Infantile infection and diabetes insipidus in children with optic nerve hypoplasia.

BACKGROUND: Bilateral optic nerve hypoplasia (BONH) is often associated with other central nervous system midline abnormalities (septo-optic dysplasia). Hormonal dysfunction, caused by anterior (cortisol) and posterior (ADH) pituitary involvement, can be sudden, severe, and life threatening. METHODS: Case series. Three cases of septo-optic dysplasia (SOD) presenting as infantile infection with associated diabetes insipidus are reported. The diagnosis of SOD was suspected only after ophthalmological evaluation; further evaluation led to the diagnosis of panhypopituitarism. CONCLUSIONS: A high index of suspicion is required to diagnose SOD in children when the disorder presents with infantile infection and hypernatraemia. Early warning signs of neonatal jaundice and hypoglycaemia should prompt ophthalmological evaluation.

Response of IGF-1 to nutritional support in malnourished hospital patients: a possible indicator of short-term changes in nutritional status.

IGF-1 is a circulating growth factor with hepatic release dependent on nutritional status. To determine if IGF-1 could be a useful nutritional index, 15 malnourished patients were assessed during nutritional support. Patients with protein or protein-calorie malnutrition had lower IGF-1 (39 +/- 7 micrograms/L) than did patients with calorie-only malnutrition (109 +/- 25 micrograms/L, p less than 0.005); transferrin concentrations did not differ between the two groups. Nutritional supplementation produced an increase in IGF-1 (123 +/- 32 micrograms/L, p less than 0.005); the relative increase in IGF-1 (264 +/- 62%, p less than 0.001) exceeded increases in albumin or transferrin (9 +/- 6% and 59 +/- 16%, NS and p less than 0.005, respectively). Reduction or termination of support was followed by a decrease in IGF-1 to 59 +/- 9% of peak values (p less than 0.001) but neither albumin nor transferrin decreased significantly. Changes in IGF-1 were correlated with nitrogen balance (r = 0.45, p less than 0.005). The strong relationship between IGF-1 and nutritional status suggests that IGF-1 determinations may be useful in guiding nutritional therapy in patients whose nitrogen balance is difficult to assess.

Visual field defects after temporal lobe resection: a prospective quantitative analysis.

OBJECTIVE: To evaluate and quantify prospectively visual field changes in patients undergoing temporal lobe resections for intractable epilepsy. BACKGROUND: Visual field abnormalities occur after temporal lobe resections for epilepsy; however, we have not encountered published reports using automated static visual field analysis. METHODS: Humphrey visual fields (program 30-2) were obtained before and after partial temporal lobe resection in 32 consecutive patients with intractable epilepsy. A quantitative point-by-point analysis was made in the affected superior quadrant, and the defects were averaged for the whole patient group. RESULTS: Thirty-one patients developed a visual field defect, but none was aware of the defect. The points nearest fixation were relatively spared. The defects were greatest in the sector closest to the vertical meridian in the eye ipsilateral to the resection. The ipsilateral and contralateral mean field defects also differed in both topography and depth. A significant correlation was found between the extent of lateral temporal lobe resection and the degree of the defect in the contralateral eye. CONCLUSIONS: There are differences in the shape and depth of the ipsilateral and the contralateral field defects not previously reported. These findings demonstrate that certain fibers from the ipsilateral eye travel more anteriorly and laterally in Meyer's loop, and support the hypothesis that visual field defects due to anterior retrogeniculate lesions are relatively incongruous because of anatomic differences in the afferent pathways. Automated perimetry is a sensitive method of evaluating and quantifying visual field defects.

Tenotomy delays both synapse elimination and myogenesis in rat lateral gastrocnemius.

To investigate a possible relationship between synapse elimination and myogenesis, we examined both phenomena during the first 2 weeks of postnatal life in the rat lateral gastrocnemius muscle. Synapse elimination and myogenesis occur simultaneously. Sixty per cent of the number of fibers observed in adult muscles is generated during the first 10 days of postnatal life; during this time, the majority of muscle cells in lateral gastrocnemius also become singly innervated. We delayed synapse elimination by cutting the tendon of insertion of lateral gastrocnemius (tenotomy) on the day of birth. Both synapse elimination and postnatal myogenesis were slowed by tenotomy. Tenotomized muscles contained fewer detectable cells than unoperated contralateral control muscles. These results suggest that synapse elimination may be altered by altering postnatal muscle fiber addition.

Common ocular infections. A prescriber's guide.

