DKA

Question 1

What is the mechanism of action of ondansetron?

Answer 1

A competitive serotonin type 3 receptor antagonist. It is effective in the treatment of nausea and vomiting caused by cytotoxic chemotherapy drugs, including cisplatin, and has reported anxiolytic and neuroleptic properties.

Question 2

What is novomix?

Answer 2

A rapid acting form of insulin aspart

Question 3

What is the management of DKA?

Answer 3

Sequential 1 litre bags of 0.9% sodium chloride saline given over progressively longer lengths of time (30 minutes, 60 minutes, 120 minutes, 240 minutes, 360 minutes)
10 units of actrapid insulin IM followed by fixed rate IV actrapid insulin at 6units/h.
40mmol/L potassium replacement therapy through IV pre-mixed 0.9% sodium chloride and potassium chloride bags.

Question 4

Why is potassium elevated in DKA?

Answer 4

As a result of hyperglycemic hyperosmolality, potassium shifts along with water from inside cells to the extracellular space and is lost in the urine.
Insulin normally promotes cellular potassium uptake but is absent in DKA, compounding the problem.
A total body potassium deficit therefore develops in the body, although serum potassium may be normal or even paradoxically elevated.
Insulin deficiency → hyperosmolality → K+ shift out of cells + lack of insulin to promote K+ uptake → intracellular K+ depleted → total body K+ deficit despite normal or even elevated serum K+