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Show 72 LETTERS TO THE EDITOR References 1. Osako M, Keltner JL. Botulinum A toxin ( oculinum) in ophthalmology. Surv Ophthalmol 1991; 36: 28- 46. 2. Perman KI, Baylis HI, Rosenbaum AL, Kirschner DG. The use of botulinum toxin in the medical management of benign essential blepharospasm. Ophthalmology 1986; 93: 1- 3. 3. Klara HK, Magoom EH. Side effects of the use of botulinum toxin for treatment of benign essential blepharospasm and hemifacial spasm. Ophthalmol Surg 1990; 21: 5; 335- 8. 4. Dutton JJ, Buckley EG. Long- term results and complications of botulinum A toxin in the treatment of blepharospasm. Ophthalmology 1988; 95: 1529- 34. 5. Sanders DB, Massey EW, Buckley EG. Botulinum toxin for blepharospasm: single fiber EMG fibers. Neurology 1986; 36: 545- 7. Chronic Headaches Due to Vitamin A Abuse To the Editor: Vitamin A or retinol is a fat- soluble vitamin that plays an essential role in various biochemical and physiological processes ( retina, growth and development of epithelial tissue, bone, reproduction, etc.) ( 1). Excess intake of vitamin A results in hy-pervitaminosis A, which can cause chronic headaches, vomiting, nausea, loss of appetite, fatigue, dermatitis, myalgia, gingivitis, nystagmus, and the entity called pseudotumor cerebri ( 2,3). Hyper-vitaminosis A is frequently an overlooked cause of chronic headaches. We would like to call attention to a patient who was evaluated in the headache clinic and a neuro- ophthalmology service for 2 years with a history of chronic headache and nausea. A 62- year- old man was evaluated by the headache unit and the neuro- ophthalmology service for chronic headaches and nausea. He had an extensive workup, including neuroimaging studies of the head, which were all normal. The headache was described as an ever- present pressure and tightness sensation. These headaches wake the patient from sleep, accompanied by nausea and sometimes vomiting. The patient was asked several times about his medications, and he reported the use of Ibuprofen, aspirin, and Advil. No focal triggers were found. Neurological, neuro- ophthal-mological and ENT examinations were all essentially normal. After 2 years of follow- up, the patient reported to us that he was (?) taking 20,000 IU of vitamin A daily, and, although he was asked about his medication consumption, he never realized that vitamin intake is considered to be a medication. The vitamin A intake was discontinued and the patient reported significant relief of his symptoms within 2- 3 weeks. Although in most instances, the average American diet does not require vitamin supplementation, many people are convinced that they need additional and better nutrients than their diet provides. Advertising, the need and desire to be fit, and the natural food popularity are examples of factors that have resulted in a significant increase in the consumption of vitamins. Vitamin A is obtained from organ meats, fish, butter, eggs, milk, carrots, squash, and pumpkin. Since the vitamin is sufficiently stored in the liver, high doses can result in excessive amount and toxicity ( 4,5). The U. S. recommended daily allowance values for vitamin A is 5,000 IU for adult males and 4,000 IU for adult females. The dose of vitamin A necessary to induce pseudotumor cerebri varies from 20,000 to 6,000 IU daily ( 3). The increased popularity of vitamin A consumption even in the oph-thalmological community ( possible role in retinitis pigmentosa patients?) should alert us to the side effects of its abuse, especially since patients do not recognize the fact that vitamins are considered as medication and thus do not report its intake. Special attention should be paid to vitamin A consumption whenever the clinical setting is adequate. This work was supported in part by an unrestricted departmental grant from Research to Prevent Blindness, Inc., New York. Shmuel Friedland, M. D. Ronald M. Burde, M. D. Department of Ophthalmology and Visual Sciences Albert Einstein College of Medicine/ Montefiore Medical Center 111 East 210th Street Bronx, NY 10467 References 1. Mandel HG, Cohn VH. Fat- soluble vitamins: vitamins A, K and E. In: Goodman and Gilmans' the pharmacological basis of therapeutics, 6th Ed. New York: Macmillan; 1980: 67 and 1583. 2. Howroth JC, Ranee CP, Roy C, et al. The use and abuse of vitamin A. Can Med Assoc J 1971; 104: 521- 2. 3. Lombart A, Carton H. Benign Intracranial hypertension due to A hypervitaminosis in adults and adolescents. Eur Neurol 1976; 14: 340- 50. 4. Fenny L, Berman ER. Oxygen toxicity: membrane damage by free radicals. Invest Ophthalmol Vis Sci 15: 789- 92, 1976. 5. Pfander H. Carotenoids: an overview. Methods Enzymol 1973; 123: 3- 13. / Neuro- Ophthalmol, Vol. 26, No. 1, 19% |
