A Man With a History of Polio Who Developed Hand Weakness and Numbness
A 61-year-old hypertensive man presented with a 2-month history of progressive weakness and wasting in the left hand and mild numbness in the fifth digit.
His past medical history was positive for poliomyelitis as a child, which left residual weakness in both legs. He had an almost complete recovery except for a mild deformity of the left foot. He did have occasional fasciculations in the leg. Family history was noncontributory. He denied alcohol or tobacco use.
On examination the left-hand interossei muscles were wasted but without fasciculations. He had a positive Froment sign ( Fig. 7-1A ) and a Tinel’s sign right below the left elbow. When extending his fingers, the last two digits had a tendency to remain flexed ( Fig. 7-1B ). He could not “cup” the left hand. Adson’s maneuver was negative. On sensory examination, there was decreased pain sensation in the left fifth digit and the ulnar half of the fourth with questionably decreased pain sensation in the ulnar aspect of the dorsum of the hand. Sensation in the lower extremities was normal. The left foot had an equinovarus deformity. All reflexes were mildly depressed.
Fig. 7-1
A , Patient showing the Froment sign in the left hand. He has to flex the distal phalanx to hold the paper, secondary to adductor weakness and a normal median-innervated flexor pollicis longus. There is also atrophy of the first dorsal interosseous muscle. B , The benediction sign, showing partial flexion of the last two digits when the patient extends his fingers and hand.
What is the Clinical Diagnosis?
Patients with polio may develop progressive weakness and atrophy or post-polio amyotrophy, but it is unlikely in this patient who had symptoms and clinical findings suggestive of an ulnar neuropathy at the elbow. This is consistent with the numbness in the last two digits, atrophy of the first dorsal interosseous muscle and the Froment sign, and the inability to cup the hand from palmaris brevis muscle weakness.
Another finding in ulnar neuropathy is the benediction sign , characterized by the tendency of the last two digits to flex when the patient is asked to extend the wrist and the fingers (see Fig. 7-1B ). This sign is produced by hyperextension of the metacarpophalangeal joints of the last two fingers from weakened lumbrical muscles and unopposed extension of the extensor digitorum communis. The flexion of the distal phalanges is caused by flexion of the stretched tendons of the flexor digitorum. The name “benediction,” “orator sign,” or “papal benediction sign” originates from catholic priests who extend the thumb and first two fingers and flex the last two fingers during benediction. A similar position occurs in median neuropathy (see Case 5); in this, the patient is asked to flex the fingers, or make a fist but cannot do so because of an inability to flex the first three digits due to weakness of the median-innervated finger flexors. Patients with ulnar neuropathy could also show wasting of the ulnar-innervated hand muscles and have a characteristic “claw hand.”
