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Biomedical subjects

D L Knox

Publications and source records attributed to D L Knox.

At least 19 recordsLinked to original sources
PubMed1989

Ocular pseudomyasthenia or ocular myasthenia 'plus': a warning to clinicians.

Myasthenia gravis (MG) commonly presents with weakness and fatigability of the lids and extraocular muscles, which respond to treatment with anticholinesterase medication. However, certain intracranial mass lesions may mimic these features of MG; alternatively, MG may mask the signs of a coexistent intracranial mass. We describe 8 patients originally diagnosed as having MG by knowledgeable clinicians, in whom an intracranial lesion instead of, or in addition to, MG was later identified. The lesions included parasellar tumors and aneurysms. In patients presenting with clinical features of ocular MG, it is therefore essential to establish a definite diagnosis of MG, to exclude other possible causes of "pseudomyasthenia," and to exclude other diseases that might be masked by coexisting myasthenic weakness. We recommend that patients with clinical features of MG limited to the ocular or cranial musculature be thoroughly evaluated for intracranial mass lesions, using CT or MRI if warranted.

Adolescent↗
PubMed1988

Uremic optic neuropathy.

Vision loss progressing over several days, reduced pupil reactions to light, and swollen optic nerves were the clinical features in six patients with severe renal disease manifested by uremia, anemia, and (in four patients) moderately or severely elevated blood pressure. In two patients pale edema of the optic nerve head extended into the macula. One patient with renal transplant rejection was in the early phases of cryptococcal meningitis that went undiagnosed for two weeks. Medical management with hemodialysis was followed by improvement of vision in four patients. In one patient, resumption of oral corticosteroid therapy was followed by improvement in vision. The patient whose vision improved the most rapidly was managed by prompt use of both dialysis and oral corticosteroid therapy. The patient with cryptococcal meningitis did not recover vision.

Adolescent↗
PubMed1987

Uveitis.

Diagnosis and management of the child with an ocular inflammation demands that all of the standard tools of medicine be employed: family and individual history, particularly of allergy, social and diet history, system review, physical examination, and basic laboratory testing with special tests for certain microorganisms and allergies. Close cooperation among pediatrician, ophthalmologist, and family is important. Cases are rare, and management often requires special experience.

Child↗
PubMed1987

Clinical features, laboratory investigations, and survival in ocular reticulum cell sarcoma.

The authors report 32 cases of histologically proven ocular reticulum cell sarcoma (RCS). Follow-up data are available for all patients. Twenty-six patients (81%) have died and the mean survival time was 20 months from the time of diagnosis of RCS. Diagnosis of ocular involvement was made by vitreous biopsy in 56% of cases, enucleation in 13%, and postmortem examination in 31%. The mean age at the time of diagnosis was 60 years. Central nervous system (CNS) involvement was present in 56% of patients, visceral involvement in 16%, and both CNS and visceral involvement in 6%. Isolated ocular disease occurred in 22% of patients. Results of head computed tomography (CT) and cerebrospinal fluid examination more often disclosed evidence of RCS than did body CT or nuclear medicine scans. Responses to treatment were variable, but prognosis for survival is poor.

Adult↗
PubMed1987

Presumed varicella zoster retinitis in immunocompromised patients.

The acute retinal necrosis (ARN) syndrome is a morphologically defined necrotizing retinitis, occurring in apparently otherwise healthy patients. It has been shown that the varicella zoster virus is at least one cause of the ARN syndrome; treatment with acyclovir has proven to be effective for the infectious component of ARN. We report three immunocompromised patients who developed cutaneous herpes zoster and a necrotizing retinitis that was morphologically similar to the ARN syndrome. All three patients responded promptly to treatment with acyclovir, an agent highly effective against varicella zoster and herpes simplex viruses, but ineffective in the treatment of cytomegalovirus. While cytomegalovirus retinitis is more common in immunocompromised patients, these patients may occasionally develop an ARN-like retinitis, presumably as a result of the varicella zoster virus, which responds to treatment with acyclovir.

Acyclovir↗
PubMed1986

Clinicopathologic studies of a case of aortic arch syndrome.

The clinicopathologic features of a 62-year-old woman with the aortic arch syndrome who presented with ischemic ocular inflammation, followed by complete loss of vision, is presented. The pathophysiology and ocular manifestations of chronic ocular ischemia are discussed.

Aortic Arch Syndromes↗
PubMed1986

Ocular features of carotid occlusive disease.

This article presents the clinicopathologic features of five patients with ocular involvement secondary to carotid artery disease. Three patients had the features of hypotensive retinopathy and two had panocular ischemia. In demonstrating the possible ocular and nonocular sequelae of carotid artery disease, this study stressed the importance of the recognition of the variable ocular features associated with carotid artery occlusive disease.

Aged↗
PubMed1979

Psoriasis and intraocular inflammation.

