health : a state of optimal physical, mental, and social well-being,
and not merely the absence of disease and infirmity.
sanity : soundness, especially soundness of mind.
disease / illness / sickness / maladie : any deviation from or interruption
of the normal structure or function of a part, organ, or system of the
body as manifested by characteristic symptoms and signs; the etiology,
pathology, and prognosis may be known or unknown.
infirmity : 1. a feeble or weak state of the body or mind.
2. a (chronic) disease or condition producing weakness
affection : an affliction or disease
disorder : a derangement or abnormality of function; a morbid physical
or mental state.
indisposition : the condition of being slightly ill; a slight illness.
handicap : any physical or mental defect or characteristic, congenital
or acquired, preventing or restricting a person from participating in normal
life or limiting his capacity to work
disability : 1. a lack of the ability to function normally, physically
or mentally; incapacity. 2. anything that causes disability.
3. as defined by the federal government: “inability to engage in any substantial
gainful activity by reason of any medically determinable physical or mental
impairment which can be expected to last or has lasted for a continuous
period of not less than 12 months.”
developmental disability : a substantial handicap having its onset
before the age of 18 years and of indefinite duration. Examples are mental
retardation, autism, cerebral palsy, epilepsy, or other neuropathy.
mutilation : the act of depriving an individual of a limb, member,
or other important part; deprival of an organ; severe disfigurement
invalid : 1. not well and strong. 2. a person who is disabled by
illness or infirmity.
activities of daily living (ADL) : activities routinely performed
daily by the average person in a given society; rehabilitation following
illness or injury often aims to help patients achieve independence in performing
Cultural and professional models of illness influence decisions on
individual patients and delivery of health care. The biomedical model of
illness, which has dominated health care for the past century, cannot fully
explain many forms of illness. This failure stems partly from three assumptions:
all illness has a single underlying cause, disease (pathology) is always
the single cause, and removal or attenuation of the disease will result
in a return to health. Evidence exists that all three assumptions are wrong.
We describe the problems with current models and describe a new model,
derived from the World Health Organization's international classification
of functioning frameworkref,
that provides a more comprehensive, less biologically dependent account
of illness. The model of illness adopted by society can have important
consequences. In the first world war, for example, soldiers complaining
of symptoms after experiencing severe stresses were sometimes shot as malingerers,
but today they are considered victims and eligible for financial settlements
Social acceptance that a behaviour or reported symptom constitutes an illness
bestows privileges on an individual and formal duties on society. Currently,
most models of illness assume a causal relation between disease and illness—the
perceived condition of poor health felt by an individual. Cultural health
beliefs and models of illness help determine the perceived importance of
symptoms and the subsequent use of medical resourcesref.
The assumption that a specific disease underlies all illness has led to
medicalisation of commonly experienced anomalous sensations and often disbelief
of patients who present with illness without any demonstrable disease process.
Despite their importance, models of illness are rarely explicitly discussed
or defined. The often criticised but nevertheless dominant 20th century
biomedical models originate from Virchow's conclusion that all disease
results from cellular abnormalities. The biomedical model is clearly relevant
for many disease based illnesses, has intuitive appeal, and is supported
by a wealth of supporting biological findings. By embracing reductionism,
however, biomedical models of illness combine several closely related sets
of beliefs. These can be summarised as follows:
all illness and all symptoms and signs arise from an underlying abnormality
within the body (usually in the functioning or structure of specific organs),
referred to as a disease.
all diseases give rise to symptoms, eventually if not initially, and although
other factors may influence the consequences of the disease, they are not
related to its development or manifestations.
health is the absence of disease.
mental phenomena, such as emotional disturbance or delusions, are separate
from and unrelated to other disturbances of bodily function
the patient is a victim of circumstance with little or no responsibility
for the presence or cause of the illness
the patient is a passive recipient of treatment, although cooperation with
treatment is expected.
Many different models of illness exist, originating in professionsref
specialties, and elsewhereref.
