Birth-Related (Obstetrical) Brachial Plexus Injuries Clinical Presentation

Updated: May 10, 2018
  • Author: Alison Snyder-Warwick, MD; Chief Editor: Jeffrey D Thomson, MD  more...
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Presentation

History

Infants are evaluated as early in the postnatal period as possible. A careful history is necessary to elicit risk factors, establish chronology, and differentiate brachial plexus and nonbrachial plexus etiologies of upper-extremity motor weakness.

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Physical Examination

The evaluation of an infant with suspected birth-related brachial plexus palsy (BRBPP) should be performed by a multidisciplinary team, including physical and occupational therapy, to appropriately assess motor function and competency with activities of daily living. The patient’s chest and upper extremities should be disrobed to allow proper motor evaluation. Presence of confounding injuries should be assessed, such as shoulder dislocation; clavicular, humeral, or rib fractures; ecchymoses; or scarring suggestive of previous fat necrosis and injury.

Upper-extremity posturing may provide clues to the level of injury within the plexus. The classic “waiter’s tip” positioning of the arm suggests an upper-plexus injury, including the roots of C5, C6, and occasionally C7. This upper plexus pattern is known as Erb palsy, and the patient keeps the arm adducted, shoulder internally rotated, elbow extended, forearm pronated, and wrist and fingers flexed.

A winged scapula indicates injury to the long thoracic nerve (C5, C6, C7). Injury to the C7 root in isolation may result in an elbow-flexed posture. A flail limb with no motor function suggests a pan–brachial plexus injury, including roots C5, C6, C7, C8, with or without T1. Horner syndrome (eyelid ptosis, pupillary miosis, and anhidrosis) indicates injury to the lower plexus with injury to the T1 root proximal to the separation of the sympathetic fibers from the somatic motor fibers. Isolated injuries to the lower brachial plexus, referred to as Klumpke paralysis, typically do not occur with BRBPP. [64]

Motor evaluation of the patient with BRBPP is essential as it is indicative of prognosis and guides therapy. This examination can be challenging owing to the age of the patient and the complexity of the injury. Several classification systems have been described to categorize motor function, particularly in the setting of BRBPP.

The Active Movement Scale (see Table 1 below) developed at the Hospital for Sick Children in Toronto [65, 66]  is a universally applicable, validated scale for motor assessment. Fifteen movements (shoulder abduction, flexion, internal and external rotation, elbow flexion and extension, forearm pronation, and wrist, finger, and thumb flexion and extension) are scored from 0 to 7. Advancement in score requires full range of motion (ROM) before strength against gravity can be assessed.

Table 1. Active Movement Scale (Open Table in a new window)

Observation

Score

Converted Score

Gravity eliminated

 

 

-No contraction

0

0

-Contraction, no motion

1

0.3

-Motion ≤ ½ range

2

0.3

-Motion > ½ range

3

0.6

-Full motion

4

0.6

Against gravity

 

 

-Motion ≤ ½ range

5

0.6

-Motion > ½ range

6

1.3

-Full motion

7

2.0

The Medical Research Council scale [67]  and the Mallet scale [68]  are other commonly used classification systems, but they require active patient cooperation and therefore are not applicable to patients of all ages [69]  and are not useful for all injury scenarios. [70]

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