DIABETIC KETOACIDOSIS: A Medical Emergency

DKA is a Medical emergency. Commonly in people with type 1 diabetes, Mortality 10-15% in developed countries, Precipitating factors: Infection, Trauma, Stress, Missed or reduced insulin, Myocardial infarction.

Pathogenesis

Insulin helps in Triglyceride and Fatty acid synthesis and inhibits fatty acid oxidation and ketone production. In absence of insulin, ketone production increases, Ketones- acetoacetate, 3-hydroxybutyrate or acetone, normally produced in small amount and utilized, In DKA, production exceeds utilization and pass into urine.

Cardinal features

Hyperglycaemia, hyperketonaemia, metabolic acidosis, Osmotic diuresis leading to dehydration, hypotension & electrolyte loss, particularly of sodium and potassium, metabolic acidosis forces hydrogen ions into cells, displacing potassium ions.

AVERAGE LOSS OF FLUID AND ELECTROLYTES

Water: 6 litres, Sodium: 500 mmol, Chloride: 400 mmol, Potassium: 350 mmol, 3 litres extracellular -replace with saline, 3 litres intracellular -replace with dextrose.

CLINICAL FEATURES (Symptoms)

Nausea, vomiting, Polyuria, thirst, Abdominal pain, Weight loss, Weakness, Leg cramps, Blurred vision.  Note :- Abdominal pain is due to progression to pancreatitis.

Signs

Tachycardia, Dehydration (dry mucous membrane, reduced skin turgor), Hypotension (postural or supine), Cold extremities/peripheral cyanosis, Tachypnea, Air hunger (Kussmaul breathing), Smell of acetone, Hypothermia, Confusion, drowsiness, coma (10%).

Precipitating Factors

Inadequate insulin administration, Infection (Pneumonia/UTI/Sepsis/Gastroenteritis), Infarction (Cerebral/coronory/mesentric/peripheral), Drugs (cocaine), Pregnancy.

Investigations

Blood glucose ( 13.9 – 33.3 mmol/l or 250- 600 mg/dl)

Arterial blood gases (PH 6.8 – 7.3)

Plasma Bicarbonate < 12 mmol/l = severe acidosis

Urine and plasma ketone = ++++

RFT: urea , creatinine  & electrolytes,

Osmolality 300 – 320 mosm/l

Anion Gap = Increase

ECG

Infection screen: FBC, blood and urine culture, CRP, CXR.

Monitoring In ketoacidosis

Serum Osmolality = [2 x (serum sodium + serum potassium) + plasma glucose (mg/dl)/18 + BUN/2.8]

The principal components of treatment

The administration of short-acting (soluble) insulin, Fluid replacement, Potassium replacement, Antibiotics if infection is present.

Fluid replacement

0.9% saline (NaCl) i.v, 1 litre over 30 minutes, 1 litre over 1 hr, 1 litre over 2 hrs, 1 litre over next 4 hrs. When blood glucose < 15 mmol/l, Switch to 5% dextrose, 1 litre 8-hourly. If still dehydrated, continue 0.9% saline and add 5% dextrose 1 litre per 12 hrs. Typical requirement is 6 litres in first 24 hrs but avoid fluid overload in elderly patients.

Insulin

50 units soluble insulin in 50 ml 0.9% saline i.v. via infusion pump

6 units/hr initially

3 units/hr when blood glucose < 15 mmol/l (270 mg/dl)

2 units/hr if blood glucose declines < 10 mmol/l (180 mg/dl)

Check blood glucose hourly initially-if no reduction in first hour, rate of insulin infusion should be increased

Aim for fall in blood glucose of 3-6 mmol/l (∼55-110 mg/dl) per hour.

Potassium

If plasma potassium < 3.5 mmol/l, give 40 mmol added potassium

Avoid infusion rate of > 20 mmol/hr

If plasma potassium is 3.5-5.5 mmol/l, give 20 mmol added potassium

If plasma potassium is > 5.5 mmol/l, or patient is anuric, give no added potassium

Later, according to lab report.

Note = If initial serum K+ < 3.3 mmol/l then stop insulin infusion until K+ is corrected > 3.3mmol/l.

Other treatments

Continue Above until pt is stable and glucose goal is 150 – 250 mg/dl & Acidosis is resolved then

Insulin infusion is /may decreased to 0.05 – 0.1 U/kg/hr.

Catheterisation if no urine passed after 3 hrs

Nasogastric tube to keep stomach empty in unconscious or semiconscious patients.

Central venous line if cardiovascular system compromised.

Plasma expander if systolic BP is < 90 mmHg or does not rise with i.v. saline.

Antibiotic if infection demonstrated or suspected

ECG monitoring in severe cases

Monitoring Vitals (BP, pulse, RR, Temp)

Complication of DKA