The social model primarily focuses on the causation of disability by society
rather than the whole spectrum of illness. The biopsychosocial model is
perhaps the most popularref1,
Over 400 Medline titles include the word, and it is increasingly used in
many areas of medicineref1,
In contrast to the biomedical model, it recognises that psychological and
social factors influence a patient's perceptions and actions and therefore
the experience of what it feels like to be ill. People often experience
The model of illness adopted will influence whether a person or their health
adviser interprets a change in their state as indicating diseaseref,
when someone should enter and leave the sick role, and often the health
care given. Only a small minority of potential symptoms lead to involvement
with health care, but a small change in the rate of interpreting anomalous
sensations as symptoms by any party will have a major influence on the
use of healthcare systems. Being ill, and being allowed to enter the sick
role, has social and personal advantages for the person. Sick people may
be absolved from social responsibilities, they are not held responsible
for their condition, and they will often be eligible for healthcare benefits
for which they do not pay directly. The sick role is most effective when
it is validated by a doctor, but increasingly other health and non-healthcare
professionals contribute to validation; indeed, ill people can now classify
themselves as sick—for example, through self completed incapacity benefit
forms in the United Kingdom. Already many patients present with symptoms
that are not attributable to any underlying pathology or diseaseref.
Nevertheless, such patients are often given a medical diagnosis, implying
an underlying structural cause and reflecting cultural expectations. Unfortunately,
the use of diagnostic labels has implications for the patient, society,
and ultimately for the credibility of medicine. Any illness provided with
a (medically validated) diagnostic label is widely assumed to be secondary
to defined pathology, to be capable of confirmation independently of the
symptoms, and to have a specific treatment that health services should
supply. The problems arising from illnesses without a definable cause have
been well documented. They are most appropriately termed functional somatic
recognising that psychological and social factors strongly influence the
presentation of somatic symptomsref1,
However, suggesting that patients do not have a disease (pathology) to
explain their illness may understandably upset themref
and creates difficulty for healthcare bureaucracy which relies on the patient's
specific disease label. Funding is determined by diagnosis (in health related
groups or similar) and ignores the initial cost associated with diagnosis
(patients present with problems, not diagnoses). It also fails to recognise
that a major part of healthcare cost relates to disabilityref.
Resources are primarily allocated for the diagnosis and specific treatment
of disease. Little attention is paid to other interventions despite good
evidence of their effectiveness. Examples include the provision of equipmentref
the use of specialist multidisciplinary stroke rehabilitation units, and
the altering of patients' beliefs. Most healthcare systems also assume
that treatment after diagnosis is brief and acts quickly. Indeed, the medical
model might more accurately be termed the surgical model, given the pre-eminence
of surgery in popular culture and health organisation. Finally, most biomedical
models also seem strongly linked to primitive forms of intuitive mind-body
dualism. Health commissioners, budgetary systems, healthcare professionals,
and the public all act as if there is some clear, inescapable separation
between physical and mental health problems, ignoring evidence that a person's
emotional state always affects their function and presentation of physical
For example, separate services exist for people with physical disability
and for those with mental health problems. 2 main factors fostered our
new model. Firstly, WHO's international classification of impairment, disability
and handicap and its later development, the international classification
of functioning, disability and health, both recognise that disease has
consequences at different levels, often influenced by contextual factors.
Secondly, the power of a systems analytical approach to illness has been
An earlier version of this model formed the basis of the UK national guidelines
on stroke and multiple sclerosis. The main modifications to the international
classification of functioning model are:
a division of each main domain into a subjective (patient experienced)
and objective (externally observed) componentref
The addition of a further human factor that is essential in any analytical
model—namely, the potential contribution of free will and personal choiceref.
a clarification of context, with separation of personal and social contexts.
This model suggests that illness is a dysfunction of the person in his
(or her) physical and social environment. It is centred on the (ill) person,
who does not necessarily have to consider himself ill (for example, if
someone is deluded).
