Visual abnormalities

Patients with abetalipoproteinaemia, a rare inborn disorder of lipoprotein metabolism, are totally deficient in vitamin E fiom birth and, if untreated, invariably develop a characteristic pigmentary retinopathy similar to that seen in retinitis pigmentosa and peroxisomal disorders. The same retinopathy has been observed in other patients with severe and chronic vitamin E deficiency. A essive vitamin E replacement therapy in all these patients has been shown either to prevent, to halt the progression of, or in some cases, to improve the characteristic visual abnormalities (Muller and Lloyd, 1982). 

Visual abnormalities Retinal vascular thrombosis has been reported. Discontinue medication pending examination if there is sudden partial or complete loss of vision or a sudden onset of proptosis, diplopia, or migraine. 

Nausea, vomiting, visual abnormalities, such as spots before eyes, difficulty focus ng, blurred vision, dry mouth or pharynx, tongue irritation, water retention, increased sweating, constipation, or diarrhea... 

Strokelike episodes are the hallmark feature of this disorder. In many patients with MELAS, presentation occurs with the first stroke-like episode, usually when an individual is aged 4-15 years. Episodes initially may manifest with vomiting and headache that may last up to several days. These patients also may be affected with episodes of seizures and visual abnormalities followed by hemiplegia (total or partial paralysis of one side of the body). Seizure types may be tonic-clonic or myoclonic. Migraine or migrainelike headaches observed in these patients also may reflect the strokelike episodes. Pedigrees of patients with classic MELAS identify many members whose only manifestations are migraine headaches. 

Hajnal BL, Ferriero DM, Partridge JC, Dempsey DA, Good WV. Is exposure to cocaine or ciagarette smoke during pregnancy associated with infant visual abnormalities Dev Med Child Neurol 2004 46 520-5. 

If ethambutol is not withdrawn when visual symptoms occur, optic atrophy or permanent blindness can occur. Patients therefore have to be instructed to interrupt treatment if they experience any visual abnormality. Hydroxocobalamin can accelerate recovery (18). 

Manuchehri K, Goodman S, Siviter L, Nightingale S. A controlled study of vigabatrin and visual abnormalities. Br J Ophthalmol 2000 84(5) 499-505. 

D. Enhanced elimination. Hemodialysis rapidly removes both methanol (half-life reduced to 3-6 hours) and formate. The indications for dialysis are suspected methanol poisoning with significant metabolic acidosis, visual abnormalities, an osmolar gap greater than 10 mOsm/L, or a measured serum methanol concentration greater than 50 mg/dL. Dialysis should be continued until the methanol concentration is less than 20 mg/dL. 

Macroadenomas (>1 cm) occupy the pituitary fossa and may cause visual abnormalities when they put pressure on the optic chiasm. Macroadenomas also tend to invade the cavernous sinus and erode the bony floor. The extent of the tumor can be determined by means of contrast-enhanced MR imaging. 

The predominance of coronary anomalies is composed of abnormal branching patterns of the proximal segments. CT is therefore used in many instances of suspected coronary anomalies after catheterization angiography to verify or supplement suspected findings. The supplemental function includes visualizing abnormal branches that could either not be reached by the catheter tip during the catheterization procedure or were not at all detected. For this application, CT offers the only way to assess the peripheral parts of that particular branch. Hence, all the restrictions apply as mentioned in the section on initial CAD workup. 

A retrospective review of patients receiving TAC for prevention of GVHD after allogeneic Stem Cell Transplant (SCT) identified 19 patients with PRES. Altered mental status, seizures and visual abnormalities were experienced by 78.9%, 52.6% and 31.5% of the patients, respectively, at the time of PRES onset. 

An unusual visual effect was described by Goldhammer and Lawton-Smith (12 ). A patient who had taken 250 mg of chloro-quine daily for 10 years for chronic rheumatoid arthritis developed a bitemporal hemianopia. Ophthalmological examination showed appearances typical of chloroquine retinopathy. Despite extensive investigation, no other condition capable of producing visual abnormality could be discovered. Although chloroquine was stopped the patient s visual field defects continued to increase. 

A report of defective vision in heroin addicts subjected to chronic administration of low doses of quinine, which is used to dilute heroin in the open drug market, was followed up by detailed ophthalmological examination of the patients. Despite the demonstration of visual abnormalities, using the Amsler chart test, no evidence of retinal disease was found. The cases were therefore termed examples of toxic maculopathy . The authors felt that the occurrence of such visual defects could be regarded as a warning of impending retinopathy and should lead to close supervision of the subjects with frequent ophthalmological examination (20 , 21 ). 

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