Weakness in the Upper Extremity After a Fall

Answer: C. Radial nerve compression

Discussion. The diagnosis of the radial nerve palsy is made based on the clinical features, location of the deficits, and a complete physical examination to help rule out other possibilities in the differential diagnoses. The radial nerve can become compressed in the area where it runs adjacent to the humerus, known as the spiral groove.¹ Compression in this area often creates prolonged pressure on the nerve by an object or surface. This disorder is often called "Saturday night palsy.”¹

On examination, patients may present with weakness in extension of the wrist (wrist drop), fingers, and brachioradialis. The triceps retains its full strength. This injury can be associated with sensory loss over the dorsum of the hand, sometimes extending up the posterior forearm.¹ In our patient, however, sensation remained intact. Comparing the affected extremity with the unaffected side is useful. Radial nerve palsy generally has a good prognosis for full recovery with wrist splinting and physical therapy.²

Differential diagnosis. The diagnosis of Carpal tunnel syndrome (median nerve compression at the wrist) made based on the clinical features of pain, palmar numbness, or tingling involving the first 3 digits and the radial half of the fourth digit.^1,3 Reproduction of symptoms with provocative testing (eg, Tinel sign and Phalen test) is helpful diagnostically.³ Patients often awaken with symptoms at night or have symptoms provoked by the activities involving the hand and wrist, such as driving, typing, and holding a telephone.

In cases of cerebrovascular accident (acute stroke),  patients usually present with several generalized features, including unilateral weakness, often in both upper and lower extremities, with partial or complete loss of motor reflexes and sensation.⁴Speech difficulties, facial asymmetry, and visual symptoms are often associated with stroke. The neurologic examination plays an important role in differentiating between central and peripheral nervous system diseases.⁵ This patient’s weakness was confined to the right upper extremity and her history and examination did not include other common acute stroke features.

Cubital tunnel syndrome is due to ulnar nerve compression at the elbow.^1,6 The most frequent initial symptoms are numbness or paresthesia over the volar aspect of the fourth and fifth digits, dorsal ulnar or palmar cutaneous territory, and ulnar aspect of the hand. It is often associated with loss of grip due to weakness of the lumbricals and interossei.^1,6

Cervical radiculopathy was not unlikely in our patient, as those cases usually present with acute neck and arm pain with radiation to posterior shoulder and periscapular region.⁷ As part of our initial examination, we conducted a Spurling maneuver, which entails passively moving the neck into a position of lateral flexion and extension, with the intent to close the neural foramen, and then applying downward pressure to create an axial load. A positive Spurling test may reproduce radicular symptoms.⁷

Treatment and management. Non-operative treatment of radial nerve palsy generally results in good functional return within several weeks to months. Patient education, physical therapy, activity modification, and splinting are recommended. In some circumstances, selective use of imaging and electrodiagnostic testing may provide additional useful data to help support clinical decision-making.⁷

Patient outcome. Our patient underwent a course of physical and occupational therapy with complete recovery of function over a couple of months.

Conclusion. Upper extremity weakness evaluation requires obtaining a thorough history and performing a physical examination to help rule out other possibilities in the differential diagnosis