Orobuccolingual Dyskinesia: A Rare Complication Following Gas Geyser Encephalopathy.

Liquefied Petroleum Gas (LPG) geysers are often used as a cheaper and more regular source of energy in place of the expensive and erratic electrical supply in many parts of India. However, the carbon monoxide released as a byproduct can be a source of significant neurologic toxicity, especially in ill-ventilated surroundings.

This simple economical device in many Indian households may cause significantly disabling neurological events [Table 1].[1] The most severe effects are seen in organs with high basal oxygen consumption such as the heart and brain.[2] Carbon monoxide (CO) poisoning should always be considered when a comatose person is found in a confined area with poor ventilation, and the correct diagnosis is confirmed by blood carboxyhemoglobin (COHb) estimation.[3]

Table 1

Neurological manifestations of CO poisoning[123467]

Acute
	Degree of COHb in blood	Manifestations
1	<20%	Asymptomatic, headaches
2	21%-40%	Headache, drowsiness, impaired judgement, blurred vision, dizziness
3	>41%	Severe headaches, marked drowsiness, increasing confusion, worsening vision, seizures; unconsciousness and death if exposure continues
Delayed
	Encephalopathy	Cognition only Cognition and behavior involved Disturbed communication
	Behavioral disorders	Depression, psychosis
	Movement disorders	Parkinsonism
		Akinetic mute state Dystonia Chorea Myoclonus
	Seizures	New-onset seizures Aggravation in a known case of seizure disorder
	Combinations of above

A 37-year-old right-handed man was residing in a shared apartment in Agra, a city in north India, having a gas geyser for water heating. One day while bathing, he did not emerge out of the bathroom for over 25 min (longer than his usual 15 min bath). When he did not respond to their calls, the roommates broke open the door to find him unresponsive lying on the floor of the bathroom. There was no frothing, tongue bite, or jerks. He was rushed to the nearest hospital where he regained sensorium approximately 20 min from the time of being first found unresponsive. His blood counts and metabolic profile were normal. He gradually recovered a normal sensorium over next few hours. A magnetic resonance imaging (MRI) done 3 days later showed bilateral symmetrical hyperintense signals in the hippocampus, lentiform nucleus, and cerebellum with restricted diffusion [Figure 1]. His acute phase recovery was good and he was discharged without any cardiac or respiratory problems and was put on prophylactic antiepileptic medication (levetiracetam 500 mg twice daily). Since then he had short-term memory loss, which was persistent even 6 months after the event. He also developed orobuccolingual dyskinesias 2 months from the event. There was no history of consuming any medications known to cause drug-induced orobuccolingual dyskinesias.

Figure 1

T2 weighted MRI scan showing T2 hyperintensity in bilateral globus pallidus internus without any signal change on T1 weighted MRI scans. The DWI Image shows a corresponding restricted diffusion in bilateral pallidus internus

We saw him for the first time 6 months after the initial carbon monoxide poisoning. At that time, his Mini-Mental State Examination score was 27/30 (lost 2 points on orientation to time and 1 point on delayed recall). His detailed memory testing was particularly remarkable for poor performance on immediate verbal and visual recall. He spoke with a normal speech interrupted often by the orobuccolingual dyskinesias. Cranial nerve, motor, sensory, and cerebellar system examinations were normal. His routine blood workup including thyroid panel and Vit-B12 levels were normal. His electroencephalogram was unremarkable. At 1-year follow-up from the carbon monoxide poisoning, the orolingual dyskinesias had responded well to a combination of tetrabenazine and amantadine. However, the cognitive disability persisted making it untenable for him to continue in the workforce.

CO is a colorless, odorless toxic gas formed due to incomplete combustion. Sources include smoke from fires, misuse of nonelectric cooking and heating devices burning fuel, and snow-obstructed exhaust system of motor vehicles. The clinical presentation is nonspecific and may range from nausea, headache, dizziness, confusion to profound central nervous system dysfunction and even death.[4] Clinical suspicion of CO poisoning may be corroborated by obtaining blood carboxyhemoglobin levels from the blood. Poisoning is considered at carboxyhemoglobin levels of over 10%, and severe poisoning may be associated with levels over 20%–25%. Heavy smokers, however, are known to have higher baseline values.[5] After the disappearance of initial symptoms, delayed neurological symptoms may develop in 2 to 40 days in up to 40% of the survivors of acute CO poisoning.[2]

The patient described here recovered from the acute event, but had short-term memory loss. He did not have seizures or parkinsonian features, which are the more commonly noted delayed central nervous system manifestations. He presented with orobuccolingual dykinesias after 2 months from the exposure. Orobuccolingual dyskinesia has not been described commonly as a delayed neurologic sequel to CO poisoning.

Lee and Marsden in a series of 31 patients with sequel of CO poisoning described patients with parkinsonism or further progressing to an akinetic mute state. No dyskinesias were reported.[6]

Choi and Cheon described 242 patients with CO poisoning between 1986 and 1996. Delayed movement disorders were diagnosed in 32 patients (13.2%). Parkinsonism was seen in 23 (71.9%), dystonia in five, chorea in three, and myoclonus in one.[7]

Of the 26 cases of gas geyser syndrome from north India, six developed delayed neurological sequel, four had subtle cognitive defects, and two developed early parkinsonian features.[1]

Globus pallidus lesions as in this case as well as diffuse white matter lesions have been most often described in patients with CO poisoning.[89] Globus pallidus lesions in many cases do not correlate directly to clinical status and outcome; however, the presence of diffuse white matter disease is a more reliable index of both and also a predictor of a chronic sequel.[89] Radiologically, CO poisoning predominantly involves the globus pallidus while hypoxic-ischemic encephalopathy predominantly involves cortical gray matter followed by basal ganglia depending upon the severity of hypoxic damage.

In MRI, changes in the rest of the basal ganglia, hippocampus, white matter, cerebral cortex, and cerebellum have also been reported in a study of 19 cases by O’Donnell et al. Normal appearances were seen on the initial MRI in seven patients.[10]

In conclusion, orobuccolingual dyskinesias are a rare delayed manifestation (probably the first reported case to the best of our knowledge) of carbon monoxide poisoning secondary to gas geyser syndrome.

Legend to the video: The video of the patient demonstrates orolabial dyskinesias aggravated while talking and while performing tasks with other parts of the body.

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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

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