Numb Chin Syndrome in Sickle Cell Disease

Dear Editor, Damage to the inferior alveolar nerve causes numb chin syndrome. It is indicative of an aggressive lymphoproliferative disease or metastatic malignancy when no obvious mandibular cause can be discerned [1]. Sickle cell disease is an autosomal recessive disorder that results in glutamic acid being substituted by valine at the 6th position of the β-globin chain of the haemoglobin molecule [2]. Change in the morphology of the erythrocyte due to polymerisation of deoxygenated haemoglobin results in acute and chronic complication of the disease out of which mental nerve neuropathy and numb chin syndrome are rarely encountered [3]. A 24-year-old female, a known case of sickle cell “SS” pattern diagnosed 4 years earlier presented to us with the complaints of severe backache, pain in extremities, fever, numbness of lower lip and chin of 2 days duration. There was no history of cough, expectoration, breathlessness or burning micturition. On examination she was conscious and oriented, pulse was 102/min, blood pressure was 100/70 mmHg, respiratory rate was 36/minute and her oxygen saturation was 93% on room air. Central nervous system examination showed loss of sensation localised to the lower lip and chin. Cranial nerves were intact and no abnormal findings were present on motor system examination. On auscultation air entry was equal on both sides and normal heart sounds were heard. The abdomen was soft and non tender with no organomegaly. Her laboratory investigation were suggestive of a haemoglobin level of 6.4 mg/dL, mean corpuscular volume of 54 fL, white blood cells count of 12,300/cumm, platelet count of 83,000/cumm, Serum glutamic-oxalacetic transaminase of 96 IU/L, serum glutamic-pyruvic transaminase of 45 IU/L, serum bilirubin of 1.6 mg/dL, serum protein of 5.4 mg/dL, urea of 17 mg/dL, creatinine of 0.4 mg/dL, sodium of 143 mmol/L and potassium of 4.0 mmol/L. Chest X-ray and ultrasound of abdomen and pelvis revealed no abnormality. In view of numb chin syndrome Magnetic Resonance Imaging (MRI) of temporomandibular joint and brain was done, which were normal [Table/Fig-1,2]. With no positive finding at local site or on imaging studies she was treated with blood transfusions, amoxicillin plus clavulanic acid, levofloxacin, hydroxyurea, folic acid, zinc supplementation, sodium bicarbonate tablets, i.v. fluids and analgesics. Within the next 48 hours she improved significantly with a resolution in most of her symptoms but persistence of numbness in