mononeuropathie

Mononeuropathy is a focal peripheral neuropathy that affects a single peripheral nerve or a discrete nerve trunk. It causes sensory and/or motor deficits confined to the nerve’s distribution and is distinct from polyneuropathy, which involves multiple nerves diffusely, and from mononeuritis multiplex, which affects several noncontiguous nerves.

Causes and sites of involvement are diverse. Commonly, mononeuropathies arise from compression or entrapment (for example, median nerve at the carpal tunnel, ulnar nerve at the elbow, or peroneal nerve at the fibular head). Trauma, ischemia, inflammatory or autoimmune processes (such as vasculitis), infectious etiologies, or metabolic factors (notably diabetes) can also cause focal nerve injury. Less frequent etiologies include tumors, space-occupying lesions, or intrinsic nerve diseases.

Clinical presentation depends on the affected nerve. Patients typically report sensory disturbances (numbness, tingling, or dysesthesia) in the nerve’s sensory territory, and may notice weakness or muscle wasting in the corresponding muscles. Reflexes may be reduced in the involved myotomes. The onset can be acute after trauma or gradual with chronic entrapment.

Diagnosis relies on a focused neurological examination and targeted tests. Nerve conduction studies and electromyography help localize the lesion and differentiate demyelinating from axonal injury. Imaging (ultrasound or MRI) can identify compression or structural causes. Laboratory workup may assess diabetes, B12 deficiency, thyroid disease, or inflammatory markers as indicated.

Treatment targets the underlying cause and function preservation. Decompression or splinting may relieve compression; analgesics and neuropathic pain agents (for example, gabapentinoids or certain antidepressants) may alleviate pain. Physical or occupational therapy supports recovery, and management of systemic diseases improves prognosis. Recovery varies, with compressive etiologies often amenable to full or substantial improvement, while axonal injuries may take longer or leave residual deficits.