CONCEPT OF ILLNESS AND DISEASE

ILLNESS

• Illness is a highly personal state in which the person's physical, emotional, intellectual, social, developmental, or spiritual functioning is thought to be diminished.
• It is not synonymous with disease and mayor may not be related to disease.
• Illness is highly subjective; only the individual person can say he or she is ill.

DISEASE

• Disease is defined as pathologic change in the structure or function of the body or mind.
• Disease can be described as an alteration in body functions resulting in a reduction of capacities or a shortening of the normal life span.
• Primitive people thought "forces" or spirits caused disease. Later this belief was replaced by the single-causation theory. Today multiple factors are considered to interact in causing disease. 

DIFFERENT CONCEPTS ON CAUSATION OF DISEASES

ANCIENT VIEWS

Demonic theory

• Religion, philosophy and medicine were integral part in the early part of civilization. Religion recognized multiplicity of Gods, both good and evil. Philosophy accepted the influence of inanimate bodies such as sun, moon and stars on living bodies. Thus, a co relation between these with health and disease was established in primitive ages.
• One concept prevalent was that the evil spirit entering the body directly and pursuing nefarious actions.  Another concept was the evil spirit   as a messenger of Gods giving warnings in the form of diseases. Some other concept was a human enemy with supernatural powers, send evil spirits to harm others. The souls of dead ancestors influencing his family members were another belief.
• Demonic possession is held by many belief systems to be the control of an individual by a malevolent supernatural being. Expressions include erased memories or personalities, convulsions, “fits” and fainting as if one were dying, access to hidden knowledge and foreign languages, drastic changes in vocal intonation and facial structure, sudden appearance of injuries (scratches, bite marks) or lesions, and superhuman strength.
• Many cuneiform tablets contain prayers to certain gods asking for protection from demons, while others asked the gods to expel the demons that invaded their bodies.

Punitive theory

• Punitive theory has its origin with the religion with the belief that one's attitude toward the deity is responsible as a cause of sickness. From a period centuries prior to the Christian era down to the present time, there have been beliefs   that disease was a punishment meted out by an outraged God for the sins of the individual or the race. There are recorded statements in biblical writings where in punishment is meted for  a sin of David,  with devastating plague in which the whole nation suffered and which was stayed only by David's repentance and the making of a sacrifice.
• Such references are abundantly available in Hindu mythology also especially those related to eruptive fevers such as Small pox, Chicken Pox etc.

Humoral theory

• The Greeks rejected the super natural theories and looked up on disease as a natural process. They advocated that the matter is made up of four elements- Earth, Air, Fire and Water and these elements have the corresponding qualities of being Cold, Dry, Hot and Moist.  With this concept they hypothesized that these qualities are represented in the body by four humors- Phlem, yellow bile, black bile and blood. According to this theory, the equilibrium among these humours characterizes health (eucrasia), and disequilibrium (dyscrasia) characterizes disease.
• Hippocrates moved medicine from magic and metaphysics to give it a scientific basis. He introduced logic into medical thinking, elaborated the theory of humours and recognized the importance of the environment in health. He also suggested that an excess of one of the humours would result in various idiosyncrasies - hematic, phlegmatic, choleric and melancholic.
• The theory of humours was known in India, China, Egypt and Greece.

Miasmatic theory

• Miasmatic theory is based on the inference that the air arising from certain kinds of ground, especially low, swampy areas, was a cause of disease. Certain places were thus given a very evil reputation, because the ground was said to exude some invisible, insensible vapour, called it  miasm, which produced disease.
• The invention of miasma was really beginning to be scientific medicine. People were searching for a material and natural causes, instead finding shelter on god or a devil. Rational thinking that something cannot come out of nothing was the basis of this concept. The fact that malaria was prevalent in the vicinity of swampy land, and some evidence that people who ventured out in these swampy places were more likely to get the disease, lent plausibility to this theory. It was the belief in the air as the causative agent that gave malaria its name, mal aria ('bad air' in Medieval Italian).

Contagion theory

• Girolamo Fracastoro (1478-1553), an Italian physician, contended that there is a large class of diseases caused by contagion rather than humoral imbalances.
• This was based on the observation that persons could contract infections even if their humors are normally balanced. Fracastoro defined a contagion as a "corruption which develops in the substance of a combination, passes from one thing to another, and is originally caused by infection of the imperceptible particles”. He called the particles the seminaria (seeds or seedlets) of contagion. Fracastoro was unable to say much about the nature of these suspected particles; bacteria were not observed by van Leeuwenhoek until 1683, and their role in infection was not appreciated until the 1860s.
• Fracastoro nevertheless discussed the causes and treatment of various contagious diseases. He described how contagion can occur by direct contact, by indirect contact via clothes and other substances, and by long-distance transmission. In addition, he stated that diseases can arise within an individual spontaneously. His book has chapters for the arrangement of contagious diseases. His theory remained influential for nearly three centuries, before being superseded by a fully developed germ theory.