While most ocular infections are benign, others can be associated with devastating visual consequences. Most patients present with either ocular discharge, visual symptoms or a red or painful eye. The primary care physician is usually the first to evaluate these patients. We have separated ocular infections into 3 groups. Infections affecting the cornea and conjunctiva often present with eye pain and a red eye; noninfectious aetiologies can have a similar presentation. Infections inside the eye (endophthalmitis) often have devastating consequences. They usually occur following penetrating ocular trauma or after intraocular surgery. Prompt referral to an ophthalmologist is crucial. Infections in the soft tissue surrounding the eye (ocular adnexa and orbit) can involve the eye indirectly and can spread from the orbit into the brain. The purpose of this article is to review ocular infections and current opinion regarding treatment. A general guideline should be that the approach to treatment be governed by the severity of symptoms and the magnitude of possible consequences. Mild external infections can be typically treated empirically. Severe conjunctivitis, and any corneal infection, require aggressive management, often including cultures and broad spectrum antibiotics; cultures are often used to guide treatment. Devastating vision loss can occur, even with aggressive management. Preseptal cellulitis in adults and older children can be managed conservatively with oral antibiotics if the orbit and optic nerve are not involved and the patient is otherwise healthy. Orbital or optic nerve involvement, on the other hand, demands orbital imaging and more aggressive intervention. Patients who have had recent surgery are at risk for developing endophthalmitis. Complaints of pain or a red eye must be taken very seriously. These patients must be considered to have an intraocular infection until it can be ruled out, and should be aggressively managed by a physician trained in eye diseases and surgery.

Prognostic indicators for vision and mortality in shaken baby syndrome.

OBJECTIVE: To study ocular and nonocular signs of patients diagnosed as having "shaken baby syndrome" and determine prognostic indicators for vision and mortality. METHODS: Medical records of child abuse cases involving bilateral retinal hemorrhages were reviewed. Particular attention was paid to visual function and pupillary light reaction at the time of admission as well as the location of retinal hemorrhages, neuroimaging findings, ventilatory requirement, and associated skeletal injuries. These findings were correlated with visual prognosis and mortality. RESULTS: Thirty consecutive cases met the criteria for review. At the initial visit, mean age of the children was 9.3 months (range, 1-39 months) and 12 children (40%) had at least fix-and-follow vision. Preretinal and intraretinal hemorrhages (93% [n = 28] and 100% [n = 30]) were more common than vitreous hemorrhage (10% [n = 3]). Subdural hematomas were detected in 21 patients (70%). Twenty children (67%) had seizures and 16 (53%) required ventilatory support; bruises and long bone fractures were seen in 14 (47%) and 4 (13%) children, respectively. Eight patients died. All patients with nonreactive pupils on presentation died, while all patients with a pupillary light reaction lived (P<.001). Six (86%) of 7 patients with midline shift died, whereas 21 (91%) of 23 with no midline shift lived (P<.001). At follow-up, retinal hemorrhages had resolved in nearly all children by 4 months, and 16 children (73%) had at least fix-and-follow vision. Ventilatory requirement was associated with poorer vision (P<.01). CONCLUSIONS: Nonreactive pupils and midline shift of the brain structures correlate highly with mortality. Ventilatory requirement, but not visual acuity on presentation, predicts visual outcome.

Primary oblique muscle overaction: the brain throws a wild pitch.

BACKGROUND: Sensorimotor and orbital anatomical mechanisms have been invoked to explain primary oblique muscle overaction. METHODS: Review of primitive visuo-vestibular reflexes and neuroanatomical pathways corresponding to vestibulo-ocular reflexes, and correlation with known clinical abnormalities in patients with primary oblique muscle overaction. RESULTS: Bilateral superior oblique muscle overaction, which corresponds to a backward pitch in lateral-eyed animals, can occur when structural lesions involving the brainstem or cerebellum increase central otolithic input to the extraocular muscle subnuclei that modulate downward extraocular muscle tonus. Bilateral inferior oblique overaction, which corresponds to a forward pitch in lateral-eyed animals, may result from visual disinhibition of central vestibular pathways to the extraocular muscle subnuclei that modulate upward extraocular muscle tonus. CONCLUSIONS: Primary oblique muscle overaction recapitulates the torsional eye movements that occur in lateral-eyed animals during body movements or directional luminance shifts in the pitch plane. These primitive ocular motor reflexes become manifest in humans when early-onset strabismus or structural lesions within the posterior fossa alter central vestibular tone in the pitch plane.

