Ophthalmology.
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Ambulatory Surgical Procedures↗
Biomedical subjects
H M Towler
Publications and source records attributed to H M Towler.
The painful eye.
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Anti-Bacterial Agents↗
Progressive outer retinal necrosis (PORN) in AIDS patients: a different appearance of varicella-zoster retinitis.
Retinal infections caused by the varicella-zoster virus (VZV) have been reported in immunocompetent and immunocompromised individuals. Two cases of a VZV-related retinitis are described with the characteristic features of the recently described progressive outer retinal necrosis (PORN) syndrome. Both patients suffered from the acquired immunodeficiency syndrome (AIDS) with greatly reduced peripheral blood CD4+ T lymphocyte counts, and presented with macular retinitis without vitritis. The disease was bilateral in one case and unilateral in the other. The clinical course was rapidly progressive with widespread retinal involvement and the development of rhegmatogenous retinal detachment with complete loss of vision in the affected eyes despite intensive intravenous antiviral therapy. VZV DNA was identified in vitreous biopsies, by molecular techniques based on the polymerase chain reaction (PCR), in both patients. At present, the use of very high-dose intravenous acyclovir may be the best therapeutic option in these patients for whom the visual prognosis is poor. Intravitreal antiviral drugs could also contribute to the management of these cases.
AIDS-Related Opportunistic Infections↗
Retinal detachment and herpesvirus retinitis in patients with AIDS.
BACKGROUND: The prolongation of survival of patients with herpesvirus retinitis and AIDS has been associated with a rise in the incidence of retinal detachment. In such cases, however, retinal reattachment may be difficult to achieve, and postoperative visual acuity may be poor despite anatomically successful surgery. METHODS: In order to examine factors affecting the visual outcome of surgery, a retrospective review of 29 patients with retinal detachment, herpesvirus retinitis, and AIDS was performed. Retinal reattachment surgery (32 procedures) or prophylactic laser demarcation (five procedures) was performed in 28 eyes of 23 patients. RESULTS: The macula was attached in 23/28 (82%) eyes at the last outpatient visit. Best postoperative visual acuity (median 6/18, range 6/6-hand movements) was significantly greater than final postoperative acuity (median counting fingers, range 6/6-no perception of light) (Wilcoxon sign rank test, p = 0.003), and was retained for a median of 3 months (1-91 weeks) after surgery. Poor visual outcome as evidenced by submedian final visual acuity was invariably associated with persistence of macular detachment, and significantly associated with the occurrence of optic atrophy (odds ratio = 5, p = 0.02). CONCLUSION: Retinal reattachment surgery appears justified in patients with herpesvirus retinitis and AIDS, but postoperative visual deterioration may occur in association with optic atrophy.
AIDS-Related Opportunistic Infections↗
Fungal feeding-line infections: beware the eyes and teeth.
Twenty-four fungal feeding-line infections occurred in 17 patients during 1984-1992. Thirteen were receiving long-term home parenteral feeding and, in them, the first infection occurred after a median of 30 months (range 1-120) continuous feeding with a line that had been in situ for a median of 20 months (range 1-37). Four were receiving short-term feeding through a line that had been inserted 1-2 months previously. At the time of the first infection all patients were febrile and most were anaemic (15/16), however a leucocytosis was rare (three of 16). The fungi isolated were Candida albicans(6), Candida parapsilosis(5), Candida glabrata(2), Candida guillermondii(2) and other species (2). In 16 patients, the feeding-line was removed at the time of the first infection and no other treatment was given, and no other complications occurred in eight (50%) of these. In 11, the line was reinserted a median of 7 days after removal (range 1-11). Four patients (24%) developed a Candida infection of the eye 1-8 weeks after the diagnosis, uveitis (2) and endophthalmitis (2) which, in one patient, led to complete blindness in one eye. Two patients had recurrent infections which began within a month of dental therapy. In one, the infections stopped after dental extractions and, in the other, after a dental clearance. An ophthalmoscopic examination should be performed in all patients with a fungal feeding-line infection. Recurrent candidal infections may have a dental origin.
Candidiasis↗
Uveitis presenting de novo in the elderly.
