Themed case notes on diabetes – Notes for further leaning

Diabetes is a chronic health condition with increasing prevalence in the population

  • 10- 25% of patients admitted to hospital will have diabetes
  • Diabetes tends to prolong hospital stay, prolonged recovery from infection increased CVrisk and mortality after hospital admission
  • There is good evidence that good control of diabetes improves long term morbidity and mortality.
  • On average the life expectancy of a person with diabetes is 10 years less than general population

Types of diabetes

    • Type 1- autoimmune/ Idiopathic ( Antibodies – GAD, Insulin Ab, Islet cell ab)
    • Type 2 Diabetes
      • Combination of Insulin resistance and beta cell dysfuntion
    • Genetic defects (MODY) – monogenic causes of diabetes
      • HNF1Alpha (Ch12), Glucokinase (Ch 7), HNF 4 Alpha (Ch 20) Insulin promoter factor (Ch 13)
    • Mitochondrial diabetes – Maternal transmission only
    • Genetic defects in insulin action –
      • Leprachaunism, Lipoatrophic diabetes
    • Gestational diabetes
    • Endocrinopathies –
      • Cushings, Acromegaly, Somatinostatinomas
    • Associated with other diseases – Pancreatitits, FCPD, Cystic FibrosisTurners, Klinefelters, Turners syndrome


Interpreting blood gas in Patient with DKA

Ph – 7.1 (normal range 7.35 – 7.45)

  • This is the first column to look at this tells you the person is acidotic

PO2 – 10.4 (normal)

  • This tells you partial pressure of oxygen in the blood. this needs to be looked at  bearing in mind two factors
    • a) Is the patient on supplemental oxygen
    • b) Is this an arterial blood gas or venous blood gas

PCO2 – 2.9 (4.5 – 6.7)

  • In metabolic acidosis normally the person hyperventilates to blow out CO2 to induce respiratory alkalosis. so you would expect the PCO to be low

Bicarbonate 15 (24 – 28)

  • This is blood bicarbonate level. when there is metabolic acidosis, bicarbonate ions combine with H+ to form carbonic acid and then CO2 and water. So levels of HCO3 will falls

BE (Base Excess) –   -17.9 ( normal range +2.5 to – 2.5)

  • This tells you severity of the acidosis. Venous bicarbonate will be low in both metabolic acidosis and respiratory alkalosis. Both conditions coexist in DKA so how will you tell how much HCO3 has been used up? by looking at base excess (or base deficit)… the machine calculates predicted HCO3 for a PCO2 of 5.0. Whatever bicarbonate is still missing ( – 9.7- in this case) is the metabolic component.

Videos – 15 minute teacher Diabetic KEtoacidosis

Video – 15 minute teacher Hypoglycemia