Biomedical subjects
Publications and source records attributed to B T Troost.
We present a common cause of vertigo, benign positional paroxysmal vertigo (BPPV), and its history, diagnosis, and therapy. BPPV is suggested by history, readily diagnosed by office examination, and cured by appropriate exercise therapy. Since the condition is so common and often unrecognized, physicians are encouraged to consider BPPV as a possible cause of treatable dizziness.
BACKGROUND: Earlier reports of cocaine-associated cerebral vasculitis have been based primarily on angiographic findings without pathological verification. CASE DESCRIPTION: We present a case of acute encephalopathy following intravenous and intranasal administration of cocaine. Brain biopsy revealed vascular changes involving primarily small arteries. Findings included lymphocytic infiltration, endothelial thickening, and deposition of proteinaceous amorphous material within and around vessel walls. CONCLUSIONS: These abnormalities are consistent with pathological features of arteritis previously reported in association with amphetamine and multiple-drug abuse. Vasospasm-induced changes are an alternative explanation for the vascular picture seen in this case. The patient made modest improvement with high-dose intravenous steroids.
Amaurosis fugax in a younger person in whom premature atherosclerotic disease and cardiac emboli have been eliminated is usually benign. We describe a 25-year-old man with recurrent painless left monocular visual loss lasting from 5 to 45 minutes. Initial physical examination, carotid ultrasound, and electrocardiogram were normal. Goldmann visual field testing demonstrated a small, left paracentral defect. Neuroimaging studies were initially declined for economic reasons, but later a magnetic resonance image disclosed a large pituitary tumor displacing the left optic nerve and chiasm. The tumor was removed via a transphenoidal approach, and the episodic visual symptoms disappeared. We stress that amaurosis fugax in young patients is not necessarily benign. A specific etiology should be diligently sought, particularly when ocular signs are present.
Transcranial Doppler ultrasound is a relatively new diagnostic modality which allows the noninvasive assessment of intracranial circulation. A total of 10 migraine patients were studied and compared to healthy controls without headaches. Migraineurs during the headache-free interval demonstrated excessive cerebrovascular reactivity to CO2, evidenced by an increase in middle cerebral artery blood flow velocity of 47% +/- 15% compared to 28% +/- 14% in controls (p = 0.026). Differences between the two study groups revealed no significant decrease in middle cerebral artery blood flow velocity with hypocapnia. However, the differences between middle cerebral artery blood flow velocity during hyperventilation and CO2 inhalation were significantly different (p = 0.004) comparing migraineurs and controls. Instability of the baseline blood flow velocities was also noted in migraineurs during the interictal period. Characteristics which may allow differentiation of migraineurs from other headache populations could possibly be obtained from transcranial Doppler ultrasound flow studies.
We identified 60 patients (42 men and 18 women with an average age of 62.6 years) with angiographically documented carotid stenoses of greater than or equal to 95%; a string sign was demonstrated in 28. Twenty of the 60 patients (33%) were asymptomatic on presentation, 26 (43%) had hemispheric transient ischemic attacks, 21 (35%) had amaurosis fugax, and nine (15%) had previous ipsilateral infarctions. Demographics, mode of presentation, and prevalence of atherosclerotic risk factors were not significantly different between patients with and without a string sign. Doppler frequencies recorded in patients with a string sign were less than 6 or greater than 16 KHz. Real-time ultrasonography imaged a patent lumen in all but three cases with a string sign. Surgery was performed in 26 patients with a string sign and in 21 patients without a string sign. The rate of major perioperative complications was not influenced by the presence of a string sign, contralateral extracranial stenosis, or ipsilateral siphon stenosis. Average lumen size of the endarterectomy specimens was 0.94 mm in those with and 1.7 mm in those without a string sign. We conclude that combined noninvasive testing has a sensitivity of 83% for demonstrating a residual lumen in patients with greater than or equal to 95% carotid stenosis and that the angiographic string sign does not affect the mode of presentation or surgical outcome of these patients.
Explore the source record for details and available documents.
We describe an unusual patient with periodic alternating oscillopsia caused by periodic alternating nystagmus. A dramatic cessation of her symptomatology and disappearance of periodic alternating nystagmus was achieved with baclofen and has been maintained for a period of over nine months. The importance of proper diagnosis and therapy of patients with oscillopsia is described.
Cerebral blindness is usually a transient event that can complicate cardiac catheterization. The neurologic deficit clears in 1-3 days. We present a patient who developed permanent cerebral blindness after undergoing transfemoral cardiac catheterization. Bilateral hemorrhagic occipitotemporal infarcts were demonstrated on magnetic resonance imaging (MRI). The patient also demonstrated denial of blindness and had transient memory disturbances due to occipitotemporal lobe infarct. The probable source of the emboli was cardiac.
Explore the source record for details and available documents.
A 49-year-old man presented with blurred vision 9 days following frontal head trauma. Visual loss progressed to bilateral blindness. Magnetic resonance imaging revealed hemorrhage and swelling within the optic nerves and chiasm. Indirect trauma to the anterior visual pathways may cause delayed blindness due to hemorrhage and edema within these structures.
We report a photographically documented false-positive edrophonium test in a patient with a histologically verified brainstem glioma. While a positive response to intravenous edrophonium should usually be regarded as confirmatory for myasthenia gravis, the possibility of a false-positive test must be considered in patients with atypical physical findings.
Explore the source record for details and available documents.
A review of different types of nystagmus is presented. The review includes characteristic features of the history and findings on examination of nystagmus which allow classification. Types of nystagmus reviewed include congenital, acquired pendular, acquired jerk nystagmus, special nystagmus types such as periodic alternating and downbeat, and the related ocular oscillations such as ocular myoclonus and superior oblique myokymia.
Two patients who were treated with lithium for psychiatric illness developed primary position downbeat nystagmus. Previous reports have suggested that lithium causes this type of nystagmus, but other known causes were present in most cases. Several months after stopping the lithium, one patient had marked resolution, while the second patient had only minimal improvement. Valproate sodium proved to be useful in suppressing the nystagmus in the second patient. Lithium carbonate is a cause of primary position downbeat nystagmus. The nystagmus may be permanent or require several months of abstinence for improvement.
Explore the source record for details and available documents.
Facial numbness and dysesthesia have not been emphasized as presenting features in spontaneous internal carotid artery dissection. Progressive facial pain, accompanied by oculosympathetic paresis, altered taste, and facial numbness suggest the possibility of basal skull neoplasm. We describe a patient, with previously undiscovered fibromuscular dysplasia, who presented with severe neck and face pain, dysgeusia, oculosympathetic paresis, and markedly reduced facial sensation due to a spontaneous vascular dissection. Altered facial sensation should now be included in the symptomatology of internal carotid artery dissection.
See-saw nystagmus has been seen with tumors of the parasellar region and diencephalon, brain-stem vascular lesions, syringobulbia, and after trauma. We report see-saw nystagmus in an adult with a Chiari malformation that was diagnosed by magnetic resonance imaging and confirmed intraoperatively. This patient's condition improved after surgical decompression. An association between see-saw nystagmus and Chiari malformation is potentially important because early diagnosis and decompression may improve neurologic function and prevent further deterioration.