MODERN VIEWS

Germ Theory

• Germ theory was proposed by Louis Pasteur (1822 –1895) and Robert Koch (1843 –1910). Germ theory postulates that every human disease is caused by a microbe or germ, which is specific for that disease and one must be able to isolate the microbe from the diseased human being.
• The Germ theory viewed diseases in terms of a causal network similar to that of Fracastoro, but with much more detail about the nature of germs and possible treatments.
• Organisms that cause disease inside the human body are called pathogens. Bacteria and Viruses are the best know pathogens. Fungi, protozoa’s and parasites can also cause disease.  Infectious diseases are typically classified as bacterial, viral, protozoal and so on. Knowing what bacteria are responsible for a particular disease indicates what antibiotic treatment to apply. Diseases are said to be infectious or communicable if pathogens can be passed from one person to another.

Epidemiological Triad

• The standard model of infectious disease causation under the epidemiological triad theory states that an external agent can cause diseases on a susceptible host when there is a conducive environment
• Within the epidemiological triad the agent is known as a ‘necessary’ factor. It has to be present for morbidity, although it may not inevitably lead to disease. For the disease to occur it needs the combination of what have been called ‘sufficient’ factors. These would include a host, which might be an individual or group of individuals who are susceptible to the agent. Susceptibility might be on the basis of age, sex, ethnic group or occupation. Environmental factors can also be sufficient factors that combine with the agent    
• The epidemiological triad can be applied to non-infectious diseases where the agent could be ‘unhealthy behaviours, unsafe practices, or unintended exposures to hazardous substances’

Multi factorial theory

• When the knowledge on diseases increased, one theory was not able to explain the causation of all the diseases. This lead to multi factorial theory to find rational explanation.  Though many diseases are infectious, other causative factors such as Genetic, Nutritional, Immunological, Metabolic, Cytological factors were identified as the cause for specific diseases.

BEINGS theory

• BEINGS concept postulates that human diseases and its consequences are caused by a complex interplay of nine different factors. By coining the first letters of these factors the theory is called BEINGS theory. These are

(1)   Biological factors innate in a human being,

(2)   Behavioral factors concerned with individual lifestyles,

(3)   Environmental factors as physical, chemical and biological aspects of environment,

(4)   Immunological factors,

(5)   Nutritional factors,

(6)   Genetic factors,

(7)   Social factors,

(8)   Spiritual factors and

(9)   Services factors, related to the various aspects of health care services.

ETIOLOGY

• The causation of a disease is called its etiology.
• Etiology of a disease includes the identification of all causal factors that act together to bring about the particular disease.
• For example, the tubercle bacillus is designated as the biologic agent of tuberculosis. However, other etiologic factors, such as age, nutritional status, and even occupation, are in-evolved in the development of tuberculosis and influence the course of infection.

Factors of disease causation

1. Predisposing factors are the factors which create a state of susceptibility, making the host vulnerable to the agent. These are age, sex and previous illnesses.
2. Enabling factors are those which assist in the development of (or in recovery from) the disease; e.g. housing conditions, socio-economic status.
3. Precipitating factors are those which are associated with immediate exposure to the disease agent or onset of disease, e.g. drinking contaminated water, close contact with a case of pulmonary TB.
4. Reinforcing factors are those which aggravate an already existing disease, e.g. malnutrition, repeated exposures. 
5. Risk factors are the conditions, quality or attributes, the presence of which increases the chances of an individual to have, develop or be adversely affected by a disease process. The risk factor need not necessarily cause the disease but does increase the probability that the person exposed to the factor may get the disease easily.

CLASSIFICATION OF DISEASES

• On various approach diseases are classified as-

1. Topographical or Systemic, by bodily region or system,

For e.g. - gastrointestinal disease, vascular disease, abdominal disease, and chest disease etc.

2. Anatomical, by organ or tissue,

For e.g. - cardiac disease, hepatic disease, and pulmonary disease etc.

3. Physiological, by function affect,

For e.g. - respiratory and metabolic syndrome etc.

4. Pathological, by the nature of the disease process,

For e.g. - Neoplastic and inflammatory disease etc.

5. Etiological (causal),

• communicable - bacterial, viral, parasitic, vector born, water born zoonotic, STDs etc.

