Postural Tremor Caused by Hirayama Disease Mimicking Essential Tremor.

Background: Postural tremor is a common clinical situation. Timely and accurate diagnosis is essential for effective treatment. However, clinicians often encounter difficulties distinguishing between essential tremor and other etiologies due to overlapping symptoms and atypical features. Case description: A twenty-year-old man presented with a five-year history of progressive hand tremors. Neurological examinations were notable for asymmetric postural tremors in both hands, with mild distal finger muscle wasting and subtle kinetic tremors. NCS/EMG revealed neurogenic changes in the C7-C8 myotome. Upon neck flexion, cervical spinal cord MRI revealed prominent flow voids in the widened posterior epidural space from C6 to T3 levels. We diagnosed him with Hirayama disease. Discussion: Hand tremors caused by Hirayama disease have distinctive patterns from that of essential tremor (ET). In our patient, the prominent postural tremor, the involvement of finger joints rather than writs and elbows, and the spiral drawing waveforms argue against ET. Moreover, the onset age, absence of family history, and right-hand intrinsic muscle wasting are also red flag signs. Recognition of these clinical nuances is important to avoid misdiagnosis. Highlights: Our case highlights the importance of thorough physical examinations and the necessity of considering Hirayama disease in young men presenting with hand tremors.