Download some key messages from the `fever` ita session

ITA Fever Session (semester 1, week 8)
Introduction
Below you will find the four patient scenarios you have discussed in your
small groups in week 7.
Once again you will find a range of supplementary learning material in the
ITA. The material should help you in your task. Tutors will also be
present in the ITA session to answer any questions.
During the first 50 minutes, please read and discuss questions at the end
of all four scenarios and visit the ITA support material.
After this time, your group will be allocated one of these scenarios to
present to all the other groups in the final period of this ITA session.
Please spend a further 25 minutes discussing your allocated scenarios
(revisit the relevant ITA material and talk to the tutors) and arranging
for one of you to talk for about 5 minutes to the full ITA group discussing the answers to the questions at the end of the scenario.
For each of the scenarios, please also see how far you can get with
answers to the following questions – and be prepared to discuss them
in your feedback presentation.
•
What is the likely infection diagnosis (ie the clinical name given to
this condition)?
•
What is the anatomical site of the infection?
•
What is the most likely micro-organism responsible – and what
generic group do they belong to?
•
What clinical sample would you collect to confirm the infecting
organism?
•
Analyse the symptoms and features of the illness into local and
systemic manifestations (that’s the exercise you started with
above)
1
Scenario 1:
Mary McDonald aged 68 had previously been diagnosed with Type 2
diabetes and hypertension, and had been taking medication for both of
these conditions for 10-15 years. She also had a chronic problem with
athlete’s foot, and one of the cracks between her right toes became more
infected, red and tender. Within a week this had spread up across the
dorsum of her foot, which became red, swollen and painful. She then
became hot and confused: her husband called the GP.
Answer the questions below. When answering each question think
about a) the basic principles underpinning your learning from this
question and b) which curriculum outcome might be related to the
question.
What factors are responsible for swelling of an infected site?
What factors made an infection site red and hot?
What causes the white appearance of pus?
(clue: think about the cells in the bloodstream)
What factors in this patient might make infection more likely?
2
Scenario 2:
Jenny Smith aged 32 presented to her GP as an emergency with a 48 hour
history of increasing severe pain in her back on the left side. She
reported a burning pain on passing urine, with increased frequency,
producing only small amounts of urine on each occasion. In the previous
24 hours she had episodes of “burning up” and episodes of uncontrollable
shivering lasting five minutes. She had vomited twice in the past 24
hours and found it difficult to keep more than sips of water down. On
examination her temperature was 39◦C, pulse 120 per minute, respiratory
rate 25 per minute, with marked tenderness in the left loin. Blood
pressure was 120/80 mm Hg.
Answer the questions below. When answering each question think
about a) the basic principles underpinning your learning from this
question and b) which curriculum outcome might be related to the
question.
Why did she develop pain in her back?
What might have happened to make her more unwell and confused?
What name is given to her uncontrollable shaking attack?
What is happening to the thermal control centre of the hypothalamus
while this feverish shivering is going on?
What evidence of renal tract infection might be produced from dipstick
testing?
We forgot to tell you that the GP had earlier prescribed an antibiotic
(amoxicillin) but it didn’t seem to help her. Try to think of reasons why a
prescribed antibiotic might not work – in general, as well as in her case.
3
Scenario 3:
Rory, a 17 year old student, was admitted to hospital with a 2 day history
of fever, lethargy, vomiting, poor appetite and increasing headache. On
examination he had a temperature of 39◦C: he was lucid but irritable,
with a purplish-red non-blanching rash, which according to his flatmate
was not present when he was seen earlier by the family practitioner.
There was no neck stiffness. His pulse rate was 110 per minute,
respiration rate 22 and blood pressure 100/70 mm Hg. Haemorrhages
were also seen in the whites of his eyes (‘scleral haemorrhages’)
Answer the questions below. When answering each question think
about a) the basic principles underpinning your learning from this
question and b) which curriculum outcome might be related to the
question.
In the management of this infection, which groups of professionals
need to be involved?
What samples should be collected to confirm the diagnosis?
Before infection this patient would need to be colonised with a
virulent strain of the micro-organism. What does ‘colonisation’
mean, and where might be the site of colonisation? How might
colonisation eventually lead to infection?
What serious complication of infection is appearing in this
scenario?
How might this also relate to the fact that some severely affected
patients with this condition (esp children) can eventually lose hands
or feet?
