A 2-hour-old boy is evaluated in the delivery room for minimal right arm movement. He was born at 37 weeks gestation by vacuum-assisted, vaginal delivery to a 39-year-old woman who had excessive weight gain during pregnancy. The delivery was complicated by a 3-minute shoulder dystocia. Birth weight was 4.6 kg (10.1 lb). Examination shows a small area of edema in the scalp that does not cross suture lines. The right upper extremity is held in adduction and internal rotation with the elbow extended, forearm pronated, and wrist and fingers flexed. Moro and biceps reflexes are absent in the right arm. The remainder of the examination is normal. Which of the following is the most appropriate next step in management of this patient's condition?

Question

A 2-hour-old boy is evaluated in the delivery room for minimal right arm movement.  He was born at 37 weeks gestation by vacuum-assisted, vaginal delivery to a 39-year-old woman who had excessive weight gain during pregnancy.  The delivery was complicated by a 3-minute shoulder dystocia.  Birth weight was 4.6 kg (10.1 lb).  Examination shows a small area of edema in the scalp that does not cross suture lines.  The right upper extremity is held in adduction and internal rotation with the elbow extended, forearm pronated, and wrist and fingers flexed.  Moro and biceps reflexes are absent in the right arm.  The remainder of the examination is normal.  Which of the following is the most appropriate next step in management of this patient's condition?

Quizplus · Accepted Answer

11ec25c8_d708_3972_bc81_6157538cdc27_MD0003_00 This infant's delivery was complicated by shoulder dystocia due to high birth weight. Several maternal risk factors (advanced maternal age, obesity, multiparity) may contribute to fetal macrosomia (birth weight ≥4.5 kg [9.9 lb]). Application of excessive traction on the head and neck while extracting a trapped infant can cause injury to the brachial plexus roots. The most common type of brachial plexus injury is Erb-Duchenne palsy, which involves the 5th, 6th, and sometimes 7th cervical nerves (C5-7). Weakness of the deltoid and infraspinatus muscles (innervated by C5), biceps (innervated by C6), and wrist/finger extensors (innervated by C7) leads to predominance of the opposing muscles. The resulting appearance is the characteristic "waiter's tip" posture, as seen in this infant. Management involves observation and physical therapy because up to 80% of patients have spontaneous recovery within 3 months. Prognosis depends on whether the damage resulted from mild nerve stretching or compression as opposed to severe rupture or avulsion. Surgical intervention (eg, nerve graft, reconstruction, decompression) can be considered for infants with no improvement by age 3-9 months but is not necessarily curative (Choice D). (Choice A) Botulinum toxin injections may be considered if contractures develop over time as the result of a brachial plexus injury. However, because this patient's injury occurred 2 hours prior to examination, physical therapy to prevent contractures is more appropriate. (Choice B) This patient has a cephalohematoma (subperiosteal scalp swelling), which is more common in an instrumental delivery and usually resolves spontaneously without sequelae. In contrast, intracranial hemorrhage is a potential complication of vacuum use that can cause upper motor neuron injury, leading to decreased arm movement, hyperreflexia, and hypertonia (not seen in this patient). This infant's symptoms are localized to peripheral nerves; therefore, brain MRI is not indicated. cephalohematoma (Choice C) In patients whose palsy is not improving, MRI of the cervical spine may be used to detect proximal nerve root avulsion, which typically requires surgical repair. A period of observation is appropriate prior to imaging. Educational objective: Fetal macrosomia is a risk factor for shoulder dystocia. Excessive traction on the head and neck during a difficult delivery can result in Erb-Duchenne palsy with the characteristic "waiter's tip" posture. Management involves observation alone because most infants recover arm function spontaneously within a few months. References: Current concepts in the management of brachial plexus birth palsy. (http://www.ncbi.nlm.nih.gov/pubmed/20141905) Obstetric brachial plexus palsy: a prospective, population-based study of incidence, recovery, and residual impairment at 18 months of age. (http://www.ncbi.nlm.nih.gov/pubmed/20041937)

A 2-Hour-Old Boy Is Evaluated in the Delivery Room for Minimal