Monday, November 24, 2003
Aspirin for diabetic retinopathy
The earliest clinically recognisable lesions in diabetic retinopathy are capillary occlusions, which can be shown on fluorescein angiograms, a standard investigation in patients with retinopathy. The response to capillary blockage is dilation of neighbouring ones, leading to breakdown of the blood-retina barrier and leakage. Later large vessels become affected, and the result is retinal ischaemia, which is responsible for the secretion of vasoactive cytokines, leading to formation of the sight threatening proliferative lesions.
Aggregation of platelets is increased in diabetes, and this has been proposed as the underlying abnormality.1 An early paper by Pope et al showed platelet thrombi in retinal capillaries of diabetic patients.2 Furthermore, observational evidence showed that patients treated with acetyl salicylic acid had less retinopathy than expected in a general diabetic population.3
Important advances have occurred in the understanding of diabetic retinopathy in the past 10 years. Platelets by themselves are no longer thought to be of prime importance in blocking retinal capillaries; rather, changes in the endothelial cells and white cells are responsible for capillary occlusion,
in the diabetic rat model showed that high dose aspirin (2 mg/kg/day) reduced leucocyte adhesion in diabetic retinal capillaries, arterioles, and venules.7 Aspirin also reduced expression of integrins on the surface of leucocytes and the adhesion molecules, ICAM-1, in the capillary wall. Further effects included reduction of nitric oxide synthetase (eNOS) levels and reduced production of the vasoactive cytokine, tumour necrosis factor , found to be raised in diabetic retinopathy. Thus there seems to be ample reason for using of aspirin in diabetic retinopathy.
Evidence that aspirin causes increased risk of haemorrhage in patients with diabetes and proliferative retinopathy is lacking. Patients treated with aspirin do not have their drug stopped during cataract extraction, and recent work indicates that it does not have to be discontinued even during vitreo-retinal surgery. (Williamson, personal communication, 2003)
Should we give aspirin to patients with diabetes for the treatment of retinopathy? In a recent detailed review of all important previous work (but before the publication of the work of Adamis's group), Berghoff et al thought that there were no real indications and no contraindications to the use of aspirin in diabetic retinopathy.10 In view of recent basic investigations this view may have to be reconsidered, and high dose aspirin may become one of the possible additions to preventive treatment in diabetic retinopathy.
The earliest clinically recognisable lesions in diabetic retinopathy are capillary occlusions, which can be shown on fluorescein angiograms, a standard investigation in patients with retinopathy. The response to capillary blockage is dilation of neighbouring ones, leading to breakdown of the blood-retina barrier and leakage. Later large vessels become affected, and the result is retinal ischaemia, which is responsible for the secretion of vasoactive cytokines, leading to formation of the sight threatening proliferative lesions.
Aggregation of platelets is increased in diabetes, and this has been proposed as the underlying abnormality.1 An early paper by Pope et al showed platelet thrombi in retinal capillaries of diabetic patients.2 Furthermore, observational evidence showed that patients treated with acetyl salicylic acid had less retinopathy than expected in a general diabetic population.3
Important advances have occurred in the understanding of diabetic retinopathy in the past 10 years. Platelets by themselves are no longer thought to be of prime importance in blocking retinal capillaries; rather, changes in the endothelial cells and white cells are responsible for capillary occlusion,
in the diabetic rat model showed that high dose aspirin (2 mg/kg/day) reduced leucocyte adhesion in diabetic retinal capillaries, arterioles, and venules.7 Aspirin also reduced expression of integrins on the surface of leucocytes and the adhesion molecules, ICAM-1, in the capillary wall. Further effects included reduction of nitric oxide synthetase (eNOS) levels and reduced production of the vasoactive cytokine, tumour necrosis factor , found to be raised in diabetic retinopathy. Thus there seems to be ample reason for using of aspirin in diabetic retinopathy.