Seventy-one consecutive patients presenting with their first episode of uveitis at the age of 60 or more years, were studied retrospectively. The majority were found to have idiopathic uveitides on investigation. In those who did have associated systemic disease, the commonest finding was non-insulin-dependent diabetes mellitus or an autoimmune disease. There were no cases of ocular lymphoma in this series. We conclude that, contrary to some previous reports, idiopathic uveitis may occur in the elderly, and that the relative frequencies of acute anterior, chronic anterior, intermediate and posterior uveitides are similar to those seen in young patients.
Age Factors↗
The diagnosis of delayed post-operative endophthalmitis by polymerase chain reaction of bacterial DNA in vitreous samples.
Delayed post-operative endophthalmitis is a complication of modern cataract extraction and posterior chamber lens implantation. Propionibacterium acnes has been isolated in a few such cases but the majority are culture-negative, compounding surgical and medical management decisions. A method of detecting bacterial, and specifically P. acnes, DNA by the polymerase chain reaction (PCR) directed at 16S rDNA is reported. Nested PCR with universal eubacterial primers complimentary to regions of 16S rDNA conserved sequences detected 50 fg of bacterial DNA spike in normal vitreous. Nested PCR with P. acnes primers detected 10 fg of DNA. Vitreous samples from 29 patients undergoing vitrectomy for reasons unrelated to infection and 23 samples from 19 patients with delayed post-operative endophthalmitis were analysed. Four (14%) of 29 normal individuals and 17 (74%) of 23 delayed cases gave positive results with universal eubacterial primers. None of 29 and eight of 23 samples gave positive results with P. acnes primers. The 14% positive rate with universal primers in non-infected cases may limit their use in delayed post-operative endophthalmitis. PCR detection of bacterial DNA with specific primers from vitreous samples may prove a useful means of diagnosing delayed post-operative endophthalmitis and facilitating management decisions when conventional bacterial culture is negative.
Base Sequence↗
Low-dose cyclosporin therapy of ocular inflammation: preliminary report of a long-term follow-up study.
Cyclosporin A (CsA) is an effective therapy for severe intraocular inflammation but nephrotoxicity and hypertension are major side effects even in low dose in combination with oral corticosteroids and clinical studies on the long-term effects of low-dose CsA therapy outside the field of organ transplantation are lacking. This multicentre, open, longitudinal study has been established to evaluate the long-term efficacy and side effects of low-dose CsA therapy (initial dose less than or equal to 5 mg/kg/day, with a maximum dose of 7 mg/kg/day, and total treatment duration greater than 3 months) in severe ocular inflammation where conventional therapy had failed to control the disease or caused intolerable side effects. Visual response to treatment, clinical signs and symptoms of side effects, biochemical and haematological parameters have been recorded at 3-monthly intervals since January 1987 and will continue until December 1993. Data for 74 patients (age 35.5 +/- 16.6 years) and 293 follow up visits are presented in this preliminary report. [table: see text] Other side effects include (% of all visits): hypertrichosis (4.2), headache (2.8), cramps (1.8), arthropathy (1.8), paraesthesiae (1.8), abdominal pain (1.5), weakness (1.5), dyspepsia (1.4), nausea (1.4), others (4).
Blood Pressure↗
The use of lithium clearance studies in the early detection of cyclosporin A (CsA) nephrotoxicity: a protocol of renal function assessment with CsA therapy.
Cyclosporin A nephrotoxicity was studied with the use of lithium and creatinine clearance tests in 18 patients with chronic intraocular inflammation (duration of treatment 3-48 months). In 11 patients lithium clearance and fractional excretion of lithium were significantly reduced (compared with pretreatment levels) within the first six months of treatment. There was no significant change in either serum creatinine or creatinine clearance within this period. In 14/18 patients there was a significant reduction in lithium clearance and fractional excretion of lithium during the treatment period. 7 patients whose therapy was stopped because of continuing nephrotoxicity despite dose reduction, demonstrated some reversibility of renal function on cessation of cyclosporin A. We propose a protocol for the assessment of renal function in these patients so that with dose modulation the changes in these parameters can be minimised, reducing the risk of renal impairment, whilst maximising immunosuppressive treatment.
Chronic Disease↗
Combination low dose cyclosporin A and steroid therapy in chronic intraocular inflammation.
