Diabetes mellitus is a group of metabolic disorders characterized by high blood sugar levels over a prolonged period (hyperglycaemia).

Classification of Diabetes Mellitus

Type 1 (Insulin-dependent diabetes mellitus)
Usually occurs in children and young adults and is associated with ketoacidosis. These patients are insulinopenic and require insulin to sustain life.

Type 2 (Non-insulin dependent diabetes mellitus)
Usually afflicts adults, a large number of whom are obese and tend to have elevated blood pressure (metabolic syndrome).

Prediabetes

A condition in which blood sugar is high, but not high enough to be type 2 diabetes.

Gestational diabetes

A form of high blood sugar levels affecting pregnant women.

Clinical Presentation

Commonest symptoms are polyuria, polydipsia, polyphagia and weakness. Wasting tends to occur in type 1 diabetes while obesity may predominate in type

Sequelae of target organ damage in the kidneys, blood vessels, heart, nerves, the eyes, may be the main manifestations.

Diagnostic Investigations

Blood glucose:

• Fasting venous blood glucose more than 7.8 mmol/L on more than one occasion.

• Random blood glucose more than 11.1 mmol/L in symptomatic patients.

Urinalysis - for protein, sugar, ketones

General management of diabetes mellitus

Aim of management is to:

1. Abolish symptoms of diabetes.
2. Correct hyperglycaemia, glycosuria.
3. Prevent and manage complications.

Modification of the diet is important in both types 1 and 2. The dietary modification must be individualized.

Type 1 diabetes mellitus patients experience weight loss and will gain weight with therapy. Aim for a caloric intake of 35 Kcal/kg body weight to maintain ideal body weight.

Type 2 diabetes mellitus patients are often obese, and such patients caloric restriction of 15–20 Kcal/kg body weight is recommended. Exercise is important because modest weight reduction in obese diabetic patients leads to improved glycaemic control.

Food composition.

• Carbohydrate 50–60% in complex form, e.g., rice, beans, peas, etc.
• Protein 10–20%. Vegetable protein source includes soya beans, lentils and beans.
• Fat 25–30%. The fibre in the diet can prolong the absorption of sugar. Fibre containing foods include beans, legumes and bran.
• Artificial sweeteners, e.g., saccharin and aspartate, are helpful in maintaining a palatable diet.
• Strict adherence to meals schedule is important.

Management of Type 2 diabetes mellitus

Manage as outpatient preferably in the diabetic clinic or medical clinic.

Consult a nutritionist for dietary modification.

Pharmacological Management

Use of Oral hypoglycaemics

First-generation sulfonylureas:

Chlorpropamide 125–500mg PO OD max 500mg/day should be started in the response to dietary modification is inadequate (nocturia, blood sugar more than 14 mmol/L).

Dose adjustment should be gradual (weekly) to avoid hypoglycaemia.

Tolbutamide 500–3,000mg/day in 2–3 divided doses.

Tolazamide 100–1,000mg/day in 1–2 divided doses.

Second-generation sulfonylureas:

• Glibenclamide

• Glipizide 5–40mg/day in 1–2 divided doses

• Glimepiride 1–8mg/day in one dose

Biguanides:

• Metformin 500–2,550mg/day in 2–3 divided doses
• Glyburide 250–2,000mg/day in 2 divided doses

Alpha-glucosidase inhibitors:

• Acarbose 75–300mg/day in 3 divided doses
• Miglitol 75–300mg/day in 3 divided doses

Thiazolidinediones:

• Pioglitazone 15–45mg/day in 1 dose

• Rosiglitazone 4–8mg/day in 1–2 doses

Insulin is indicated in Type 2 DM if:

Oral hypoglycaemic drugs are not effective, e.g., persistent polyuria, hyperglycaemia
Ketonuria occurs
Infection occurs

Other complications, e.g., renal failure are present
Patients undergoing surgery.

Admit patients for insulin therapy

Teach the patient how to measure insulin, the technique of injection, care of syringe, and recognition and management of hypoglycaemia.

