Erb's Palsy - Presentation

Presentation

The paralysis can be partial or complete; the damage to each nerve can range from bruising to tearing. The most commonly involved root is C5 (aka Erb's point: the union of C5 & C6 roots) as this is mechanically the furthest point from the force of traction, therefore, the first/most affected. Erb–Duchenne palsy presents as a lower motor neuron syndrome associated with sensibility disturbance and vegetative phenomena.

The most commonly involved nerves are the suprascapular nerve, musculocutaneous nerve, and the axillary nerve.

The signs of Erb's Palsy include loss of sensation in the arm and paralysis and atrophy of the deltoid, biceps, and brachialis muscles. "The position of the limb, under such conditions, is characteristic: the arm hangs by the side and is rotated medially; the forearm is extended and pronated. The arm cannot be raised from the side; all power of flexion of the elbow is lost, as is also supination of the forearm". The resulting biceps damage is the main cause of this classic physical position commonly called "waiter's tip."

If the injury occurs at age early enough to affect development (e.g. as a neonate or infant), it often leaves patients with stunted growth in the affected arm with everything from the shoulder through to the fingertips smaller than the unaffected arm. This also leaves the patients with impaired muscular, nervous and circulatory development. The lack of muscular development leads to the arm being much weaker than the unaffected one, and less articulate, with many patients unable to lift the arm above shoulder height unaided, as well as leaving many with an elbow contracture.

The lack of development to the circulatory system can leave the arm with almost no ability to regulate its temperature, which often proves problematic during winter months when it would need to be closely monitored to ensure that the temperature of the arm was not dropping too far below that of the rest of the body. However the damage to the circulatory system also leaves the arm with another problem. It reduces the healing ability of the skin, so that skin damage takes far longer than usual to heal, and infections in the arm can be quite common if cuts are not sterilized as soon as possible. This will often cause many problems for children since they often injure themselves in the course of their childhoods.

The nervous damage is often the most problematic of the side effects to Erb's Palsy, but it is also the most varying. There have been cases of patients who have lost complete sensory perception within the arm after procedures whereas they had full sensory perception before. The most common area for a loss of sensory perception (except where the arm faces a total loss) is that between the shoulder and the elbow since the nerves which provide information from that area to the brain are also those first damaged in the initial causative trauma.