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Transient Cortical Blindness and Bioccipital Brain Lesions in Two Patients with Acute Intermittent Porphyria
- Hugo Kupferschmidt, MD;
- Adriano Bont, MD;
- Hans Schnorf, MD;
- Theodor Landis, MD;
- Eike Walter, MD;
- Jurg Peter, MD;
- Stephan Krahenbuhl, MD, PharmD; and
- Peter J. Meier, MD
- From University Hospital, Zurich; University Hospital, Basel; and University Hospital, Geneva, Switzerland. Requests for Reprints: Peter J. Meier, MD, Division of Clinical Pharmacology and Toxicology, Department of Medicine, University Hospital CH-8091, Zurich, Switzerland. Current Author Addresses: Drs. Kupferschmidt, Krahenbuhl, and Meier: Division of Clinical Pharmacology and Toxicology, Department of Medicine, University Hospital, CH-8091, Zurich, Switzerland.
The most common neurologic manifestations of acute intermittent porphyria are autonomic visceral neuropathy, peripheral motor neuropathy, and central nervous system dysfunctions, including seizures and neuropsychiatric disturbances [1]. In rare instances, however, patients with acute intermittent porphyria have presented with acute cortical blindness [2-5], for which deleterious vasospasm in both posterior cerebral arteries has been inferred [3, 6].
We describe two patients in whom cortical blindness was the first symptom of acute intermittent porphyria. Magnetic resonance imaging showed extensive lesions involving primarily white matter of both occipital lobes consistent with vasospasm-induced ischemic lesions. However, the pathogenesis of the suspected vasospasm in acute intermittent porphyria is unknown. Because the enzyme nitric oxide synthase is a hemoprotein [7] and nitric oxide is a major vascular dilator [8], we hypothesize that severe heme deficiency during acute attacks may cause unopposed cerebral vasoconstriction due to a decrease in cerebral nitric oxide production.
Case Reports
Patient 1
A 35-year-old woman was hospitalized because of sudden loss of vision. With the exception of a brother with partial porphobilinogen deaminase deficiency, she had no family history of porphyria, and she had no known exposure to porphyrinogenic drugs. At admission, she appeared to be blind, …
