A 1-day-old boy is evaluated in the nursery for minimal right-hand movement. He was born at 39 weeks gestation by forceps-assisted, vaginal delivery to a mother with insulin-controlled gestational diabetes mellitus and obesity. The delivery was complicated by shoulder dystocia. Birth weight was 4.4 kg (9.7 lb). Examination of the right upper extremity shows extension of the wrist, hyperextension of the metacarpophalangeal joints, and flexion of the interphalangeal joints. Grasp reflex is absent. Moro and biceps reflexes are intact. There is no crepitus. The left arm is normal. There is slight ptosis of the right eyelid, and the right pupil is 2.5 mm smaller than the left. The remainder of the examination is unremarkable. Which of the following is the most likely cause of this patient's presentation?

Question

A 1-day-old boy is evaluated in the nursery for minimal right-hand movement.  He was born at 39 weeks gestation by forceps-assisted, vaginal delivery to a mother with insulin-controlled gestational diabetes mellitus and obesity.  The delivery was complicated by shoulder dystocia.  Birth weight was 4.4 kg (9.7 lb).  Examination of the right upper extremity shows extension of the wrist, hyperextension of the metacarpophalangeal joints, and flexion of the interphalangeal joints.  Grasp reflex is absent.  Moro and biceps reflexes are intact.  There is no crepitus.  The left arm is normal.  There is slight ptosis of the right eyelid, and the right pupil is 2.5 mm smaller than the left.  The remainder of the examination is unremarkable.  Which of the following is the most likely cause of this patient's presentation?

Quizplus · Accepted Answer

11ec25c8_d707_9d31_bc81_71b767194ff6_MD0003_00 This infant has Klumpke palsy, a brachial plexus injury caused by shoulder dystocia. Risk factors include fetal macrosomia (birth weight ≥4.5 kg [9.9 lb]), maternal diabetes, and maternal obesity. Excessive traction of the 8th cervical (C8) and 1st thoracic (T1) nerves during delivery can result in the rare complication of hand paralysis with a "claw hand" appearance. Associated damage to the sympathetic fibers that run along C8 and T1 manifests as ipsilateral miosis and ptosis (Horner syndrome). Klumpke palsy Horner syndrome Prognosis depends on whether the damage was due to nerve stretching or compression as opposed to avulsion. Horner syndrome portends a suboptimal outcome. Treatment usually involves gentle massage and physical therapy to prevent contractures. In most cases, function returns within a few months. If there is no improvement by age 3-9 months, surgical intervention may be considered. (Choices A and B) Brachial plexus injury can sometimes accompany clavicular and humerus fractures; however, this patient does not have crepitus or bony irregularity over the clavicle or humerus, making fracture unlikely. (Choice C) Erb-Duchenne palsy is the most common type of brachial plexus injury and involves the 5th and 6th cervical nerves, leading to the "waiter's tip" posture. The affected arm may have decreased or absent Moro reflexes, but grasp reflex remains intact. Erb-Duchenne palsy (Choice E) Perinatal asphyxia results from compromised placental or pulmonary gas exchange. Severe hypoxia leads to poor perfusion and acidosis, initially in peripheral tissues followed by the brain. This infant has neither systemic symptoms nor encephalopathy, making perinatal asphyxia unlikely. (Choice F) Perinatal stroke can result in abnormal arm movement with upper motor neuron signs (eg, hyperreflexia, hypertonia). This infant's symptoms are isolated to the lower brachial plexus, making cerebral infarction unlikely. Educational objective: Klumpke palsy is a rare complication of shoulder dystocia caused by injury to the 8th cervical and 1st thoracic nerves. Presentation can include hand paralysis (ie, "claw hand") and ipsilateral Horner syndrome. References: Current concepts in the management of brachial plexus birth palsy. (http://www.ncbi.nlm.nih.gov/pubmed/20141905)

A 1-Day-Old Boy Is Evaluated in the Nursery for Minimal