Adult onset acquired myasthenia gravis in three Great Dane littermates.

Acquired canine myasthenia gravis is an autoimmune disease in which autoantibodies are directed against muscle postsynaptic nicotinic acetylcholine receptors. Three adult great dane littermates were evaluated over a four month time period for an acute onset of generalised neuromuscular signs. All three dogs had elevated serum acetylcholine receptor antibody titres, which were considered diagnostic for acquired myasthenia gravis. Identification of three littermates with acquired myasthenia gravis in a breed with a low relative risk of developing the disease suggests a familial and possibly a genetic predisposition to myasthenia gravis in this family of dogs.

Painful oculomotor palsy caused by posterior-draining dural carotid cavernous fistulas.

BACKGROUND: Carotid cavernous fistulas cause conjunctival hyperemia and orbital soft-tissue swelling because of increased flow directed anteriorly in ophthalmic veins. Less well recognized is that when fistular flow is directed posteriorly, these congestive features will be absent and the diagnosis of the "white-eyed shunt" will be missed unless angiography is performed. METHODS: Two patients who had oculomotor nerve palsies caused by posteriorly draining dural carotid cavernous fistulas were studied, and the 28 previously described cases were reviewed. RESULTS: One patient had a chronic painful palsy of the sixth cranial nerve, and the other, a palsy of the third cranial nerve. Cerebral angiography disclosed the fistulas. The clinical and imaging features of these cases conform to those of the 28 previously reported white-eyed shunts. Angiographic features do not explain why some posterior-draining fistulas cause sixth-nerve palsies and others cause third- (or rarely, fourth-) nerve palsies. CONCLUSIONS: Dural carotid cavernous fistulas that drain primarily into the inferior petrosal sinus may cause painful oculomotor palsies that elude diagnosis because they lack congestive orbito-ocular features. Treatment by embolization leads to more rapid resolution of manifestations.

DEA 1 expression on dog erythrocytes analyzed by immunochromatographic and flow cytometric techniques.

BACKGROUND: The Dog erythrocyte antigen (DEA) 1 blood group system was thought to contain types DEA 1.1 and 1.2 (and possibly 1.3 [A3]). However, DEA 1.2+ dogs are very rare and newer typing methods reveal varying degrees of DEA 1 positivity. OBJECTIVES: To assess if variation in DEA 1 positivity is because of quantitative differences in surface antigen expression. To determine expression patterns in dogs over time and effects of blood storage (4°C). To evaluate DEA 1.2+ samples by DEA 1 typing methods. ANIMALS: Anticoagulated blood samples from 66 dogs in a research colony and from a hospital, and 9 previously typed DEA 1.2+ dogs from an animal blood bank. METHODS: Research study: Samples were analyzed by flow cytometry and immunochromatographic strip using a monoclonal anti-DEA 1 antibody. RESULTS: Twenty dogs were DEA 1-, whereas 46 dogs were weakly to strongly DEA 1+. Antigen quantification revealed excellent correlation between strip and flow cytometry (r = 0.929). Both methods reclassified DEA 1.2+ samples as weakly to moderately DEA 1+, but they were not retyped with the polyclonal anti-DEA 1.1/1.X antibodies. Dogs and blood samples retained their relative DEA 1 antigen densities over time. CONCLUSIONS AND CLINICAL IMPORTANCE: The blood group system DEA 1 is a continuum from negative to strongly positive antigen expression. Previously typed DEA 1.2+ appears to be DEA 1+. These findings further the understanding of the DEA 1 system and suggest that all alleles within the DEA 1 system have a similarly based epitope recognized by the monoclonal antibody.

Idiopathic intracranial hypertension in men.

OBJECTIVE: To compare the characteristics of idiopathic intracranial hypertension (IIH) in men vs women in a multicenter study. METHODS: Medical records of all consecutive patients with definite IIH seen at three university hospitals were reviewed. Demographics, associated factors, and visual function at presentation and follow-up were collected. Patients were divided into two groups based on sex for statistical comparisons. RESULTS: We included 721 consecutive patients, including 66 men (9%) and 655 women (91%). Men were more likely to have sleep apnea (24% vs 4%, p < 0.001) and were older (37 vs 28 years, p = 0.02). As their first symptom of IIH, men were less likely to report headache (55% vs 75%, p < 0.001) but more likely to report visual disturbances (35% vs 20%, p = 0.005). Men continued to have less headache (79% vs 89%, p = 0.01) at initial neuro-ophthalmologic assessment. Visual acuity and visual fields at presentation and last follow-up were significantly worse among men. The relative risk of severe visual loss for men compared with women was 2.1 (95% CI 1.4-3.3, p = 0.002) for at least one eye and 2.1 (95% CI 1.1-3.7, p = 0.03) for both eyes. Logistic regression supported sex as an independent risk factor for severe visual loss. CONCLUSION: Men with idiopathic intracranial hypertension (IIH) are twice as likely as women to develop severe visual loss. Men and women have different symptom profiles, which could represent differences in symptom expression or symptom thresholds between the sexes. Men with IIH likely need to be followed more closely regarding visual function because they may not reliably experience or report other symptoms of increased intracranial pressure.

Vertical diplopia.

The diagnosis of an acquired vertical strabismus is not always straightforward. There is no one specific test that will diagnose a vertical deviation. The clinical presentation, signs, and symptoms are the driving forces that will help lead to the correct diagnosis. Patients with binocular vertical diplopia may have symptoms of recent onset or that have been long-standing. Others may not even be completely aware that their ocular symptoms are attributable to a doubled vertical image. The differential diagnosis for vertical diplopia includes oculomotor nerve palsy, superior oblique palsy, restrictive ophthalmopathies, myasthenia gravis, and skew deviation. This differential diagnosis is best used to sort out signs and symptoms in a patient with a vertical misalignment and diplopia. Because most clinicians feel more comfortable addressing the patient with complaints of horizontal diplopia, this paper will discuss the causes of vertical diplopia so that recognition will be easier, thus leading to more accurate diagnoses.

Two types of oscillopsia in a patient with idiopathic vestibulopathy.

A patient with an idiopathic bilateral vestibulopathy described two types of oscillopsia, one induced by head movement, the other induced by changing pressure in the right external auditory canal. This is the first report of both types of oscillopsia occurring in the same individual and illustrates their different mechanisms and symptomatology.