Golden Rules
of Infectious Diseases
Allen Yung
November 2008
What are Golden Rules?
Mental short cuts we use to expedite
clinical decision making
Triggering devices to remind us what
not to miss
Broad statements that advocate
a course of action
Caveates
Roughly correct but not intended to be
scientifically accurate
Oversimplifications while the world is complex
May not be true for all times
Not substitutes for thinking
May easily become platitudes
Proverbs are always platitudes until you
have personally experienced the truth of
them.
~Aldous Huxley
Bowen JL N Eng J Med 2006;355:2217-25
Strategies used in clinical reasoning
Intuitive
Event driven plan of action
Rule Out Worst Scenarios
Pattern recognition
Golden rules
Heuristics/ ‘Rules of thumb’
Identifying syndromes,
Anatomical, physiological/biochemical abnormalities
Golden rule 1
Recurrent rigors are most likely to
be caused by bacterial infections.
Rigor
A shaking chill that cannot be stopped
voluntarily
May occur in some viral infections, eg.
influenza, infectious mononucleosis.
Should generally be regarded as indicators of
significant sepsis, in conditions such as
bacteraemia, pneumonia, abscesses,
endocarditis, cholangitis.
Implications of chills
Infections No infections Total
All patients 399 65 464
Patients with 146 (36.6%) 8 (12.3%) 154
chills
Van Dissel et al. Lancet 1998; 352:374
Implications of chills
Pts with chills Pts w/o chills Uncertain
154 235 75
Bacteraemia 49 (31.8%) 36 (15.3%) 5 (6.7%)
RR 2.50 (95% CI 1.5-4.1)
Death 13 (8.4%) 14 (6%) 6 (8%)
Van Dissel et al. Lancet 1998; 352:374
Implications of chills
113 febrile patients consecutively admitted to
another hospital
Chills were associated with bacteraemia (RR
4.3, CI 1-5-12)
Van Dissel et al. Lancet 1998; 352: 374
Chills in Bacteraemia
Sensitivty 58% and 73%
Specificity 65% and 62%
Van Dissel et al. Lancet 1998; 352:374
The rigor rule
Any patient, young or old,
presenting with a rigor should be
admitted to hospital for observation
and investigation.
Golden rule 2
Severe muscle pain may be a
symptom of sepsis, even in the
absence of fever.
Severe pain in extremities,
neck, back or elsewhere
May be an early symptom of meningococcal,
staphylococcal or streptococcal bacteraemia.
May occur in the absence of overt fever.
Is more prominent in patients with
meningococcal meningitis than in those with
other forms of bacterial meningitis.
Severe pain
Anterior thigh pain and tenderness has
been found to be a useful indicator of
bacteraemia.
657-
Louria DB, Sen P. et al. Arch Intern Med 1985; 145: 657-658
Caveat
Pain may be a false localising symptom.
Golden rule 3
Fever in the elderly is rarely caused
by a viral infection.
FEVER 50 years
Diabetes mellitus
WBC > 15 000/cmm
Band count > 1 500/cmm
ESR > 30 mm/h
None 5% chance of bacterial infection
1 33%
≥3 55%
Golden rule 4
Sepsis in the elderly may not
present with fever:
‘the older the colder’.
Infections in Elderly Patients
Fever may not be high
Fever absent in 20-30% of elderly patients with
serious infections
Nonspecific or atypical symptoms & signs
Disease may progress rapidly
Viral infections less common
38°C in the elderly indicates a possible sepsis
Golden rule 7
Jaundice in a febrile patient is
rarely caused by viral hepatitis.
Fever and jaundice
Golden rule 10
Malaria must be excluded on
presentation of a febrile traveller
returning from a malaria-endemic
area.
Golden rule 8
Early meningococcaemic rash may
resemble a nonspecific viral rash.
Meningococcal rash
Meningococcal rash
Early meningococcal rash
Blanchable Rash in
Meningococcaemia
Macular or maculopapular (or rarely urticarial) rash
Usually begins within 12 hours of onset
Mimics a non-specific viral rash
May completely disappear or dramatically evolve into
haemorrhagic rash
Present in 37% of children with meningococcal
disease in one series
Golden rule 19
Think of vertebral osteomyelitis and
epidural abscess in a patient with fever
and back pain.
Case of missed epidural abscess
37-year-old mother of three, had a caesarean section in
Sydney in May 2001, under epidural anaesthetic.
A healthy boy was delivered.
