Diabetes Mellitus


Diabetes mellitus is a metabolic disorder characterized by a prolonged increase in the buildup of sugar in the blood (hyperglycaemia) and impairment of glucose metabolism, as a result of reduced insulin secretion or because of a decrease of sensitivity of body cells to insulin. The main cause is not at present known, which is why it remains a chronic and non-curable disease.


Some of the symptoms of diabetes mellitus include polyuria (frequent urination), polydipsia (increased thirst), polyphagia (increased hunger / binging), unexplained weight loss.  In diabetes type 1, the onset of the illness is usually sudden and frequently its first manifestation can be the development of diabetic ketoacidosis, accompanied by nausea, vomiting, diffuse abdominal pain and loss of consciousness.  In diabetes type 2, the illness develops gradually; while increased hunger is less common, the condition is frequently accompanied by weakness, fatigue, dizziness and susceptibility to infections. Often, however, for a long time diabetes mellitus type 2 has no symptoms at all.


The main types of diabetes mellitus are diabetes type 1, diabetes type 2 and gestational diabetes.

  • Diabetes mellitus type 1: It is an autoimmune disease characterized by the destruction of the β-cells of the pancreas which are responsible for the production of insulin, the result being minimal or complete lack of insulin secretion. This type is most commonly seen in children (“juvenile diabetes”), although it can also appear in adults.  The onset of diabetes type 1 is sudden. When it is inadequately dealt with, it often leads to the development of ketosis, diabetic ketoacidosis and even death if the deficiency in insulin and fluids is not remedied immediately.  The patient is completely dependent on insulin administration which will maintain blood sugar levels at normal levels.
  • Diabetes mellitus type 2:  This is a metabolic disorder characterized by the combination of reduced secretion of insulin and decreased sensitivity of cells to its action.  Diabetes type 2 is most frequently seen in adults. A very important predisposing factor for the development of diabetes type 2 is obesity, but also unhealthy diets in general. Largely to blame are both our inactive, sedentary lifestyle and our present-day’s food industry and plethora of fast-food outlets that provide ready, processed foods which are inexpensive, convenient and tasty. Obesity predisposes to the development of insulin resistance, probably because of the production by adipose tissue of substances that reduce the cells’ sensitivity to insulin. Other predisposing factors are age and family history. The symptoms are milder than those of type 1.  Nevertheless, the risk of eventual very serious complications remains high. The first step for the management of diabetes type 2 is the patient’s change of lifestyle, including weight loss, increase in physical exercise and a healthy diet. The primary goal is maintenance of the subject’s metabolism at levels permitting the consumption of calories and food components through a correct diet as well as suitable anti-diabetic medication, these adapted individually to each patient. If this treatment fails, the administration of insulin is considered advisable. It is important to mention that a large proportion (20-30%) of patients who suffer from diabetes mellitus are not aware of it; also that the number of diabetics is expected to multiply in the coming decades.
  • Gestational diabetes:  This is diabetes mellitus that appears for the first time during pregnancy (i.e. the term does not include those women with known diabetes before the start of pregnancy). Gestational diabetes resembles diabetes type 2.  Obese women or women with a previous medical history of gestational diabetes or a previous history of giving birth to an overweight (>4000 gr) or underweight are at risk.
  • Hormonal-cause metabolic disorders of glucose / blood sugar (acromegaly, thyroid diseases, cortisol hypersecretion, pituitary disorders, obesity, menopause, oestrogen deficiency)
  • Genetic forms

Risks – Complications

In diabetes mellitus, which has a chronic course, high levels of blood sugar persisting over a long period of time can bring about an array of serious complications, such as:

