Pregnant patient with mitochondrial degenerative disorder

garychleung

PIG Meeting: 25th February 2021

34yo lady booked for elective CS.

Background

  • Mitochondrial degenerative disorder POLG (DNA Polymerase gamma gene – responsible for the integrity of mitochondrial DNA)
    • OSA – Central and peripheral
    • Bulbar dysfunction
    • Ophthalmoplegia
    • Ataxia, pre-pregnancy 2km with FASF, now mostly in wheelchair. Falls
    • Epileptiform EEG
  • Obesity BMI 38
  • Pregnancy:
    • G1PO
    • Pregnancy itself uneventful.
    • Nil genetic testing of partner or foetus
    • On prophylactic clexane due to immobility
  • Distance patient (Tamworth)

Issues

  • Exercise tolerance reduction
    • TTE in December normal, but known risk of cardiac decompensation
    • Fatigue and SOB increasing. Progressive orthopnoea + possible PND. ? Pregnancy v. Pathologic process
    • Risk of cardiac dysrhythmias. Nil reported palpitations
    • Hasn’t seen cardiologist as part of antenatal care
    • Spirometry in clinic showed normal volumes
  • ? Seizures
    • Recent episodes of 50-60 desaturation events overnight. ? CPAP malfunction v. CCF v. seizures
    • Known epileptiform EEG.
    • Risks of rapid progression from partial seizures to refractory, fatal seizures with POLG
    • Lamotrigine being empirically up-titrated by neurologist
    • Ambulatory EEG cancelled by patient due to logistic challenges and lack of understanding about significance
    • Sodium valproate and MgSO4 contraindicated.
  • CPAP use
    • Machine alarming ? Cause
    • Patient now non-adherent

Discussion

  • Pre-op investigations
    • Baseline lactate (in anaesthetic bay) helps team to understand intra/postoperative levels
    • Baseline CK, CMP
  • Preop multidisciplinary reviews
    • Needs input from cardiology – speak with the cardiologist (Hatton) who works with high risk obstetric patients.
    • Needs CPAP review and optimisation
    • Needs ambulatory EEG
  • Post op care location
    • Given risks of refractory seizures, and need for repeated lactate monitoring and strict fluid balance, ICU level 2 necessary
    • Patient accepting of this.
    • Father of baby will be admitted to care for baby.
  • Anaesthetic technique
    • Neuraxial
      • Nil specific contraindications.
      • Spinous processes palpable and patient’s body habitus relatively conducive to positioning.
      • May require some head-up positioning. Negotiate with surgeons.
      • IT morphine(+/-) and TAP catheters to minimise postop systemic opioids to avoid gut stasis (known issue with POLG) and hypoventilation
      • Patient prefers SAB but happy to go with safest option
      • EDB (without spinal) for slow onset (avoid sudden resp accessory muscle paralysis) ideal.
      • Intrathecal catheter also an option
    • GA?
      • No MH risk
      • Non-depolarising MRs safe
      • Attention to vent/CO2 mx given seizure propensity
      • Difficult to detect seizures
    • Dedicated obstetric anaesthetist
    • IVF with dextrose while fasting