Integrated Medical Education Resources: 210331P - CHARACTERIZATION OF NON-COMMUNICABLE DISEASES

Presentation at a course held online via Zoom on April 01, 2021. By Professor Omar Hasan Kasule Sr. MB ChB (MUK). MPH (Harvard), DrPH (Harvard)

CHARACTERISTICS OF NON-COMMUNICABLE DISEASES

► Chronic diseases (non-communicable, degenerative disease) are defined by the following characteristics:

o Multiple causes,

o A prolonged course,

o Lack of spontaneous resolution,

o Rare complete cure,

o Non-transmissibility from the victim to the susceptible.

COMMUNICABLE vs. NON-COMMUNICABLE DISEASE

► Communicable diseases have a single defined necessary cause specific for the disease. Non communicable diseases are multi-causal, the causes are not known definitively, and the cause-disease relation is seldom specific.

►  Communicable diseases result from a single exposure and cause acute disease after a short incubation period. Non-communicable diseases have a long latency and chronic disease follows repeated exposures to the agent.
►  A communicable disease is followed by acquired immunity but non-communicable diseases are not.
►  Diagnosis of a communicable disease is based on an agent-specific test. Diagnosis of non-communicable disease is based on non-specific symptoms and signs.

CHANGING TRENDS OF NON-COMMUNICABLE DISEASES

► Changing patterns in the incidence of non-communicable diseases have been observed over the past century due to:

o Ecological

o Demographic

o Epidemiologic transition (changing population structure).

► There is a general increase in incidence explained by

o relative decrease of infectious diseases as competing causes of death

o an aging and older population

o a more complex society causing stress and depression

o environmental pollution due to increased industrialization and disturbance of the natural eco-system

o better detection and diagnostic characterization.

► The overall increase in incidence of non-communicable diseases is not uniform.

o Economically developed countries are experiencing a more rapid increase.

o Even within the same country, there are different trends in different population sub-groups.

NEOPLASTIC DISEASE - 1: Definition and classification

►  The neoplastic process is essentially loss of control of cell growth;
►  The neoplastic cells may invade local tissues or may spread, metastasize, to other parts of the body. The primary site of a neoplasm is the tissue where malignant change first occurs. The secondary site is where the malignancy metastasizes.
►  Carcinomas are neoplasms of epithelial tissues, the endodermal and the ectodermal. More than 85% of malignant neoplasms are carcinomas (ie epithelial origin). This explains why the term cancer is used for all malignancies although it strictly refers to epithelial neoplasms only.
►  Sarcomas are from mesodermal tissues.
►  Leukemias and lymphomas are from cells of the bone marrow and the immune system.

NEOPLASTIC DISEASE - 2: Symptoms of neoplastic disease

►  Symptoms and signs due to malignancy may be due to local pressure effects or may be systematic effects.
►  Systemic effects may be due to pressure effects, destruction of vital organs such as the bone marrow and endocrine glands, or overwhelming the circulatory and excretory systems with many malignant cells.
►  Some neoplasms produce systemic effects by secreting chemicals such as enzymes or hormones.

NEPLASTIC DISEASE - 3: Staging

► TNM system because it is based on the Tumor bulk, Nodal involvement and existence of Metastasis. TNM staging is used to determine the type of treatment and also to forecast prognosis.
► Stages 1-4

NEOPLASTIC DISEASE - 4: Etiology

►  Ultra-violet irradiation leads to basal cell carcinoma and melanoma.
►  Irradiation is involved in the cancers of the breast, leukemia, and the thyroid.
►  Tobacco in cigarettes leads to lung cancer.
►  Chemicals e.g. polycyclic hydrocarbons in cigarettes
►  Viruses e.g. EBV in Burkett Lymphoma and Nasopharyngeal Carcinoma, HBV in HCC
►  Alcohol in liver and esophageal cancers

INFLAMMATORY DISEASE:

►  Inflammation may be infective or non-infective.
►  Examples of infective inflammatory disease are: rheumatic heart disease due to delayed effects of the childhood beta hemolytic streptococcal throat infection; Chagga’s heart disease due to trypanosoma cruzi, and syphilitic heart disease.
►  Acute inflammation may turn into chronic inflammation. It is the chronic irritation of such inflammation that leads to several diseases. The common chronic inflammatory conditions are: chronic ulcers, chronic bronchitis, emphysema, and asthma.

