Delayed Leukoencephalopathy after Acute Carbon Monoxide Intoxication in a Married Couple

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pISSN: 1229-6538 eISSN: 2383-5699 Korean J Clin Geri 2018;19(2):101-104 https://doi.org/10.15656/kjcg.2018.19.2.101

CASE REPORT

Received August 20, 2018; revised October 1, 2018; accepted October 27, 2018.

Corresponding author: In-Uk Song, Department of Neurology, Incheon St. Mary’s Hospital, The Catholic University of Korea, 56 Dongsu-ro, Bupyeong-gu, Incheon 21431, Korea. E-mail: [email protected]

This is an open access article distributed under the term s of the Creative Com m ons Attribution Non-Com m ercial License (http://creativecom m ons.org/licenses/by-nc/4.0) which perm its unrestricted non-com m ercial use, distribution, and reproduction in any m edium , provided the original work is properly cited.

Delayed Leukoencephalopathy after Acute Carbon Monoxide Intoxication in a Married Couple

Seunghee Na

¹

, Jooyeon Im

²

, Young-Je Heo

¹

, In-Uk Song

¹

1

Departments of Neurology, Incheon St. Mary’s Hospital, The Catholic University of Korea;

²

Departments of Radiology, Incheon St.

Mary’s Hospital, The Catholic University of Korea, Incheon, Korea

Carbon monoxide intoxication often causes immediate neurologic deterioration and delayed neurologic sequelae after several weeks from the onset of anoxic event. A 65-year-old woman visited the emergency department with the lack of ability to move or speak for the past two weeks. Brain imaging test identified lesions in the bilateral basal gangli and extensive white matter lesions. Brain imaging findings of her spouse shared the similar findings of the patient. The patient and her spouse reported that both used to sleep in the self-made loess-sedimentary deposit-interior room. One day in the morning, her spouse found the patient with loss of consciousness in this room. When exhaust systems in loess interior spaces do not perform appropriately, amounts of carbon monoxide exceed the safe threshold and lead to an intoxication or near lethal range even in a short period of time such as less than 24 hours since exposure. Timely hyperbaric oxygen therapy can reduce the risk of delayed neurologic sequelae. Any physicians caring older adults with acute loss of consciousness should consider the possibility of carbon monoxide poisoning when witness or caregivers provide loess interior spaces as their living environment, especially, in rural areas.

Key Words: Akinetic mutism, Carbon monoxide poisoning, Complications

INTRODUCTION

Delayed neurologic sequelae (DNS) is shown to develop after 1 or 3 weeks from the onset of anoxic exposure such as carbon monoxide intoxication [1,2]. DNS includes predom- inant extrapyramidal symptoms, abulia, and various cognitive and affective symptoms [2,3].

There are several reversible causes to induce dementia, such as vitamin deficiency, thyroid disease, exposure to toxins, and carbon monoxide intoxication. Therefore, it is essential that both a surveillance for reversible causes at the step for the diagnosis of dementia and an appropriate prevention of that causes. Carbon monoxide intoxication can be caused by

inhalation from fire, camping, or suicide using coal briquette.

About 12∼46% of patients with acute carbon monoxide in- toxication eventually develop DNS [1,4]. Thus, physicians treating patients with carbon monoxide intoxication usually warn them and caregivers about the development of DNS af- ter the urgent treatment and recommend medical follow-up [2]. Moreover, if the information of exposure to carbon mon- oxide is missing, the patient with DNS can be diagnosed as a kind of rapidly progressive dementia.

Patients with DNS usually show a characteristic pattern on brain imaging, although it is not a pathognomonic finding.

At the stage of acute carbon monoxide poisoning, brain mag-

netic resonance imaging (MRI) usually show predominant bi-

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102 Korean J Clin Geri 2018;19(2):101-104

Figure 1. Brain magnetic reso- nance imaging (MRI). (A) At the initial admission with loss of consciousness, diffusion-weighted images (DWI) revealed hyperin- tense lesions in the right globus pallidus and left frontal subcortex.

Magnetic resonance angiography of the intracranial vessels showed no definite abnormality. (B) After one month from the onset, DWI and T2-weighted images (T2WI) of the patient with progressive akinetic mutism showed extensive bilateral hyperintense lesions on the white matter and basal ganglia.

(C) Brain MRI of the spouse also showed a high signal intensity on bilateral white matter on the DWI and T2WI, which was smaller than his wife’s.

lateral globus pallidus (GP) lesions and sometimes it is asym- metric [4-6]. After 2∼8 weeks, patients often reveal ex- tensive bilateral cerebral white matter (CWM) high signal in- tensity on T2-weighted images and the extent of hyperintense CWM is more widespread after the development of DNS symptoms [7]. Because of the characteristic imaging pattern, brain imaging can be helpful in making a diagnosis and pro- viding a clue to draw key history from the patients.

We introduce two DNS cases of a married couple without hyperbaric oxygen therapy, diagnosed with a thorough history taking based on the typical brain imaging findings.

CASE REPORT

A 65-year-old woman with hypertension and coronary heart disease visited the emergency room because of pro- gressive akinetic mutism, lasting for 2 weeks. About one month ago, she slept in a self-made loess interior room with her spouse and then he found her unconscious in the morning. She was immediately transferred to the nearest hos- pital and admitted with the diagnosis of acute ischemic

infarction. The neurologic examination revealed left sided weakness, dysarthria, and loss of awareness at the time of admission. Considering the last-normal-time, intravenous tis- sue plasminogen activator was administrated. Diffusion- weighted brain MRI showed an oval-shaped high signal in- tensity (SI) on the right basal ganglia and a dot-like high SI on the left frontal subcortex (Figure 1A). She rapidly recov- ered and was discharged after seven days later.

