Cerebral edema is the most feared emergent complication of pediatric diabetic ketoacidosis.  Fortunately, it is relatively rare, but the rarity can lead to some confusion when it comes to its management.  We recently discussed the use of mannitol and hypertonic saline for pediatric traumatic brain injury, but when should we consider these medications for the patient presenting with DKA?

Cerebral Edema with Pediatric DKA Basics

• Cerebral Edema is a relatively rare.
  • Incidence <1% of patients with DKA.
  • Overall tends to occur in the newly diagnosed diabetic patient (4.3% vs 1.2%).
• While rare, it is a devastating complication.
  • 1990 study showed case fatality rate was 64%.
  • Those treated BEFORE respiratory failure had lower rate of mortality (30%).
  • Lesson = treat early!
• The exact mechanism is not known… and may be varied between individual patients.
• Signs and Symptoms develop in:
  • 66% within the first 7 hours of treatment (these tend to be younger).
  • 33% within 10-24 hours of treatment.
• The diagnosis is clinical!
  • ~40% of initial brain imaging of kids with cerebral edema are NORMAL!

Risk Factors for Developing Cerebral Edema

This is the area that often leads to finger pointing… most often those fingers being pointed toward the Emergency Physician who was initially caring for the kid.

• Much of the literature focused on interventions, but:
  • Administration of Bicarb
    • Sodium Bicarb was shown to be associated with Cerebral Edema in one study…
    • Unfortunately, this study did not adjust for illness severity.
  • Type of IV Fluids
    • Generally, there is an absence of evidence that associates volume, tonicity, or rate change in serum glucose with Cerebral Edema development.
  • There are cases presenting with cerebral edema prior to any therapies.
• Risk Factors that seem to stay consistent:
  • Kids < 5 years of age
    • More likely to have delayed diagnosis
  • More severely ill at presentation
    • Severity of Acidosis
    • Elevated BUN
    • Greater degree of dehydration

Treatment Considerations

• Early detection and treatment is the best means to prevent brain injury and death.
• But, abnormal neurological signs are common in kids with DKA and they don’t all need therapy.
• GCS score is not sensitive enough.

• Muir et al published a Bedside Evaluation of Neuro State of Kids with DKA
  • Diagnostic Criteria
    • Abnormal motor or verbal response to pain
    • Decorticate or Decerebrate posture
    • Cranial Nerve Palsy (especially III, IV, or VI)
    • Abnormal neurologic respiratory pattern (grunting, Cheyne-Stokes, etc)
  • Major Criteria
    • Altered mentation / fluctuating level of consciousness
    • Heart rate decelerations (decline of more than 20 bpm) not due to improved hydration or sleep
    • Age-inappropriate incontinence
  • Minor Criteria
    • Vomiting
    • Headache
    • Lethargy or being not easily aroused from sleep
    • Diastolic BP > 90 mmHg
    • Age < 5 yrs

     

  • Having either 1 Diagnostic Criterion, 2 Major Criteria, or 1 Major and 2 Minor criteria lead to 92% sensitivity and 96% specificity for recognition of Cerebral Edema early enough for intervention.
  • This does lead treating an additional 5 children who don’t have Cerebral Edema for every 1 child who does.

   

• A critical MORSEL is that for every child you treat for DKA needs to have an initial thorough neuro exam including Cranial Nerves and then frequent reassessments… and document it (so your colleagues who take over care for the kid can know if there has been a change)!

Treatment

• Mannitol 1 gram/kg over 20 minutes.
  • May repeat as needed in 1-2 hours.
• Hypertonic Saline 5-10 mL/kg 3% saline is an option if no improvement with Mannitol.
• Decrease IV Fluids
• Head of Bed at 30 degrees.
• Intubation
  • AVOID if able to… associated with worse outcomes.
  • Reserve only for those with respiratory failure.
  • The consideration of cerebral edema does not require intubation.

References