• non-communicable - Hereditary, Life style related, accidental, injuries, nutritional

6. Juristic,

For e.g. - Medicolegal, Non-medicolegal etc.

7. Epidemiological,

For e.g. - Sporadic, outbreak, epidemic, pandemic and endemic etc.

8. Statistical basis of classification

For e.g. - WHO | International Classification of Diseases (ICD)-10

INTERNATIONAL CLASSIFICATION OF DISEASES (ICD – 10)

• Work on ICD-10 began in 1983 and was completed in 1992 and is in use from 1999 to 2018
• The ICD - 10 allows more than 14,400 different codes and permits the tracking of many new diagnoses. The codes can be expanded to over 16,000 codes by using optional sub-classifications.
• ICD – 10 is arranged in 21 major chapters.

International Statistical Classification of Diseases and Related Health Problems 10th Revision
Chapter	Blocks	Title
I	A00–B99	Certain infectious and parasitic diseases
II	C00–D48	Neoplasms
III	D50–D89	Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
IV	E00–E90	Endocrine, nutritional and metabolic diseases
V	F00–F99	Mental and behavioral disorders
VI	G00–G99	Diseases of the nervous system
VII	H00–H59	Diseases of the eye and adnexa
VIII	H60–H95	Diseases of the ear and mastoid process
IX	I00–I99	Diseases of the circulatory system
X	J00–J99	Diseases of the respiratory system
XI	K00–K93	Diseases of the digestive system
XII	L00–L99	Diseases of the skin and subcutaneous tissue
XIII	M00–M99	Diseases of the musculoskeletal system and connective tissue
XIV	N00–N99	Diseases of the genitourinary system
XV	O00–O99	Pregnancy, childbirth and the puerperium
XVI	P00–P96	Certain conditions originating in the perinatal period
XVII	Q00–Q99	Congenital malformations, deformations and chromosomal abnormalities
XVIII	R00–R99	Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
XIX	S00–T98	Injury, poisoning and certain other consequences of external causes
XX	V01–Y98	External causes of morbidity and mortality
XXI	Z00–Z99	Factors influencing health status and contact with health services
XXII	U00–U99	Codes for special purposes

TYPES OF ILLNESS

Acute Illness

• Acute illness is characterized by severe symptoms of relatively short duration (typically less than six months).
• The symptoms often appear abruptly and subside quickly and, depending on the cause, may or may not require intervention by health care professionals.
• An acute illness, most people return to their normal level of wellness.

Chronic Illness

• A chronic illness is one that lasts for an extended period, usually 6 months or longer, and often for the person's life.
• Chronic illnesses usually have a slow onset and often have periods of remission (symptoms disappear) and exacerbation (symptoms reappear).
• Care needs to be focused on promoting the highest level possible of independence, sense of control, and wellness. Clients often need to modify their activities of daily living, social relationships, and perception of self and body image. In addition, many must learn how to live with increasing physical limitations and discomfort.

Terminal Illness

• Terminal illness is an incurable disease that will soon progress until death with near absolute certainty, regardless of treatment, within a short period of time.
• Terminal patients have many options for disease management after diagnosis. Examples include caregiving, continued treatment, hospice care, and physician-assisted suicide.
• Decisions regarding management are made by the patient and his or her family, although medical professionals may give recommendations or more about the services available to terminal patients.
• Lifestyle after diagnosis largely varies depending on management decisions and also the nature of the disease, and there may be living restrictions depending on the condition of the patient.
• Terminal patients may experience depression or anxiety associated with oncoming death, and family and caregivers may struggle with psychological burdens as well. Psychotherapeutic interventions may help alleviate some of these burdens, and is often incorporated in palliative care.
• Because terminal patients are aware of their oncoming deaths, they have more time to prepare advance care planning, such as advance directives and living wills, which have been shown to improve end-of-life care. While death cannot be avoided, patients can still strive to die a good death.

ILLNESS BEHAVIORS

• illness behavior means, behavior of individuals when they are ill
• Illness behavior is a coping mechanism, involves ways individuals describe, monitor, and interpret their symptoms, take remedial actions and use the health care system

Parsons four aspect s of the sick role

• Clients are not responsible for their conditions
• Clients are excused from certain social roles and tasks
• Clients are obliged to try to get well as quickly as possible
• Clients or their families are obliged to seek competent help