Tonic ocular tilt reaction simulating a superior oblique palsy: diagnostic confusion with the 3-step test.

BACKGROUND: The tonic ocular tilt reaction (OTR) consists of vertical divergence of the eyes (skew deviation), bilateral conjugate ocular torsion, and paradoxical head tilt. The head and superior pole of both eyes are rotated toward the hypotropic eye. OBJECTIVE: To describe ocular motility and torsion findings in 5 patients with OTRs that mimicked superior oblique palsies (SOPs). RESULTS: In 5 patients, results of the 3-step test suggested an SOP (bilateral in 1 patient); however, no patient had the expected excyclotorsion of the hypertropic eye. Two patients had conjugate ocular torsion (intorsion of the hypertropic eye and extorsion of the hypotropic eye), and 2 patients had only intorsion of the hypertropic eye. All had other neurologic features consistent with more widespread brainstem disease. CONCLUSIONS: Vertical ocular deviations that 3-step to an SOP are not always caused by fourth nerve weakness. When a patient with an apparent fourth nerve palsy has ocular torsion that is inconsistent with an SOP, OTR should be suspected, especially if vestibular system or posterior fossa dysfunction coexists. The rules for the 3-step test for an SOP may be fulfilled by damaging the otolithic projections corresponding to projections of the contralateral anterior semicircular canal. Because results of the Bielschowsky head tilt test may be positive in patients with the OTR, the feature distinguishing OTR from an SOP is the direction of torsion. We advocate use of a fourth step-evaluation of ocular torsion-in addition to the standard 3 steps.

Empiric treatment of endophthalmitis. Are aminoglycosides necessary?

OBJECTIVE: To reevaluate the necessity of empiric gram-negative therapy for postoperative endophthalmitis based on the recognition of aminoglycoside-induced toxic effects. METHODS: A review of 162 cases of culture-positive bacterial endophthalmitis to determine bacterial prevalence, antibiotic susceptibilities, and laboratory staining results of intraocular material. RESULTS: One hundred fifty (93%) gram-positive and 12 (7%) gram-negative isolates. All the gram-positive bacteria were susceptible to vancomycin hydrochloride; and gram-negative bacteria were susceptible to gentamicin sulfate, amikacin sulfate, and ceftazidime sodium. Bacterial rods were observed on smear of intraocular material in 10 gram-negative cases submitted for examination. CONCLUSION: Vancomycin is an appropriate single agent if laboratory studies rule out gram-negative infection. In the absence of laboratory support, an aminoglycoside (possible toxic effects) or another gram-negative antibiotic (possibly ceftazidime) should also be administered.

Use of formamide increases the number of detectable inputs to polyneuronally innervated mammalian skeletal muscle.

We evaluated the extent of polyneuronal innervation in neonatal rat lateral gastrocnemius muscle with intracellular recording techniques using both formamide and d-tubocurarine as paralytic agents. We detected more polyneuronal innervation during the first postnatal week using formamide than d-tubocurarine. Both the average number of inputs per muscle cell and the percentage of polyinnervated cells were greater when formamide, rather than d-tubocurarine, was used to diminish muscle contraction. The difference in the extent of polyneuronal innervation detected using the two methods declines during the first postnatal week and the number of inputs observed with formamide during the second postnatal week does not differ from that seen with d-tubocurarine.

Recurrence of idiopathic intracranial hypertension after weight loss: the carrot craver.

PURPOSE: To describe a patient with stable idiopathic intracranial hypertension whose papilledema worsened. METHOD: Case report. RESULTS: A patient with documented idiopathic intracranial hypertension had resolution of disc edema with weight loss. Recurrence of papilledema led to the discovery that she consumed large quantities of raw carrots to help maintain her weight. Her increased vitamin A levels normalized, and the disc edema resolved when she stopped eating carrots. CONCLUSION: Patients with idiopathic intracranial hypertension should be counseled regarding carrot intake.

Human immunodeficiency virus-associated vision loss: electroretinogram attenuation.

PURPOSE: To report a 35-year-old man with human immunodeficiency virus (HIV) and bilateral progressive decrease in vision thought to be caused by HIV optic neuropathy but associated with a severe attenuation of the electroretinogram. METHODS: Case report, review of laboratory studies, visual fields, and electroretinogram. RESULTS: Visual function deteriorated in an asymmetric fashion over 9 months of follow-up and continued to deteriorate, even when the patient had no detectable viral load. No evidence of cytomegalovirus retinitis or HIV retinopathy was present. An electroretinogram showed severe attenuation of both rod and cone-mediated functions. CONCLUSIONS: In addition to producing retinal ganglion cell axonal degeneration, HIV may also damage the other retinal elements. The progression of visual loss in the absence of detectable virus has implications for the pathogenesis and prognosis of HIV-associated vision loss.