4
Scenario 4:
Tracy aged four had always been healthy and was a very happy and
sociable member of her nursery school class. An illness seemed to be
going round the class however, and early one morning Tracy was found to
be hot and feverish, listless and uncooperative, bending up her knees with
the pain in her tummy, and producing a couple of loose stools. She
became worse during the day: painful diarrhoea continued, and her bowel
motions were noted to contain fresh blood and mucus. Just as the GP
was called out he received a report that stool samples from other
affected children in the class had been found to be positive for Shigella
organisms.
Answer the questions below. When answering each question think
about a) the basic principles underpinning your learning from this
question and b) which curriculum outcome might be related to the
question.
The factors associated with the spread of this type of dysentery
are said to be “the four Fs” . What do you think these might be?
Antibiotic treatment for Tracy is probably much less important
than the management of disordered body homeostasis. What
aspects of body homeostasis likely to be most disturbed?
Can you think of any reasons why it might not be a good idea to give
anti-diarrhoeal treatments like Lomotil to Tracy?
5
Fever area 1/1
Other Infections
Here is a nasty infection between the toes (Scenario 1)
The right leg has signs of a spreading subcutaneous infection,
typical of streptococcus.
The red spots on the left leg are a common normal finding.
This is a close up picture of quite a severe case of oral thrush –
fungal infection at the rear of the palate.
Fever area 1/2
Colony cultures of bacteria can be grown in Petri dishes containing
appropriate nutrients
Dip slide kits containing suitable nutrient material assist in the
rapid identification of infecting organisms
A rash like this with many small raised red spots or ‘papules’ can
occur following a viral infection – this example is like the pattern
occurring in measles, and is called ‘morbilliform’ after the latin
name for measles. A morbilliform rash like this can also be caused
by hypersensitivity to medication.
This scan shows an enlarged kidney in a patient suffering from
pyelonephritis
Fever area 2/1
Meningitis
This wee boy is severely ill with meningococcal
septicaemia
These pictures show examples of the rash which can
appear as a consequence of meningococcal septicaemia
This is a slide showing severe gram positive infection with
diplococci – probably meningitis
Fever area 2/2
This post-mortem brain has pus on its surface from
inflammation of the meninges – i.e meningitis. Pus like this
is perhaps more likely to be the result of pneumococcal
meningitis than meningogoccal meningitis
These are subconjunctival (scleral) haemorrhages in a case
of meningitis, which are analogous to the ‘purpuric’ rash
seen on the skin
Fever Area 3/1
Fever and Sepsis
REGULATION OF BODY TEMPERATURE
Human body temperature normally varies throughout a 24 hour
cycle, often varying between about 36.0º C or lower in the early
hours of the morning to 37.5º C or more in the afternoon, so
perfectly healthy individuals can at times have a body
temperature higher than the “normal” value of 37.0º C
Within this circadian rhythm, however, body temperature is
closely regulated by homeostatic mechanisms that balance heat
production and heat loss.
Heat is a by-product of all metabolic processes; at rest,
metabolic activity in the liver and heart produce much of the
body’s heat. During exercise, skeletal muscle produces even
more heat.
Heat is normally lost via the skin - about 90 percent, with the
lungs losing most of the remaining 10 percent. At rest, about 70
percent of the body’s heat is lost by radiation and 30 percent
lost by insensible perspiration.
When there is a rise in the surrounding temperature or when
increased metabolism produces extra heat, then increased
evaporation from skin, plus heat radiation from dilated blood
vessels help to maintain heat balance.
The thermal control centre is situated in the preoptic nucleus of
the anterior hypothalamus in the brain. This maintains body
temperature at a set value, the so-called hypothalamic thermal
set point.
In response to elevations in core body temperature, the
hypothalamus stimulates the autonomic nervous system to
cause dilatation of skin blood vessels and sweating. If core body
temperature falls, the hypothalamus conserves heat by causing
constriction of skin blood vessels. In extreme cold, the
hypothalamus acts to increase heat production by stimulating
muscular activity in the form of shivering; although this is
mediated by the action of somatic nerves, shivering is automatic
and involuntary.
Fever Area 3/2
DISORDERS OF BODY TEMPERATURE
Since antiquity, fever has been appreciated to be a cardinal feature
of disease, but understanding of the pathophysiology of fever is
much more recent. For more than 100 years, it has been known that
pus is pyrogenic (ie causes fever), but only with the work of Dr. Paul
Beeson in 1948 did it become clear that the ultimate cause of fever
is not a bacterial product (a so-called exogenous pyrogen) but a
product of host inflammatory cells (i.e., an endogenous pyrogen).
