DIABETES

About 5% of patients with advanced cancer have diabetes mellitus.

The patient is usually known to have pre-existing diabetes, but occasionally it occurs secondary to carcinoma of the pancreas or to high dose steroids (or rarely, to ectopic ACTH). Diabetes should be suspected if there is thirst, drowsiness or increasing weakness.

Patients with diabetes generally feel better if blood glucose levels are controlled. Strict control to avoid long-term vascular damage is no longer appropriate, but hyperglycemia should still be avoided.

«  Aim to keep pre-prandial blood glucose levels below 170mg/dL.

Patients who have carefully controlled their own diabetes (sometimes for many years) feel psychologically better if strict control is maintained. It is one of the things they can still be positive about, and it helps to give them a feeling that they remain in control.

Mild hyperglycemia may be controllable with an oral hypoglycemic.

Patients with advanced illness starting on insulin should initially have a safe starting dose of 10 units of insulin 2 times a day, preferably using Mixtard or Novolin 70/30 biphasic insulins (which are more convenient to use at home). Adjust the dose daily until pre-prandial capillary blood glucose levels are around 170mg/dL. At first, monitor capillary blood glucose levels 4 times a day (before meals and at bedtime) for in-patients, and at least 2 times a day if the patient is at home. (An increasing number of diabetic patients are successfully using portable glucometers at home, enabling closer monitoring and increased independence.) Once controlled, monitor capillary blood glucose levels once every few days unless hypoglycemia is suspected.

A diabetic patient starting insulin needs specialist education and advice.

The goal of diet is to spread carbohydrate intake over the whole day and to have it covered by insulin. Patients with a short prognosis can relax dietary restrictions on cakes and candy, increasing insulin dosage as necessary. 

Patients started on insulin should be warned about hypoglycemia in the usual way, and should carry sugar. Hypoglycemia is commonest after a missed meal and should be suspected if the patient has headaches, confusion, sweating or tremor.

If the patient is vomiting it is better to use regular insulin 3 times a day, adjusting the dose according to capillary blood glucose levels as follows:

When changing back to a 2 times a day insulin regime, give the same total number of units per day.

Insulin requirements in advancing disease may decrease due to weight loss and anorexia.

During the terminal phase, insulin may still be needed. Even if the patient is not eating, the liver continues to produce glucose. The basal requirement is usually about 10 units 2 times a day (more in a large or obese patient). If the patient becomes unconscious during the terminal phase, insulin should be stopped.

The author and publisher have taken precautions to ensure that the information in this book is error-free. However, readers must be guided by their own personal and professional standards of good practice in evaluating and applying recommendations made herein. The contents of this book represent the views and experience of the author, and not necessarily those of the publisher.