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OPTOMETRY CLINICAL PICTURE
Central retinal vein occlusion as a presenting feature in a young patient with protein S deficiency Clin Exp Optom 2014
Rupak Roy* MS Kumar Saurabh* MS Amit B Jain† MD Debmalya Das† DO DNB Anindya K Majumder† DO DNB Aneesha Lobo† MS * Aditya Birla Sankara Nethralaya, Kolkata, West Bengal, India † Shri Bhagwan Mahavir Vitreoretinal Services, Sankara Nethralaya, Chennai, Tamil Nadu, Índia E-mail: [email protected]
Submitted: 25 May 2014 Revised: 20 August 2014 Accepted for publication: 23 August 2014 Under normal physiological conditions, protein S works as a cofactor of protein C to prevent activation of thrombin and factor X and thereby prevents thrombosis.1 Homozygous protein S deficiency presents in infancy, while heterozygous deficiency presents in the third to fourth decades of life as thrombotic disorders.1 Protein S deficiency may lead to recurrent coagulopathies, which can present as superficial or deep vein thrombosis and embolism.2 It has been reported as a cause of non-arteritic anterior ischaemic optic neuropathy.3 Acquired protein S deficiency together with other thrombophilic conditions such as systemic lupus erythematosus have been associated with central retinal vein occlusion (CRVO).4 Here, we report the first case of CRVO associated with isolated hereditary protein S deficiency in India.
CASE REPORT A 26-year-old woman presented with a complaint of diminution of vision in the left eye for one month. She did not give any history of diabetes mellitus, systemic hypertension, bleeding disorder, malignancy or oral contraceptive use. The visual acuity in her right eye was 6/6, N6 and in the left eye was 6/60, N36. The right ocular fundus was normal.
Figure 1. A. Fundus photograph of left eye showing haemorrhages in all four quadrants of the retina with optic disc oedema. B. Optical coherence tomographic line scan image of the macula of the left eye showing macular oedema and neurosensory retinal detachment.
The left fundus revealed optic disc oedema with tortuous retinal vessels and retinal haemorrhages in all quadrants, along with macular oedema (ME) (Figure 1A). A diagnosis of CRVO was made. Laboratory investigations revealed normoglycaemia and normolipidaemia along with normal total and differential cell counts (Table 1). Her coagulation profile was normal except for the isolated abnormality of protein S deficiency (Table 1). Optical coherence tomography (OCT) of the left eye confirmed macular oedema (Figure 1B). She was advised to undergo intravitreal ranibizumab (0.5 mg/0.05 ml) in the left eye. She was also examined by a haematologist and was started on warfarin therapy. After one month, the vision in the left eye had improved to 6/18, N18 with reduction of the macular oedema (Figure 2 A and B). She was instructed that a second intravitreal injection of ranibizumab may be necessary and advised to return in one month. DISCUSSION Protein S acts as a cofactor for protein C, where it aids the binding and breakdown of
© 2014 The Authors Clinical and Experimental Optometry © 2014 Optometrists Association Australia
coagulation factors Va and VIIIa. Lack of protein S renders protein C inactive, leading to uninhibited activity of factor Va and VIIIa. This activates the coagulation system because of unchecked activity of thrombin and factor X.1 Though protein S deficiency is a known risk factor for systemic thrombosis, there are few, if any, reports of retinal vein occlusion. Pierre-Filho Pde and colleagues5 reported a case of central retinal vein prethrombosis, in which CRVO was averted by oral warfarin therapy. In our patient fullblown CRVO was the first manifestation of protein S deficiency, which reiterates the importance of detailed history and extensive investigation in young patients with CRVO. Screening for thrombophilia should be prescribed in patients with CRVO, who are below 50 years of age. The present case is the first report of the efficacy of intravitreal ranibizumab in CRVO related to protein S deficiency. No cardiovascular complications were noted after one and a half months. Reporting of ophthalmic diseases attributed to protein S deficiency is necessary to create awareness among ophthalmic caregivers to consider it as a cause in young patients with retinal vascular occlusion. Clinical and Experimental Optometry 2014
CRVO in protein-S deficiency Roy, Saurabh, Jain, Das, Majumder and Lobo
90 mg/100 ml
70–100 mg/100 ml
160 mg/100 ml
45 mg/100 ml
80 mg/100 ml