We now know that this is produced by white cells in the bloodstream.
The products of white cells which cause fever are called cytokines,
and the names of important cytokines include interleukin-1 (IL-1), IL6,interferon gamma, and tumornecrosis factor(TNF).
Abnormal elevation of body temperature, or pyrexia, can occur in
one of two ways: hyperthermia or fever. In hyperthermia, control
mechanisms fail, and heat production exceeds heat loss. In true
fever, on the other hand, the hypothalamic thermal set point rises,
and intact thermal control mechanisms are brought into play to bring
body temperature up to the new set point.
Hyperthermia
Thermoregulatory homeostasis is influenced by increased heat
production, decreased heat dissipation, or hypothalamic insult.
During exercise, heat production can increase up to 20-fold, often
overwhelming heat dissipation mechanisms. Heavy exercise in hot
countries can cause life-threatening heatstroke in which body
temperature can rise above 41º C. Some clinical disorders can also
result in hyperthermia
Treating high temperature
So-called antipyretic drugs like aspirin and paracetamol
(acetaminophen) can be used in fever because they lower the
thermal set point.
Fever and hyperthermia can both be treated with physical cooling
methods – eg sponging with tepid water, or covering the patient with
a wet sheet.
Fever
Fever is defined as an oral temperature greater than 38º C, although
some authorities do not consider a fever significant until the
temperature exceeds 38.5º C
SEPSIS
“Sepsis is an increasing and major health-care problem worldwide.
Using data from 91 intensive care units collected between 1995 and
2000, there were estimated to be 51 cases of sepsis per 100,000
population in England, Wales and Northern Ireland over this period. It
was also reported that 27% of all admissions to critical care suffered
from severe sepsis within the first 24 hours. There was 47% hospital
mortality among these patients and they occupied 45% of total
hospital critical care bed-days. The incidence of sepsis also appears
to be increasing: there has been a 53% increase in the UK between
1996-1997 and 2001-2002.”
David Saunders and Simon Baudouin,
Clinical Medicine 5: 431-439 2005.
Intensive Care Medicine.
Fever area 4/1
History Corner
MEET YOUR DISTANT COUSINS!
The theory of evolution (The Origin of Species, Charles Darwin, 1859)
tells us that bacteria and humans had a common ancestor billions of
years ago, so the diagram which was handed out last week in the
microbiology practical session introduced you to the names of some of
your (very) distant cousins.
If you’re not sure about evolution, read some of Richard Dawkins’
books, such as “The Blind Watchmaker” and “The Ancestor’s Tale”,
and read some of the essays by Stephen Jay Gould.
The American biologist Lynn Margulis has argued that the origin of the
eukaryotic cell is the result of bacteria being incorporated symbiotically
into other bacteria. Mitochondria in animal cells and chloroplasts in
plant cells contain their own unique DNA. So it is considered that
organelles like mitochondria inside our cells represent a distant
evolutionary symbiosis of different bacteria.
Endosymbiosis: Lynn Margulis
The Modern Synthesis established that over time, natural
selection acting on mutations could generate new adaptations
and new species. But did that mean that new lineages and
adaptations only form by branching off of old ones and inheriting the genes of the old lineage? Some researchers answered no. Evolutionist Lynn Margulis showed that a major
organizational event in the history of life probably involved
the merging of two or more lineages through symbiosis.
Symbiotic microbes =
eukaryote cells?
In the late 1960s Margulis (left) studied
the structure of cells. Mitochondria, for
example, are wriggly bodies that generate
the energy required for metabolism. To
Margulis and others hypothesized that chloroplasts
Margulis, they looked remarkably like
(bottom) evolved from cyanobacteria (top).
bacteria. She knew that scientists had been struck by the similarity ever since
the discovery of mitochondria at the end of the 1800s. Some even suggested that mitochondria
began from bacteria that lived in a permanent symbiosis within the cells of animals and plants. There
were parallel examples in all plant cells. Algae and plant cells have a second set of bodies that they
use to carry out photosynthesis. Known as chloroplasts, they capture incoming sunlight energy. The
energy drives biochemical reactions including the combination of water and carbon dioxide to make
organic matter. Chloroplasts, like mitochondria, bear a striking resemblance to bacteria. Scientists
became convinced that chloroplasts (below right), like mitochondria, evolved from symbiotic
bacteria — specifically, that they descended from cyanobacteria (above right), the light-harnessing
small organisms that abound in oceans and fresh water.
