Endocrinology - DKA

Question 1

What is DKA? Name the 3 main features.

Answer 1

1. ketonaemia >3mmol/L or significant ketonuria (>2+ on standard urine sticks)
2. blood glucose >11 mmol/L or known DM (degree of hyperglycaemia not reliable indicator of DKA, may rarely be normal or only slightly elevated).
3. venous pH <7.3 and/or HCO3- <15mmol/L

Question 2

describe the pathophysiology of DKA

Answer 2

Lack of insulin causes:

1. corresponding increase in glucagon… increase glucose release from liver via glycogenolysis and gluconeogenesis… glycosuria and osmotic diuresis… polyuria, dehydration and polydipsia.
2. lipolysis and free fatty acid release from adipose tissue… converted by liver into ketone bodies (acetoacetate, B-hydroxybutyrate and acetone) by B-oxidation… low pKa cause metabolic acidosis with depletion of bicarbonate buffering system.

Question 3

why does DKA occur?

Answer 3

Usually occurs in T1DM but can happen in T2DM.

May be no obvious precipitating factors, but these can include:

• any physiological stress, inc. infection, pregnancy, trauma or surgery
• inadequate (or lack of compliance) insulin
• CVD, e.g. stroke or MI
• drugs, e.g. corticosteroids, thiazides, SGLT2i, a-/B-blockers

Question 4

describe the usual symptoms of DKA

Answer 4

Usually develops over 24 hrs.

• polyuria
• polydipsia
• abdo. pain
• vomiting

Question 5

describe the usual signs of DKA

Answer 5

• signs of dehydration, e.g. dry mucous membranes, decreased skin turgor and cap. refill
• Kussmaul respiration (deep laboured breathing due to resp. compensation of acidosis)
• acetone smell of breath
• hypotension and tachycardia
• altered mental state, inc. coma

Question 6

which investigations would you perform on someone with suspected DKA?

Answer 6

Check blood glucose and ABG and if these suggest DKA, immediately begin resuscitation and management.

1. Bedside tests:
   - CBG: increased
   - urine dipstick: marked glycosuria and ketonuria
   - urine MandC: ?UTI
   - ECG: ?MI, ?arrythmias
   - CXR: ?pneumonia
   - CT/MRI head: if decreased consciousness or focal neurology
2. Bloods:
   - ABG: metabolic acidosis
   - plasma glucose: increased
   - FBC: raised WCC often seen but doesn’t necessarily indicate infection
   - UandE: Na+ may be raised from dehydration; K+ may be raised due to acidosis; urea and creatinine may be raised due to pre-renal AKI
   - plasma osmolality: raised >290 mOsm/kg (less than HHS)
   - troponin I and T: if MI suspected
   - blood cultures: ? sepsis
   - CK: ?rhabdomyolysis

Question 7

describe the immediate management of a pt with DKA

Answer 7

Continuous monitoring of: SaO2, ECG, BP/HR and UO (catheterisation).

1. Fluid resuscitation if systolic BP <90 mmHg: IV 0.9% NaCl 500 ml stat. Repeat if required. Once BP >90 mmHg, maintenance 0.9% NaCl + K+.
2. Start fixed rate insulin infusion at 0.1 u/kg/hr.

Monitor blood ketone and glucose conc. hourly.

Question 8

Describe follow-up treatment of DKA.

Answer 8

1. treat any precipitating cause.
2. once blood glucose <14 mmol/L, 10% glucose given by IV infusion at rate of 125mL/hr in addition to 0.9% NaCl infusion.
3. continue insulin infusion until blood ketones <0.3 mmol/L, blood pH >7.3 and pt able to eat and drink

Question 9

describe possible complications of DKA.

Answer 9

1. cardiac arrythmias due to electrolyte imbalances (e.g. iatrogenic hypokalaemia) or metabolic acidosis
2. venous thrombosis, MI
3. ARDS
4. diabetic retinopathic changes
5. Tx related cerebral oedema