Why is my brother's blood sugar high after surgery at 34?

Question

Hello doctor,

My brother is 34 years old. He recently underwent a low anterior resection with coloanal anastomosis and ileostomy for stage 2 Ca rectum. On day 2 of surgery, he started to have nausea and vomiting. On day 4, after surgery, we were told he had developed some post-operative ileus, and they had put a tube called an NG tube.

His fasting blood sugar levels have been increasing and have been 116 mg/dL, 124 mg/dL, 136 mg/dL on days 2, 3, 4 post-operative, respectively, and he is non-diabetic at least before surgery. Right now, he has no sepsis, abdominal pain, fever, abdominal distention, nothing except for nausea, vomiting, and mild anemia (Hb - 10 g/dL).

His electrolytes, including Na, K, Cl, HCO3, serum creatinine, and BUN, are normal.

Can you please tell us why his blood sugar levels are increasing?
Did he develop diabetes, and if so, does he need HbA1c?

No family history of diabetes, and he is currently getting IV fluids.

Kindly help.

Answer 1

Hi,

Welcome to icliniq.com.

I understand your concern for your brother.

I am not sure if the sugar values mentioned here are taken at a particular time of the day. I assume them to be random blood sugar levels. Nausea and vomiting could be because of the effect of anesthesia and the antibiotics he is put on.

He might have also been prescribed medications to control them. They should settle in a day or two. Because the patient will be put on nil by mouth and he has an NG tube, he should be given Dextrose and DNS solutions to meet his carbohydrate requirements.

The values are of no concern, and he does not require HbA1c. Considering his age and no family history, I do not think he has diabetes now. It could all be post-operative fluids he has been given (because he is not allowed orally). It should settle as soon as he resumes taking oral liquids or food over time.

Do not worry about blood sugar values as of now, and they are of no absolute concern.

I hope this helps.

Thank you, and Take care.

Answer 2

Hello,

Welcome back to icliniq.com.

Increased blood sugar levels are due to IV fluids (Dextrose and DNS contain glucose to meet energy requirements as the patient is nil orally) and postoperative stress, which increases cortisol levels in the blood, which also increases blood sugar levels.

If I have to label him as diabetic, I will wait for at least two to three months and observe the sugar levels. Postoperative complications are a possibility and cannot be ruled out. I am not sure if the readings are by a glucometer or sent to the lab.

If blood is drawn from the same side as IV fluid has been given, it is possible to have a high sugar reading. In any case, the values are not high enough to be of concern (especially in the postoperative period, which is common).

I would observe the reading for a few more days and consider treating it.

I hope this helps.

Thank you, and take care.