Ddx: Upper Limb Entrapment syndromes

Question 1

Ddx: Neuropathies

Answer 1

Idiopathic Inflammatory Neuropathies:

Guillain-Barre

Chronic Inflammatory Demyeliating Polyneuropathy

Entrapment Neuropathies:

Median, ulnar, radial thoracic outlet, peroneal.

Question 2

Guillain-Barré syndrome

Answer 2

An acute or subacute polyneuropathy that can follow minor infective illnesses, inoculations, or surgical procedures or may occur without obvious precipitants.

Dx: The cerebrospinal fluid (CSF) often shows an increased protein concentration but normal cell count (cytoalbuminologic dissociation), but abnormalities may not occur in the first week. Electrophysiologic studies may reveal marked slowing of motor and sensory conduction velocity or evidence of denervation and axonal loss.

Tx: Plasmapheresis appears to reduce the time required for recovery and may decrease the likelihood of residual neurologic deficits. It is best instituted early, and it is indicated especially in patients with a severe or rapidly progressive deficit or respiratory compromise. Intravenous immunoglobulin (400 mg/kg/d for 5 days) appears to be equally
effective and should be used in preference to plasmapheresis in adults with cardiovascular instability and in children; the two therapies are not additive.

Question 3

Chronic inflammatory demyelinating polyneuropathy

Answer 3

Is clinically similar to Guillain-Barré syndrome except that it follows a chronic progressive course, or a course characterized by relapses, and no improvement is apparent within
the 6 months after onset.

Question 4

Median Nerve Compression

Answer 4

Carpal tunnel syndrome (CTS) occurs when the median nerve which runs from the forearm into the hand becomes squeezed at the wrist. May occur during pregnancy and as a complication of trauma, degenerative arthritis, tenosynovitis, diabetes mellitus, myxedema, and acromegaly.

Hx: Early symptoms are pain and paresthesias confined to a median nerve distribution in the hand, that is, involving primarily the thumb, index, and middle fingers and the lateral half of the ring finger.

Weakness occurs in thumb abduction, not flexion as the flexor pollicis longus is innervated before the nerve enters the carpal tunnel. The palmar sensory branch for the thenar eminence also does not go through the carpal tunnel, so sensation here should be intact in CTS.

Carpal tunnel syndrome is the most frequent neuropathy of pregnancy. It usually begins in the 3rd trimester and resolves after delivery. It is attributed to generalized edema.

Px: There may be a positive Tinel sign (percussion of the nerve at the wrist causes paresthesias in its distribution) or a positive response to the Phalen maneuver (flexion of the wrist for 1 minute exacerbates or reproduces symptoms).

Tx: If the symptoms fail to respond to local corticosteroid injectionsor simple maneuvers such as wearing a nocturnal wrist splint, surgical decompression of the carpal tunnel may be necessary.

Question 5

Ulnar Neuropathy

Answer 5

Ulnar nerve dysfunction at the elbow leads to paresthesias, hypesthesia, and nocturnal pain in the little finger and ulnar border of the hand.

Question 6

Radial Neuropathy

Answer 6

The radial nerve may be compressed in the axilla by pressure from crutches or other causes; this is frequently seen in alcoholics and drug addicts who have fallen asleep with
an arm draped over some hard surface (so-called “Saturday night palsy”).

Question 7

Thoracic outlet syndrome

Answer 7

A cervical rib or band or other anatomic structure may compress the lower part of the brachial plexus. Symptoms include pain, paresthesias, and numbness in a C8 and T1
distribution.

Question 8

Fibular (peroneal) Neuropathy

Answer 8

Fibular (peroneal) nerve lesions can follow trauma or pressure about the knee at the fibular head. The resulting weakness or paralysis of foot and toe extension—and foot eversion—is accompanied by impaired sensation over the dorsum of the foot and the lower anterior aspect of the leg.