Diabetes mellitus

Introduction

Insipidus

Sugar              Type 1                                    Type 2           

Pancreas       Insulin

 

Diagnosis

Fasting > 7                 Random > 11.1         (WHO criteria)

 

Glucose physiology

3.5 - 8 mmol per litre                         Renal threshold is 11 mmol/l

The brain must have glucose                       Glucose lowered by  - insulin

Glucose raised by - glucagon, adrenaline, cortisol, growth hormone

 

Aetiology

Type 1

MZ twins 30 - 35%                                        Diabetic father 1:20 - 40 chance per child

Viral  à  autoimmunity                                 Peak incidence 10 - 13 years, spring and autumn

Incidence has doubled over past 30 years

 

Fibrotic disease of the pancreas will lead to insulin deficiency

 

Type 2

MZ almost 100%                                           1st degree relatives 25%

Obesity                                                           50% due to beta cell loss

50% from increased insulin resistance

 

 

Presentation

Polyuria                      Thirst               Weight loss                Lack of energy           Blurred vision

Puritis                         Candida infection

In type 1 the beta cells die over a two year period, but the disease may appear to start on a specific day due to a stress or infective trigger factor

 

Complications

Staphylococcal skin infections        Retinopathy                            Polyneuropathy          Impotence

Arterial microvascular                       Arterial macrovascular         Renal                         

Insulin resistance                               Hypoglycaemia

 

Screening

May go undiagnosed for years

 

Smoking

 

Treatments

Diet alone                              Diet and oral                                      Diet and insulin

Insulin may be short acting or long acting mixed with protamine or zinc

Diet

Complex carbohydrates       Calories - matched to requirements

 

Absorption if insulin

Hot - fast                     Cold - slow     Tummy - fastest         Leg - in between       Arm - slowest

 

Hypoglycaemia

Say a blood sugar of below 2.5 mmol/l

 

Causes

Too much insulin                   Not enough food                    Vigorous exercise                 Infections

Onset - 5 - 20 minutes after injection of soluble insulin, several hours after slower acting

insulins.

 

Signs and symptoms

from release of adrenaline from the CNS when blood sugar falls rapidly

nervousness from release of adrenaline from the CNS when blood sugar falls rapidly

sweating         tremor             pallor               tachycardia    palpitations

 

from depression of the CNS when blood sugar levels fall

headache                               light-headedness     confusion                     emotional change    

inappropriate behaviour       slurred speech           memory lapse           

lack of co-ordination             staggering gait          double vision             drowsiness

convulsions                            coma                          numbness of the lips and tongue

 

Management

Eat sugar                   IV. glucose 50 mls of 50% dextrose           IM glucagon               Medalert

 

Hyperglycaemia

Ketoacidosis and coma

Causes

failure to take insulin insufficient insulin                  resistance to insulin

systemic infections               physiological stress

 

Onset

slow, days rather than hours

 

Early features

Polyuria                      thirst                malaise          drowsiness    abdominal pain         Headache weakness                        shortness of breath               fever                hot dry skin.

 

Later features

Kussmaul breathing              sweetish odour of breath                  lowered BP

Drowsiness                            coma                                                  glucose

ketones and protein in the urine

 

DKA

Diabetic ketoacidosis

 

Causes

Stabilisation                                                   Disruption to insulin therapy

Stress of intercurrent infection                     Insulin should never be stopped

Omit insulin only when patient will not be eating for whatever reason

 

Pathogenesis

In DKA there is uncontrolled catabolism associated with insulin deficiency

Insulin inhibits hepatic ketogenesis

 

Increased serum glucose                                                                 Ketones

 

Hyperglycaemia and glucosurea                                                     Acidosis

 

Osmotic diuresis                                                                               Vomiting

 

 

                                                Fluid and electrolyte depletion

 

 

                                                Renal hypoperfusion

 

 

                                                Impaired excretion of ketones and hydrogen ions

 

 

 

Patient education

Food

Insulin

Activity and exercise

Urine testing shows glucose > 11

Blood tests

Glycosylated HB

IDDM - no HGV PSV PPL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Type 1

Abrupt onset of,

weight loss                 muscle wastage                    weakness                   polyuria           polydipsia

polyphagia                 hyperglycaemia                     glycoseuria                osmotic diuresis

electrolyte imbalance                                                ketosis

 

Type 2 diabetes

Insidious onset of,

fatigue                        drowsy after meals                irritability                     nocturea                     pruritis

poorly healing skin    blurred vision                         loss of weight             muscular cramps      

stress will induce hyperglycaemia                          but symptoms may be absent in mild cases.

 

Management.

 

Dietary

Aim is to achieve normal body weight and normal growth.

Meal plan should contain adequate calories, proteins, vitamins, minerals

Adults require 30 calories/kg/day of ideal body weight.

Increase this by 35-40 calories/Kg for children and very active adults.

Reduce this by 15-25 calories/ Kg for obese and sedentary adults.

Carbohydrate should be 60% of total calories.

Try to give the right sort of fat, so HDLs are increased and LDLs are decreased.

Protein 0.5 - 1.2g/Kg

Use high fibre food.

Use complex carbohydrates.

Vary menu to individuals cultural background/preferences.

Ensure there is enough CHO on board to correspond to insulin dosage.

Prevent/treat obesity.

No smoking.

Moderation in C2H5OH

Use BDA exchange list to vary the menu.

Teach patient how to measure and calculate portions.

Routine Blood sugar assays.

 

Exercise

Promotes metabolism and increases use of CHO, therefore lowers insulin requirements.

Enhances the effect of insulin.

Prevents arterial disease, improves blood lipid ratios.

 

Insulin therapy

A form of HRT.

Effects various aspects of metabolism.

One or more injection a day.

Human insulin made by bacterial with human genes in them.

Prescribed in U-100, 100 iu. per ml.

Use British standard 1 or 2 ml insulin syringe.

26-28 G needle, usually orange. (higher the number the thinner the needle).

Dose may be titrated.

Regular urine tests.

Ask patient to keep own records.

Attend OPD, Gly. Hb.

Avoid hypoglycaemia.

 

 

 

 

Complication of insulin therapy

Allergy, usually only local.

Lipidodystrophy, may present as fat atrophy or hypertrophy.

Oedema, generalised fluid retention

Insulin resistance, over 200 iu./day in the absence of infection

NB. Surgery, change in activity or infection can alter control.

 

 

Long term complications of diabetes

Increases likelihood of strokes and IHD.

Amputations for gangrene occur in smokers and diabetics, diabetic neuropathic and vascular complications.

Life expectancy in young diabetics is two thirds that of their contempories.

Microvascular complications occur less frequently if blood sugar level is well controlled.

 

Macrovascular complications

Results from thickening of the capillary basement membranes, this also occurs in the glomeruli causing glomerulosclerosis

Seems to be associated with poor control

Often accounts for skin complications and peripheral nerve damage

Major vessels are also affected with the usual consequences

 

Renal complications

The usual picture of chronic renal failure - Diabetic neuropathy

 

Effects the peripheral and autonomic NS

 

Feet

watch out for lesions                         compare the colour in both feet

check for temperature                                  check for fungal infections

check for volume of pulses                           keep warm

professional help                                           remember possible analgesia

 

Diabetic retinopathy

Most common cause of blindness in 35-64 years of age

Half of the diabetic population ten years after diagnosis have some

Caused by haemorrhage into the vitreous, formation if scar tissue and detachment

Treat with photocoagulation, yearly funduscopy, prevent with good control