When one of her professors saw DNA inside chloroplasts, Margulis was not surprised. After all,
that's just what you'd expect from a symbiotic partner. Margulis spent much of the rest of the
1960s honing her argument that symbiosis (see figure, below) was an unrecognized but major
force in the evolution of cells. In 1970 she published her argument in The Origin of Eukaryotic
Cells
The genetic evidence
In the 1970s scientists developed new tools and
methods for comparing genes from different species.
Two teams of microbiologists — one headed by Carl
Woese, and the other by W. Ford Doolittle at Dalhousie
University in Nova Scotia — studied the genes inside
chloroplasts of some species of algae. They found that
the chloroplast genes bore little resemblance to the
genes in the algae’s nuclei. Chloroplast DNA, it turns
out, was cyanobacterial DNA. The DNA in
mitochondria, meanwhile, resembles that within a
group of bacteria that includes the type of bacteria that
causes typhus (see photos, right). Margulis has
maintained that earlier symbioses helped to build
nucleated cells. For example, spiral-shaped bacteria
called spirochetes were incorporated into all organisms
that divide by mitosis. Tails on cells such as sperm
eventually resulted. Most researchers remain skeptical
about this claim.
Mitochondria are thought to have descended
from close relatives of typhus-causing bacteria.
It has become clear that symbiotic events have had a profound impact on the organization and
complexity of many forms of life. Algae have swallowed up bacterial partners, and have themselves been included within other single cells. Nucleated cells are more like tightly knit communities than single individuals. Evolution is more flexible than was once believed.
Phylogenetic analyses based on genetic sequences support the endosymbiosis hypothesis.
text and images from http://evolution.berkeley.edu/evolibrary/article/0_0_0/history_24
Fever area 4/2
CLASSIFICATION OF GRAM POSITIVE ORGANISMS
Strep. pneumoniae (pneumonia, meningitis)
α-haemolytic
Strep. “viridans” (endocarditis)
Group A Strep (throat, skin infections)
(aka Strep. pyogenes)
chains - Streptococci
β -haemolytic
Group B Strep (neonatal meningitis)
cocci
non-haemolytic
Enterococcus sp.(gut commensal, UTI)
coagulase +ve
Staph. aureus (wound, skin infections etc.etc)
coagulase -ve
Staph. epidermidis
clusters - Staphylococci
Aerobic
Corynebacterium diphtheriae (diphtheria)
Corynebacterium sp.
small
bacilli
large
cocci
anaerobic streptococci
bacilli
Clostridium sp.
Anaerobic
Diphtheroids (skin commensals)
Listeria monocytogenes. (meningitis)
Bacillus cereus (food poisoning)
Bacillus sp.
Bacillus anthracis (anthrax)
Cl. tetani (tetanus)
Cl. perfringens (gas gangerene)
Cl. difficile (antibiotic associated colitis)
CLASSIFICATION OF GRAM NEGATIVE ORGANISMS
Aerobic (strict)
Legionella sp
Pseudomonas aeruginosa
bacilli
Neisseria gonorrhoeae (gonorrhoea)
cocci (diplococci)
Neisseria meningitidis (meningitis)
Aerobic
Bordetella pertussis (whooping cough)
small
Haemophilus influenzae (exacerbation COPD)
bacilli
E(scherichia) coli
gut commensals
Klebsiella sp.
large (coliforms)
Proteus sp.
Salmonella sp
gut pathogens
Shigella sp.
E. coli O157
Microaerophilic
Small curved bacilli
Campylobacter sp
Spiral bacilli
Helicobacter sp. (gastritis)
bacilli
cocci (not relevant)
Anaerobic (strict)
bacilli
Bacteroides sp. (gut commensal, wound infection)
}
}urinary tract infection
}
}wound infection
}
Fever area 4/4
SOME TIMELINES
TIME
EVENT
4,000 million yr ago
Formation of the Earth
3,000 million yr ago
RNA particles evolve into life forms
2,000 million yr ago
First eukaryotic cells produced (cooperation between bacteria?)