Evidence that aspirin causes increased risk of haemorrhage in patients with diabetes and proliferative retinopathy is lacking. Patients treated with aspirin do not have their drug stopped during cataract extraction, and recent work indicates that it does not have to be discontinued even during vitreo-retinal surgery. (Williamson, personal communication, 2003)
Should we give aspirin to patients with diabetes for the treatment of retinopathy? In a recent detailed review of all important previous work (but before the publication of the work of Adamis's group), Berghoff et al thought that there were no real indications and no contraindications to the use of aspirin in diabetic retinopathy.10 In view of recent basic investigations this view may have to be reconsidered, and high dose aspirin may become one of the possible additions to preventive treatment in diabetic retinopathy.
Duration of children's illness is often underestimated
bmjVolume 327, Number 7423, Issue of 8 Nov 2003
Doctors often tell carers that children with suspected acute viral infection of the upper respiratory tract will get better quickly, but less than half recover within four days. In a secondary analysis on 290 children from a randomised trial Butler and colleagues (p 1088) found that four days after the initial consultation 56% of the children were still unwell. The percentage decreased to 26% on the 7th day and to 6% by the 14th day. The authors believe that giving carers this information will help them to know what to expect and will reduce the need for further consultations.
bmjVolume 327, Number 7423, Issue of 8 Nov 2003
Doctors often tell carers that children with suspected acute viral infection of the upper respiratory tract will get better quickly, but less than half recover within four days. In a secondary analysis on 290 children from a randomised trial Butler and colleagues (p 1088) found that four days after the initial consultation 56% of the children were still unwell. The percentage decreased to 26% on the 7th day and to 6% by the 14th day. The authors believe that giving carers this information will help them to know what to expect and will reduce the need for further consultations.
bmjVolume 327, Number 7423, Issue of 8 Nov 2003
Deep vein thrombosis is most likely within two weeks of long flights
An aeroplane passenger has four times the risk of venous thromboembolism, but only in the first two weeks after a long haul flight.
Deep vein thrombosis is most likely within two weeks of long flights
An aeroplane passenger has four times the risk of venous thromboembolism, but only in the first two weeks after a long haul flight.
BMJ 2003;327:1144-1146 (15 November), doi:10.1136/bmj.327.7424.1144
Screening for depression in primary care with two verbally asked questions: cross sectional study
The questionnaire included two questions about depressed mood: during the past month have you often been bothered by feeling down, depressed, or hopeless? and, during the past month have you often been bothered by little interest or pleasure in doing things?
depression
Screening for depression in primary care with two verbally asked questions: cross sectional study
The questionnaire included two questions about depressed mood: during the past month have you often been bothered by feeling down, depressed, or hopeless? and, during the past month have you often been bothered by little interest or pleasure in doing things?
depression
BMJ Volume 327, Number 7425, Issue of 22 Nov 2003
COX 2 inhibitors may cause temporary visual impairment
Two new selective anti-inflammatory cyclo-oxygenase-2 inhibitors can cause temporary visual impairment. Coulter and associates (p 1214) report on cases of visual disturbance associated with the use of celecoxib and rofecoxib. Analysing data from the New Zealand intensive medicine monitoring programme and the database of the WHO Collaborating Centre for International Drug Monitoring, they identified more than 470 cases of temporary visual disturbance associated with these drugs. Loss of vision is likely to be temporary, resulting from the inhibition of synthesis of prostaglandins and other compounds that control retinal blood flow.
COX 2 inhibitors may cause temporary visual impairment
Two new selective anti-inflammatory cyclo-oxygenase-2 inhibitors can cause temporary visual impairment. Coulter and associates (p 1214) report on cases of visual disturbance associated with the use of celecoxib and rofecoxib. Analysing data from the New Zealand intensive medicine monitoring programme and the database of the WHO Collaborating Centre for International Drug Monitoring, they identified more than 470 cases of temporary visual disturbance associated with these drugs. Loss of vision is likely to be temporary, resulting from the inhibition of synthesis of prostaglandins and other compounds that control retinal blood flow.
