Ocular findings in sickle cell patients on Curaçao

[Proliferative sickle cell retinopathy revealing Glanzmann thrombasthenia]

Glanzmann thrombasthenia is a rare qualitative platelet abnormality of autosomal recessive transmission caused by absence of GP IIb/IIIa and resulting in disturbance of platelet aggregation and bleeding time extension. We report the case of a 16-year-old female suffering from SC sickle cell disease and presenting with bilateral vitreous hemorrhage revealing Glanzmann thrombasthenia. Despite vitrectomy, the functional prognosis was poor. Indeed, association of a severe hemorrhagic disease and sickle cell retinopathy makes surgical management difficult.

Ocular Manifestations of Sickle Cell Disease at the Korlebu Hospital, Accra, Ghana

Purpose

TO determine the magnitude and pattern of ocular manifestations in sickle cell disease at Korlebu Hospital, Accra, Ghana.

Methods

Hospital-based cross-sectional study including all patients with sickle cell disease reporting for routine follow-up at the Sickle Cell Clinic at Korlebu Hospital, Accra, Ghana.

Results

A total of 201 patients with sickle cell disease (67 male and 134 female) were enrolled, comprising 114 subjects with genotype HbSS, aged 6–58 years, mean 19.26 (SD 11.70), and 87 with genotype HbSC, aged 6–65 years, mean 31.4 (SD 16.76). Visual impairment was found in 5.6% of eyes examined. Causes were cataract, proliferative sickle retinopathy (PSR), optic atrophy, phthisis bulbi, and central retinal artery occlusion. Common anterior segment signs of sickle cell disease, which were more common in HbSC patients, were tortuous corkscrew conjunctival vessels, iris atrophy, and cataract. Eyes with iris atrophy or depigmentation were 1.8 times more at risk of PSR than eyes without. Overall, PSR was found in 12.9% of subjects examined (3.5% of HbSS, 25.3% of HbSC; 15.9% of males and 11.2% of females). The prevalence of proliferative sickle retinopathy increased with age and increased systemic severity of sickle cell disease; sex did not have an influence.

Conclusions

There is a high prevalence of ocular morbidity in sickle cell disease patients at Korlebu Hospital. Prevalence increased with age, systemic severity of sickle cell disease, and HbSC genotype.

[Epidemiology and prognostic factors for sickle cell retinopathy in Ouagadougou (Burkina Faso)]

INTRODUCTION

The frequency of sickle cell disease varies from 5% to 20% in Africa.

PATIENTS AND METHOD

This retrospective study investigated 173 patients in an ambulatory setting from August 2000 to July 2006. The study included 98 women and 75 men, aged 15-62 years, with a mean age of 26.7 years.

RESULTS

Only 89 patients (71 SC and 18 SS) were seen in ophthalmology, 44 (49%) had sickle cell retinopathy with 26 (29%) cases nonproliferative and 18 cases proliferative (20%). Among the 71 SC patients, 35 (50%) had sickle cell retinopathy, with 40% the proliferative form. Of the 18 SS patients, nine had a retinopathy (50%), with four cases proliferative.

DISCUSSION

Retinopathy is a frequent complication of sickle cell disease, which can lead to blindness, and its management better accessibility to the ophthalmologic examination and preventive treatment by laser photo coagulation.

Role of AIF in caspase-dependent and caspase-independent cell death

The major challenge in treating cancer is that many tumor cells carry mutations in key apoptotic genes such as p53, Bcl family proteins or those affecting caspase signaling. Such defects render treatment with traditional chemotherapeutic agents ineffective. Many studies have demonstrated the importance of caspase-independent cell death pathways in injury, degenerative diseases and tumor tissue. It is now recognized that in addition to their critical role in the production of cellular energy, mitochondria are also the source of key proapoptotic molecules involved in caspase activation. More recently, it has been discovered that in response to apoptotic stimuli, mitochondria can also release caspase-independent cell death effectors such as AIF and Endonuclease G. In this review, we examine the role of Bcl family proteins and poly(ADP-ribose) polymerase-1 signaling in the regulation of these apoptotic pathways and address the ongoing controversies in this field. Continued study of the mechanisms of apoptosis including caspase-independent death processes are likely to reveal novel therapeutic targets for the treatment of diverse human pathologies including cancer, neurodegenerative diseases and acute injuries such as stroke or myocardial infarction.

Vitreous Hemorrhage

The incidence of spontaneous vitreous hemorrhage is approximately 7 cases per 100,000 population. Proliferative diabetic retinopathy (32%), retinal tear (30%), proliferative retinopathy after retinal vein occlusion (11%) and posterior vitreous detachment without retinal tear (8%) are the most common causes of spontaneous vitreous hemorrhage. Vitreous hemorrhage can be caused by the pathologic mechanisms of disruption of normal retinal vessels, bleeding from diseased retinal vessels or abnormal new vessels, and extension of hemorrhage through the retina from other sources. Hemorrhage into the vitreous gel results in rapid clot formation and is followed by slow clearance of approximately 1% per day. The cellular response to vitreous hemorrhage is unusual with regard to hemorrhage in any tissue outside the vitreous cavity and has been compared to a "low-turnover" granuloma. Unique clinicopathologic features of long-standing vitreous hemorrhage include cholesterolosis bulbi (synchysis scintillans), hemoglobin spherulosis, and vitreous cylinders. Complications of nonclearing vitreous hemorrhage are hemosiderosis bulbi and glaucoma. Ghost cell glaucoma, hemolytic glaucoma, and hemosiderotic glaucoma may result from vitreous hemorrhage. The established treatment option for nonclearing vitreous hemorrhage is pars plana vitrectomy. Experimental nonsurgical treatment options involve improvement of physiologic clearance mechanisms in order to accelerate fibrinolysis, liquefaction, hemolysis and phagocytosis.