Clinical Scenario:
A previously healthy 9-year-old boy is brought to the emergency department with a 3-day history of polyuria, polydipsia, weight loss, and increasing lethargy. On examination, he is dehydrated, tachycardic, and has deep, rapid respirations. He is diagnosed with severe diabetic ketoacidosis.
Initial investigations:
- Blood glucose: 34 mmol/L (612 mg/dL)
- Venous pH: 6.91
- Serum bicarbonate: 4 mmol/L
- Serum sodium: 130 mmol/L
- Serum potassium: 5.5 mmol/L
He receives fluid resuscitation according to protocol and is started on an intravenous insulin infusion. Six hours later, the nursing staff report that he has become increasingly irritable and difficult to arouse. He complains of a severe headache and vomits twice. His vital signs now show:
- Heart rate: 68 beats/min (previously 126 beats/min)
- Blood pressure: 130/84 mmHg (previously 96/58 mmHg)
His pupils are equal and reactive, and there are no focal neurological deficits.
What is the most appropriate next step in management?
A. Administer intravenous sodium bicarbonate to correct severe acidosis
B. Administer intravenous mannitol (or hypertonic saline) immediately
C. Increase the insulin infusion to accelerate correction of ketoacidosis
D. Obtain an urgent CT scan of the brain before initiating treatment
E. Perform lumbar puncture to exclude meningitis
Correct answer & Explanation
Correct answer: B
Explanation: Neurological complication of DKA
Cerebral injury is a life-threatening complication of pediatric diabetic ketoacidosis (DKA). It may develop before treatment begins or during treatment and can progress rapidly. Early recognition and prompt intervention are essential.
Warning signs include:
Altered mental status or a progressive decline in consciousness
Severe or worsening headache
Recurrent vomiting
Irritability or unusual behavior
Bradycardia, hypertension, or abnormal respiratory patterns, which may indicate raised intracranial pressure
In a child with DKA who develops new neurological deterioration, suspect cerebral injury and initiate emergency treatment without waiting for neuroimaging. Although cerebral edema is often used clinically to describe this complication, the underlying injury can involve more than swelling alone.
Why Option B Is Correct
B. Administer intravenous mannitol or hypertonic saline immediately.
When cerebral injury is clinically suspected, prompt treatment with an osmotic agent is recommended in this neurological complication of DKA. Commonly used regimens include:
Mannitol: 0.5–1 g/kg intravenously over 10–15 minutes.
3% hypertonic saline: 2.5–5 mL/kg intravenously over 10–15 minutes, according to the local pediatric DKA protocol.
These are alternative initial treatments; the choice depends on the clinical situation and local protocol. Reassess the child’s neurological and cardiorespiratory status closely, involve pediatric intensive care, and review fluid administration. Avoid abrupt or excessive fluid restriction; fluid adjustments should be guided by the child’s perfusion, hydration, and specialist assessment.
Treatment must not be delayed to obtain a CT scan or MRI.
Why the Other Options Are Incorrect
A. Sodium bicarbonate
Routine bicarbonate administration is not recommended for DKA-related acidosis. It may cause harm and is generally reserved for exceptional circumstances specified in specialist protocols, such as life-threatening hyperkalemia or severe acidosis with compromised cardiac function.
C. Increase insulin infusion
Increasing insulin above the recommended DKA protocol is not an appropriate treatment for cerebral injury. Continue insulin according to the protocol while addressing the neurological emergency.
D. CT scan before treatment
Neuroimaging may be useful when the diagnosis is uncertain or another intracranial cause is suspected, but treatment must not be delayed in a child with clinical signs of cerebral injury.
E. Lumbar puncture
Lumbar puncture is not an appropriate initial investigation when raised intracranial pressure or cerebral injury is suspected. It may be dangerous in an unstable child and should be considered only after appropriate specialist assessment.
High-Yield Exam Pearls
Cerebral injury can occur before or during treatment of pediatric DKA.
New neurological deterioration during DKA requires immediate assessment and treatment.
Give mannitol or 3% hypertonic saline promptly when cerebral injury is clinically suspected; do not wait for imaging.
Review fluid administration and involve pediatric intensive care.
Bicarbonate is not routine therapy for DKA-related acidosis.
Find High Yield Board exam MCQ on hyponatremia in DKA.
External Resources
Canadian Paediatric Society: Current Recommendations for Management of Paediatric Diabetic Ketoacidosis
Practical guidance on recognizing and treating cerebral injury during pediatric DKA.ISPAD Clinical Practice Consensus Guidelines 2022: Diabetic Ketoacidosis and Hyperglycemic Hyperosmolar State
International guidance on DKA management, neurological monitoring, and complications.Royal Children’s Hospital Melbourne: Diabetic Ketoacidosis
Pediatric emergency guidance on DKA management and neurological complications.
References
Glaser N, Fritsch M, Priyambada L, Rewers A, Cherubini V, Estrada S, et al. ISPAD clinical practice consensus guidelines 2022: diabetic ketoacidosis and hyperglycemic hyperosmolar state. Pediatr Diabetes. 2022;23(7):835–856. doi:10.1111/pedi.13406. Available from: https://doi.org/10.1111/pedi.13406
Gripp KE, Trottier ED, Thakore S, Sniderman J, Lawrence S. Current recommendations for management of paediatric diabetic ketoacidosis. Paediatr Child Health. 2023;28(2):128–138. doi:10.1093/pch/pxac119. Available from: https://doi.org/10.1093/pch/pxac119
