Stroke in Sickle cell Disease (SCD) is common, frequently recurrent, peaks in late childhood and can cause profound neurological deficits. The mechanism is thought to involve abnormal adherence of sickled cells to the vascular endothelium and as a result of haemolysis stimulating endothelial cell activation, hypercoaguability and alterations in vasomotor tone. Nitric Oxide is a free radical and potent vasodilator which can decrease platelet activation, adhesion receptor expression on the vascular endothelium and vascular smooth muscle proliferation, affecting ischemia-reperfusion injury, modulating endothelial proliferation, and regulating inflammation.
Case History
We present a 12 year old girl with SS disease on a transfusion programme (Hbs <30%) for known multiple large vessel stenosis and a previous history of cerebrovascular bypass surgery (EDAS). She presented with central abdominal pain, vomiting and diarrhea whilst in Africa on holiday. She was transferred to UK and treated with IV fluids, transfusion and analgesia. On day 5 she had multiple seizures and developed left upper limb weakness with bilateral lower limb weakness. An MRI showed widespread multiple fresh infarcts in the posterior temporal, cerebellar and superior parietal lobes bilaterally. In view her poor condition inhaled Nitric Oxide, 22 parts per million was administered over 48 hours in the intensive care unit. She made a rapid clinical recovery with no focal deficits and a post recovery MRI showed resolution of almost all of previous infarcts.
Conclusion
This case report presents additional anecdotal evidence that NO therapy has a potential role in management of SS related stroke and justifies additional trials to evaluate its potential role
Discussion
Inhaled nitric oxide could be beneficial in treatment of stroke in sickle cell disease, by increasing nitric oxide bioavailability, improving blood flow and oxygenation by preventing erythrocyte, platelet, and leukocyte adhesion to the vascular endothelium. Our case demonstrated a dramatic clinical and radiological recovery following the nitric oxide administration and therefore more studies are needed to research its usefulness in comparison with conventional management like exchange transfusion. Abbreviations SS: Sickle cell anaemia; EDAS: Encephalo-duro-arterio-synangiosis
ADP-induced platelet aggregation of normal individuals and of patients with unstable angina were studied. Abnormalities of platelet function included increased aggregability. The ADP concentration required for half-maximal aggregation was significantly lower (4.28±0.30μM) in the unstable angina patients compared with that for normal individuals (5.24±0.15μM). The results are suggestive of platelet aggregation as a useful prognostic indicator for unstable angina.
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