1 million yr ago
Evolution of mankind
1719
Leeuvenhoek’s single-lens ‘microscope’ – saw microbes from the
mouth of an old man who’d never cleaned his teeth
1846
Ignaz Semmelweis (Austria) insisted on hand washing in his
maternity unit to prevent ‘childbed fever’ (empirical observation)
1859
Charles Darwin’s ‘Origin of Species’
1860s
Louis Pasteur’s germ theory of disease, based on studies of
fermentation in wine and beer, and diseases of silkworms
1870
Joseph Lister (Glasgow) read Pasteur’s theory and prevented
gangrene by treating an open fracture with carbolic antiseptic
1880s
Proof that diseases like anthrax, tuberculosis, cholera, diphtheria,
rabies, were caused by microbial infection.
1880s
Pasteur coined the word “virus” (Latin = “poison”) because he
considered rabies to be transmitted by a non-living substance.
1884
Hans Christian Gram devised staining, +ve and –ve, based on cell
wall structure – became useful 60 yr later in antibiotic selection
1891
First successful use of ‘antitoxin’, developed to cure diphtheria
1901
First Nobel prize - from the profits of dynamite - awarded to Emil
von Behring (for diphtheria antitoxin serum therapy)
1910
Paul Ehrlich developed arsenical drugs which could cure syphilis
1918
‘Spanish flu’ influenza pandemic
1930s
‘Sulphonamide’ antimicrobial drugs used to treat some infections
1940s
Penicillin used to treat infections for the first time
1983
Peptic ulceration – a new infectious disease!
(Barry Marshall is the 2005 Nobel prizewinner for medicine)
1983
Recognition of viral cause of of HIV infection and AIDS
Fever Area 5/1
Antibiotic Treatment
TAYSIDE AREA DRUG FORMULARY
A drug formulary provides guidance on the appropriate use of medicines, which
usually takes account of both clinical effectiveness and cost effectiveness.
Here are a few pages copied from the Tayside Area Drug Formulary, which give
some guidance on prophylaxis in contacts of a case of meningitis and
recommendations for treatment of urinary tract infections
Medical students can access this formulary on line from the MESMIS site
(B) Haemophilus influenzae B Meningitis
Give prophylaxis to household members only where there is a child aged 3 years or under in the same
household as the index case.
Treat all household members except pregnant or breast feeding women, any person with severe hepatic
impairment and children under 3 months.
12 years and over
3 months -12 years
Rifampicin 600mg orally, once daily for 4 days
Rifampicin 20mg/kg (max. 600mg) orally, once daily for 4 days
Meningitis Prophylaxis
NB. Inform Consultant in Public Health Medicine (CPHM) with responsibility for the control of infectious disease, at the earliest opportunity. Do not wait for laboratory confirmation. Time
is of the essence in contact tracing. In particular, where the clinical suspicion is of Meningococcal meningitis/septicaemia, telephone the CPHM and discuss.
N.B. Treatment of the index case with rifampicin prior to discharge is unnecessary where ceftriaxone was used in the treatment of infection.
(A) Meningococcal infection
Establish a list of close (kissing) household contacts. Give chemoprophylaxis as outlined beloW. Caution is required with pregnancy,breastfeeding, children under the age of three
months and any person with severe hepatic impairment. The CPHM can advise.
12 years and over
1-12 years
under 1 year
Rifampicin
Rifampicin
Rifampicin
600mg orally, twice daily for 2 days
10mg/kg orally, twice daily for 2 days
5mg/kg orally, twice daily for 2 days
Patients taking rifampicin should be advised that it stains body secretions. The urine may turn yellow/orange in colour and soft contact lenses may be similarly discoloured. Also,
rifampicin is a potent liver enzyme inducer which, theoretically at least, may enhance the metabolism of oestrogens contained in the combined oral contraceptive. Women taking the pill
should be warned that additional precautions are required during their current cycle. In the case of pregnant women, ceftriaxone should be given in a dose of 250mg i.m. stat. The index
case should be treated with rifampicin prior to discharge to eliminate carriage but only if ceftriaxone was not used in the treatment of infection.
Note: Ciprofloxacin is also known to clear the organism from the throat. The dosage is 500mg orally stat. This Is for adults only. Ciprofloxacin is not licensed for use in children under
12 years.