Pupil-sparing third nerve palsy associated with sildenafil citrate (Viagra).

PURPOSE: To report unilateral pupil-sparing third nerve palsy after use of sildenafil citrate (Viagra). METHOD: Case report. RESULTS: A 56-year-old man with a history of tobacco abuse was treated for erectile dysfunction. Viagra, 50 mg, was taken once without adverse effect. Three weeks later, the patient took a second dose of Viagra (50 mg); 36 hours later he experienced a complete pupil-sparing third nerve palsy. Erythrocyte sedimentation rate, blood glucose level, magnetic resonance imaging, and magnetic resonance angiography were normal. CONCLUSION: In a patient with microvascular disease, use of sildenafil may be associated with pupil-sparing third nerve palsy.

False-negative hydroxyamphetamine (Paredrine) test in acute Horner's syndrome.

PURPOSE: To describe a false-negative hydroxyamphetamine test. METHOD: Two patients with acute unilateral Horner's syndrome whose pupils initially dilated equally to hydroxyamphetamine had pharmacologic localization to the postganglionic nerve in the second week following the onset of symptoms. RESULTS: Neuroimaging confirmed the postganglionic location in both cases. CONCLUSION: Falsely negative localization with hydroxyamphetamine can occur during the first week after injury, during which time the function of the boutons at the presynaptic terminal is lost.

Hourglass-shaped visual fields as a sign of bilateral lateral geniculate myelinolysis.

PURPOSE/METHODS: Bilateral visual field defects resembling an hourglass could be produced by bilateral lateral geniculate lesions. We recently encountered such deficits in a 37-year-old woman after an episode of central pontine myelinolysis. RESULTS/CONCLUSIONS: Automated static perimetry demonstrated the congruous visual field defects to involve both halves of the visual field. They were confirmed with kinetic perimetry, and they remained stable for four years. Magnetic resonance imaging demonstrated enhancing lesions characteristic of myelinolysis in each lateral geniculate.

Horner's syndrome in subadventitial carotid artery dissection and the role of magnetic resonance angiography.

PURPOSE/METHODS: A 47-year-old man with a postganglionic Horner's syndrome and severe right facial pain was found to have a normal carotid angiogram. We obtained a magnetic resonance angiogram of the neck because of our continued clinical suspicion of dissection. RESULT/CONCLUSION: An area of hyperintensity was identified along the lumen of the right internal carotid artery, suggesting a subadventitial dissection. Magnetic resonance angiography is a noninvasive, sensitive technique for identifying some carotid dissections.

Automated perimetry in amblyopia: a generalized depression.

PURPOSE: To quantitate the visual field abnormalities associated with amblyopia. METHODS: In a prospective study, 37 amblyopic patients (11 anisometropic, 13 strabismic, 9 combination, 4 deprivation) performed automated perimetry in each eye using the Humphrey 30-2 program. Primary outcome measures were foveal threshold, mean deviation, and average threshold. RESULTS: When the probability plots were examined, 21 visual fields in amblyopic eyes were normal, 8 had central scotomas, and 7 had diffuse depressions. No focal defects other than mild central scotomas were seen. However, the foveal threshold of amblyopic eyes was decreased by an average of 7.2 +/- 8.0 dB (P < .0001) compared with fellow eyes; intereye differences in mean deviation (3.2 +/- 5.4 dB; P < .001) and average threshold (2.9 +/- 5.3 dB; P < .005) were also seen. This decrease in sensitivity for the amblyopic eye occurred for all types of amblyopia. The depression in threshold was greatest at the fovea but was detectable and significant at all eccentricities of the 30-degree field. The average threshold in the amblyopic eye was highly correlated with visual acuity (r = .839; P < .001). CONCLUSIONS: Although automated visual fields in amblyopic eyes typically appear normal, all four types of amblyopia are associated with a generalized depression of light sensitivity, which is proportionately greatest at the fovea and highly correlated with visual acuity loss. In general, amblyopia is not associated with any area of focal loss of threshold light sensitivity. If a focal defect is present in the visual field of the amblyopic eye, organic causes of visual loss should be suspected. The Humphrey visual field analyzer STATPAC program (Allergan-Humphrey, Inc, San Leandro, California) may artifactually transform small and generalized full-field depressions in a manner that makes them appear to be isolated central defects.

