Diabetes Mellitus - Symptom, Treatment and cause of Diabetes Mellitus

DESCRIPTION: Excessive levels of glucose in the blood. Glucose is usedas fuel by every cell in the body. When glucose is eaten, it is absorbedinto the blood from the small intestine. Once it reaches a cell, it mustcross the fine membrane that forms its outer skin. This is normallyimpermeable to all substances, but insulin has the ability to combinewith glucose and transport it across the membrane from the blood intothe interior of the cell. Insulin is made in the pancreas, which sits inthe centre of the abdomen. There are two totally different types ofdiabetes - juvenile diabetes (type 1 or insulin dependent diabetesmellitus - IDDM) and maturity onset diabetes (type 2 or non-insulindependent diabetes mellitus - NIDDM). Diabetes affects approximately 2%of the population, with 90% of diabetics suffering from the maturityonset form. The cause and treatment of the two types is quite different.

CAUSE: Juvenile diabetes - a lack of insulin production by thepancreas. Most people develop this type as a child or in early adultlife.Maturity onset diabetes - far more common in obese patients. There isadequate insulin production, but cells throughout the body fail torespond to the insulin.

SYMPTOMS: Juvenile diabetes - excessive tiredness, thirst, excesspassing of urine, weight loss despite a large food intake, itchy rashes,recurrent vaginal thrush infections, pins and needles and blurredvision. Patients become steadily weaker because their muscles and otherorgans cannot work properly.Maturity onset diabetes - similar symptoms, but less thirst and urinaryfrequency, and more visual problems, skin infections and sensory nerveproblems than those with the juvenile form. Many patients are totallywithout symptoms when the diagnosis is discovered on a routine blood orurine test.

INVESTIGATIONS: - Blood and urine glucose levels are high in untreatedor inadequately treated patients.- A blood glucose tolerance test (GTT)is performed to determine theseverity of both types of diabetes. After fasting for 12 hours, a bloodsample is taken, then a sweet drink is then swallowed, and further bloodsamples are taken at regular intervals for two or three hours. Thepattern of absorption and elimination of blood glucose will give thediagnosis.- By measuring the amount of glucose in certain blood cells, theaverage blood glucose level over the past three months can also bedetermined.- The level of insulin can also be measured in blood.Juvenile diabetes - daily self-testing is necessary to ensure thatdisease control is adequate. Both blood and urine tests for glucose areavailable, but the blood tests are far superior.Maturity onset diabetes - regular blood testing of glucose levels isalso necessary, but normally on a weekly rather than daily basis. Urinetests are often inaccurate in the elderly, as their kidney function maybe reduced to the point where glucose cannot enter the urine.

TREATMENT: Diet is essential in both forms because the amount of glucoseeaten is not normally constant, and diabetics lack the means ofadjusting the amount of glucose in their blood with insulin. The dietmust restrict the number of kilojoules (calories) being eaten, and sugarin all its forms should be eaten only with great caution. Fat should notaccount for more than a third of the total calories, and cholesterolintake should be restricted. Protein should be obtained more frompoultry and fish than red meats. Carbohydrates other than sugar can beconsumed freely. Grains and cereals with a high fibre content should bethe main part of the diet. Artificial sweeteners such as aspartame(NutraSweet) can be used to flavour food and drinks. Fat cells can reactabnormally to insulin very easily, and so overweight diabetics must loseweight. Exercise is encouraged on a regular daily basis. Patientsshould carry glucose sweets with them at all times to use if their bloodsugar levels drop too low.Juvenile diabetes - when first diagnosed, patients are often quite ill,and most are hospitalised for a few days to stabilise their condition.Insulin injections must be given regularly several times a day for therest of their life. Initially derived from pigs and cattle, humaninsulin has now been produced by genetic engineering techniques. Insulincannot be taken by mouth as it is destroyed by acid in the stomach, butcan be injected into any part of the body covered by loose skin,although the same site should not be used repeatedly. The newerpen-style delivery systems enable diabetics to easily dial the requireddose and inject as necessary with minimal inconvenience. There are manydifferent types of insulin that vary in their speed of onset andduration of action.Maturity onset diabetes - education of patients with this type ofdiabetes is very important, so that they understand what they can andcannot eat and drink. Older people who develop diabetes can often havethe disease controlled by diet alone or a combination of tablets anddiet. Tablets (eg. tolbutamide, chlorpropamide, glibenclamide,glipizide) make the cell membrane respond to insulin again. Weight lossis a vital part of treatment because if normal weight levels can bemaintained, the disease may disappear.

COMPLICATIONS: Juvenile diabetes - an increased risk of both bacterialand fungal skin and vaginal infections, the premature development ofcataracts in the eye, microscopic haemorrhages and exudates that destroythe retina at the back of the eye, damage to the kidneys that preventsthem from filtering blood effectively, poor circulation to theextremities (hands and feet) that may cause chronic ulcers and evengangrene to the feet, the development of brown skin spots on the shins,and sensory nerve damage (diabetic neuropathy) that alters the patient'sperception of vibration, pain and temperature. There are alsocomplications associated with treatment such as a 'hypo' in which toomuch insulin is given, excess exercise undertaken or not eat enough foodis eaten, and blood glucose levels drop (hypoglycaemia) to anunacceptably low level. The patient becomes light-headed, sweats,develops a rapid heart beat and tremor, becomes hungry, then nauseatedbefore finally collapsing unconscious. Glucose drinks or sweets givenbefore collapse can reverse the process, but after collapse, aninjection of glucose is essential. In an emergency, a sugary syrup orhoney introduced through the anus into the rectum may allow a diabeticto recover sufficiently to take further sugar by mouth. Rarercomplications of treatment are adverse reactions to pork or beefinsulin, and damage to the fat under the skin if the same injection siteis used too frequently. Diabetic ketoacidosis (see separate entry) isthe most severe complication.Maturity onset diabetes - the elderly are very susceptible to all thecomplications listed above, particularly foot damage and eye damage.High blood pressure is more common than in the average person of theirage.

PROGNOSIS: With the correct treatment and careful control, patients withboth types of diabetes should live a near-normal life, with anear-normal life span.