Fever Area 5/2
SELECTIVE TOXICITY
Here is an astute observation made by a distinguished British
scientist, T H Huxley, 20 years before the origin of chemotherapy
and 60 years before the first clinical use of penicillin:
“There can surely be no ground for doubting that, sooner or later,
the pharmacologist will supply the physician with the means of
affecting, in any desired sense, the functions of any physiological
element of the body. It will, in short, become possible to introduce
into the economy a molecular mechanism which, like a very
cunningly contrived torpedo, shall find its way to some particular
group of living elements, and cause an explosion among them,
leaving the rest untouched. The search for the explanation of
diseased states in modified cell life; the discovery of the important
part played by parasitic organisms in the etiology of disease; the
elucidation of the action of medicaments by the methods and the
data of experimental physiology – appear to me to be the greatest
steps which have ever been made towards the establishment of
medicine on a scientific basis. I need hardly say they could not
have been made except for the advance of normal biology”
T H Huxley The connexion of the biological sciences with
medicine. Lancet 1881 ii 272
SELECTIVE TOXICITY - “MAGIC BULLETS”
The expression ‘magic bullet’ has been used to illustrate the
concept of selective toxicity of drugs like antibiotics – ideally killing
the invading microorganism without harming the host. Antibiotics
like penicillin have a uniquely selective effect on the bacterial cell
wall – which does not exist in mammalian cells; but other
antibiotics which influence protein synthesis inside the cell are
perhaps more likely to interfere with similar cellular mechanisms in
humans, so can be considered potentially more toxic than
penicillin.
The term ‘magic bullet’ probably came into public imagination
following the appearance of the opera by Carl Maria von Weber
called “Die Freischutz” , first performed in 1824, which is a story
about a forester/huntsman who obtained magic bullets from the
devil to help him to shoot more accurately.
All drugs have toxicity problems, so in real life it is the ratio
between the effective dose and the toxic dose which matters.
This ratio is sometimes called the “therapeutic index” of a drug
Increased selective toxicity is of course also the aim of cancer
chemotherapy – but it’s even more difficult to kill cancer cells and
spare normal cells, but newer treatments continue to refine the
management of malignant disease.
PSYCHOSOCIAL PRINCIPLES
Scenario 1
Remember the original scenario...
Mary Mc Donald aged 68 had previously been diagnosed with Type 2 diabetes and hypertension,
and had been taking medication for both of these conditions for 10-15 years. She also had a problem with “athlete’s foot” and one of the cracks between her toes became more infected, red and tender. Within a week this had spread up across the dorsum of her foot, which had become red, swollen and painful. She then became hot and confused: her husband called the GP.
BUT - you could go further...
Mrs Mc Donald is usually well and active and the main carer for her husband who had a “stroke” 5
years ago and has been in a wheelchair since then. They have one daughter who lives and works in
the USA.
Consider this extended scenario, and think about the problems Mary’s illness may cause not only for
her, but also for her family. What factors might the Primary Care Team have to consider with regard
to Mary, her husband and her daughter when managing Mary’s condition?
The duties of a doctor registered with the General Medical Council are described below.
Patients must be able to trust doctors with their lives and well-being. To justify that trust, we as a
profession have a duty to maintain a good standard of practice and care and to show respect for
human life.
Which of the duties listed below must be considered when managing Mary’s illness?
In particular as a doctor you must:
v make the care of your patient your first concern;
v treat every patient politely and considerately;
v respect patients' dignity and privacy;
v listen to patients and respect their views
v give patients information in a way they can understand;
v respect the rights of patients to be fully involved in decisions about their care;
v keep your professional knowledge and skills up to date;
v recognise the limits of your professional competence;
v be honest and trustworthy;
v respect and protect confidential information;
v make sure that your personal beliefs do not prejudice your patients' care;
v act quickly to protect patients from risk if you have good reason to believe that you or a
colleague may not be fit to practise;
v avoid abusing your position as a doctor;
v work with colleagues in the ways that best serve patients' interests.
Source: GMC Good Medical Practice, third edition 2001)
PSYCHOSOCIAL PRINCIPLES
Scenario 2
Scenario 2 asks you to consider the case of Jenny:
Jenny Smith aged 32 presented to her GP as an emergency with a 48 hour history of increasing severe
pain in her back on the left side. She reported a burning pain on passing urine, with increased frequency, producing only small amounts of urine on each occasion. In the previous 24 hours she had
episodes of “burning up” and episodes of uncontrollable shivering lasting five minutes. She had vomited
twice in the past 24 hours and found it difficult to keep more than sips of water down. On examination
her temperature was 39?C, pulse 120 per minute, respiratory rate 25 per minute, with marked tenderness in the left loin. Blood pressure was 120/80 mm Hg.
