A 19-year-old man presents to A&E with a 3 day history of drowsiness, polyuria, vomiting and confusion. His mother reports he has recently been eating less due to an episode of food poisoning a week ago. He denies any recreational drug use. He has type 1 diabetes and uses a combination of short- and long-acting insulin. His heart rate is 110 bpm, blood pressure 100/75 mmHg, temperature 37.2 °C and oxygen saturation of 98% on air.



Arterial blood gases (ABGs) on room air:


||||
|--------------|:-------:|------------------|
|pH|7.28|7.35 - 7.45|
|PaO₂|8.9 kPa|11 - 15|
|PaCO₂|3.6 kPa|4.6 - 6.4|
|Bicarbonate|12 mmol/L|22 - 30|
|Sodium|136 mmol/L|135 - 145|
|Potassium|4.2 mmol/L|3.5 - 5.3|
|Fasting Glucose|22 mmol/L|3.5 - 5.5|




A urine dipstick is positive for ketones (++++) and glucose (+++).



What is the next step in his management?

Options:
explanation: This patient is in DKA. The initial management is fluid resuscitation, followed by an insulin infusion of 0.1 U/kg/h. 0.05 U/kg/h is the treatment of choice for hyperosmolar hyperglycaemic state if there is inadequate response to fluid therapy. Patients with DKA are profoundly dehydrated due to the osmotic effects of hyperglycaemia; therefore, fluid resuscitation is the first action to take, followed by insulin administration to enable ketone clearance.
name: 0.05 U/kg/h Actrapid in 50 ml 0.9% NaCl
label: c
answer: no
explanation: This patient is in diabetic ketoacidosis (DKA). The initial management is fluid resuscitation, followed by an insulin infusion of 0.1 U/kg/h. The key elements of the history supporting the diagnosis include polyuria, confusion and recent illness in someone who is a known diabetic. When patients become unwell and eat less, they can omit insulin doses due to concerns over hypoglycaemia, pushing themselves instead into DKA. This is the likely situation for this patient.
name: One litre 0.9% NaCl over 1 h
label: a
answer: yes
explanation: This patient is in DKA. The initial management is fluid resuscitation, followed by an insulin infusion of 0.1 U/kg/h. Patients with DKA are profoundly dehydrated due to the osmotic effects of hyperglycaemia; therefore, fluid resuscitation is the first action to take, followed by insulin administration to enable ketone clearance.
name: 0.1 U/kg/h of Actrapid in 50 ml 0.9% NaCl
label: b
answer: no
explanation: This patient is in DKA. The initial management is fluid resuscitation, followed by an insulin infusion of 0.1 U/kg/h. This patient's potassium is within the normal range at present, but will fall once the insulin infusion is running since this will drive potassium intracellularly. Therefore, potassium replacement is usually given in subsequent bags of normal saline; however, the first bag of normal saline, which is given rapidly over an hour, should not contain any potassium.
name: 1 litre 0.9% NaCl with 40 mmol KCl over 4 h
label: e
answer: no
explanation: This patient is in DKA. The initial management is fluid resuscitation, followed by an insulin infusion of 0.1 U/kg/h. Patients with DKA are profoundly dehydrated due to the osmotic effects of hyperglycaemia; therefore, fluid resuscitation is the first action to take, followed by insulin administration to enable ketone clearance.
name: 10% glucose infusion at 125 ml/h
label: d
answer: no

Correct answer: a

One litre 0.9% NaCl over 1 h

Learning point: In the management of diabetic ketoacidosis (DKA), initial treatment typically involves administering fluids, such as one litre of 0.9% NaCl over 1 hour, to rapidly rehydrate the patient and restore circulatory volume.