JRSM > Volume 96, Number 9 > Pp. 459-460

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A not-so-simple collapse

E Raw BM BS  ¹ L Hudsmith MRCP MA   G P Aithal FRCP PhD     T Jaspan FRCP FRCR  

Departments of Gastroenterology, Queen's Medical Centre, Nottingham NG7 2UH, UK
¹ Neuroradiology, Queen's Medical Centre, Nottingham NG7 2UH, UK

Correspondence to: Dr E Raw E-mail: elizabethraw{at}doctors.org.uk

In unexplained collapse, the possibility of carbon monoxide poisoning must not be neglected.

CASE HISTORY

A man of 40 was admitted having collapsed. His only medical history was treatment for depression. Examination was unremarkable except for complete short-term memory loss to such an extent that he was unable to recall his address. Blood tests and electrocardiography were normal. CT and MRI (Figures 1 and 2) revealed symmetrical lesions in the globus pallidus and posterior putamen. There were also ill-defined lesions in the posterior periventricular white matter. The following day the patient's neighbour reported finding a hosepipe attached to his car's exhaust pipe.

View larger version (130K): [in this window] [in a new window]   Figure 1. CT of brain

 

View larger version (153K): [in this window] [in a new window]   Figure 2. MRI of brain

 

The radiological findings are characteristic of carbon monoxide poisoning. The patient was referred for hyperbaric oxygen therapy. The results of psychometric testing improved but he was left with defects that limited his everyday function.

Box 1 Differential diagnosis of the CT and MRI appearances in carbon monoxide poisoning Vascular Lacunar infarcts Late-stage hypertensive haemorrhage Hypoxic injury Toxic Carbon monoxide poisoning Methanol poisoning Cyanide poisoning Manganese poisoning Metabolic Mitochondrial cytopathies Wilson's disease Hallervorden–Spatz disease Neurodegenerative Acquired hepatocerebral degeneration Physiological Giant perivascular spaces Age-related iron deposition Infective Acute disseminated encephalomyelitis Acute bilateral striatal necrosis Congenital Neurocutaneous syndrome: neurofibromatosis type 1.

 

COMMENT

Carbon monoxide poisoning is responsible for about 50 deaths and up to 200 severe injuries a year in England.¹ Most cases are accidental. Signs and symptoms of poisoning depend upon exposure, and range from those of a non-specific viral illness to arrhythmias, coma and death.² The classic cherry-red lips, cyanosis and retinal haemorrhages rarely occur. Diagnosis is by measurement of carboxyhaemoglobin, although there is poor correlation between severity of symptoms and concentration of carboxyhaemoglobin. Patients may present for imaging studies with unexplained loss of consciousness or neurological abnormalities where carbon monoxide is not initially suspected. The differential diagnosis of the CT and MRI appearances is summarized in Box 1.

Treatment requires oxygen to shorten the half-life of carboxyhaemoglobin. A recent double-blind randomized trial demonstrated a reduced incidence of cognitive sequelae at six weeks in patients treated with hyperbaric oxygen,³ though the optimum number of sessions and the maximum time to therapy were not established.

REFERENCES

1. Walker E, Hay A. Carbon monoxide poisoning is still an under recognised problem. BMJ1999; 319:1082 -3[Free Full Text]

2. Ernst A, Zibrak JD. Carbon monoxide poisoning. N Engl J Med 1998;339:1603 -8[Free Full Text]

3. Weaver LK, Hopkins RO, Chan KJ, et al. Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med2002; 347:1057 -67[Abstract/Free Full Text]

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This Article Figures Only Full Text (PDF) Send a Quick Comment Alert me when this article is cited Alert me when Quick Comments are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Raw, E Articles by Jaspan, T Search for Related Content PubMed PubMed Citation Social Bookmarking                      What's this?