Global visual field involvement in acute unilateral optic neuritis.

PURPOSE: To quantify automated visual field defects seen at entry in the Optic Neuritis Treatment Trial (ONTT) to determine whether particular areas of the field are preferentially affected and to determine the extent of visual field involvement in patients having "localized" field defects. METHODS: Review of Humphrey 30-2 Visual Field (Allergan-Humphrey, Inc, San Leandro, CA) data from the involved and fellow eyes of 440 patients who were enrolled in the ONTT. Field defects were evaluated by comparing the involved eye to the fellow eye. RESULTS: Patients with diffuse visual field defects had a relatively equal diminution of visual threshold throughout the tested 30-2 field. Patients with localized central and cecocentral scotomas had their greatest depression of threshold centrally; however, even those patients with mild defects (mean defect, <6 dB) had diminution of visual threshold throughout the entire tested 30-degree field. Patients with moderate (mean defect, 6 to 20 dB) and severe (mean defect, >20 dB) central and cecocentral defects had even greater peripheral depression. Patients with altitudinal or quadrant defects had involvement of the "unaffected" field that also varied with the mean defect. The overall average depression of visual threshold for all patients averaged 36%+/-4% and was relatively uniform throughout the tested field. CONCLUSIONS: Optic neuritis affects the entire central 30-2 field, even in patients who appear to have localized depression of visual threshold. Optic neuritis does not appear to have a predilection for any particular area of the visual field.

Recovery of visual field function in the optic neuritis treatment trial.

PURPOSE: To assess the pattern of recovery of the visual field of patients with optic neuritis and to determine whether all affected portions of the visual field recover similarly or certain portions of the visual field have greater recovery. METHODS: We reviewed the Humphrey Visual Field (Allergan-Humphrey Inc, San Leandro, California) data from the initial and 6-month examination for the involved and fellow eyes of patients enrolled in the Optic Neuritis Treatment Trial (ONTT). The average threshold for each patient was calculated for the entire tested field and for locations within concentric rings having a radius 3, 9, 15, 21, and 27 degrees from fixation. The absolute amount of improvement and percentage improvement in average threshold between entry and the 6-month follow-up examination were determined for each patient. These measurements were compared within the concentric rings to assess patterns of recovery. RESULTS: Patients with localized defects recovered 86%+/-20% of their initial defect in average threshold, whereas those having diffuse defects recovered an average of 85%+/-23%. The area about fixation had the greatest relative recovery of threshold (87%+/-21% at 3 degrees); the relative recovery decreased with increasing eccentricity from fixation (P<.01). CONCLUSIONS: Patients with optic neuritis have a marked return of visual field function that does not appear to differ between patients with diffuse or localized field defects. The reduced redundancy of axons in the periphery of the field compared with near fixation may be responsible for the greater relative recovery of threshold near fixation.

Skew deviation and inferior oblique palsy.

PURPOSE: To describe ocular motility and neuro-ophthalmologic findings in six patients with an ocular tilt reaction (OTR) that mimicked an inferior oblique palsy (IOP). DESIGN: Observational Case Series. METHODS: Series of six patients presenting to tertiary care pediatric or neuro-ophthalmologist. RESULTS: Five patients had ocular motility and three-step test results suggesting an IOP; one patient had a suspected bilateral IOP. All six patients had excyclotorsion of the hypotropic eye, and four had incyclotorsion of the hypertropic eye. This is contrary to that expected with an IOP (incyclotorsion of the hypotropic eye). In addition, all six patients had other neurologic findings in the history or examination that were associated with neurologic insult rather than an isolated IOP. Two patients had surgery consisting of a superior rectus recession; this was successful in eliminating diplopia in both patients and in eliminating the vertical deviation and head posturing in one patient. CONCLUSION: While many vertical deviations that appear to be due to an inferior oblique palsy based on the results of the three-step test may be caused by inferior oblique weakness, skew deviation should also be considered in any patient with a history of head trauma, or other neurologic findings. The cyclotorsion observed in IOP is opposite that seen with OTR, and differentiates the two entities clinically. We postulate that these deviations are caused by damage to the otolithic projections that correspond to those from the ipsilateral posterior semicircular canal (on the side of the hypotropic eye).