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Diabetic Ketoacidosis

A relative or absolute insulin deficiency leads to a state of acidosis, ketonemia.  Frequent causes include stress and infection in a new diabetic or a missed insulin dose in an established diabetic.  Characteristics of a patient in ketoacidosis include:

Hyperglycemia:  In insulin deficiency, there is decreased cellular uptake of glucose, increased proteolysis, lipolysis, gluconeogenesis, and glycogenolysis.

Hyperketonemia with acidosis:  Without insulin, ketones cannot be processed.  There is increased lactic acid production secondary to tissue hypoperfusion.  Serum bicarbonate levels of less than 15 are common.  An anion gap acidosis exists.

Dehydration:  Elevated glucose and ketones result in an osmotic diuresis.  Dehydration of 10% in children and up to 15% in infants is common.  If plasma osmolarity exceeds 320, coma may result.

Hyponatremia:  Serum sodium may diluted by hyperlipidemia and hyperglycemia.

Hypokalemia:  In all DKA, there is a total body deficit of potassium, even if initial serum measures demonstrate normal levels.


Treatment:

(also see detailed guidelines)
Vascular repletion:  If shocky, bolus with 20 mL/kg of 5% albumin.  Otherwise, bolus with 20 mL/kg of lactated Ringer's solution or Normal Saline to be infused over 1-2 hours.  After this, change to the appropriate maintenance fluid.   The remainder of the calculated fluid deficit should be infused over 24 hours.  If the plasma osmolarity is above 320, replete over 36 hours, and if above 340, over 48 hours.

Electrolyte correction:   Sodium should correct itself as osmotic dilution resolves.  If potassium is under 3, add potassium at 20 mEq/L to the D5.  Otherwise, do not add potassium until the serum potassium is less than 6 and the patient has voided.    Phosphate is often depleted, the maintenance fluid should contain 10 mEq from KCl and 10 mEq from potassium phosphate during the first 8 hours of rehydration; after that, use 20 mEq/L of KCl.  Additional KCl riders may be needed for persistently low potassium.  Bicarbonate may be considered with blood pH of less than 7.1.  1-2 mmol per kilogram (or 80 mmol per m2) can be given over 20 minutes.  The solution should not be pushed rapidly because this would trigger sequestration of potassium into cells and a precipitous hypokalemia.

Insulin administration:  An insulin drip is started at 0.1 units per kilogram per hour.  Alternatively, 0.1 unit per kg dose can be given IM each hour.  Insulin IV solutions should be allowed to run through the tubing to saturate binding sites.  Once the drip is started, the goal is to decrease serum glucose about 50-100 mg/dL per hour.  If the glucose is declining less than 50 mg/dL per hour, the drip rate can be raised to 0.14-0.2 units/kg/hour.  If the glucose is dropping more than 100 mg/dL per hour, switch to a solution containing 5% dextrose.  When the glucose drops to 250, add 5% dextrose. The drip is continued until the blood pH is greater than 7.3, there is no ketosis, and the patient has taken good po for an hour or two.  An hour prior to stopping the drip, IM insulin should be administered.  If the patient previously used insulin, they should return to that schedule.  If it is a new patient, between 0.1 and 0.25 units of regular insulin per kilogram can be administered q 6 hours for 24 hours.  This total amount is then divided 2/3 into the morning, 1/3 into the evening dose.  The morning dose is then split into 2/3 intermediate (NPH) and 1/3 regular (R).  The evening dose is split in the same manner between NPH and regular.  If blood glucose measurements exceed 270, an additional 0.1 units per kilogram of regular can be given prior to meals.

Monitoring:  An initial weight should be obtained if possible.  The patient should be placed on a cardiac monitor.  Strict I/O should be recorded.  Vital signs should be taken q 30 minutes.  While greater than 6 or less than 3, potassium should be checked every hour.  Glucose should be checked every hour by Dstick.  A Chem-7 and urine dipstick for ketones should be obtained every 4 hours.  Calcium and phosphate should be included in the chemistry every 12 hours.  Once the iv drip has been stopped, the patient's blood glucose should be monitored by Dstick before meals and snacks.

Emergency Management:  The greatest morbidity in DKA is associated with cerebral edema during treatment.  If there is any change in mental status, headaches, incontinence, vomitting, opthalmopelagia, pupillary changes, papilledema, posturing, seizures, or fluctuations in vital signs, administer 1g/kg of mannitol over 15 minutes.  This treatment can be repeated as required.
 
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Last modification: April 30, 1998