Start patient on soluble insulin 10–16 units subcutaneously half an hour before meals TDS. The severity of hyperglycaemia will aid in the selection of the dose.

Maintain plasma glucose in the range of 8.3–13.4mmol/L in the hospital to avoid hyperglycaemia at home. Optimum control at home is blood sugar less than 10mmol/L and more than 4mmol/L.

Plasma glucose should be monitored before meals and at bedtime. Gradual adjustment of insulin dosage by 5 units are essential when blood glucose is near the desired range. When blood glucose level is between 8.3 and 11.0 mmol/L, change to intermediate-acting insulin.

The dose of intermediate-acting insulin is two-thirds of the total daily soluble insulin requirement. An alternative strategy is to base control on 2 doses of intermediate-acting insulin two-thirds in the morning and one-third before supper.

Type 1 Diabetes Mellitus with Diabetic Ketoacidosis

Usually presents with diabetic ketoacidosis (DKA).

Patients with type 2 DM can also present with DKA, especially in situations of stress such as infection or neglect of therapy.

Clinical features include intense polydipsia, abdominal pain, vomiting, dehydration, acidotic breathing, or coma.

Investigations

Urinalysis should reveal ketonuria and glycosuria.

Blood sugar should show hyperglycaemia.

Management

DKA is a medical emergency and should be treated as such. Not all patients with DKA are in a coma. Most patients with Type 1 diabetes mellitus need hospitalization and are best managed with divided doses of intermediate-acting insulin two-thirds lente am and one-third lente pm.

Alternative therapy is to combine soluble insulin with intermediate-acting insulin. Admit the patient:

Fluid replacement:

Initiate fluid replacement with normal saline then change to 5% dextrose alternating with N/S when blood sugar is between 12.0 and 14.5 mmol/L. If severely dehydrated, continue normal saline and 5% dextrose together. Continue intravenous fluids until fluid losses have been corrected and ketonuria has disappeared.

Insulin therapy

Initial: 10 units IV + 10 units IM STAT, then 6–10 units every hour until blood sugar is 14mmol/L, then change to soluble insulin 8–16 subcutaneously 4–6 hourly. Change to soluble insulin subcutaneously TDS when the patient is taking orally.

Potassium replacement

Hypokalemia is a common feature. Confirmation should be through ECG and electrolytes. If present supplement.

Deficit: 300–600 mmol. Potassium replacement should commence immediately after the first dose of insulin and 1 litre of fluids. Potassium can safely be given at the rate of 10–20mEq/hour (10ml of 15% KCL = 20 mEq K) in an infusion.
Never give potassium as a bolus.

Rectal diazepam 10–20mg may be as effective as intravenous diazepam.
Use rectal solution at 0.5mg/kg.

Acidosis

If PH is <7.2 and serum potassium is >4mmol/L, give NaHCO3 8.5% (diluted to 4.2%).
Use the following formula:

Base excess x 0.3 x body mass (kg).

Give 25% over 1 hour and reassess (1ml NaHCO3 8.5% = 1mmol HCO3).

Use NaHCO3 with caution.

Antibiotics

The precipitating factor is usually an infection. Treat with broad-spectrum bactericidal antibiotic while awaiting results of cultures where applicable.

Anticoagulation

Heparin 2,500 units SC BD to prevent deep venous thrombosis. Low molecular weight heparins such as enoxaparin and dalteparin can also be used.

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Monitoring

Monitor 2 hourly plasma potassium (since potassium infusion is being given). Hourly blood sugar estimations are mandatory in the first few hours by using glucose oxidase reagent strips.

Monitor urine output; if no urine after 3 hours catheterize patient.

Nasogastric suction should be done in comatose patients to prevent aspiration.

Oral intake is initiated after ketoacidosis has been corrected

Careful monitoring of patients especially the elderly or those with renal or cardiac impairment.

Hypoglycaemia should be considered in all diabetic patients who present with altered consciousness or coma. Take blood for glucose and give 20ml of 50% dextrose immediately.
All diabetics with complications such as diabetic foot should be admitted.

Patient Education

Teach patients how t

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