Actigall

By H. Domenik. Hampton University.

The spatial and temporal characteristics of the diplopia may help to ascertain its cause buy cheap actigall 300mg on-line. Diplopia may be monocular, in which case ocular causes are most likely (although monocular diplopia may be cortical or functional in origin), or binocular, implying a divergence of the visual axes of the two eyes. With binocular diplopia, it is of great importance to ask the patient whether the images are separated horizontally, vertically, or obliquely (tilted), since this may indicate the extraocular muscle(s) most likely to be affected. Whether the two images are separate or overlapping is important when trying to ascertain the direction of maximum diplopia. The experience of diplopia may be confined to, or particularly noticeable during, the performance of particular activities, reflecting the effect of gaze direction; for example, diplopia experienced on com- ing downstairs may reflect a trochlear (IV) nerve palsy; or only on looking to the left may reflect a left abducens (VI) nerve palsy. Double vision experienced on looking at a distant object after looking down (e. The effect of gaze direction on diplopia should always be sought, since images are most separated when looking in the direction of a paretic muscle. Conversely, diplopia resulting from the breakdown of a latent tendency for the visual axes to deviate (latent strabismus, squint) results in diplopia in all directions of gaze. Examination of the eye movements should include asking the patient to look at a target, such as a pen, in the various directions of gaze (versions) to ascertain where diplopia is maximum. Then, each eye may be alternately covered to try to demonstrate which of the two images is the false one, namely that from the nonfixing eye. Thus in a left abducens (VI) nerve palsy, diplopia is maximum on left lateral gaze; when the normal right eye is covered the inner image disappears; the nonfixing left eye is responsible for the remaining false image, which is the more peripheral and which disappears when the left eye is covered. Other clues to the cause of diplopia include ptosis (unilateral: ocu- lomotor (III) nerve palsy; bilateral: myasthenia gravis), and head tilt or turn (e. Manifest squints (heterotropia) are obvious but seldom a cause of diplopia if long-standing. Latent squints may be detected using the cover-uncover test, when the shift in fixation of the eyes indicates an imbalance in the visual axes; this may account for diplopia if the nor- mal compensation breaks down.

Pharmacotherapy The mainstay of pharmacotherapy is oral acetazolamide discount actigall 300 mg with mastercard, though there are no clinical trials proving efficacy. For children, the initial dose is 30 mg=kg=day orally divided into four doses, whereas for teens the dose is 1 g divided into four doses per day. Higher doses have been used, with the most frequent side effect being paresthesias. Systemic corticosteroids have been found in some patients to be helpful, especially when the PPTC is associated with systemic inflammatory disease, like sarcoidosis. Some patients have been found to be responsive to other diuretics, especially furose- mide. Lumbar Puncture Serial lumbar punctures are performed to lower the pressure. This approach may work by creating a number of holes in the dura of the spinal canal allowing enough cerebrospinal fluid egress to normalize the intracranial pressure. This method is dif- ficult to accomplish in children over a long period of time for practical reasons, but can be used over a short period of time until more definitive therapies can be arranged. Surgical Treatment of PPTC Surgical treatment is not often needed for PPTC, possibly because there are frequent associations, which can be corrected with rapid normalization of the pressure. How- ever, the physician must be prepared to intervene when there is optic neuropathy, very high pressure, or documented progression of optic nerve damage. Unfortu- nately, there is insufficient published evidence to clearly recommend one over the other procedure. Repeat eye examinations are required to monitor the outcome of either surgical drainage procedure. Lumboperitoneal Shunt Lumboperitoneal shunting involves the placement of a silicone tube from the lumbar subarachnoid space to the peritoneal cavity. These have long been used by neurosur- geons for PPTC, though not always successfully. This approach leads to a rapid resolution of the PPTC, but the tubes can obstruct, become infected, and are 242 Repka associated with the development of a Chiari malformation. Failure to drain is com- mon and blockage leads to a rapid increase in pressure, which can cause catastrophic damage to the optic nerve.