The model suggests that people with illness should be considered as
people have 2 major systems—their whole self, with dysfunction termed impairment,
and their organs, with dysfunction called pathology.
2 influencing factors affect each person—personal context (that is, beliefs,
attitudes, expectations, values etc, which derive partly from past experience)
and free will.
each person interacts with two contexts—physical and social or cultural.
the interactions are considered in term of activities (which are usually
goal directed actions) and (social) participation (which reflects the meanings
attributed to their behaviours by themselves and others).
This model has many implications (see table A on bmj.com). One characteristic
of a systems model is that abnormalities in one system can occur without
any of its components being faulty, and so the model explicitly predicts
that illness will occur without discernable pathology. The mystery of non-organic
illness is no longer medically unexplainedref.
This analysis does not deny the reality of the illness but rather provides
the rationale and support for explanations and treatments that direct their
focus to the non-medical reasons why people may feel ill. This model also
predicts that the effects of an abnormality may depend crucially on the
characteristics of other parts of the system. For example, hip arthritis
may become apparent only after a stroke affects the other leg. Consequently,
reduction of illness may require intervention at several points, and indeed
may not necessarily include removal of the main abnormality; this may explain
the success of specialised stroke rehabilitation. The model suggests that
some resources should be focused on altering contextual factors. Evidence
already supports this approach: teaching carers of stroke patients benefits
both the patient and healthcare systemsref1,
changing social contextref
may be effective—for example, reducing time off work with back painref;
altering personal context may help in some illnessesref—for
example, using cognitive behaviour therapy; and improving the physical
context reduces expenditure on health careref.
The role of personal choice, absent in many biomedical models of illness
is central to any progressive explanation of human behaviour: "People are
rational, aware self creating agents of their own health... influenced
by consciously chosen goals."ref
Personal choice plays an important part in the genesis or maintenance of
illness, particularly in and through the domain of activities. This model
also illuminates some of the current stresses within health care and illness
related benefits systems. Systems focused on pathology (that is, hospitals)
work in short time scales and ignore all patient context. However, they
have to manage patients with activity limitations, in whom the time scale
is longer and context is important. A coherent approach to rehabilitation
inevitably requires action from other agencies such as social, housing,
or employment services. When the characteristics (speed of priorities,
available interventions) across organisational boundaries do not match
each other or the needs of the patient, stresses may arise (often referred
to as bed blocking in hospital). The new model undoubtedly has several
weaknesses but it strives to provide a fuller understanding of the factors
involved in illness at the level of both the individual and healthcare
systems. The model could also be applied outside the health arena—for example,
to people in the criminal justice systemref.
Healthcare systems are social organisations, and their continuing health
depends on members of society using a congruent model of illness and system
of values to decide the rights and responsibilities associated with illness
and the sick role, and how these are to be policed where individuals choose
to take advantage of the role. The use of this model might improve the
delivery of better health more than any other change in healthcare organisation.
It is time that the medical models underpinning health delivery were debated
The classification of diseases according to
tissue(s)/organ(s) involved is mainly used by clinicians in order to evaluate
the systemic consequences of a disease and the right therapy.
Many diseases (if not all) involve more than one tissue/organ : this is
1) ... in genetic diseases, often the defective gene sequence or expression
is required in more than one cell type
2) ... in extrinsic aetiology, often ...
a) ... energy distributes itself on a wide volume
b) ... chemical destroys the barrier(s) among tissues or is carried
by the blood- (and/or lymph-) stream
c) ... toxic properties of the infectious agent are pleiotropic (i.e.
: the virus receptor is widely expressed on cell surface, the bacterial
toxin acts on widely represented substrates, ...)
