Transcript Fever in the ICU

Fever in the ICU
Bahram Hadjikarim MD / MPH
Zanjan University of Medical Science
Assistant Professor of Infectious and Tropical Dis.
January 2010
Fever, A Little History
 Hippocrates
recognized fever as a beneficial
sign during infection
 Thomas Sydenham (1624-1689), English
physician: “Fever is Nature’s engine which
she brings into the field to remove her
enemy.”
 Fever therapy used in many societies worldwide
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Fever, Late 1800s
 Liebermeister,
German physician
 Fever is the regulation of body
temperature at a higher level
 Fever dangerous if too high or
prolonged
 Antipyretic drugs should be used only
for high fevers or of long duration
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Fever, Late 1800s
 Antipyretic
drugs widely available: aspirin,
other salicylates
 Many physicians advocated reducing fever
 Fever considered harmful by-product of
infection, not host-defense response
 Why? Perhaps because salicylates are
analgesic and antipyretic
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Evolutionary Biology
 Fever
is energetically costly
 In mammals increasing temperature 2-3ºC
increases energy consumption 20%
 Since such a response is preserved across
invertebrates and vertebrates, fever must
have an adaptive function
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Mechanism of Protective Effect
 Enhanced
neutrophil migration
 Increased production of antibacterial
substances by neutrophils
 Increased production of interferon
 Increased antiviral and antitumor activity of
interferon
 Increased T-cell proliferation
*Kluger MJ. Inf Dis Clin of NA 10:1-20, 1996
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Nosocomial Fevers
 Hospital-acquired
fevers occur
in one-third of all medical
inpatients
 Nosocomial fevers even more
common in the ICU
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Fever in the ICU
 ICU
patients have several underlying
medical/surgical conditions
 ICU patients undergo many invasive
diagnostic and therapeutic procedures
 Therefore, fever in ICU patients must be
thoroughly and promptly evaluated to
discriminate infectious from non-infectious
etiologies
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Diagnostic Approach
 Fever
is a non-specific sign seen in
inflammatory processes that may be


infectious
noninfectious, including neoplastic
 The
“102º Rule”
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Temp < 102º
Acute cholecystitis
 Acute MI
 Dressler’s Syndrome
 Thrombophlebitis
 GI bleed

Acute pancreatitis
 Pulmonary embolism
or infarct
 Viral hepatitis
 Uncomplicated
wound infection

10
Temp 102º
Cholangitis
 Suppurative phlebitis
 Pericarditis
 Septic pulmonary
embolism
 Pancreatic abscess

Non-viral liver
disease: drug fever,
leptospirosis…
 Complicated wound
infection
 Bowel infarction

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Causes of Fever in the ICU

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SIRS
Intravenous-line
infections
Nosocomial
pneumonia
Nosocomial sinusitis
Intraabdominal
infections




Urinary catheterassociated bacteriuria
Drug fever
Post-operative fever
Neurosurgical causes
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Systemic Inflammatory Response Syndrome
 Definition




of SIRS
T > 38ºC or < 36ºC
HR > 90
RR > 20 or pCO2 < 32
WBC > 12 or < 4
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SIRS
 Often



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noninfectious etiology found:
Pulmonary embolism
Myocardial infarction
Gastrointestinal bleed
Acute pancreatitis
Cardiopulmonary bypass
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Intravenous-line Infections
 Prevalence:
5% in ICU patients in a
University of VA study of triple-lumen
and pulmonary artery catheters*
 Bloodstream infection is a serious
catheter-related complication: case
fatality rate ~10-20%
*Cobb DK. NEJM 327:1062-8, 1992
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Intravenous-line Infections
 Look
for local signs of infection:
present in < 50%
 Remove line if no other source
and T > 102º
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Scheduled Replacement?
 UVA

study*
Inclusion criteria: All patients admitted to
the ICU who needed triple-lumen central
venous catheters or pulmonary artery
catheters inserted via SC or IJ for > 3 days
*Cobb DK. NEJM 327:1062-8, 1992
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Scheduled Replacement?
 Four

