Myotonic muscular dystrophy
Induce with RSI with roc and reverse with sugammadex. Sux, roc, and neostigmine may produce atypical responses.
|Signs and symptoms|
There are two types of myotonic dystrophy caused by two mutations in two distinct gene loci: myotonic dystrophy types 1 and 2. Type 1 is a multisystem disease affecting the musculoskeletal system, the heart, the respiratory system, the central nervous system and the endocrine system. Type 2 has similar manifestations, but is less severe.
Muscle weakness begins distally and progresses proximally, with muscle wasting developing over time.
Succinylcholine produces exaggerated contractures severe enough to impair ventilation, and can make intubation/ventilation very difficult. May have enhanced response to NDNMBs due to chronic myopathy. Neostigmine may provoke myotonia. Peripheral nerve stimulators may provoke myotonia.
The generally preferred option for induction is RSI with rocuronium and eventual reversal with sugammadex.
Related surgical procedures
Myotonic dystrophy is theorized to be caused by an abnormality in the intracellular adenosine triphosphate system, causing a failure of calcium to return to the sarcoplasmic reticulum and hence a myotonic response (delayed relaxation of skeletal muscle after voluntary contraction).
Signs and symptoms
MSK: Myotonic responses to voluntary movement.
Respiratory: Pulmonary function test reveals restrictive lung disease pattern due to contractures of intercostal muscles. Ventilatory response to hypoxia and hypercarbia is impaired. Patients are predisposed to developing pneumonia due to reduced lung volume and ineffective cough mechanism. Patients are especially sensitive to the respiratory depressant effects of common anesthetic medications
Endocrine: insulin resistance
Cardiac: defects in cardiac conduction
CNS: neuropsychiatric impairment
HEENT: Cataracts, frontal balding in males
GU: Testicular atrophy.
Gyn: High incidence of OB complications including polyhydramnios, breech, premature labor, impaired cervical dilation, uterine atony, retained placenta, postpartum hemorrhage. Symptoms are exacerbated by pregnancy due to elevated progesterone levels.