Anyway, from a clinical point of view, diseases can be classified according
to the following criteria :
the most important damaged tissue/organ
the location of the primary tumour, even if often the most important
damage is given by metastasis rather than by the primary tumour (e.g. :
In the following classification, when a disease is recognized as
having a monofactorial aetiology, then a link to the aetiological factor
According to localizations, diseases are
classified as :
focal disease : one which is localized at one or more foci
local disease : a condition which originates in and remains confined
to one part of the body.
systemic disease : one affecting a number of organs and tissues.
According to duration, diseases are classified
acute disease : lasting < 3 months
self-limited disease : one which by its very nature runs a limited
and definite course.
crisis : the turning point of a disease for better or worse; especially,
a sudden change, usually for the better, in the course of an acute disease.
A disease terminates by crisis when recovery is indicated by a sudden and
definite decrease in the intensity of the symptoms
false crisis : pseudocrisis.
febrile crisis : an attack of chilliness, fever, and sweating.
subacute disease : 3 < lasting < 6 months
chronic disease : lasting > 6 months
organic disease : one associated with demonstrable change in a bodily
organ or tissue.
complicating disease : one which occurs in the course of some other
disease as a complication.
paleopathology : the study of disease in bodies preserved from ancient
times, such as mummies.
forme fruste [Fr. “defaced”] : an atypical, especially a mild or
incomplete, form, as of a disease or anomaly.
forme tardive [Fr. “late”] : a late-occurring form of a disease
that usually makes its appearance at an earlier age
public health : the field of medicine concerned with safeguarding
and improving the health of the community as a whole
biomedicine : clinical medicine based
on the principles of the natural sciences (biology, biochemistry, biophysics,
problem-oriented record (POR) : an approach to patient care record
keeping that focuses on those specific health problems of the patient that
require immediate attention and on the structuring of a cooperative health
care plan designed to cope with the identified problems. The components
basic to the POR are:
the data base, which provides information obtained from the variety
of sources required for each patient regardless of diagnosis or presenting
the problem list, which contains those major problems currently
needing attention and serves as the basis of a plan of care;
the plan, which specifies what is to be done with regard to each
problem; the progress notes, which document the observations, assessments,
nursing care plans, physician's orders, etc., of all health care personnel
directly involved in the care of the patient.
SOAP : a device for conceptualizing the process of recording the
progress notes in the POR :
S indicates subjective data obtained from the patient and others close
O designates objective data obtained by observation, physical examination,
diagnostic studies, etc.
A refers to assessment of the patient's status through analysis of the
problem, possible interaction of the problems, and changes in the status
of the problems
P designates the plan for patient care.
a medical visit
looks at the status praesens (the condition of a patient
at the time of observation) and is made up of :
anamnesis : collection
of subjective symptoms
(any subjective evidence of disease or of a patient's condition, i.e.,
such evidence as perceived by the conscious patient and referred during
dialogue; a noticeable change in a patient's condition indicative of some
bodily or mental state).
a capite ad calcem : from head to heel,
the classic order for describing symptoms
personal physiological anamnesis
past pathological anamnesis / past medical
history (PMH)/past surgical history (PSH) (including
names of active principles and posology of used drugs)
current pathological anamnesis (if in hospital,
it corresponds to the cause of entrance; some include also the history
of the condition related to the cause of admission)
iterative anamnesis : iterative hypothesis
testing from symptom to problem (reversed order). It aims to give an immedite
solution to the problem during medical emergencies but may be incomplete
Symptoms may be :
one that is obvious to the senses of the observer
: one that is perceptible to the patient only.
presenting symptom : the symptom or group
of symptoms of which the patient complains the most or from which he seeks
static symptom : an unchanging symptom.
negative symptom : one in which a characteristic
of normal health is diminished or absent in disease, such as the flat affect
or alogia of schizophrenia.
constitutional or general symptom : a symptom
which is indicative of or due to disorder of the whole body.
local symptom : one due to local disease or
to a particular lesion
localizing symptoms : symptoms that indicate
the location of a lesion.
