Clinical Commentary: Obstetric and Respiratory Management of Pregnancy with Severe Spinal Muscular Atrophy

Abstract

We present a combined obstetric and respiratory perspective on two pregnancies for a woman with severe Type 2 Spinal Muscular Atrophy (SMA). Our patient had the lowest prepregnancy weight (20 kg) and vital capacity of 0.34 L (VC 11% predicted) yet to be reported in the sparse literature on pregnancy with SMA. She delivered two live healthy infants via planned caesarean section without pregnancy or neonatal complication. We describe the respiratory and obstetric management techniques used for a pregnancy with this degree of respiratory compromise.

Combined spinal-epidural anesthesia in a patient with spinal muscular atrophy type II undergoing cesarean section: A case report

“…General anesthesia in patients with SMA was complicated by underlying restrictive lung disease (RLD), sensitivity to nondepolarizing muscle relaxants, potential for hyperkalemia with succinylcholine and likelihood of difficult intubation 15 . It may be necessary to perform an awake fiberoptic intubation (FOI) if the patient has predictors for a difficult airway 2,16 . Dexmedetomidine has been administered for sedation during an awake FOI 17 .…”

“…The administration of a depolarizing muscle relaxant agent (e.g. succinylcholine) is contraindicated due to chronic denervation that can lead to rhabdomyolysis and severe hyperkalemia 2,5,18 . Nondepolarizing muscle relaxant (NDMR) agents can safely be administered and reversed using neostigmine 4 , however, patients with SMA are sensitive to NDMR drugs and therefore a reduced dose should be administered with close monitoring followed by complete reversal 2 .…”

Anesthetic management of spinal muscle atrophy type II in a parturient

“…These complications carry significant sequelae for patients who often have a history of recurrent pneumonias and prolonged recoveries from general anesthesia. Reviewing the literature, awake fiberoptic guided intubations (FIOs) were chosen in four out of six intubations for planned cesarean sections under general anesthesia on patients with SMA type II and III 9,15,16,18. Case reports of local anesthetic infiltration for cesarean section paired with light sedation exist 21…”

Neuromuscular Disorders in Pregnancy

“…77,79 In operative deliveries, regional anesthesia is preferred over general anesthesia, though establishing regional anesthesia may be challenging in patients with pre-existing spine deformities. 80,81 In vitro fertilization with preimplantation genetic diagnosis should be offered to patients with SMA who are considering pregnancy. If preimplantation genetic diagnosis is not desired, prenatal genetic testing during pregnancy is still advisable, and this may expedite the treatment of affected infants with nusinersen, an antisense oligonucleotide that may substantially improve outcomes in infants with SMA.…”