DEGENERATIVE DISEASE - 1: Coronary artery disease or ischemic heart disease

►  The commonest degenerative conditions: atherosclerosis leading to coronary heart disease (CHD), Alzheimer's disease, osteoporosis, and osteoarthritis.
►  The terms coronary artery disease (CHD), ischemic heart disease (IHD), are used interchangeably. It is a progressive disorder due to obstruction of the coronary arteries by cholesterol-rich fibro-fatty deposits, causes fibrillation, and thrombosis leading to infarction.
►  Manifestations of CHD are angina pectoris, chronic heart failure, and sudden death due to myocardial infarction.
►  Angina is treatable medically by Trinitron, beta blockers, calcium blockers, long acting nitrates, and aspirin. It is treatable surgically by coronary artery bypass graft (CABG) and percutaneous coronary angioplasty (PTCA).
►  Chronic ischemia may lead to impaired cardiac pump efficiency with limited exercise tolerance, which is known as chronic heart failure. A
►  An ischemic attack is preceded by prodromal symptoms of chest pain; dyspnea, tiredness, but they have low predictive value. It is treatable by defibrillation, aspirin, and anti-coagulants.

DEGENERATIVE DISEASE - 2: Osteoporosis

►  Osteoporosis is absolute decrease in the amount of skeletal bone. It is a personal health hazard especially in menopausal women because it leads to fractures.
►  It is due to decreased calcium absorption because of hormonal imbalances.
►  Hormonal disturbances are usually involved: hyperthyroidism, hyper-parathyroidism, hyperactive corticolemia, and hypopituitarism.
►  Low calcium intake, gastric or bowel resection, malabsorption, anorexia nervosa. Post-menopausal osteoporosis occurs 10-15 years after menopause.
►  It is associated with crush fractures of the vertebrae, fracture of the lower fore arm, loosening of teeth. Senile osteoporosis causes widespread fractures due to the aging process.

METABOLIC AND ENDOCRINE DISEASE-1: Diabetes mellitus

►  Two forms of diabetes: insulin and non-insulin dependent diabetes mellitus.
►  Insulin-dependent diabetes mellitus (IDDM) is the most severe form and occurs early in life. Non-insulin dependent diabetes is mature-onset
►  Among the complications of DM:

o diabetic retinopathy leading to blindness and cataracts.

o Renal complications

o Arterial disease.

TRAUMATIC INJURY

►  Traumatic injury occurs in all human activities: at work, at home, and during recreation.
►  The most serious traumatic injury is sustained in road traffic accidents (RTA). Injury of motor vehicle occupants is due to sudden deceleration. Industrial accidents are increasing.
►  There are new forms of traumatic injury that are being described such as the injury to the hand tendons due to repetitive work.

PSYCHIATRIC DISORDERS

►  The organic mechanisms of many such disorders are becoming unraveled. There is however a core of psychiatric disorders for which an organic basis may not be found because they have to do with innate disturbances of the human psyche or nafs.
►  DSM (diagnostic and statistical manual) of the American Psychiatric Association has specific but arbitrary criteria for classification of psychiatric disorders. It is backed up by a questionnaire that can be scored.
►  Schizophrenia and depression are the commonest psychiatric disorders.
►  Schizophrenia, besides being an economic burden and a source of family stress, leads to a marginalized life, poverty, homelessness, and higher risk of imprisonment.
►  Depression has both somatic and psychological symptoms. It is an economic burden.

ORAL DISORDERS

►  Oral diseases impair speech and eating in addition to causing disfigurement and pain.
►  Dental caries are caused by acid-producing bacteria that lead to progressive decalcification of the dental enamel leaving a cavity called a dental Cary.
►  Most oral bacteria are cariogenic. Frequent ingestion of carbohydrates provides a substrate for the bacteria.

DEFINITION AND TYPES OF PREVENTION

►  Primary prevention prevents occurrence. E.g. proper nutrition, health knowledge, exercise, avoiding addictions to alcohol and drugs, and following all recommended safety measures such as seat belts.
►  Secondary prevention (early detection and treatment) prevention shortens the duration of disease: BSE, testicular examination, hem occult test, Pap smear, glaucoma tests, BP checks, and regular dental check-up.
►  Tertiary prevention prevents complications. It consists of providing the necessary hospital facilities, medication compliance, exercise, and diet.

THE LAST FRONTIER: HUMAN BEHAVIOR and LIFESTYLE

►  Epidemiological knowledge available today is sufficient to make a major impact on many diseases.
►  Persuasion of people to change their behavior is not enough.
►  Consideration of using more coercive legislative measures violates the basic human rights of freedom of choice.
►  The matter becomes more complicated when the rights of the individual have to be considered against the welfare of the general society.
►  Most non-communicable diseases can be prevented by changes in human behavior or lifestyle. This is the Achilles' heel of epidemiology and public health because human behavior is very complex.
►  It is difficult to fully understand what motivates humans to engage in some life-style activities and not others.

CRITERIA FOR SETTING PREVENTIVE PRIORITIES

►  Number of deaths from the disease: biggest causes of death in industrialized countries are: cardio-vascular disease, cancer, COPD, and accidents
►  years of potential life lost (YPLL) is calculated by subtracting the age at death from 65,
►  economic cost of the disease: economic data is needed to compute the economic cost of a disease. This includes lost earnings and money spent caring for the patient.