Following 3-4 days considerable back pain.
Discharged a week after delivery; back pain persisted
Phoned obstetrician in Sydney because of persistent
pain. Suggested mastitis or a urinary tract infection.
Told to see LMO.
Case of missed epidural abscess
2 weeks after delivery, went to Dubbo Base
Hospital because of back pain.
ER doctor suspected epidural abscess and
admitted her.
Her assigned GP forgot to see the patient and
did not order a scan.
Case of missed epidural abscess
Saw no doctor for 2 days. Nurses asked the
medical registrar on duty to see her.
Registrar: sacroiliitis; prescribed analgesic drugs
and discharged home.
22 days after delivery, pain was excruciating.
Her family was becoming desperate.
Case of missed epidural abscess
25 days after giving birth, rushed semi-conscious
by ambulance to Dubbo Hospital
Placed in intensive care. By then she was brain
dead.
She saw 5 doctors, at 3 different hospitals over
25 days, remained undiagnosed and died.
Golden rule 6
‘When a patient has a fever
postoperatively, it is usually related to
the surgical procedure’ (Petersdorf’s
law).
Golden rule 17
Think of acute bacterial epiglottitis in an
adult patient with a normal-looking throat
who is complaining of acute sore throat,
pain on swallowing and/or hoarse voice.
Adult epiglottitis
Adult epiglottitis
Less likely than children to have dyspnoea, fever, or
cough
Tend to complain more of sore throat and painful
swallowing
Stridor uncommon
More likely to have neck tenderness.
Severity of sore throat and odynophagia out of
proportion to any visible change in the pharynx
The diagnosis may not be considered
Adult epiglottitis
Tongue
Narrowing of the vallecula
The “vallecula sign”
of epiglottitis
Note the “thumb sign”
of a swollen epiglottis
Swollen epiglottis in
an adult One week later
Lateral soft tissue radiograph
•The ‘thumb print’ sign
(E)
•The ‘vallecula’ sign (V)
can be determined by
identifying the base of
tongue (B) and tracing it
inferiorly to the hyoid
bone (H).
•If there is no pocket of
air extending almost to
the hyoid bone and
roughly parallel to the
pharyngotracheal air
column, then the
diagnosis of epiglottitis is
confirmed.
•Laryngeal inlet (L).
Ducic et al. Ann Emerg Med 1997; 30 (1): 1-6
Golden rule 11
An elderly patient from a tuberculosis-
endemic setting with fever and
multisystem disease has disseminated
tuberculosis until proven otherwise.
Tuberculosis
TB is one of the great mimics of ID.
A perplexing fever is often the presentation of
TB of the pericardium, liver, peritoneum, lymph
nodes, genital-urinary system or miliary TB.
The tuberculin skin test may be negative.
It is impossible to exclude this infection in any
PUO.
Tuberculosis
A trial of anti-tuberculous therapy should be
considered for patients with unexplained PUO,
who are at increased risk of TB and whose
condition is deteriorating.
No such patients should die without such a trial.
Golden rule 22
Not everyone with aseptic meningitis has
viral meningitis; unless confirmed by PCR,
viral meningitis is a diagnosis made after
the patient has recovered.
(2005)
Golden rule 22
Viral meningitis is a diagnosis made after
the patient has recovered.
(2001)
Aseptic meningitis
Most cases are caused by viruses.
Most of the remainder are caused by treatable
conditions.
How to pick out the treatable conditions: the key is to
recognise when the patient’s illness is
incompatible with typical viral meningitis.
The terms ‘aseptic meningitis’ and ‘viral meningitis’ are
not synonymous.
Overview
Diagnosis in ID is made in one of 2 ways:
Pattern recognition
or
Positive laboratory finding.
In the absence of a diagnosis we need to
decide what to do.
Overview
Differential diagnosis should include:
The most likely conditions, based on clinical
pattern and its prevalence at the particular
time and place
Diseases which must not be missed
Overview
Differential diagnosis should include:
The most likely conditions, based on clinical
pattern and its prevalence at the particular
time and place
Diseases which must not be missed
The correct diagnosis
Overview
Identify patients who are ‘at risk’
Clinical pointers (fever, rigors, pain, rash, jaundice)
Patient’s age and medical background (elderly,
immunocompromised, operations)
Exposure history (travel etc)
Golden rules are simply triggering devices
to help us do this.
John Dewey’s formula for education
Study + Experience + Reflection = Education