Presented in this series were seven men and three women. Ages when seen, ranged from 32 to 68 years (average 54). Psoriasis had begun in childhood in the women and in the late 20's and 30's in the men. Arthritis (ankylosing spondylitis) was present in only one. Their ocular inflammations began from ages 26 to 62 (average 41). The onset of the inflammation was acute iritis in four and in indolent iridocylcitis in six. All but one were bilateral and chronic. The vitreous had heavy debris in nine of the ten patients. The retina was normal in only three. Boggy congestion was present in two with cystoid edema. Patches of edema. fluorescein leaking, depigmentation of both maculae, pars plana exudate, and retinal vessel obliteration to grey-white, shaggy cords was present in at least one of the remaining five patients. Systemic corticosteroid therapy has been used in eight of the ten patients described in this report. Doses no higher than 30 mg of prednisone per day were used to initiate reversal of the inflammatory response. In case 10, knowledge of the sensitivity of the process to steroids led to the successful rapid reversal of a recalcitrant iritis with only 20 mg of prednisone as a first dose and 20 mg per day for less than three weeks. Maintenance corticosteroid therapy ranged from 40 mg of prednisone every other day in case 9, prednisone 12.5 mg one day and 5 mg the next in case 8, to 8 mg of Aristocort or methylprednisolone acetate (M-edrol) daily in cases 1 and 2. In summary, these patients are older, have an indolent onset bilateral uveitis with dense vitreous debris, retinal abnormalites, and are extremely sensitive to systemic corticosteroids. Many of these patients had undergone the series of clinical evaluations known as a "uveitis survey." Many different systemic abnormalities were found and merited treatment which rarely made a difference in their ocular disease, though two improved after infected teeth were treated. Assuming that these ocular diseases were related to psoriasis, one can then challenge the value of anything found by a "uveitis survey." The author uses information gained from such studies to insure that the patient is in the best possible heatlh and then makes clinical correlations such as presented in this paper. The rarity of this combination of ocular inflammations in patients with psoriasis makes it risky to propose that this is a significant association. Arguments that this is a disease entity began with the clinical similarities: older age, indolent onset, vitreous and retinal involvement, and the extreme sensitivity to systemic corticosteroids. None of these patients had psoriatic arthritis and only one had ankylosing spondylitis. The best explanation for the fact that this disorder has not been emphasized in the past would be an attitude of ophthalmologists and physicians that the eye and skin disease were coincident.

Adolescent↗
PubMed1978

Hypoplasia of the optic nerve.

Premorbid ophthalmoscopic and histopathologic findings were correlated in a case of bilateral optic nerve hypoplasia in a 9-month-old infant with bilateral hydranencephaly. The double-ring sign was due to an extension of retina and retinal pigment epithelium (RPE) over the outer portion of the lamina cribrosa. The outer ring was the junction between sclera and lamina cribrosa, and the inner ring was the termination of the RPE. The center of the inner ring was the hypoplastic nerve head, which appeared whitish because of fibroglial tissue surrounding the central retinal vessels where they entered the optic nerve head. We speculate that an in utero vascular insult, after the third month of development, led to cystic cavitation of the anterior cerebral hemispheres, with subsequent retrograde degeneration of developing retinal ganglion cells.

Abnormalities, Multiple↗
PubMed1977

Cytomegalovirus retinitis in adults. A manifestation of disseminated viral infection.

Retinitis caused by cytomegalovirus (CMV) infection is unusual in adults. Sixteen of the 17 cases reported have occurred in immunologically compromised patients, most frequently renal transplant recipients. CMV retinitis is associated with a distinctive ophthalmoscopic appearance and, in the majority of cases, was the first clinical manifestation of systemic viral infection. Severe and permanent visual deficits are characteristic. Since retinitis is a reliable sign of disseminated disease and ophthalmoscopic examination a rapid method of establishing its presence, recognition of this manifestation should allow earlier diagnosis of serious CMV infection.

Adult↗
PubMed1977

Follow-up study in eyes with choroidal neovascularization caused by presumed ocular histoplasmosis.

Sixty-four eyes of 60 patients with ocular histoplasmosis, and choroidal neovascularization documented by fluorescein angiography, and not treated with photocoagulation, were followed for an average of 29 months. The primary determinant of visual outcome was the proximity of the neovascular membrane to the fovea. Sixty-four percent of eyes with membranes 0.25 disk diameter or greater from the fovea had a final visual acuity of 6/12 (20/40) or better, and 71% of such eyes maintained or improved initial visual acuity. All eyes with subfoveal neovascularization had a poor visual result. Other factors related to visual prognosis included initial visual acuity, size of the neovascular membrane, size of sensory retinal detachment, and presence of hemorrhage.

Adolescent↗
PubMed1976

The tilted disk syndrome.

We noted occasional diagnostic confusion with papilledema and chiasmal compression when its true congential nature was not recognized in 12 patients with a benign ocular syndrome. Retinoscopy, fluorescein angiography, ocular ultrasonography, and histopathology suggested that associated visual field defects were related to a localized staphylomatous ectasia of the posterior globe.

Adolescent↗
PubMed1976

Neurologic disease in patients with treated Whipple's disease.

Four patients with Whipple's disease which had responded to antibiotic therapy, later developed neurologic disease identical to that seen in patients with Whipple's disease who died without treatment. Dementia, myoclonus, ataxia, and supranuclear ophthalmoplegia were the main neurologic features. Restarting antibiotics has been followed by stabilization of disease in all four. Two have improved. In three, the previously diagnosed and treated Whipple's disease was not considered as a possible cause of the neurologic disease until the symptoms and signs were far advanced. It is advisable to periodically evaluate all patients with Whipple's disease, even after successful treatment. Signs of neurologic disease should be considered a possible recurrence of Whipple's disease and antibiotics restarted.

Adult↗