Clinical Features: Diabetes mellitus is a clinical syndrome characterized by hyperglycemia, due to deficiency or diminished effectiveness of insulin. Main clinical features of diabetes are thirst, polydypsia, polyuria, tiredness, loss of weight, white marks on clothing, pruritus vulvae or balanitis and paraesthesia or pain in the limbs.
Two main types have been recognized, type 1, (Insulin dependent diabetes mellitus, IDDM) treated with insulin and diet and Type 2 (non-insulin dependent diabetes mellitus, NIDDM) treated with diet and oral ant-diabetic agents.
Maintenance Therapy in Adults and children.
Diet Dietary control and maintenance of correct weight for height. Advice on diabetic diets.
Insulin
Maintenance therapy is twice daily subcutaneous injections of a mixture of short acting and long acting insulin in the ratio of 1:3. 2/3 of the daily dose given in the morning 1/3 of the dose in the evening. In pregnancy an additional dose of short acting insulin may be given with the midday meal.
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NOTE
• During surgery omit the usual morning dose of insulin
• Give small doses of short acting insulin during the surgery and continue with short acting insulin until the patient has resumed his usual meals
• Most diabetics properly informed and managed soon become experts in their own care
• Be cautious about changing regimens and do not change dietary and drug regimens simultaneously
• Advice on diabetic diet is given later in the chapter
Infections may require increased dosage.
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Oral antidiabetic agents
Tolbutamide 500 mg give every 8 hours.
Chlorpropamide 125-500 mg give every 24 hours.
Glibenclamide 2.5-15 mg give every 24 hours before meals.
NOTE Treatment for diabetes mellitus is for life. |
FIGURE: PROTOCOL FOR TREATMENT WITH ORAL ANTIDIABETIC DRUGS
Hyperglycemic Coma and Precoma in Adults
Pass a nasogastric tube and allow free drainage in the unconscious or semiconscious patient. Search for cause and treat infections promptly.
Fluid Replacement (Adults)
Normal saline is the recommended IV fluid; as much as 8 litres may be required in 24 hours:
Sodium chloride 0.9% (IV infusion) according to the following schedule;
first litre |
over 30 minutes |
second litre |
over 1 hour |
third litre |
over 2 hours |
fourth litre |
over 4 hours |
fifth litre |
over 6 hours |
Give subsequent litres of normal saline every 8 hours.
The above regimen may be modified depending on the state of hydration. When blood sugar falls to 16 mmol/L, change to dextrose 5%.
CAUTION Fluid overload is a danger in elderly patients |
Potassium Replacement
In conditions where blood potassium levels cannot be determined add to IV fluid.
Potassium chloride 20 mmol with every litre after the first litre. Increase to 40 mmol with each litre given over 8 hours.
Where serum potassium levels are available; start replacement of potassium at a rate of 20 mmol per litre of IV fluid as soon as insulin has been started. Assess serum potassium regularly and adjust replacement as needed to maintain potassium at 4.0-5.0 mmol/L. Continue with oral replacement for one week.
Potassium chloride (O) 1-2 tablets of 600 mg twice daily.
Insulin Therapy (Adults)
Initially give by intramuscular injection;
Soluble insulin (IM) 10 units as a single dose, then 5 units every hour until blood sugar is down to 16 mmol/L.
When blood sugar is 16 mmol/L or less and clinical condition shows clear improvement, change to subcutaneous administration;
Soluble insulin (SC) every four hours; dose based on a sliding scale.
Blood sugar (mmols/L) |
Units of Insulin |
>16 |
12 units |
>12-16 |
8 Units |
<8 |
0 Units |
NOTE Use blood sugar reagent strips, “Dextrostix” or glucometer blood sugar readings. Sliding scales using URINE glucose tests are unreliable and should be avoided where possible. |
An alternative to the sliding scale is to use an empirical dose:
Soluble insulin (SC):
a reasonable starting dose is 10 units three times a day.
Insulin doses and frequency may need to be adjusted to achieve glycaemia control. As soon as the patient's condition is stable, start appropriate maintenance therapy.
On this regimen, most cases show definite clinical improvement within 6-10 hours. Clinical and (if available) biochemical reassessments should be made at frequent intervals during treatment. Modifications of the fluid and electrolyte therapy should be made as necessary.
CAUTION Sodium bicarbonate Injection should be used ONLY in cases of extreme acidosis and if complete biochemical data are available. |
Diabetes in Children
A significant number of new cases of insulin dependent diabetes occurs in children who usually present with classical features of diabetic ketoacidosis with polyuria, polydipsia etc.
Hyperglycaemic Coma and Precoma
Fluid Replacement (children)
Approximately 200 ml/kg in 24 hours is required for hydration. Start with rapid infusion of:
Sodium chloride 0.9% at 20 ml/kg for the first hour; then for the remaining volume give:
1/3 over next 4 hours
1/3 over next 8 hours
1/3 over next 12 hours
After the first hour,
Add
Potassium chloride 20 mmol/L
When Blood sugar is less than 16 mmol/L change to:
Dextrose 5% (IV infusion) OR
half strength Darrows dextrose
Plus
Potassium chloride 40 mmol/L
Insulin Therapy (Children)
Initially by intramuscular administration;
Soluble insulin (IM) 0.1 units/kg every hour; reduce to 0.05 units/kg every hour when blood sugar falls below 15 mmols/L;
When condition stabilises change to subcutaneous administration:
Soluble insulin (SC) 0.75-1 units/kg/day in 3 divided doses before meals.
Later, change dose to twice daily, applying the rule of thirds (see “Maintenance Therapy” above).
Honeymoon period: In the months after initial diagnosis insulin requirements may decline to less than 0.5 units/kg/day as the pancreas continues to produce some endogenous insulin. Requirements invariably revert to higher doses as endogenous insulin levels decline.
NOTE DIET-Important in children but attempts at too rigid control may prove to be counter-productive. The diabetic child should be allowed to indulge in normal activities at school. Teachers need to be informed about the condition |
Diabetic Diet
Ideally a dietician should calculate dietary requirements for individual patients.
Aim of diet: to reduce the blood sugar to normal and to maintain a constant blood sugar level.
• 45-50% of energy intake should be in the form of carbohydrates; the amount of carbohydrates should be consistent from day to day
• Complex carbohydrates are preferable to simple sugars.
• Carbohydrates and calories should be evenly distributed through the day. Meals must not be missed. An insulin dependent diabetic may have snacks between meals
• Alcohol is not allowed
• Sugar and sugar-containing food/drinks should be totally avoided. The only exceptions are when a patient feels faint, or is ill and cannot eat normally
• Exercise should be encouraged. A snack should be taken before and after playing sport.
General Advice for Diabetics
NOTE All diabetic patients should be advised to have a “medic-alert” bracelet or necklace and to join the Tanzania Diabetic Association. |
Syringes/Insulin Storage
Reuse 1 ml disposable syringes for 2-3 weeks. Clean with soap and all soap remains should be rinsed with water and store dry. Sterilisation is not necessary. Insulin should be stored in a cool place.
Injection technique
Clean and dry skin. Inject subcutaneously NOT intradermally. The site of injection should be varied (abdomen and thighs are the most suitable sites).
Foot Care for Diabetics
Advice about foot care is important: keep clean and dry, wear well-fitting shoes, take care to avoid burns.
