level was maintained and then reduced. Three days later the patient could say a few single words and extra-ocular movement returned to normal. Four months later, she continued to exhibit decreased fluency and dysarthria with ataxia. One year later, decreased fluency and mild ataxia persists. Rapid identification of speech loss linked to FK506 may be important because reduction or cessation of the drug may be associated with reverse of speech loss.

An unusual complication of total intravenous anesthesia: mutism

IMPLICATIONS

We report a case of mutism secondary to total IV anesthesia with propofol, as an unusual complication that we have not found in the literature.

Selective mutism and obsessive compulsive disorders associated with zonisamide

We treated 27 children with idiopathic epilepsy with zonisamide monotherapy over a period of 2 years and observed behaviour disturbances in a prospective study. In all cases, seizure control was excellent; however, two cases (7.4%) had behaviour disturbances. The first (Case 1) was a 14-year-old girl with partial epilepsy which began at age 4 years. Zonisamide was administered at age 6 years, which was effective against her seizures, but selective mutism, violent behaviour, and lack of concentration developed at age 10 years. The second (Case 2) was a 15-year-old girl with generalized tonic-clonic seizures which began at age 10 years. Zonisamide was also effective against her seizures, but obsessive compulsive disorders (OCD) developed at age 13 years. The patients have had no other physical or mental problems and decreasing the dosage of zonisamide reduced the problems. There are few reports of behaviour disturbances provoked by zonisamide monotherapy in epileptic children who are neither physically nor mentally disturbed. While problems can develop several years later, in the present study, decreasing the zonisamide dosage maintained adequate prevention of seizures and eliminated the behaviour disturbances. Zonisamide is still a useful anticonvulsant for epileptic seizures, but physicians should be wary of its adverse behavioural side effects, which may arise several years later.

Tacrolimus-associated mutism after orthotopic liver transplantation

BACKGROUND

Mutism/speech apraxia has been well documented as a toxic effect of cyclosporine after liver transplantation but has been reported only rarely with tacrolimus. Brain imaging with magnetic resonance or computed tomography has failed to demonstrate abnormalities in affected patients.

METHODS

We present the first example of an acute onset of loss of speech associated with a sudden elevation of serum tacrolimus level after successful orthotopic liver transplantation. We also describe the positron emission tomography (PET) scan of this patient's brain.

RESULTS

PET scan imaging of the brain was abnormal, demonstrating decreased metabolism in the posterior temporo-parieto-occipital regions. Statistical probability mapping revealed additional areas of hypometabolism in the cingulate gyrus.

CONCLUSIONS

PET scan revealed abnormalities of the brain in a patient with tacrolimus-induced mutism. The cingulate gyrus may play a role in the mutism/speech apraxia syndrome seen with cyclosporine/tacrolimus neurotoxicity.

Cyclosporine-associated mutism in liver transplant patients

Four liver transplant recipients treated with cyclosporine developed a reversible neurologic syndrome characterized by a speech disorder leading to mutism. This complication, previously reported in a few liver transplant recipients treated with the immunosuppressive drug FK506, had not been described with cyclosporine. Recognition of this syndrome should prompt withdrawal of the drug and avoidance of unnecessary diagnostic procedures.

Dilantin toxicity presenting as mutism following severe head injury: case report

A case is presented in which a patient was placed on phenytoin following open depressed skull fracture. He subsequently was lost to follow-up, and then presented with several complaints, among them mutism, found to be related to phenytoin toxicity. There are no reports to date of this condition being caused by phenytoin. The issue is again raised of the risk versus benefits of long-term anticonvulsant prophylaxis following severe head injury.

Unsuspected quinine intoxication presenting as acute deafness and mutism

A case of unsuspected quinine overdose is reported in a 14-year-old girl. Presenting symptoms included deafness and mutism. Diagnosis was delayed for approximately 4 hours because of the absence of an accurate history. Case details, laboratory values, and hospital course are discussed. Signs of cinchonism and common ototoxins are discussed. Strategies for the management of quinine overdose are reviewed.

Stupor and affective state: alleviation of psychomotor disturbances by lorazepam and recurrence of symptoms after Ro 15-1788

In a single patient suffering from a major depressive episode with melancholia (DSM-III), both severe psychomotor symptoms, such as stupor and mutism, and mood disturbances could be abolished completely and promptly by administration of the benzodiazepine lorazepam. Remission of symptoms was entirely and immediately reversed by the benzodiazepine antagonist Ro 15-1788. These drug effects were constantly reproducible. Possible mechanisms of action and the influence of GABAergic neurotransmission on affective and psychomotor state are discussed.

Unusual neurological complications of lumbar myelography with dimeglumine iocarmate (Dimer X)

In this report two unusual and serious neurological complications of dimeglumine iocarmate (Dimer X) myelography is presented. One patient became paraplegic six hours after myelography, and the other was mute for 24 hours after having generalised convulsions. The reasons are discussed.

Metrizamide myelography risk factors: a pseudopsychiatric case presentation

A case of neurologic sequelae from intrathecal metrizamide is presented. The patient had a convulsion, became comatose, and transiently developed mutism and hemiparesis, with eventual full recovery. Metrizamide is generally safe, but side effects do occur, and they may require clinical attention and follow-up.

Mutism induced by phenothiazines

The purpose of this communication is to present a group of patients who, while receiving treatment with one of the phenothiazine derivatives in average range of doses regarded as suitable for adults, developed a syndrome comprising mutism and a number of other neurological features. In the majority of these patients speech loss is almost complete; but, unlike aphasics, they may respond to repeated questioning by simple utterances usually spoken in a whisper, or else are capable on rare occasions, quite unexpectedly, of delivering remarks which are appropriate and may be spoken normally. Speech deprivation is as a rule associated with an inability to communicate either by gestures or writing and also an inability to perform many customary tasks. Mutism is, therefore, not an isolated disability, but is associated with a wide range of disturbances of behaviour and of level of consciousness. In addition, some of the patients exhibit one or more of the neurological toxic phenomena encountered in the course of medication with phenothiazine derivatives, e.g. akathisia, buccal dyskinesias, dystonias, tremor and parkinsonism.