Diabetic Ketoacidosis Flashcards
Define Diabetic Ketoacidosis
Acute metabolic complication of diabetes characterised by the biochemical triad of hyperglycaemia, ketonemia an acidaemia with rapid onset of symptoms.
What differentiates mild, moderate, and severe DKA
Mild DKA: venous pH 7.2- 7.29 or bicarbonate < 15 mmol/l. Assume 5% dehydration
Moderate DKA: venous pH 7.1-7.19 or bicarbonate < 10 mmol/l. Assume 7% dehydration
Severe DKA: venous pH less than 7.1 or serum bicarbonate < 5 mmol/l. Assume 10% dehydration
What causes DKA and what may precipitate it
Complication of T1DM
Precipitating events
Insulin (non-adherence)
Infection
MI
Stroke
Surgery, trauma
Pancreatitis
Chemotherapy, hyperthyroidism, Cushing’s steroids, thiazides, antipsychotics etc.
What is the pathophysiology behind DKA
Ketoacidosis (alternative metabolic pathway used in starvation states, which produces acetone as a by-product Due to the lack of insulin, the excess glucose cannot be absorbed in cells to be metabolised → hyperglycaemia + acidosis due to ketones)
What are the symptoms of DKA
Gradual drowsiness, lethargy, confusion
Unexplained vomiting, abdominal pain, polyuria, polydipsia, anorexia, coma or deep breathing
Dehydration in T1DM
Polyphagia
Fruity smell on breath
Preceding history of:
Increased thirst and urinary frequency
Weight loss
Visual disturbance
What are the signs of DKA
Weight and height (measure dehydration)
Obs: hypotension, tachycardia
General
Dehydration: dry mucous membranes, reduced skin turgor, sunken eyes, prolonged >CRT
Poor peripheral perfusion
GCS, Lethargy, drowsiness, decreased level of consciousness
Ketotic/acetone breath
Kussmaul respiration - rapid and deep respiration
Hypothermia
What investigations should be done for DKA
Capillary glucose: >11
Urine dipstick: Glucose +++, ketones ++
ECG: look for precipitation factors or hypokalaemia
Blood gas: Metabolic acidosis
Ketones: >3 mmol/L
Blood glucose: >11
FBC, U&Es, LFTs, Amylase
Rule out infections: throat swab, blood cultures, CXR
What is the management for DKA
Immediate admission to hospital
- A-E assessment and resuscitation
- Fluid resuscitation (10ml/kg bolus of 0.9% saline over 1h)
- Full clinical assessment (GCS, weight, investigations)
- Start fluid replacement (maintenance + deficit) and re-assess
- Ensure all fluids contain 40mmol/L KCL (definitely before insulin given)
- 1-2h after fluids: Insulin (50 units human soluble to 50mL saline), 0.05 units/kg/hour
- Re-assess: GCS, blood glucose and ketones, fluid status
- Consider catheter if urine has not passed within 1 hour, or NG tube if vomiting or drowsy
- When Glucose <14mmol/L → start 5% glucose and reduce insulin infusion rate to 0.05
- Continue insulin until blood ketones <0.6mmol/L (urine ketones remain positive)
What is the definition of DKA resolution
pH >7.3 and
blood ketones < 0.6 mmol/L and
bicarbonate > 15.0mmol/L
What are the complications of DKA
Cerebral oedema (headache, irritability, slowing pulse, rising BP, papilloedema) → hypertonic saline + mannitol
Aspiration pneumonia
Hypokalaemia
Hypomagnesaemia
Hypophosphatemia
Thromboembolism
Femoral vein thrombosis (very sick children with a. femoral line inserted
What is the prognosis for DKA
Mortality rate 5% in experienced centres
Death is usually caused by the underlying illness that causes the hyperglycaemia or ketoacidosis
Prognosis worsened at extremes of age and in the presence of coma and hypotension