  • Cardiovascular disease (stroke, myocardial infarction – heart angina)
  • Chronic renal failure / insufficiency:  the endocrinologist will asses the patient’s GFR (glomular filtration rate, a test to evaluate kidney function) and will diagnose the problem, adjusting the treatment of high blood sugar and also referring the patient to a nephrologist.
  • Lesions to the retina (diabetic retinopathy) which, if not treated, can lead to blindness.  The endocrinologist is able, via direct ophthalmoscopy, to observe the fundus of the patient’s eye; he will collaborate with the ophthalmologist should any changes / deteriorations appear signaling diabetic retinopathy.
  • Damage to the peripheral nerves (diabetic neuropathy) which causes reduced mobility in the limbs and numbness, pain and reduced sensitivity to high or low temperatures, this resulting in the patient running the risk of injury and wounds of which he is unaware at the instant of impact.
  • Disorders to the autonomic nervous system that can result in irregularities in cardiac rate and the risk of sudden death; problems with reduced perspiration in the lower extremities; orthostatic or postural hypotension, digestive disorders because of sluggish bowel movements or diarrhoea.
  • Dermatological foot problems and dislocation or destruction of the bony architecture of the foot, resulting in the increased risk of callus formations, blisters and ulcerous wounds in areas of the foot not built to receive the weight of the whole body and that could possibly lead to gangrene when infected regions are not treated promptly.  In this instance, the endocrinologist needs to examine the diabetic’s feet via specific diagnostic tests to determine whether there is diabetic neuropathy so as to preclude progression of the disease and its abovementioned complications.  Should the latter already exist at patient consultation, the endocrinologist must evaluate the risk and recommend treatment in collaboration with a specialized podiatrist as well as refer the patient to a specialized centre if this is judged necessary.
  • Male erectile dysfunction, this being diagnosed with the use of a questionnaire and treated via suitable medication and injectable formulations
  • Lesions (obstructions) in vessels of the feet and in the carotids
  • Susceptibility to infections and mycoses (fungal infections) of the external genitalia:  here the endocrinologist will administer / prescribe suitable treatment which will be of longer duration than that for non-diabetics.
  • Periodontitis, which requires careful blood sugar monitoring carried out by the endocrinologist
  • Hyperlipidaemia, fatty infiltration of the liver, xanthomas and xanthelasmas, these requiring that the endocrinologist proceed to a more aggressive treatment than that accorded to patients who do not have diabetes mellitus
  • Hypertension:  again, the diabetic patient requires a more aggressive treatment undertaken by his endocrinologist than would a patient with hypertension who does not suffer from diabetes mellitus


Hypoglycaemia, or low blood sugar, is a common complication of diabetes mellitus.  It can occur due to an incorrect dosage of the administered / prescribed antidiabetic medication or insulin, reduced food intake, low-carbohydrate diet. The patient exhibits irritability and increased sweating, food cravings, transient loss of consciousness and even coma. Such conditions demand an immediate intake from the mouth of sugar (2-3 teaspoons in water), or processed juices containing sugar, or, in the event that the patient has lost consciousness, an intravenous glucose or glucagon injection.




Dermopathy caused by diabetes in

the tibial (shin bone) area

Fungal infection in the oral cavity of a

patient with diabetes mellitus

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Ischaemic lesion of toe tip in a patient with diabetes Ulcer in the big toe in diabetes
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Necrosis in the tip of the 3rd toe and

dorsal ulcer of the 2nd toe

Plantar ulcer in diabetes
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Axillary (armpit) acanthosis nigricans in a

in patient with insulin resistance

Myoatrophy in a diabetic patient
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Foot skin lesions in diabetes: dermatopathy of the tibia Dilated left pupil in a patient with DM

Atrophy of subcutaneous fat of the arm in a

patient after injecting insulin in only one site

Hypertrophy of the thighs in a patient who has

diabetes mellitus after long-term use of insulin

Doppler assessment of foot arteries in diabetes


Neuropathy: assessment for diabetic neuropathy

with tuning fork

Direct fundoscopy:  assessing the

fundus vessels of the eye in diabetes |

Assessment of diabetic neuropathy in the

lower limb with a monofilament |