However, Jenny’s past history may be just as revealing as the results of the tests reported above.
Previous to this episode Jenny had a history of recurrent urinary tract infections causing a burning pain
on passing water and to need to pass urine frequently. They usually resolved when she treated herself
by drinking cranberry juice, and she didn’t usually bother the doctor with these symptoms. Jenny felt she
could control her symptoms, and didn’t want to waste the doctor’s time as as she didn’t feel she had an
illness.
ILLNESS OR DISEASE?
Illness can be a synonym for disease or it can be a person’s perception of having poor health. Disease
is an actual, physical, pathophysiological, diagnosable process which can cause an abnormal condition
of the body or mind. Illness and disease are therefore not necessarily the same, and some conditions
illustrate clearly the differences (see the box below). This case gives us an opportunity to explore what
is meant by disease and illness.
Most people who have a disease will feel ill, while
others will feel perfectly healthy. A third group (alILLNESS
NO ILLNESS
though small) may claim illness although they do not
actually have a disease.
Acute MI
HIV
DISEASE
Influenza
Early Cancer
Rabies
Jenny’s current symptoms, and previous symptoms
she has experienced with the same disease are
different. What do you think may have have caused
Undiagnosable
Jenny to experience more illness ths time?
Or
NO DISEASE
Psychosomatic
conditions
Jenny works from home so doesn’t find needing to
pass urine frequently too inconvenient and is happy
to give the cranberry juice time to work.
J
But what if that were not the case. Consider the effects which some of the symptoms of Jenny’s recurrent urinary tract infections would have on her ability to work if she was, for example, a bus driver or a
teacher.
How do you think this difference in occupation might affect her perception of urinary tract infections as
an illness?
PSYCHOSOCIAL PRINCIPLES
Scenario 3
Preventative Care
Rory was a fit young adult probably much like yourself until a few days ago. However he is now seriously unwell with major sepsis. Could this have been avoided? Who else is at risk? Can you think of
two distinct strategies that apply here?
It is possible that his decisions and behaviour have contributed to him becoming unwell. Many people carry infections but remain well. Why might his risk increase at this time of life?
Understanding the whole
person
The Patient-Centered model
(see box on right) suggests
that we need to consider not
simply the disease/illness but
also the person and their context. Look in particular at the
area inside the green box, labelled Understanding the
whole person. What sort of
personal or contextual factors
might favour or deter appropriate preventative health in a
young student of this age? Can
you relate this to the Health
Belief Model which you were
introduced to in ITA before?
The PatientPatient-Centered Clinical
Clinical Method
Method
1 - Exploring Both
Disease and
Illness Experience
History
Physical
Lab
Person
Illness
3 - Finding
Common
Ground
Proximal Context
Distal Context
• problems
• goals
• roles
4 - Incorporating
Prevention and
Health Promotion
6 - Being Realistic
Mutual
Decisions
5 - Enhancing the PatientPhysician Relationship
Perceived
severity
Perceived
benefits
Disease
Feelings
Ideas
Function
Expectations
Perceived
susceptibility
Demographic
variables
2 - Understanding
The Whole Person
Cues & Prompts
Behaviour
The Health Belief Model (see box on left) proposes that people will be motivated to carry out
protective health behaviours in response to a
perceived threat to health. The perceived benefits of a course of action are weighed against
the perceived barriers. It also proposes that a
trigger event is often necessary to make a person change their behaviour.
Perceived
barriers
Cues to
action
Self care
What is the relevance of this to you? What preventative health options are open to you at present
and which have you taken up? Does this differ between you all? Why?
PSYCHOSOCIAL PRINCIPLES
Scenario 4
Tracy’s illness, whilst potentially serious for her, is a good illustration of how an acute infection of an
indivdual patient can be a part of a much bigger picture. In the case of many infectious diseases, it
is required that doctors notify cases to a central system of disease surveillance and communication.
In Scotland the central agency is The Scottish Centre for Infection and Environmental Health
(SCIEH), which is a part of Health Protection Scotland. The sort of data which SCIEH records is
illustrated in the box below.
Laboratory isolates of Shigella spp. in humans
reported to HPS, 1993-2004*
Year
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004*
Sh sonnei
Sh flexneri
Sh boydii
Sh dysenteriae
613
376
522
150
81
83
65
62
62
61
46
70
34
56
34
24
33
20
20
24
19
13
21
31
18
4
13
7
3
8
3
3
7
3
7
2
0
5
5
1
2
3
0
1
2
0
2
1
*Data for 2004 remain provisional .
