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Biomedical subjects

Jonathan D Trobe

Publications and source records attributed to Jonathan D Trobe.

27 records · Page 2Linked to original sources

Late ipsilateral recurrence of ischemic optic neuropathy in giant cell arteritis.

A patient with arteriosclerosis, diabetes mellitus, and giant cell arteritis (GCA) treated continuously with low-dose prednisone developed anterior ischemic optic neuropathy (AION) at 5 and 13 months after clinical diagnosis of GCA. At the time of late recurrent AION, there were no systemic symptoms or elevations in acute phase reactants to signal active arteritis, yet temporal artery biopsy disclosed dramatic inflammation, forcing the presumption that the infarct was arteritic. Recurrent systemic symptoms and elevation of acute phase reactants are not reliable warning signs of reactivated GCA. In patients at high risk for corticosteroid complications, late biopsy may be a reasonable guide to corticosteroid weaning.

Aged↗

Linear magnetic resonance enhancement and optic neuropathy in primary angiitis of the central nervous system.

A 38-year-old woman developed incoherent mentation, tremor, ataxia, and bilateral optic disc edema with mildly depressed visual acuity, nerve fiber bundle defects, and a left afferent pupillary defect. Magnetic resonance imaging of the brain disclosed striking linear contrast enhancement radiating from the ventricular borders. Lumbar puncture showed a normal opening pressure with a lymphocytic pleocytosis and elevated protein. On the basis of these findings, the initial diagnosis was viral or post-viral meningoencephalitis and the patient was not treated. During the next 4 weeks, her condition worsened. A brain and meningeal biopsy disclosed findings typical of primary angiitis of the central nervous system. With aggressive treatment, her neurologic status and magnetic resonance imaging normalized and her optic neuropathy improved markedly. Optic neuropathy and linear magnetic resonance imaging enhancement should be recognized as features of primary angiitis of the central nervous system.

Adult↗

Hemifacial spasm caused by vertebral artery dolichoectasia.

PURPOSE: To display the characteristic magnetic resonance imaging (MRI) abnormalities associated with hemifacial spasm caused by compression of the seventh cranial nerve by a dolichoectatic vertebral artery. DESIGN: Interventional case report. METHODS: Correlation of imaging and clinical findings. RESULTS: In a 36-year-old man with mild left hemifacial spasm, MRI showed an enlarged (dolichoectatic) vertebral artery that compressed the seventh cranial nerve at its exit from the caudal pons. Manifestations of hemifacial spasm were relieved with periocular botulinum toxin injections. CONCLUSION: In hemifacial spasm, MRI may show compression of the ipsilateral seventh cranial nerve or other structural abnormalities. Relief of hemifacial spasm may occur with botulinum toxin injection or with neurosurgical intervention designed to relieve the compression.

Adult↗

Spasm of accommodation associated with closed head trauma.

Spasm of accommodation, creating pseudomyopia, is generally associated with miosis and excess convergence as part of spasm of the near reflex. It may also exist as an isolated entity, usually attributed to psychogenic causes. We present six cases of accommodative spasm associated with closed head injury. All patients were male, ranging in age between 16 and 37 years. The degree of pseudomyopia, defined as the difference between manifest and cycloplegic refraction, was 1.5 to 2 diopters. A 3-year trial of pharmacologically induced cycloplegia in one patient did not lead to reversal of the spasm when the cycloplegia was stopped. All patients required the manifest refraction to see clearly at distance. The pseudomyopia endured for at least 7 years following head trauma. This phenomenon may represent traumatic activation or disinhibition of putative brain stem accommodation centers in young individuals.

Accommodation, Ocular↗

Spontaneous direct carotid-cavernous fistula in Ehlers-Danlos syndrome type IV: two case reports and a review of the literature.

Two unrelated adults with Ehlers-Danlos syndrome type IV developed acute unilateral ophthalmoplegia and ipsilateral headache as a consequence of spontaneous (nontraumatic) direct carotid-cavernous fistulas. Because the interventional radiologist suspected the diagnosis of Ehlers-Danlos syndrome type IV, the carotid-cavernous fistulas were closed via the venous rather than the more standard arterial route in an attempt to avoid arterial dissection or rupture. In any patient presenting with a spontaneous direct carotid-cavernous fistula, family history and clinical examination should be targeted toward a diagnosis of Ehlers-Danlos syndrome type IV because of risks attendant to angiography and repair of the fistula. For these patients, ancillary medical care must be approached cautiously to avoid hollow viscus rupture. Molecular tests can be used to confirm the diagnosis and provide family members with accurate genetic counseling and predictive genetic testing.

Adult↗

Delayed visual loss following pergolide treatment of a prolactinoma.

A patient who had achieved marked improvement in vision and shrinkage of a prolactinoma following treatment with pergolide (0.1 mg/day) suffered a marked worsening of vision 7 months after continued treatment at the same dose. Brain magnetic resonance imaging (MRI) at the time of visual loss showed further shrinkage of the tumor and prolapse of the chiasm into the pituitary fossa. The dose of pergolide was cut in half (0.05 mg/day); 12 months later, vision had completely recovered. Brain MRI at the time of visual recovery showed no change in the position of the prolapsed chiasm. This is the 11th reported case of delayed visual loss following dopaminergic treatment of prolactinoma. Recovery of vision always occurs with reduction of the medication dosage. Many patients whose prolactinomas are treated in this fashion display chiasmal prolapse, and few suffer visual loss. Considering that visual recovery occurs without a visible change in the position of the chiasm, traction is an unlikely cause of delayed visual loss. Therefore, the term chiasmal traction syndrome, used to describe visual loss with prolapsed chiasm following surgical and radiation treatment of sellar tumors, should not be applied in this setting lest it prompt consideration of surgical chiasmapexy. The proper management is reduction of the dopaminergic agonist dosage.

Dopamine Agonists↗

Blindness after liver transplant.

A 58-year-old woman developed a generalized seizure 12 days after undergoing liver transplantation and awakened with persistent hand motions vision binocularly. Cyclosporine levels were normal and blood pressure was only mildly elevated. The ophthalmic and neurologic examinations were otherwise normal. Brain MRI revealed bilateral parieto-occipital white matter signal abnormalities consistent with vasogenic edema. The cyclosporine was abruptly replaced with tacrolimus and the patient recovered normal vision within 48 hours. A subsequent brain MRI taken 30 days later showed that the patient had reverted to normal. This is an example of posterior leukoencephalopathy owing to cyclosporine toxicity. It points out that visual loss may be an isolated or most prominent clinical manifestation, cyclosporine and blood pressure levels may be normal, deficits are reversible if cyclosporine is promptly discontinued, and tacrolimus, a similar immunosuppressive agent, may be a safe substitute.

Blindness↗