The images show a wrist drop and normal CT scan of the brain. The next best step in management is to assess whether the wrist drop is the only neurological symptom the patient is experiencing. Do this by confirming that the grip strength normalizes when the wrist is held in extension by the contralateral arm. If it does, a diagnosis of radial nerve palsy can be made, and the patient may be treated with a splint. Arrange a follow-up consultation with a neurologist and/or orthopedist.
Radial nerve palsy is a form of neuropraxia caused by prolonged compression on the radial nerve. This most commonly occurs after falling asleep with an arm draped over the edge of a chair that traps the radial nerve between the midhumerus and a firm surface. Grip strength is not directly affected but is compromised when the wrist is fixed in a flexed position. Radial nerve palsy is known as “Saturday night palsy” as it is often the result of over-consumption of alcohol or sedatives. The radial nerve is responsible for extension of the fingers, wrist, and elbow. Grip strength should return to normal when the affected wrist is held in extension by the other hand, which helps to confirm the diagnosis. Sensory function is typically spared.
When the clinical picture is unambiguous, no diagnostic testing is required. Brain or spine imaging should be reserved for unclear cases. Nerve conduction studies may be done selectively but are not urgent. Treatment of radial nerve palsy typically requires 4 to 6 weeks of splinting, but recovery can take up to 6 months in more severe cases. Patients should be referred to an orthopedist and/or a neurologist.
The patient in this case was referred to a neurologist who ordered magnetic resonance imaging of the brain and cervical spine; results from these were negative. The patient was discharged home and recovered within 6 weeks.
Pregerson DB. Emergency Medicine 1-Minute Consult Pocketbook. Emresource.org; 2017;5