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Clinical Opal – Clare presents with polyuria & thirst

11 July 2023 - Grace Larson

A 19 year old woman presents to the urgent care GP clinic, she has been feeling unwell for the last 24 hours.

She has insulin dependent diabetes and is known to have poor compliance. She is describing associated symptoms of polyuria and thirst.

Temp 36.5
BP 113/62
HR 89
Chest clear
Perioral herpes present
Urinalysis = Ketone 2+ Glucose 4+

The urgent care takes off an ABG and this is the result:

Calculate out the anion gap for this patient using the equation:

(Na+ + K+) – (Cl- + HCO3-)

Is the anion gap, normal or raised and what does this mean in the context of a pH of 7.26?

The Anion Gap is 32.7, this is elevated.

An anion gap greater than 10 in the context of acidosis and Clare's presenting history indicates Diabetic Ketoacidosis (DKA).

In DKA decreased insulin and increased glucagon causes the liver to release glucose via glycogenolysis and gluconeogenesis. Increased glucose in the blood leads to osmotic diuresis which in turn causes dehydration and loss of sodium and potassium. The lack of insulin also leads to lipolysis where the free fatty acids undergo beta-oxidation in the liver and ketone bodies form. This causes acidity with a low blood pH and an increase in organic acids to create a higher anion gap.


Grace Larson
Grace Larson

Grace Larson, RN, BN, CertIV(TAE), GradDipClinNurs(PaedCritCare), MAdNursPrac(PaedCritCare), has extensive experience in paediatric nursing, with 13 years in Paediatric Intensive Care Units (PICU). She’s published journal articles in the specialty area of pain and sedation in PICU, and has presented at national and international conferences on the area of pain and sedation in paediatrics. Grace has previously worked with the ACCCN delivering Paediatric Advanced Life Support in Victoria, bringing a wealth of experience into her clinical teaching on paediatric resuscitation. She has also consulted with NSW Health on quality and safety delivering within PICU, and has been contracted with the ANMF to develop nursing programs for nurses who require additional education as part of their practice requirements.

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