However, about 1 week after the discharge, akinetic mu-

tism was developed and then slowly progressed. She had nev-

er consumed any of herbal medicines, extracts, or other drugs

except for already prescribed antihypertensive and antiplatelet

pills. At the time of her visit to the emergency room, her vi-

tal signs were within normal limits and she showed severe

akinetic mutism, generalized bradykinesia, and gait

disturbance. Laboratory tests including a complete blood

count, blood chemistry, and viral markers such as HIV and

syphilis were within normal limits. The T2-weighted images

showed hyperintense bilateral GP and extensive CWM le-

sions (Figure 1B). Although the initial measurement of car-

bon monoxide concentration was missing, it can be suspected

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Seunghee Na et al.: Delayed Leukoencephalopathy after Acute Carbon Monoxide Intoxication in a Married Couple 103

that she was suffering from DNS considering the disease course and the history of sleeping in the loess interior space.

With conservative care, she did not progress and her fluency slightly improved 2 weeks after follow-up.

The spouse suffered from non-vertiginous dizziness, de- pression, and loss of concentration for one month. Because they slept together in the loess interior room, we suspected that his symptoms may be the affective aspects of DNS and obtained his brain MRI. His brain MRI also revealed high signal intensities on the bilateral GP and CWM, which were less extensive than his wife (Figure 1C). These findings sug- gest that carbon monoxide poisoning might have occurred in the loess interior space.

DISCUSSION

We assumed that the patient with progressive akinetic mu- tism as DNS, based on the thorough history taking and the characteristic imaging findings. In spite of minimal symp- toms, the spouse also revealed similar imaging patterns on brain MRI. Taking all these together, they got anoxic insults variously and then DNS symptoms insidiously appeared.

Carbon monoxide is generated when the hydrocarbons are incompletely combusted. Acute carbon monoxide intoxication can be caused by various sources, such as poorly functioning heating system, coal fuels, smoke from a fire or camping [8].

In rural area, self-made loess interior houses with a heating system has been increasing and the poorly functioning ex- haust system can cause carbon monoxide. Sometimes patients cannot notice a gas leak in the loess interior room and then are not aware of any possibility of exposure to carbon mon- oxide, especially without a carbon monoxide detector. Several carbon monoxide intoxication from the loess interior rooms have been reported in the news. There was a previous case report about a married couple with akinetic mutism, as de- layed neurologic sequelae, after taking unspecified herbal medicines [9]. Although the patients denied any history of carbon monoxide inhalation, they also used to sleep in the self-made loess interior room before the onset of the disease.

DNS is a demyelinating syndrome, often developed after an exposure to cerebral hypo-oxygenation [10]. The diagnosis

of DNS can be made based on disease course, clinical history of exposure to carbon monoxide or substances overdose, and characteristic imaging finding [10]. Although predicting the development of DNS is unclear, previous studies revealed that age of 36 years or more, longer exposure than 24 hours, patients who revealed any acute brain lesion on brain MRI during the acute stage, and the presence of cerebellar dys- function have more risk of developing delayed neurological sequelae [4,11,12].

Typically, patients with DNS often show bilateral basal gangli lesions, especially in the globus pallidus, and extensive white matter lesions. Although the globus pallidus lesions are the commonest site and these patterns are typical, they are not diagnostic findings [6,7,13]. Other substances including heroin, cyanide, narcotics intoxication and various global cere- bral hypoxic damage can cause similar findings [10,14].

Carbon monoxide inducing hypoxemia and its direct myelino- toxic effect can cause widespread white matter lesions. The basal gangli are commonly injured because of the poor arte- rial supply and the damaged basal ganglia induce surge in dopamine. After eliminating carbon monoxide, prolonged ex- cessive dopamine can last for several weeks and cause oxida- tive stress metabolism and serotonergic axonal injury [10].

Although there are no effective treatments to reduce DNS symptoms, hyperbaric oxygen therapy at acute carbon mon- oxide poisoning stage is accepted as a method of preventing the development of DNS. Appropriate hyperbaric oxygen therapy can reduce the incidence of DNS from 46% to 25%

[4]. Considering the underlying pathophysiology including tissue hypoxia, oxidative stress, and microglia activation through lipid peroxidation [2], various neuroprotection thera- pies such as therapeutic hypothermia therapy, administration of anti-oxidants or corticosteroids are suggested [15].

Although the initial evaluation of carbon monoxide satu- ration was lacking, a married couple was diagnosed as DNS based on the disease course, brain MRI findings, and a shared history of sleeping in the loess interior room which provided a clue that they may have inhaled carbon monoxide.

Carbon monoxide poisoning can induces permenant cognitive

impairment and an appropriate surveilance and treatment are

able to prevent the complications. It is because that although

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104 Korean J Clin Geri 2018;19(2):101-104

exposure to carbon monoxide is regarded as a kind of cur- able cause of dementia, it is difficult to recover completely from the dementia status if DNS had once developed.

Considering the increasing number of self-made loess in- terior houses, physicians who confront patients with loss of consciousness should consider the possibility of carbon mon- oxide poisoning, especially in rural areas. A detailed and thorough history taking is essential because if acute carbon monoxide intoxication is suspected, a prompt hyperbaric oxy- gen therapy is necessary to reduce the possibility of DNS.

CONFLICTS OF INTEREST

No potential conflict of interest relevant to this article was reported.

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