Suchman's 5 Stages of Illness

• Suchman (1979) describes five stages of illness - symptoms, sick role, medical care contact, dependent client role, and recovery or rehabilitation.
• Stage 1 - Symptom experiences
• At this stage the person comes to believe something is wrong.
• Stage 1 has three aspects:
• The physical experience of symptoms - such as pain, rash, cough, fever, or bleeding
• The cognitive aspect (the interpretation of the symptom in terms that have some meaning to the person)
• The emotional response (e.g., fear or anxiety)
• During this stage, the unwell person usually consults others about the symptoms or feelings, validating with a spouse or support people that the symptoms are real. At this stage the person may try home remedies. If self-management is ineffective, the individual enters the next stage.
• Stage 2 - Assumption of the sick role
• The individual now accepts the sick role and seeks confirmation from family and friends, continue with self-treatment and delay contact with health care professional as long as possible.
• During this stage people may be excused from normal duties and role expectations.
• Emotional response such as withdrawal, anxiety, fear, and depression are common depending on the severity of the illness, degree of disability, and duration of the illness.
• When symptoms of illness persist or increase, the person is motivated to seek professional help.
• Stage 3 - Medical Care Contact
• In this stage sick people seek the advice of a health professional. they are asking for three type of information: -
• Validation of real illness
• Explanation of the symptoms in understandable terms
• Reassurance that they will be alright or prediction of what the outcome will be
• The client may accept or deny the diagnosis. If the diagnosis is accepted, the client usually follows the prescribed treatment plan. If the diagnosis is not accepted, the client may advice of other health care professionals, who will provide a diagnosis that fit for the client.
• Stage 4 - Dependent Client Role
• After accepting the illness and seeking treatment, the client become dependent on the health care professional, family and friends for help.
• Stage 5 - Recovery or Rehabilitation
• During this stage the client is expected to relinquish the dependent role and resume former roles and responsibilities.
• In acute illness, the time as an ill person is generally short and recovery is usually rapid, and most find it relatively return to their former lifestyles. But those who have long-term illnesses or permanent disability, must adjust their lifestyles may find recovery more difficult.
• Not all clients progress through stage. For example, the client who experiences a sudden heart attack is taken to the emergency room and immediately enters stages 3 and 4, medical care contact and dependent client role.

IMPACT / EFFECTS OF ILLNESS

• Illness brings about changes in both the involved individual and in the family. The changes vary depending on the nature, severity, and duration of the illness, attitudes associated with the illness by the client and others, the financial demands, the lifestyle changes incurred, adjustments to usual roles, and so on.

Impact on Client

• Ill clients may experience -
• Behavioral & Emotional Change
• Physical Changes
• Loss of autonomy
• Lifestyle Changes
• Behavioral & Emotional Change
• Behavioral and emotional changes associated with short-term illness are generally mild and short lived such as irritability and lack the energy or desire to interact in the usual fashion with family members or friends. Acute responses such as anxiety, fear, anger, withdrawal, denial, a sense of hopelessness, and feelings of powerlessness are all common responses to severe or disabling illness.
• Nurses need to help the client s by giving the psychological support to improve the emotional condition.
• Physical Changes
• Certain illnesses can also change the client's body image or physical appearance, especially if there is severe scarring or loss of a limb or special sense organ.
• The client's self-esteem and self-concept may also be affected. Many factors can play a part in low self-esteem and a disturbance in self-concept: loss of body parts and function, pain, disfigurement, dependence on others, unemployment, financial problems, inability to participate in social functions, strained relationships with others, and spiritual distress.
• Nurses need to help clients express their thoughts and feelings, and to provide care that helps the client effectively cope with change.
• Loss of autonomy
• Ill individuals are also vulnerable to loss of autonomy, the state of being independent and self-directed without outside control. Family interactions may change so that the client may no longer be involved in making family decisions or even decisions about their own health care.
• Nurses need to support client's right to self-determination and autonomy as much as possible by providing them with sufficient information to participate in decision-making processes and to maintain a feeling of being in control.
• Lifestyle Changes
• Illness also often changes in lifestyle. In addition to participating in treatments and taking medications, the ill person may need to change diet, activity and exercise, and rest and sleep patterns.
• Nurses can help clients to adjust their lifestyles by-
• Providing explanations about necessary adjustments
• Making arrangements wherever possible to accommodate the client's lifestyle
• Encouraging other health professionals to become aware of the person's lifestyle practices and to support healthy aspects of that life style
• Reinforcing desirable changes in practices with a view to making them a permanent part of the client's lifestyle.

Impact on the Family

A person's illness affects not only the person who is ill but also the family or significant others. The kind of effect and its extent depend chiefly on three factors:

1.      Member of the family who is ill

2.      The seriousness and length of the illness

3.      Cultural and social customs the family follows

Changes in the family include:

1.      Role Changes

2.      Task reassignments and increased demands on time

3.      Increased stress

4.      Financial problems

5.      Loneliness as a result of loss and separation

6.      Change in social customs