Page 582 - Concise Pathology for Exam Preparation ( PDFDrive )

20 Endocrinology 567

Sequence of evolution of DKA (Flowchart 20.20)

Absolute insulin deficiency

Increased lipolysis

Increased free fatty acid (FFA) to liver

Increased ketogenesis

Decreased alkali reserve

DKA
FLOWCHART 20.20. Sequence of evolution of DKA.

Nonketotic Hyperosmolar Coma
• Nonketotic hyperglycaemia is a type of diabetic coma more often associated with a Type
2 DM. The preferred term used by the ADA is hyperosmolar hyperglycaemic nonketotic
syndrome (HHNS).
• HHNS is due to severe dehydration resulting from prolonged hyperglycaemia-induced
diuresis.
• Osmotic diuresis promotes net loss of electrolytes, including sodium, potassium, calcium,
magnesium, chloride and phosphate.
• Intracellular dehydration occurs as hyperglycaemia and water loss leads to increased
plasma tonicity, causing a shift of water out of cells. This is associated with movement
of potassium from the cell to extracellular compartment.
Sequence of evolution of HHNS (Flowchart 20.21).

Relative insulin deficiency

Increased glycogenolysis Minimal ketogenesis

Hyperglycaemia

Glycosuria (osmotic diuresis)

Loss of water and electrolytes

Dehydration (decreased fluid intake leads to further exacerbation of hyperosmolarity)

Impaired renal function

HHNS
FLOWCHART 20.21. Sequence of evolution of HHNS.

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