Source: Health Protection Scotland/SCIEH
The information which SCIEH receives is used to alert community healthcare teams to potential outbreaks of infectious disease - such as the Shigella infection mentioned here. The local Health
Board’s Public Health directorate will also issue periodic advice, and will send out emergency alerts
if necessary.
This case also emphasises the importance
of working as a part of a wider healthcare
team in responding to cases of infectious
disease. Rapid communication of the results of the other children’s tests will help
the GP in this case to diagnose Tracy’s
infection more quickly - he now knows that
Shigella is one thing to look for!
SCIEH
(Data on occurrence and
locations
of Shigella infections)
Health Board Public
Health Directorate
(Local information and guidance
for health professionals)
GP and other
members of the
primary care team
It will also make it easier for them to tell all
the other parents to look out for symptoms,
and to take extra precautions with their
children’s personal hygiene, thus helping to
prevent the spread of the infection.
(reporting cases, treating patients,
advising patients and families)
Tracy
SOME KEY MESSAGES FROM THE ‘FEVER’ ITA SESSION
Here is a summary of some of the important learning issues which emerged to varying
degrees during discussion in the ITA sessions on ‘fever’:
1. The micro-organisms responsible for the infection in three of the scenarios
(cellulitis, urinary tract infection and meningitis) are quite often found as
colonising commensals sharing the body of healthy individuals – respectively
Staphylococcus aureus/Streptococcus pyogenes, Escherichia coli and Neisseria
meningitidis (meningococcus). These three infections occurred as a result of an
unfavourable balance between host defence on the one hand, and microbial
numbers and their infectivity (“pathogenicity”) on the other, after the organisms
have penetrated a part of the body where they don’t ‘normally’ live.
2. We discussed some of the factors which might lead to infective penetration of
these three organisms – eg breach of skin integrity (and diabetes) in the case of
cellulitis; inadequate hygiene and/or perhaps more motile types of E coli in the
case of urinary tract infection; and flu/colds/smoking/changes in pathogenicity in
the case of meningitis.
3. In the fourth scenario of bacillary dysentery the Shigella organism is an out-andout pathogen and isn’t found as a commensal organism sharing a healthy body –
again transmitted as a result of poor hygiene via faeces/fingers/food/flies/fomites
(this fifth ‘F’ means items in the environment which are touched and shared).
4. We discussed the important clinical signs which indicate that an infection is
becoming more serious – in other words, no longer localised and on the way
towards dangerous septic shock. These clinical signs include increasing fever,
rising pulse rate, rising respiratory rate and falling blood pressure. Septic shock
happens when inflammation and toxicity of the infection has made the circulation
collapse – once blood vessels dilate all through the body, the response of the heart
is to increase cardiac output by beating faster, to maintain the circulating blood
pressure – so a rising pulse even without an observed fall in blood pressure may
be an important danger sign that eventually the cardiac output won’t be able to
keep up.
5. We discussed the fact that resetting of the hypothalamus – resulting in fever - is
the result of endogenous substances released from the body’s white cells, not
from micro-organisms themselves.
6. We pointed out that successful antibiotic treatment illustrates the concept of
“selective toxicity” – hitting the infection without harming the host. But an
antibiotic has to penetrate via the blood stream to where the infection lies, so if an
infection is isolated, for example in a large abscess, effective treatment may also
need surgical treatment and drainage as well.
Now please take a little time to look at the following:
Here are some features of a suspected case of severe meningitis. Look at the list below
and decide which of the twelve curriculum outcomes is the most immediately applicable
to each situation:
You observe a skin rash
You know you must see whether the rash blanches under a glass tumbler
You palpate the pulse rate
You measure the blood pressure
You send a sample of cerebrospinal fluid to the microbiology laboratory
You realise that you need to inform the public health consultant
You realise that the clinical features of meningitis, together with a high
temperature, increased respiratory rate, rapid pulse rate and low blood pressure
are all leading to a diagnosis of septic shock
You administer intravenous penicillin
You add your findings to the case notes
The nurse tells you that you forgot to wash your hands after completing the
examination
Meningitis is confirmed and the public health consultant arranges for ‘kissing
contacts’ to receive antibiotic treatment