Retinopathy Revealing Cerebral Venous Thrombosis in Sickle Cell Disease in Niger

Cerebral venous thrombosis (CVT) in sickle cell disease has been rarely described in the literature. Some authors consider sickle cell disease as a risk factor for CVT. We report the case of a 20-year-old boy, known as sickle cell, followed at the National Reference Center for Sickle Cell Disease in Niger. Admitted in consultation for a decrease of acuity with the right eye with perception of a black spot evolving since about three (3) days, ophthalmological examination revealed sickle cell retinopathy associated with cerebral venous thrombosis on MRI. The rest of the balance showed normochromic anemia, ionic disturbance and a D-dimer at 1500 μg/l. Rehydration, strict rest, antibiotic therapy and analgesics were started with an internal medicine opinion for further treatment. There was an improvement in visual acuity of 6/10 in 48 hours with disappearance of black spot perception, after three weeks, an ad integrum recovery of retinal lesions to control imaging. Despite the ocular complications of sickle cell disease involving visual prognosis, cerebral venous thrombosis is another complication to be investigated in any sickle cell retinopathy.


Introduction
Sickle cell disease is the most common hereditary genetic pathology in the world. The gene frequency of the disease is 5% to 20% in Africa and 40% in Central Africa [1]. It is a real public health problem in Niger. The prevalence of sickle cell trait according to the WHO in 2010 is about 25% in Niger [2]. Niamey being an area located in the sicklemic belt [3] [4].
Retinal involvement is the most common ophthalmological complication of the disease. Peripheral vascular occlusion resulting from sickling of erythrocytes by hemoglobin polymerization is responsible for sickle cell retinopathy [5].
A cerebral venous thrombosis is a rare form of cerebral attack in sickle cell patients which is the most difficult diagnosis [6]. Magnetic resonance imaging allows its diagnosis most often.
We report the case of cerebral venous thrombosis in an SS sickle cell with retinopathy, which has the particularity of the severity of both visual and vital prognosis.

Observation
This is a 20-year-old boy, known as Sickle Cell Disease, followed at the National Reference Center for Sickle Cell Disease in Niger. The interview did not find any particular ophthalmological history, metabolic, endocrine or neurological disease. There is a family history of death of her sister sick Sickle cell in a coma table. Admitted to a private clinic (CLINIQUE LUMIERE-NIAMEY) for a visual keenness to the right eye with a perception of a black spot evolving for about three (3) days.
Clinical examination evokes (Table 1) sickle cell retinopathy. Retinophotography found a retinal vein occlusion on pre-retinal hemorrhage ( Figure 1) associated with fan-like peripheral retinal lesions achieving the classic "sea fan" (Figure 2) was demonstrated after retinophotography and coherence tomography optically objective retro hyaloid hemorrhage with presence of a clot (Figure 3). Angiography could not be performed.   A post-operative assessment showed normocytic norno chromium anemia at 6.5 a/l, hematocrit at 18%; a sodium level of 135 Méq; kaliemia: 4 Méq; TP/TCK are normal, D-dimer: 1500 ug/l. An MRI revealed partial sagittal sinus thrombosis in the Torcular with left lateral fresh blood (Figure 4 and Figure 5).
Rehydration based on 3 liters Saline-Glucose-Ringer serum, combined with a strict rest in bed was started. Ceftriaxone 100 mg/kg/day, paracetamol 60 mg/kg/day were administered. An internal medicine opinion was requested for the continuation of the care.
The clinical course in 48 hours was marked by an improvement of the visual acuity which passed to 6/10 without correction with disappearance of the perception of the black spot. Ocular control imaging after after three weeks showed recovery ad integrum Figure 6 and Figure 7.

Discussion
Sickle cell disease is the most common hereditary genetic disorder in the world and especially in Africa. In Niger, it presents a public health problem with a prevalence of hemoglobin S (HbS) carriage of 25% [7]. Ophthalmologic involvement with variable gravity according to age and type of sickle cell disease is progressing insidiously, for a long time without any functional signs, and exposes to sometimes serious complications [8].
The functional symptomatology is absent until an advanced stage of the disease, where the reduction of visual acuity then represents a serious complication. Sickle cell retinopathy affects young people and its diagnosis is based on a systematic examination of the fundus Bio microscopy and angiography [1] [9] [10]. The sudden drop in visual acuity was the revealing mode of sickle-cell retinopathy in our patient.
Cerebral venous thrombosis (CVT) is a rare disease affecting about 5 people per million per year with huge regional variations [11]. Cerebral venous thrombosis has a broad spectrum of clinical manifestations and modes of onset that can mimic many other neurological disorders and lead to frequent misdiagnosis or delayed diagnosis [12]. Some authors in Senegal have also found that sickle cell disease is a risk factor for vascular thrombosis but the mechanism could not be clarified [13]. It is a pathology very little described in the African literature.
Lalya F. et al., there has been one case of death following a CVT in sickle cell pa-N. D. Adam et al. tients in 2017 in Cotonou [6]. It should be noted that a family death in a coma context was reported by the parents of the patient of one of the sisters also sickle cell. This proves the seriousness of the disease.

Conclusion
In spite of ocular complications of sickle cell disease involving visual prognosis, cerebral venous thrombosis is another complication to look for in any sickle cell retinopathy. His clinical picture is polymorphic and nonspecific, medical imaging to improve his diagnosis.