Idiopathic Unilateral Pupillary Sparing 3rd Cranial Nerve Palsy

Background: Cranial nerve III palsy, also known as oculomotor nerve palsy, may result from various causes; such as lesions such as trauma, aneurysms, infarction, tumour, infections across the course of nerve starting from the nucleus of oculomotor nerve at upper midbrain, through interpeducular fossa, to cavernous sinus, then through orbital fissure but oculomotor nerve palsy with pupillary sparing is seen in microvascular ischemia seen in diabetes, hypertension, ischemic neuropathy, however the etiology remains unknown in some instances. Case presentation: This case report aims to present the case of idiopathic cranial nerve III palsy with pupillary sparing along with review of the literature. A 58 year old female having with no past medical history no risk factors presented to the hospital with right eye ptosis and diplopia. Patients has no complain of, weakness, diurnal variation of symptoms, pain, fever, trauma, no any addictions. on examination eyes was in down and out position, pupils bilaterally reactive to light 3mm, normal light reflex, no facial nor bulbar involvement, rest of CNS examination normal. All investigations CBC, ESR, CRP, Liver function test, renal function test, MRI Brain with orbit and brain angiogram, Hba1C, lipid profile, HIV, RPR were done and no cause was found so diagnosed with idiopathic unilateral oculomotor pupillary sparing palsy. After ruling out infections oral steroids at 1mg/kg were started and patient started recovery within 2 weeks and had complete recovery after 4 months. Conclusion: Idiopathic cranial nerve III palsy can occur in otherwise healthy individuals and often recover in several months. Careful examinations further investigations to rule out ischemic , inflammatory, vascular (aneurysms), tumors, infectious causes and others, then steroid treatment should be considered after early diagnosis which in some patientshows improvement.