Ketoacidosis

Ketoacidosis
Specialty Endocrinology

Ketoacidosis is a metabolic state associated with high concentrations of ketone bodies, formed by the breakdown of fatty acids and the deamination of amino acids. The two common ketones produced in humans are acetoacetic acid and β-hydroxybutyrate.

Cause

Three common causes of ketoacidosis are alcohol, starvation, and diabetes, resulting in alcoholic ketoacidosis, starvation ketoacidosis, and diabetic ketoacidosis respectively.[1]

In diabetic ketoacidosis, a high concentration of ketone bodies is usually accompanied by insulin deficiency, hyperglycemia, and dehydration. Particularly in type 1 diabetics the lack of insulin in the bloodstream prevents glucose absorption, thereby inhibiting the production of oxaloacetate through reduced levels of pyruvate, and can cause unchecked ketone body production (through fatty acid metabolism) potentially leading to dangerous glucose and ketone levels in the blood. Hyperglycemia results in glucose overloading the kidneys and spilling into the urine (transport maximum for glucose is exceeded). Dehydration results following the osmotic movement of water into urine (Osmotic diuresis), exacerbating the acidosis.

In alcoholic ketoacidosis, alcohol causes dehydration and blocks the first step of gluconeogenesis by depleting oxaloacetate.[2] The body is unable to synthesize enough glucose to meet its needs, thus creating an energy crisis resulting in fatty acid metabolism, and ketone body formation.

Mechanism

Ketoacidosis is a pathological metabolic state marked by extreme and uncontrolled ketosis. In ketoacidosis, the body fails to adequately regulate ketone production causing such a severe accumulation of keto acids that the pH of the blood is substantially decreased. In extreme cases ketoacidosis can be fatal.[3]

Ketoacidosis is most common in untreated type 1 diabetes mellitus, when the liver breaks down fat and proteins in response to a perceived need for respiratory substrate. Prolonged alcoholism may lead to alcoholic ketoacidosis. Ketoacidosis can be smelled on a person's breath. This is due to acetone, a direct by-product of the spontaneous decomposition of acetoacetic acid. It is often described as smelling like fruit or nail polish remover.[4] Ketosis may also give off an odor, but the odor is usually more subtle due to lower concentrations of acetone.

Management

Treatment consists most simply of correcting blood sugar and insulin levels, which will halt ketone production. If the severity of the case warrants more aggressive measures, intravenous sodium bicarbonate infusion can be given to raise blood pH back to an acceptable range. However, serious caution must be exercised with IV sodium bicarbonate to avoid the risk of equally life-threatening hypernatremia.

See also

References

  1. ↑ Steven M. Selbst (2014). Pediatric Emergency Medicine Secrets (3 ed.). Elsevier Health Sciences. p. 324. ISBN 9780323310680. Retrieved 25 May 2016.
  2. ↑ Krebs, H. A.; Freedland, R. A.; Hems, R.; Stubbs, Marion (1969-03-01). "Inhibition of hepatic gluconeogenesis by ethanol". Biochemical Journal. 112 (1): 117–124. doi:10.1042/bj1120117. ISSN 0264-6021. PMC 1187647. PMID 5774487.
  3. ↑ "Death after soup and water diet". BBC News. 27 July 2009.
  4. ↑ Diabetic ketoacidosis at medical dictionary of National Institutes of Health.
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External resources


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