Perioperative Care for Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an inherited X-linked recessive mutation in the dystrophin gene with onset in early childhood. In DMD, dystrophin in usually absent. In Becker’s muscular dystrophy, dystrophin is partially functional. Dystrophin is found in skeletal, smooth, and in cardiac muscles, as well as in the brain. It maintains the integrity muscle membrane. Approximately 1:3,500 boys are affected. Muscle weakness appears gradually between 2 and 5 years of age. With the improvements in cardiac and respiratory care, the life expectancy is in 30s, and some living into their 40s. At end, respiratory failure is the main concern.

DMD is the most common muscular dystrophy in children. It is exemplified by progressive symmetric muscle weakness and wasting of proximal muscles with gait disturbance. Presenting symptoms in DMD include a waddling walk and difficulty climbing stairs. The classic Gower maneuver describes using both arms to assist in getting from a sitting to a standing position. The disease affects the heart in ninety-percent of DMD patients. There is no association between the severity of skeletal muscle and the advancement of cardiac muscle involvement. However, dilated cardiomyopathy is seen as the disease evolvements. Cognitive impairment is also often seen in advanced DMD patients.

Preoperative workup should obtain a full history of neuromuscular motor milestones, previous medical as well as surgical procedures’ complications, and familial related disorders. Review an EKG and echocardiogram can be helpful. Patients with DMD are at risk of aspiration pneumonitis. Postoperatively, DMD patients are at risk of respiratory reduction. Scoliosis may further compromise respiratory status. Pulmonary function tests can aid in postoperative planning. Blood work should include a complete blood count, serum levels of creatine phosphokinase and electrolytes.

Serious complications in patients with DMD associated with anesthesia have repetitively been reported. The high complication rate is a result of muscle weakness with respiratory insufficiency, metabolic changes i.e. hyperkalemia and hyperthermia, and cardiomyopathy. Patient compliance occasionally is reduced because of anxiety and mild mental retardation. Potential difficult airway can be seen in patients with DMD associated with enlarged tongue and arthrodesis of the temporomandibular joints.

Succinylcholine is contraindicated due to the risk of hyperkalemic cardiac arrest and rhabdomyolysis with dark discoloration of urine. Renal deficiency and acute renal failure can occur as a result of myoglobinuria. Arrhythmias and cardiac arrest have been reported. They are mainly, but not completely, associated with succinylcholine use and most often occur shortly afterward succinylcholine administration. It seems that hyperkalemia can be precipitated by halogenated inhalational anesthetics alone halothane or isoflurane. Joint deformities and contractures make patient positioning difficult on the operating room table. Vascular access can be challenging by obesity and thickening of subcutaneous tissues. Mechanical ventilator support is almost mandatory following major surgery.

The US Food and Drug Administration has issued a warning against the routine use of succinylcholine in pediatric patients because unexplained cardiac arrest and death in children who were subsequently found to have DMD. Providing anesthesia care for patients with DMD, we need to understand that the nondepolarizing muscle relaxants have an increased potency and a prolonged duration of action. Opioids should be used cautiously to avoid respiratory depression. There is no true association between malignant hyperthermia and DMD. The volatile anesthetics should be used cautiously since volatile anesthetic use in the absence of succinylcholine may be associated with severe rhabdomyolysis in patients with DMD.

裘馨氏肌失養症 (Duchenne muscular dystrophy) 病人圍術期照護