Diabetes Case Study Answers: Lachlan's Story

Hey Everyone!

Blog Post Diabetes Answers blog photo (1)Carly here, one of the trainers at AHA. We started back up our monthly case study series last week with a case study on Lachlan. Check your answers below and let me know if you have any questions in the comments or by emailing me carly@healthcareacademy.com.au. I hope you are able to learn something new and found this case study useful! 

Case Study:

You are working as a nurse in the Emergency Department and have received the following patient:

Lachlan is a 28-year-old male, known Type 1 Diabetic. Has been unwell for 2 days with vomiting and diarrhea. Vomiting has increased over the past four hours and he is now also complaining of abdominal pain. On assessment, Lachlan is pale, diaphoretic, and you smell a sweat scent coming off his breath. Lachlan is alert and oriented but is slow to answer questions. He seems to be having some difficulty breathing and has a breathing pattern that you have never seen before. See video:


Vital signs:

T- 36

HR- 120

RR – 30

BP – 110/76

SpO2 – 97 %


Point of Care Blood Glucose – 30


1) What diagnosis are you predicting that Lachlan will receive from the RMO?

Answer: By looking at the labs and history, we can assume Lachlan is going to receive a diagnosis of Diabetic Ketoacidosis or DKA.

2) What are the normal ranges for blood glucose levels?
Answer: The normal ranges for blood glucose levels are (Diabetes QLD):

Type 1 Diabetes:

Before meals: 4-6 mmol/L

2 hours after starting meal: 4-8 mmol/L

Type 2 Diabetes:

Before meals: 6-8 mmol/L

2 hours after starting meal: 6-10 mmol/L

3) What is the breathing pattern called that Lachlan is showing?
Answer: This rapid, deep breathing is called Kussmaul’s breathing. As the body is in an acidic state, the body is trying to breath faster and deeper to expel more carbon dioxide (an acidic compound) through respiration.


4) Do you know what labs you would expect to be ordered on Lachlan and what is the most important determinator in his diagnosis?

Answer: Labs that will definitely be ordered are: blood gas, extended electrolytes, serum osmolarity, hourly BGL, BUN, creatinine, and HbA1C. The RMO may also order a FBC, blood cultures, and/or CRP if there is a thought that the patient might be in DKA due to an infection. The four diagnosis criteria for DKA are: blood glucose of greater than 13.9 mmol/L (although this will usually be much higher), pH of less than 7.3, a bicarbonate less than 18 mEq/L, and positive ketones in the blood/urine.

5) What IV medication would we be expecting to start on Lachlan once we had his bloodwork results back?
Answer: We would be expecting to start Lachlan on an insulin infusion. We would start the insulin once the bloodwork is back, DKA is confirmed, and he has received an IV bolus of normal saline.

6) What are some other symptoms of Lachlan’s diagnosis? Hint…think about what patients may experience when they are new diabetics.

Answer: The symptoms of DKA include: polyuria, polydipsia, polyphagia, nausea and vomiting, abdominal pain, weakness, fatigue, shortness of breath, difficulty breathing, fruity breath, and confusion. As we get into difficulty breathing and confusion, the body is in much distress and compensation is getting more difficult.

7) Bonus Question: Do you know what electrolyte might be falsely elevated in his blood work due to extracellular shift? Hint…this electrolyte may be added to Lachlan’s maintenance fluid even if it may appear normal on his blood work as insulin will shift this electrolyte intracellularly.
Answer: In DKA, potassium can be falsely elevated due to this shift. As insulin causes the potassium to shift back intracellularly, we may proactively add potassium to Lachlan’s IV fluids once we are sure he is not in renal failure (normal BUN/Cr).

I hope that you were able to reflect and learn more about the physiology, and treatment of DKA through Lachlan's story. Let me know if you have any further questions about the answers in the comments!