Diabetes Mellitus

Consequences of Uncontrolled High Blood Sugar: Diabetic Ketoacidosis

Jennifer Kong

Learning Objectives

By the end of this section, you will be able to:

  • Explain a consequence of uncontrolled diabetes
  • Identify the clinical manifestations and causes of diabetic ketoacidosis

 

Uncontrolled diabetes  – whether due to circumstance or lack of diagnosis – can also lead to a dangerous condition known as diabetic ketoacidosis. Because of a  lack of glucose entering cells (regardless of whether its due to lack of insulin or insensitivity to insulin), cells increasingly rely on fat stores for fuel, despite the high amounts of circulating sugar (hyperglycemia).  As a result, there is an increased production of ketones which are a byproduct of fat metabolism.  Ketones are acidic causing an acidic environment in all tissues which spill into the blood (ketoacidosis), thus altering the pH of the entire body. The acidic environment forces electrolytes to be redistributed between inside and outside of cells (e.g. blood) causing electrolyte imbalance and disturbances.  For example, DKA causes hyperkalemia  because potassium (normally in high levels within the cells) is forced out of the cell and into blood; exiting K+ is exchanged for incoming H+ (acid) as the body tries to deal with the growing acidosis by storing H+ into cells. The hyperglycemia will also cause polyuria which can quickly lead to dehydration, thus complicating the electrolyte disturbances. This scenario is known as diabetic ketoacidosis (DKA). DKA is a serious medical condition as there are concurrent stresses on the body:  electrolyte disturbances, acidic environment, hyperglycemia with no glucose entering the cells.  If DKA is left untreated, it may progress to life-threatening “diabetic coma” as the tissues starve and continue to acidify.
DKA can occur in all the different types of diabetes – but it is more common in Type 1 diabetics due to their lack of insulin.
Uncontrolled hyperglycemia that leads to DKA can be caused by:
  • unknown diagnosis of Type I diabetes where lipid metabolism is needed due to the absence of insulin. As a result, ketones are made.  DKA may develop and bring the patient for emergency care where the official diagnosis of both DKA and T1DM is made
  • insufficient insulin is administered in a Type I diabetic.  Thus, the tissues can not get glucose into the cells and, as a result, cells turn to lipid metabolism making ketones.
  • insulin demand is suddenly increased (e.g. sudden illness or injury, alcohol/drug ingestion) in a Type I diabetic leading to lipid metabolism and ketone production.
Clinical manifestations of DKA are similar to diabetes (3P’s of diabetes, fatigue, dehydration) WITH the addition of:
  • Fruity smelling breath (presence of ketones)
  • Fast, deep breathing (breathing off the acid)
  • GI upset (will complicate dehydration)
  • Malaise
  • Signs of Electrolyte disturbances (e.g. arrhythmia, loss of consciousness, seizures) [hyperkalemia will disrupt every tissue that is electrically excitable]

Section Summary

DKA is a serious condition that can result from a serious, prolonged lack of glucose intake into the cells:  usually as a result of insufficient insulin.  Fats need to be metabolized resulting in the production of acidic ketones.  High ketones causes pH changes in  the body and the as the body tries to compensate for this acidification, K+ is expelled from the cells leading to hyperkalemia and resulting electrolyte disturbances.  The resulting hyperglycemia will lead to polyuria causing dehydration which further complicate the electrolyte disturbances.  Electrolyte disturbances will manifest as irregular heart rhythms (arrhythmia) and neurological impairments (e.g. loss of consciousness, seizures).  The high amount of circulating ketones is noticeable in a fruity breath with the acidosis causing a rapid respiratory rate. This is in conjunction with the signs of DM (i.e. polyuria, polydipsia)

Review Questions

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Pathology by Jennifer Kong is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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