Functional Neurological Disorder Presenting as Acute Hemiparesis with Normal Neuroimaging: A Stroke Mimic Case Report

Background Functional Neurological Disorder (FND) is a disabling condition characterized by neurological symptoms that are not explained by structural pathology but by abnormal nervous system functioning. It commonly presents with motor and sensory deficits and may mimic acute neurological conditions such as stroke. This overlap often leads to diagnostic uncertainty, unnecessary investigations, and delayed appropriate rehabilitation. Early recognition and multidisciplinary management are essential for optimal recovery. Presentation A 30-year-old female with no known vascular risk factors presented with sudden onset numbness over the right angle of the mouth, deviation of the mouth to the opposite side, and slurred speech, followed by weakness and sensory disturbances in the right upper and lower limbs. As the symptoms progressed rapidly, she was evaluated under acute stroke protocol. Initial CT imaging suggested a possible ischemic lesion in the left sublentiform region. However, subsequent MRI brain and MR angiography did not reveal any infarction or vascular abnormality. Neurological examination showed mild weakness (MRC grade 4/5), reduced grip strength, painful restriction of proximal joint movements, gait disturbance, and inconsistent sensory findings. The patient also had significant psychosocial stress and was on treatment for anxiety and depression. Based on the absence of structural pathology and clinicoradiological dissociation, a diagnosis of Functional Neurological Disorder presenting as a stroke mimic was made. She underwent a structured physiotherapy program focusing on motor retraining, strengthening, balance training, and functional mobility, which resulted in gradual improvement in functional abilities. Conclusions Functional Neurological Disorder should be considered an important differential diagnosis in patients presenting with acute stroke-like symptoms, especially in young individuals with normal neuroimaging. Clinicoradiological dissociation, inconsistent neurological findings, and psychosocial factors are key diagnostic indicators. Early diagnosis and multidisciplinary rehabilitation, including physiotherapy and psychological support are crucial for promoting recovery, restoring functional independence, and improving overall quality of life.