Clinical Case 3

A 14 year old girl was brought to her GP’s office, complaining of: – weight loss, – dry mouth, – lethargy, – easy fatigability – and difficulty in catching the breath; The symptoms were noticed by the parents about 10 days before the visit However, the patient herself had noted an increased frequency of urination (polyuria) and increased thirst (polydipsia) about 8–10 weeks prior

A urine analysis using reagent strips revealed positive glucose and ketones respectively Her temperature was 39°C and a chest examination revealed some congestion The patient was immediately admitted to hospital for management Clinical examination revealed: – a dehydration, – fruity odour to the breath, – tachycardia (120 beats/min) – and dry mouth, lips and tongue – The respiratory rate was 30/min and her blood pressure was 110/70 mmHg

Laboratory Investigating Laboratory data indicated that: – her plasma glucose level was 470 mg/dl ( mg/dl) – serum acetone was positive – arterial blood pH was 7.18 (7.35–7.45) – with a bicarbonate level of 17 mmol/l (21–28 mmol/L) – Other serum values determined at this time were – Na (136–145 mmol/L) – K (3.5–5.0 mmol/L) – Cl – 92, (96–106 mmol/L) – and glycosylated haemoglobin 13.1% (< 6.8%) – blood islet cell antibodies were positive

What is the most likely diagnosis in this patient? What are the causes of her observed symptoms? This is a classical presentation of diabetic ketoacidosis in Type I diabetes patients The common symptoms of diabetes mellitus are: – polyuria (increased urine volume and frequency) – polydipsia (increased thirst) – and polyphagia (increased appetite) Polyuria is secondary to the osmotic diuresis (caused by excess filtered glucose in the urine) which then triggers increased thirst

Diabetic ketoacidosis is a serious acute complication that requires prompt attention – It is usually precipitated in Type I diabetes patients by a stressful stimulus (e.g. an infection, surgery or acute illness) – or by omitting several insulin injections The characteristic sweet smell to the breath is due to excretion of acetone (ketone body) formed by condensation of excess acetyl CoA in the liver appearance of other ketone bodies in the blood (acetoacetate and 3-hydroxybutyrate) decreases blood pH (metabolic acidosis) which stimulates respiration (hyperventilation)

What would be the most appropriate treatment while in hospital, and the recommended therapy on discharge? Following a diagnosis of diabetic ketoacidosis, intravenous fluid replacement and correction of hyperglycaemia/ ketonaemia is crucial for effective hospital management A precipitating cause such as an infection should also be sought and treated with appropriate antibiotics if necessary The patient was started on intravenous fluid (normal saline) and soluble insulin infusion (0.2 units/kg followed by 0.1 units/kg per hour) to correct for the underlying dehydration and metabolic abnormalities In the next 14 hours, the blood glucose was stabilized at 140 mg/dl and the patient rehydrated

Serum electrolytes returned to normal – bicarbonate level increased to 22 mmol/l – and arterial blood pH showed normalization to 7.35 – Insulin infusion was continued until next morning – when ketones were no longer present in the diluted serum – The patient was switched to subcutaneous insulin administered twice daily – She was instructed in home blood glucose monitoring methods and discharged on stable doses of insulin three days later