reflex symptom : a symptom occurring
in a part remote from that which is affected by the disease
direct symptom : one which is directly caused
by the disease.
indirect symptom : a symptom which points
to a condition that may or may not be due to a particular disease or lesion
deficiency symptom : a symptom caused by a
lack of something necessary for normal bodily functioning, such as an enzyme,
vitamin, or hormone
pathognomonic symptom : one that establishes
with certainty the diagnosis of the disease.
characteristic or guiding symptom : a symptom
that is almost universally associated with a particular disease or condition
equivocal symptom : a symptom which may be
produced by several different diseases
induced symptom : one produced intentionally
factitious symptom : one produced intentionally,
usually by the patient
accessory or assident symptom : any symptom
not necessarily characteristic of the patient's disease
concomitant symptom : a symptom not essential
to a disease, but which may have an accessory value in its diagnosis
cardinal symptom : a symptom of greatest significance
to the physician, establishing the identity of the illness. The symptoms
shown in the pulse, temperature, and respiration.
precursory, premonitory or signal symptom
: a sensation, aura, or other subjective experience that gives warning
of the approach of an epileptic or other seizure.
delayed symptom : one which does not appear
for some time after the occurrence of the causes which produce it
is a set of symptoms which occur together; the sum of signs of any
morbid state; a symptom complex. In genetics, a pattern of multiple malformations
thought to be pathogenetically related.
hemisyndrome : a syndrome that affects just one side of the body.
erethism : a morbid degree of excitement
or irritation in an organ
dyserethism : a condition of slow response to stimuli
stigma : any mental or physical mark or peculiarity which aids in
the identification or in the diagnosis of a condition
: collection of signs (an indication
of the existence of something; any objective evidence of a disease, i.e.,
such evidence as is perceptible to the examining physician, as opposed
to the subjective symptoms of the patient,
but including objective symptoms)
vital signs : the pulse, respiration, and temperature.
accessory sign : any nonpathognomonic sign of disease
antecedent sign : any precursory indication of an attack of disease
commemorative sign : any sign of a previous disease
objective sign : one that can be seen, heard, or felt by the diagnostician;
called also physical s.
diagnosis : the
determination of the nature of a case of disease; the art of distinguishing
one disease from another. It may be first differential and become
only after repeat(s) of medical visit. It may regard ..
biological diagnosis : diagnosis by tests
performed on animals.
clinical diagnosis : diagnosis based on signs,
symptoms, and laboratory findings during life.
cytologic diagnosis / cytohistologic diagnosis
: the diagnosis of disease, both benign and malignant, by study of exfoliated
differential diagnosis : the determination
of which one of two or more diseases or conditions a patient is suffering
from, by systematically comparing and contrasting their clinical findings.
direct diagnosis : pathologic diagnosis by
observing structural lesions or pathognomonic symptoms.
diagnosis by exclusion : recognition of a
disease by excluding all other known diseases.
diagnosis ex juvantibus : diagnosis based
on the results of treatment.
laboratory diagnosis : diagnosis based on
the findings of various laboratory examinations or measurements.
niveau diagnosis : localization of the exact
level of a lesion; as, for instance, of an intervertebral tumor.
pathologic diagnosis : diagnosis by observing
the structural lesions present.
physical diagnosis : determination of disease
by inspection, palpation, percussion, and auscultation.
provocative diagnosis : the induction of a
condition for the purpose of diagnosis, as the induction of a seizure in
a doubtful case of epilepsy
serum diagnosis : diagnosis by means of the
analysis of serums; immunodiagnosis.
paragnosis : diagnosis, after death, based
on contemporaneous accounts of the diseases which affected historical characters.
Pulheems : a system of medical classification for recording the
physical and mental status of recruits in the British armed services, representing:
P, physical capacity; U, upper limbs; L, lower limbs; H, hearing (acuity);
EE, eyesight (visual acuity); M, mental capacity; S, stability (emotional).
benignancy : not recurrent; favorable for recovery