Disease Process
The study of disease with an emphasis on the
structural aspects is called pathology.
The study of abnormal processes in the body
is called pathophysiology.
Disease is the manifestation of pathology or
pathophysiology in a person.
Terminology and revision
Health (Hauora) is a state of wellbeing, the
body systems are in balance and adapt to the
environment within normal parameters.
Disease is a condition of abnormal
functioning, the sum of the physiological
processes that have been altered or
disturbed.
The afferent and efferent information can
be nerve impulses or hormones. True
- genetic diseases
- physiological diseases.
The following is another way of looking at
the clinical models of diseases.
The models are:
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Cell injury and death
Cell proliferation and differentiation
Inflammation, infection and immune
defects
Metabolic and nutritional
Degeneration
Cellular injury and death
Cell injury is the damage, alteration,
destruction or malfunction of cells.
Cell injury can be caused by nutritional or
chemical imbalance (lack of vitamin C or
oxygen), physical agents (trauma), extremes
of temperature (thermal) or infection.
Cell injury starts off with inflammation,
followed by repair. If the cells are irreversibly
damaged, cell death will (necrosis,
infarction).
Allostasis refers to changes in the body that
occur as a consequence of CHRONIC
activation of the homeostatic mechanisms
resulting in a new but abnormal balance.
Disease classification
There are four main types of disease
depending on the cause:
- infectious diseases
- deficiency diseases
Cell proliferation and differentiation
Metabolic and nutritional disorders
Cellular proliferation (mitosis) and cellular
differentiation (one zygote to 200 different
cells) is a normal physiological process.
A metabolic disorder can happen when
an abnormal chemical reaction in the
body alters a normal metabolic process.
These diseases may be inherited or
diagnosed later.
If there are environmental factors that cause
the cell differentiation in the foetus to be
altered, the neonate may present with
a congenital abnormality eg cleft palate. An
example of a chromosomal change
(mutation) during gametogenesis or
fertilisation is trisomy21.
Excess cellular proliferation results in
tumours (neoplasms). These tumours can be
benign or malignant.
Metabolic disorders can be due to
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Inflammation and infection
Acute inflammation is a normal physiological
process, but chronic inflammation is
pathophysiological process.
Clinical picture of inflammation -redness,
heat, pain, swelling and loss of function.
Inflammatory mediators are released and
they cause increased capillary permeability,
vasodilation and leukocytosis.
The leukocytes is responsible for removing all
the debris.
If the blood vessels are damaged, the
coagulation cascade is activated.
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a missing enzyme or vitamin that’s
necessary for an important
chemical reaction
abnormal chemical reactions that
hinder metabolic processes
a disease in the liver, pancreas,
endocrine glands, or other organs
involved in metabolism
nutritional deficiencies
The best-known metabolic disease is
diabetes mellitus.
Nutritional diseases are caused by
any nutrient-related deficiencies or
excesses in the diet.
Nutritional diseases include
developmental abnormalities, hereditary
metabolic disorders, adverse interactions
of foods with medications and
food intolerances.
Degenerative disorders
Infections are caused by microorganisms.
Degenerative diseases are a continuous
process in any tissue or organ where there
is increasing deterioration over time. This
may be caused by normal bodily wear and
tear or lifestyle choices such as excessive
exercise or incorrect eating habits.
The degenerative disease cannot be
corrected or cured; they may be halted.
of diseases. This requires clear descriptions
or classifications of diseases.
An example of a genetic disorder due to a
mutation is ....................... and an inherited
disorder is ....................
Trisomy 21 and sickle cell anaemia
Programmed cell death is called:
Apoptosis
Disease profile - 2
Pathogenesis
The sequence of events from the cause
(aetiology) to the established disease
(pathophysiology). It can be called the
beginning or evolution of the disease.
The body can no longer maintain
homeostasis (adapt or compensate) and
abnormal functions starts.
Disease profile - 1
Pathophysiology
AETIOLOGY or CAUSE
Pathophysiology is the
altered physiology which affects cells or
organ structure and function. It is the study of
the mechanism of disease.
