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Pupil sparing in oculomotor palsy: A brief review
CURRENTOPHTHALMOLOGY
357
Homocystinuria Treated With Pyridoxine, by S. Blika, E. Saunte, and A. Ringvold. Ophthalmologica 60:894-906, 1982
H. Lunde,
L. Gjessing,
One of the most frequently encountered inborn errors of metabolism in humans is the condition known as homocystinuria, which has some clinical manifestations in common with Marfan’s syndrome. The disease is due to abnormalities in the methionine metabolism. The severity of the manifestation shows an extreme variation, probably because enzymatic defects may occur at three separate levels in the pathway, and deficiencies may not be complete. The primary ophthalmic condition seen in association with homocystinuria is lens luxation. The authors report four cases of homocystinuria with lens luxation. As judged from plasma amino acid pattern, they were all thought to respond well to a pyridoxine treatment program. Two of them discontinued treatment on their own and one of these died at the age of 17 years. The lens luxation progressed in one case despite adequate treatment. Scanning electromicroscopy of one lens revealed partly broken zonules, abnormal zonular attachment, and a sponge appearance of the capsule proper. Hoping that adequate treatment will reduce more serious complications such as thromboembolism in these patients, it is concluded that an early diagnosis largely depends on the ophthalmologist. The screening for this disorder should always be completed by the ophthalmologist in the evaluation of patients with non-traumatic lens luxation.
Comment The authors describe four patients with homocystinuria treated with pyridoxine. They make the point that it is particularly important to suspect the diagnosis of homocystinuria in any patient in whom subluxation of the lens occurs without an adequate history of trauma. An early diagnosis is particularly important because of the severe complications of thromboembolism and stroke in the untreated patient. Fortunately, if a diagnosis is made early, a portion of patients with homocystinuria can he successfully treated by administration of vitamin B6 (pyridoxine). The nitroprusside screening test, as recommended by the authors, has a fairly high false negative rate, particularly in children and mildly affected adults. If urine is dilute in children, then the nitroprusside test will be negative in patients with homocystinuria. A much more reliable test is plasma amino acid screening. This paper is of particular importance to pediatric ophthalmologists because if a child can be diagnosed as having homocystinuria during the pediatric ages, mental retardation and mental deficiency may be avoided and progressive lens subluxation halted. A. LINN MLIKPHKU:~Los AN(:I~:I.KS,C;ZI.IPOKNI.\
Pupil Sparing in Oculomotor Palsy: A Brief Review, by S.E. Nadeau New01 23: 143-148, 1983
and J.D. Trobe. Ann
Preservation of pupiliary reactions to light and near stimuli in the presence ofoculomotor nerve palsy is said to be diagnostic of ischemic damage to the peripheral nerve. The authors describe two patients with pupilsparing oculomotor nerve palsy caused by midbrain infarction and glioma, underscoring the fact that preservation of pupillary function neither specifically localizes nor defines the cause of the palsy. The accepted explanation for pupillary sparing in diabetic oculomotor palsy is the relative lack of damage to the periphery of the nerve, where the majority of pupillomotor fibers are believed to pass. Further support for this concept is provided by the fact that pupillary involvement is often present in Herpes zoster, presumpdiseases that do not consistently spare the tive viral infections, syphilis, and Guillain-Barri syndrome, periphery of the nerve. The authors’ review of the literature emphasizes that occasional berry and fusiform compressive lesions of the cavernous aneurysms involving the third nerve may spare the pupil. Moreover, sinus have also been reported not to involve the pupillomotor fibers. Although pupil sparing is usually a sign of a diabetic third nerve palsy, the authors emphasize that it is in no way pathognomonic for it. (Comment follows next abstract.)
357
Homocystinuria Treated With Pyridoxine, by S. Blika, E. Saunte, and A. Ringvold. Ophthalmologica 60:894-906, 1982
H. Lunde,
L. Gjessing,
One of the most frequently encountered inborn errors of metabolism in humans is the condition known as homocystinuria, which has some clinical manifestations in common with Marfan’s syndrome. The disease is due to abnormalities in the methionine metabolism. The severity of the manifestation shows an extreme variation, probably because enzymatic defects may occur at three separate levels in the pathway, and deficiencies may not be complete. The primary ophthalmic condition seen in association with homocystinuria is lens luxation. The authors report four cases of homocystinuria with lens luxation. As judged from plasma amino acid pattern, they were all thought to respond well to a pyridoxine treatment program. Two of them discontinued treatment on their own and one of these died at the age of 17 years. The lens luxation progressed in one case despite adequate treatment. Scanning electromicroscopy of one lens revealed partly broken zonules, abnormal zonular attachment, and a sponge appearance of the capsule proper. Hoping that adequate treatment will reduce more serious complications such as thromboembolism in these patients, it is concluded that an early diagnosis largely depends on the ophthalmologist. The screening for this disorder should always be completed by the ophthalmologist in the evaluation of patients with non-traumatic lens luxation.
Comment The authors describe four patients with homocystinuria treated with pyridoxine. They make the point that it is particularly important to suspect the diagnosis of homocystinuria in any patient in whom subluxation of the lens occurs without an adequate history of trauma. An early diagnosis is particularly important because of the severe complications of thromboembolism and stroke in the untreated patient. Fortunately, if a diagnosis is made early, a portion of patients with homocystinuria can he successfully treated by administration of vitamin B6 (pyridoxine). The nitroprusside screening test, as recommended by the authors, has a fairly high false negative rate, particularly in children and mildly affected adults. If urine is dilute in children, then the nitroprusside test will be negative in patients with homocystinuria. A much more reliable test is plasma amino acid screening. This paper is of particular importance to pediatric ophthalmologists because if a child can be diagnosed as having homocystinuria during the pediatric ages, mental retardation and mental deficiency may be avoided and progressive lens subluxation halted. A. LINN MLIKPHKU:~Los AN(:I~:I.KS,C;ZI.IPOKNI.\
Pupil Sparing in Oculomotor Palsy: A Brief Review, by S.E. Nadeau New01 23: 143-148, 1983
and J.D. Trobe. Ann
Preservation of pupiliary reactions to light and near stimuli in the presence ofoculomotor nerve palsy is said to be diagnostic of ischemic damage to the peripheral nerve. The authors describe two patients with pupilsparing oculomotor nerve palsy caused by midbrain infarction and glioma, underscoring the fact that preservation of pupillary function neither specifically localizes nor defines the cause of the palsy. The accepted explanation for pupillary sparing in diabetic oculomotor palsy is the relative lack of damage to the periphery of the nerve, where the majority of pupillomotor fibers are believed to pass. Further support for this concept is provided by the fact that pupillary involvement is often present in Herpes zoster, presumpdiseases that do not consistently spare the tive viral infections, syphilis, and Guillain-Barri syndrome, periphery of the nerve. The authors’ review of the literature emphasizes that occasional berry and fusiform compressive lesions of the cavernous aneurysms involving the third nerve may spare the pupil. Moreover, sinus have also been reported not to involve the pupillomotor fibers. Although pupil sparing is usually a sign of a diabetic third nerve palsy, the authors emphasize that it is in no way pathognomonic for it. (Comment follows next abstract.)