Thirst + polyuria
Glycosuria → osmotic diuresis → water loss
PresentationVOMITING +
VOMITING +
DEEP BREATHING
You are seeing this child before a diagnosis has been made. Start with the presentation and decide what needs explaining.
Which feature most strongly suggests this is more than simple gastroenteritis?
Narration for this step
12-year-old child
Three days of increasing thirst and frequent urination. Since yesterday: vomiting, abdominal discomfort and lethargy. Today the breathing has become deep and rapid.
HR128
RR32
BP98/62
Temp37.1°C
SpO₂99%
HydrationReduced
Reason from the patientWHAT NEEDS
WHAT NEEDS
EXPLAINING?
Don't name the disease yet. Build one problem from the findings that have to fit together.
Narration for this step
Thirst
→
Polyuria
→
Dehydration
Vomiting
Deep breathing
Normal oxygen saturation makes primary hypoxaemic lung disease a less satisfying explanation. What metabolic process could connect the rest?
InvestigateTEST THE
TEST THE
MECHANISM
Now test the hypotheses: hyperglycaemia, ketosis, acidaemia, dehydration and electrolyte disturbance.
What acid–base pattern is present?
Diabetic ketoacidosis
Hyperglycaemia, ketosis and metabolic acidosis
Narration for this step
Glucose28 mmol/L
Ketones5.6 mmol/L
pH7.12
HCO₃⁻8 mmol/L
pCO₂2.8 kPa
K⁺4.8 mmol/L
Explain the mechanismWHY DOES
WHY DOES
INSULIN DEFICIENCY DO THIS?
Return to first principles. One missing signal creates two linked physiological problems.
Narration for this step
Insulin ↓
→
Hyperglycaemia
→
Glycosuria
→
Osmotic diuresis
Insulin ↓
→
Lipolysis ↑
→
Ketones
→
Metabolic acidosis
Make the case cohereEXPLAIN
EXPLAIN
EVERY FINDING
Now every important clinical feature should follow from the mechanism.
Narration for this step
Vomiting + pain
Ketosis, acidaemia and dehydration
Deep breathing
Respiratory compensation for metabolic acidosis
Potassium
Total-body depletion can coexist with a normal or high serum value
Treat the physiologyRUN THE
RUN THE
MECHANISM IN REVERSE
Management becomes easier to remember when every intervention has a physiological purpose.
Narration for this step
Fluids
Restore circulation, renal perfusion and water deficit
Insulin
Suppress lipolysis and ketogenesis
Potassium
Anticipate depletion and the intracellular shift after insulin
Neurology
Repeated assessment for cerebral injury
ReconstructONE CHILD
ONE CHILD
ONE STORY
Rebuild the case from the initiating defect instead of memorising a list.
Narration for this step
Insulin deficiency
→
Hyperglycaemia + ketogenesis
→
Osmotic diuresis + acidosis
→
Dehydration + Kussmaul breathing
If you can rebuild that causal chain, you understand the case rather than simply recognising DKA.
Case completeGO DEEPER
GO DEEPER
IF YOU WANT TO
The teaching case is complete. Only now do references and links into the wider MeducateMe structure appear.