The aetiology or causes of a disease could
be physical, pathogens (biological), chemical,
nutritional, radiation, genetic, or the cause
may be unknown.
RISK FACTORS
Altered functionality can occur purely at a
local level eg in the breast or heart or the
disease can affect the entire body.
Risk factors contributing to the development
of a disease, they predispose to disease and
are associated with susceptibility and
virulence.
Pathology is the term used for structural
changes of cells and organs.
EPIDEMIOLOGY
Epidemiology is the study of the distribution,
prevalence, morbidity and mortality
The sequence in the pathophysiology of a
lack of oxygen (hypoxaemia) to the tissue
(hypoxia) results in:
Ischaemia (lack of oxygen), results in tissue
injury which results in necrosis
(infarction/tissue death)
Disease profile - 3
The first part is taking the vital signs.
The history (subjective data) includes
questions about the patient biographical data,
previous illnesses or surgeries, allergies,
medications used and any family history.
The initial physical assessment (objective
data) is a brief overview, followed by a
focused assessment of the relevant body
system. The physical assessment usually
follows the pattern of observation,
auscultation, palpation and percussion.
Relevant investigations (objective data) are
selected to enhance or support any previous
findings or rule out diseases. Blood and urine
tests can be done, imaging techniques may
be useful and specialised tests such as
endoscopy or biopsy may be requested.
When all the information has been gathered
a DIAGNOSIS (medical or nursing) can be
made.
The following headings may be appropriate
in developing a nursing care plan for
a specific patient you are providing care for.
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The other aspects of the management plan
will include
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Which of the following blood tests are
used to diagnose anaemia?
Mean corpuscular volume
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Disease profile - 4
PRINCIPLES OF TREATMENT or
MANAGEMENT
The principles of treatment are the same for
most patients. The difference is how the
principles are implemented and this results in
individualised patient care.
3-5 key principles of managing patient
care
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treat the cause
monitor patient progress
implement a care plan
prevent complications
some specifics for the disease
RESUSCITATION
VITAL SIGNS
ONGOING MONITORING
SPECIAL OBSERVATIONS
or INVESTIGATIONS
NUTRITION
INTAKE and OUTPUT
HYGIENE, REST, EXERCISE
PSYCHOSOCIAL MENTAL HEALTH, SOCIAL WORKER
PATIENT EDUCATION
DISCHARGE PLANNING
TREATING THE CAUSE
MEDICAL
TREATMENT - MEDICATION, SUR
GERY
PARAMEDICAL INPUT –
PHYSIOTHERAPY, SPEECH
THERAPY, OCCUPATIONAL
THERAPY
COMPLEMENTARY MEDICINE –
HERBS, HOMEOPATHY,
ACUPUNCTURE
Take special note of the pharmacological
management and study each medication
using the following headings
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Pharmacokinetics
Pharmacodynamics
Adverse reactions
Drug interactions
Disease profile - 5
COMPLICATIONS are the adverse
extensions of the disease or poor outcomes
of a disease. The complications are a new
and separate disease process.
The PROGNOSIS refers to the expected
outcome, good or bad. How long can the
patient be expected to live?
There are 3 levels of PREVENTION
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Primary prevention aims to keep the
disease from actually occurring,
preventing the disease. This includes
the removal of risk factors and
implementation of prophylaxis.
Secondary prevention is the treatment
of the disease.
Tertiary prevention is rehabilitation
from a disease. It includes
REHABILITATION is helping restore lost
skills and helping the patient to regain
maximum self-sufficiency.
Review all the concepts used to
describe a disease profile
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Consider the patient/client situation presentation signs and symptoms
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Collect cues and information - history
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Gather new information - physical
assessment and investigations
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Recall relevant knowledge
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Process the information - interpret,
discriminate, relate, infer, predict and
match
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Identify the problem - diagnosis
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Establish goals - plan
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Take action - implementation
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Evaluate and monitor
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Reflect