432 - Acute Inflammatory demyelinating polyradiculoneuropathy (AIDP) vs. Multiple Sclerosis (MS) in a patient with gait instability and recurrent falls: A Case Report for the Importance of Further Testing to Guide Diagnosis and Treatment

Case Diagnosis: 62-year-old male with recurrent falls and decreased lower limb strength, in the context of MS in the mother

Case Description: A 62-year-old male admitted to acute inpatient rehabilitation presented with gait instability for 3 weeks. He endorsed progressive leg weakness, handgrip locking, lower back and hip pain, and loss of sensation in the left toes. History included transient vision loss and MS in his mother. CTH at presentation was unrevealing. Serum protein electrophoresis, folate, SSA(Ro) and SSB(La) antibodies, ganglioside Gq,1B, and IgG antibodies were negative. TSH, A1c, RPR, and B12 were within normal limits. Lumbar puncture was refused due to fear of being paralyzed. MRI of the lumbar spine revealed no root enhancement. Brain MRI showed mild parenchymal volume loss and scattered punctate foci of nonspecific white matter abnormalities. MRI cervical showed no evidence of Guillain-Barre syndrome, but the absence of gadolinium limited the study. MRI thoracic spine was unrevealing. EMG was unremarkable. Upon discharge, the patient's functionality returned to baseline.

Discussions: AIDP is an autoimmune response triggered by infections, mistakenly targeting proteins in peripheral nerve myelin and axons. This damage impairs proper functioning of peripheral nerves, leading to weakness. MS is an autoimmune disorder, influenced by genetic and environmental factors, against the central nervous system. Its course follows a relapsing-remitting or progressive pattern, characterized by spatially and temporally separated lesions.

Conclusions: Diagnosing patients with gait instability is challenging due to overlapping symptoms of neurological disorders. Lumbar puncture allows for definitive differentiation between autoimmune diseases not properly identified through serological testing or imaging. Timely diagnosis is crucial for effective treatment. This case underscores the potential consequences of diagnostic delays and existing knowledge gap in differentiating between AIDP and MS without lumbar puncture. The patient's refusal for fear of paralysis highlights the challenges clinicians face in diagnostic decision-making and the need for alternative diagnostic strategies.