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BRIEF COMMUNICATIONS: Pasquale F. Finelli and Francis J. DiMario, Jr. Hemorrhagic infarction in white matter following acute carbon monoxide poisoning Neurology 2004; 63: 1102-1104 [Abstract] [Full text] [PDF]

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Reply to Weaver et al

Pasquale F. Finelli, M.D., Francis J. DiMario, M.D.   (23 November 2004)

Hemorrhagic infarction in white matter following acute carbon monoxide poisoning

Lindell K. Weaver, MD, Ramona O. Hopkins, PhD   (23 November 2004)

Reply to Weaver et al 23 November 2004
Pasquale F. Finelli, M.D., Hartford Hospital 80 Seymour St, Hartford, CT 06102, Francis J. DiMario, M.D. Send Correspondence to journal: Re: Reply to Weaver et al pfinell{at}harthosp.org Pasquale F. Finelli, M.D., et al.	We thank Weaver et al for their letter regarding our paper. [1] T2 weighted changes similar to those seen in our patients have been described [6-7], including FLAIR and diffusion-weighted sequence (Case 1). [7] References 6. O'Donnell P, Buxton PJ, Pitkin A, Jarois LJ. The magnetic resonance imaging appearance of the brain in acute carbon monoxide poisoning. Clin Radiol 2000;55:273-280. 7. Chalela JD, Wolf RL, Maldjian JA, Kasner SE. MRI identification of early white matter imaging in anoxic-ischemic encephalopathy. Neurology 2001:56;481-485.
Hemorrhagic infarction in white matter following acute carbon monoxide poisoning 23 November 2004
Lindell K. Weaver, MD, LDS Hospital Department of Hyperbaric Medicine, 8th Avenue & C Street, Salt Lake City, UT 84143, Ramona O. Hopkins, PhD Send Correspondence to journal: Re: Hemorrhagic infarction in white matter following acute carbon monoxide poisoning lweaver{at}ihc.com Lindell K. Weaver, MD, et al.	We read the article by Finelli et al with interest. In this article, the authors state that neuroimaging of carbon monoxide poisoned patients characteristically shows deep grey matter involvement, most commonly in the globus pallidus and their three cases describe neuropathology in the white matter. [1] The authors also assert they are not aware of similar neuroimaging findings as they described. Regarding brain hemorrhage due to carbon monoxide poisoning, we agree. However, we offer additional information regarding T2-weighted white matter hyperintensities. Brain magnetic resonance (MR) imaging of carbon monoxide (CO)- poisoned patients has demonstrated neuropathological damage in white matter. [2] Controversy exists regarding the frequency and location of basal ganglia versus white matter pathology due to CO poisoning. In a study of 73 consecutively CO-poisoned patients, we found an increase in T2-weighted white matter hyperintensities following acute carbon monoxide poisoning. [3] We prospectively performed three sequential brain MR scans per subject post CO-poisoning (within 36 hours, at 2 weeks and at 6 months following poisoning). Twelve percent of the patients had T2- weighted white matter hyperintensities, whereas in a normal matched control group only 7% had white matter hyperintensities. Only one patient had globus pallidus lesions present at 2 weeks, but not at 6 months. [3] Had we used FLAIR imaging similar to Finelli et al, we likely would have observed larger T2-weighted white matter hyperintensities and more CO- poisoned patients. In addition to the potential etiologies for the T2-weighted white matter hyperintensities, other possible mechanisms include brain iron extravasation following CO poisoning [4] and release of myelin basic protein resulting in inflammation which may lead to delayed neurologic or neurocognitive sequelae. [5] References 1. Finelli PF, DiMario F J, Jr. Hemorrhagic infarction in white matter following acute carbon monoxide poisoning. Neurology, 2004; 63:1102-1104. 2. Chang KH, Han MH, Kim HS, Wie BA, Han MC. Delayed encephalopathy after acute carbon monoxide intoxication: MR imaging features and distribution of cerebral white matter lesions. Radiology, 1992;184: 117 -122. 3. Parkinson RB, Hopkins RO, Cleavinger HB, et al. White matter hyperintensities and neuropsychological outcome following carbon monoxide poisoning. Neurology 2002;58:1525-1532. 4. Piantadosi CA. Carbon monoxide poisoning. Undersea Hyperbar Med 2004; 31:167. 5. Thom SR, Bhopale VM, Fisher D, Zhang J, Gimotty P. Delayed neuropathology after carbon monoxide poisoning is immune-mediated. Proc Natl Acad Sci 2004;101; 12660-13665.