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Dr. Ajith Kumar J MD
Dept. of Emergency Medicne
Travancore Medicity, Kollam
India
editor
DIABETIC KETOACIDOSIS
It is a major medical emergency & remains a serious cause of morbidity , principally in people with type 1 diabetes. Any form of stress particularly infection can precipitate severe ketoacidosis even in patients with type 2 diabetes.
Pathogenesis
Diabetic ketacidosis is characterised by
Hyperglycemia
Hyperketonemia
Metabolic acidosis
Hyperglycemia causes profound osmotic diuresis leading to dehydration & electrolyte loss particularly sodium & potassium.
Potassium loss is exacerbated by secondary hyperaldosteronism as a result of reduced renal perfusion.
Ketosis results from insulin deficiency , exacerbated by catecholamines & other stress hormones, resulting in unrestrained lipolysis & supply of free fatty acids for hepatic ketogenesis. When this exceeds the capacity to metabolise they accumulate in blood & produce metabolic acidosis.
FLUID LOSS
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CLINICAL FEATURE
SYMPTOMS | SIGNS |
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Diagnostic criteria
Blood glucose >250mg/dl
Arterial pH<7.3
Bicarbonate <15mEq/L
Moderate ketonuria or ketoniemia
Investigations
Hrly GRBS
Check electrolytes BUN, creatinine every 2-4 hrly
ABG
CBC
URE
Blood & urine cultures
ECG, Chest xray
Management
FLUID REPLACEMENT
Normal saline (0.9%) is used to replace the extracellular lose initially
1L/h over the first 1-2 hrs.
After the first 2L of fluid has been given, the intravenous infusion should be at the rate of 300 – 400ml/h
When blood glucose <15 mmol/L (<270mg/dl)
Switch to 5% dextrose 1L 8th hrly
If still dehydrated continue 0.9% saline & add 5% dextrose 1L per 12hrs
Typical requirement is 6L in first 24 hrs
Avoid fluid overload in elderly.
INSULIN
Initial bolus dose of 0.1 U/kg is given to prime the insulin receptors followed by 0.1U/kg/h.
Recent studies has shown that bolus dose is not required.
Insulin dose is adjusted to obtain a fall of 50-70mg/dl/hrly.
Potassium
10 – 30mEq/h should be infused during second & third hrs after beginning therapy as soon as acidosis starts to resolve (if patient has no renal failure).
If K+ <3.5mEq/L first potassium level is corrected before starting insulin.
Sodium bicarbonate
Bicarbonate therapy is not indicated routinely, unless the pH <7.0 or less , with careful monitoring to prevent overcorrection.
Bicarbonate therapy is stopped once pH reaches 7.1 or greater as it may cause rebound metabolic alkalosis as ketones are metabolised. Alkalosis shifts potassium from serum into cells which could precipitate a fatal cardiac arrythmia.
Antibiotics : Are used as indicated.
Switching to SC insulin
SC regimen is started once the patient is awake and able to eat, SC insulin therapy can be initiated.
Total daily insulin dose of 0.6U/kg is given.
Total daily dose is calculated from the insulin requirement during the last 8hrs . Half the dose is given as long acting basal insulin & other half as a short acting insulin premeals.
SC insulin should be given 1hr before stopping the infusion.
COMPLICATION
Cerebral oedema : It is characterized by sudden onset of headache or deterioration in mental status during treatment . Risk factors for its development include severe baseline acidosis, rapid correction of hyperglycemia and excess volume administration in first 4hrs. IV mannitol 1-2gm/kg is the mainstay of treatment.
Acute respiratory distress syndrome
Thromboembolism
DIC
Acute circulatory failure
Updated on 27/3/13.
Reference :
CMDT 2013
Davidson 21st edition.
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emmedonline
Dr. Ajith Kumar J MD
Dept. of Emergency Medicne
Travancore Medicity, Kollam
India
editor