Early diagnosis and treatment with a gluten-free diet can improve ataxia and prevent its progression. The effectiveness of the treatment depends on the elapsed time from the onset of the ataxia until diagnosis, because the death of neurons in the cerebellum as a result of gluten exposure is irreversible. It accounts for 40% of ataxias of unknown origin and 15% of all ataxias. Less than 10% of people with gluten ataxia present any gastrointestinal symptom and only about 40% have intestinal damage. This entity is classified into primary auto-immune cerebellar ataxias (PACA). Potassium pump
Malfunction of the sodium-potassium pump may be a factor in some ataxias. The Na+-K+ pump has been shown to control and set the intrinsic activity mode of cerebellar Purkinje neurons. This suggests that the pump might not simply be a homeostatic, "housekeeping" molecule for ionic gradients; but could be a computational element in the cerebellum and the brain. Indeed, an ouabain block of Na+-K+ pumps in the cerebellum of a live mouse results in it displaying ataxia and dystonia. Ataxia is observed for lower ouabain concentrations, dystonia is observed at higher ouabain concentrations. Cerebellar ataxia associated with anti-GAD antibodies
Antibodies against the enzyme glutamic acid decarboxylase (GAD: enzyme changing glutamate into GABA) cause cerebellar deficits. The antibodies impair motor learning and cause behavioral deficits. GAD antibodies related ataxia is part of the group called immune-mediated cerebellar ataxias. The antibodies induce a synaptopathy. The cerebellum is particularly vulnerable to autoimmune disorders.
Megalopapilla is a non-progressive human eye condition in which the optic nerve head (optic disc) has an enlarged diameter, exceeding 2.1 mm with no other morphological abnormalities. Clinical features
In megalopapilla the optic disc diameter exceeds 2.1 mm (or surface area more than 2.5 mm2) with an increased cup-to-disc ratio. Although the optic disc is looks abnormal, the disc colour, sharpness of disc margin, rim volume, configuration of blood vessels and intraocular pressure will be normal. Visual field is normal except for an enlarged blind spot. Visual acuity may be normal, or occasionally reduced. Types
There are two types of megalopapilla. Type 1, which is the most common, is bilateral with a normal configuration of the optic cup. Type 2 is unilateral with a superiorly displaced cup that eliminates the adjacent neuro-retinal rim. Diagnosis and differential diagnosis
Large disc size can be seen in fundus examination by ophthalmoscopy. Since OCT is not influenced by disc size, it can be used in differentiating normal and glaucomatous eyes with large discs.Since the clinical appearance of megalopapilla resembles that of glaucomatous optic disc, it should be differentiated from Normal tension glaucoma and other pseudo-glaucomatous diseases. Other conditions that resembles megalopapilla includes coloboma of optic disc and orbital optic disc glioma. History
Bock and Franceschetti were the first to use the term megalopapilla to describe larger-than-normal optic disks. == References ==