Thirteen patients with chronic intraocular inflammation which had not been adequately controlled with oral prednisolone entered into an open study of low-dose Cyclosporin A (mean 4.1 mg/kg/day) combined when required with oral prednisolone (15 mg prednisolone per day or less). The mean duration of treatment was 26 months (range 8-44) over a mean follow-up period of 29 months (range 8-49). Visual acuity improved overall in ten patients, and remained stable in three. Six patients have completed a course of Cyclosporin A therapy, and four of these patients have retained their visual improvement. Two have returned to the pretreatment level of vision. Only one patient has required conversion to alternative immunosuppressive therapy. The mean serum creatinine concentration had increased significantly by 26% after six months (p less than 0.05) and 32% after one year (p less than 0.01) but remained stable during the subsequent 18 months. Four patients developed hypertension requiring hypotensive therapy. On cessation of CsA treatment, the mean serum creatinine concentration fell to the upper reference limit. The elevation of serum creatinine concentration was significantly higher in patients who either developed hypertension during Cyclosporin A therapy or who were previously known to be hypertensive. Patients with nephrotoxicity were significantly older than those in whom serum creatinine concentration remained within the reference range. Lithium clearance studies showed evidence of proximal renal tubular dysfunction which was partially reversible on dose reduction or withdrawal.
Adolescent↗
Low dose cyclosporin A therapy in chronic posterior uveitis.
Nine patients with chronic posterior endogenous uveitis of varying aetiology, not satisfactorily controlled with systemic corticosteroids alone, were treated with low dose oral Cyclosporin A (mean maintenance dose 4.0 +/- 1.1 mg/kg/day). Six of the nine patients also continued to receive oral prednisolone (15 mg/day or less). During a follow up period of 6-30 (mean 17) months, seven have shown sustained visual improvement. Nephrotoxicity was the major side effect with serum creatinine concentration (mean +/- 1SD) rising from 91 +/- 7 mumol/l to 115 +/- 13 mumol/l (0.01 less than p less than 0.05) after the first twelve months of treatment. Other observed side effects have included taste disturbance, hypomagnesaemia, and hypertension. Cyclosporin A treatment is of value in the management of severe intraocular inflammation, unresponsive to conventional therapy, but the optimum duration of therapy remains to be established and nephrotoxicity is the major dose limiting effect.
Adolescent↗
Once daily amlodipine in the treatment of mild to moderate hypertension.
1. The antihypertensive efficacy of once-daily amlodipine was studied in a group of 30 patients with mild to moderate hypertension in a double-blind, placebo controlled parallel group study. The dose range of amlodipine was 2.5-10 mg daily titrated at 2 weekly intervals for a total treatment period of 8 weeks. 2. Amlodipine produced a significant reduction in blood pressure compared with placebo, the mean difference between baseline and 8 weeks (corrected for placebo effect) being 16/12 mm Hg supine, 14/4 mm Hg standing. 3. Blood pressure returned to baseline values during a terminal 4 week washout period on placebo. 4. There were no significant effects on heart rate. 5. Two patients experienced slight ankle oedema while receiving amlodipine 10 mg daily but the active drug was otherwise well tolerated. 6. Plasma concentration of amlodipine, sampled 24 h after the preceding dose, increased as the dose titration sequence was followed, averaging 2.5 ng ml-1 on 2.5 mg, 4.9 ng ml-1 on 5 mg and 10.5 ng ml-1 on 10 mg.
Adult↗
Haemostatic response to trauma.
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Blood Coagulation↗
Dizziness and vertigo.
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Cardiovascular Diseases↗
Measurement of platelet life-span in normal subjects and patients with myeloproliferative disease with indium oxine labelled platelets.
The use of 111Indium oxine as a platelet label for the performance of platelet life-span studies has been examined. Platelet life-span in normal subjects varied between 8 X 10 and 10 X 36 d. Patients with primary thrombocythaemia had clearly reduced platelet life-span whether or not they presented with vascular occlusion and this abnormality persisted after reduction of the platelet count to normal by busulphan therapy. Patients with similarly elevate platelet counts due to chronic granulocytic leukaemia or after splenectomy had platelet life-span values in the normal range. Plasma beta-TG levels could not be used to predict platelet life-span in these groups of patients. Measurement of platelet life-span using 111Indium labelled platelets is a useful technique in the examination of platelet function in occlusive vascular disease.
Adult↗
The endothelial cell in hypothermia.
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Animals↗