1
2
3

4

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groups
replaced q 3 days with a new stick
replaced every 3 days over guidewire
replaced only if clinically indicated
(fever, mechanical complications)
with new stick
replaced only if clinically indicated
over guidewire
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Scheduled Replacement?
 Total
of 160 patients enrolled; 523 catheters.
 No statistically significant difference in
catheter-related bloodstream infections
among groups
 Statistically significant increase in
mechanical complications with new sticks
vs. guidewire exchange
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Scheduled Replacement?
 No
support for changing lines every 3-5
days; change only if unexplained fever or
catheter malfunction occurs
 Concurs with CDC’s Guideline for
Prevention of Intravascular DeviceRelated Infections. Am J Infect Control
1996;24:262-293
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Nosocomial Pneumonia
 Almost
all cases occur in mechanically
ventilated patients
 Signs are




fever
leukocytosis
purulent tracheal secretions
new or worsening infiltrates on CXR
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Nosocomial Pneumonia



However, none of these are predictive of
pneumonia; nosocomial pneumonia remains a
clinical diagnosis
Can be confused with fibroproliferative phase of
ARDS, usually accompanied by low-grade fever
Semi-quantitative BAL and protected-brush
specimen may be helpful, but not widely available
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Nosocomial Sinusitis
Bacteriology differs markedly from
community-acquired disease
 Gram-negative bacilli cause most cases in
intubated patients
 Polymicrobial infection in upto 50% of cases,
reflecting ICU flora
 Paranasal sinusitis accounts for about 5% of
nosocomial ICU infections

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Nosocomial Sinusitis
 Fever
and leukocytosis often
present
 Purulent nasal discharge often
lacking
 Common in trauma and
neurosurgical units
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Nosocomial Sinusitis

Risk factors
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nasotracheal tubes
nasogastric tubes
nasal packing
facial fractures
steroid therapy
Diagnosis made easier with sinus CT, which is
more sensitive than plain films
Avoid prolonged nasotracheal intubation
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Intra-abdominal Infections
 Suspect
intra-abdominal abscess in
patients with prolonged post-operative
fever after abdominal surgery
 Acalculous cholecystitis and subsequent
biliary sepsis may complicate postoperative period
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Intra-abdominal Infections
Suspect antibiotic-associated colitis due to
Clostridium difficile in patients on broadspectrum antibiotics
 Fever and leukocytosis may be present prior to
diarrhea or abdominal symptoms
 Splenic or hepatic abscesses may complicate
other intra-abdominal infections (cholecystitis,
appendicitis) causing prolonged fevers

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Catheter-Associated Bacteriuria
 Foley



catheters
Result in acquisition of bacteriuria
Nearly always represents colonization, not
infection
Pyuria often accompanies CAB, mimicking
a UTI
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Catheter-Associated Bacteriuria
 Foley


+ high fever + bacteriuria
does not necessarily mean urosepsis
unless their is partial or total obstruction or
pre-existing renal disease
 Asymptomatic


CAB
in normal hosts need not be treated
in compromised hosts and chronically
immunosuppressed must be treated promptly
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Drug Fever
 Some
3-7% of fevers on an inpatient
medical service are drug reactions
 History of atopy is a risk factor
 Patient may have been on the “sensitizing
medication” for days to years
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Drug Fever
 On
physical patient looks “inappropriately
well” for degree of fever



fever usually 102º to 104º
relative bradycardia
5-10% have rash
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Drug Fever
 Lab

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tests show
leukocytosis with left shift
eosinophils on peripheral smear (common)
eosinophilia (low-grade)
elevated ESR
mildly elevated AP, AST, ALT
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Common Causes of Drug Fever
 Antibiotics
 Antihypertensives
 Sleep
 Antidepressants
medications
 Antiepileptics
 Stool Softeners
 Diuretics
 Antiarrhythmics
 NSAIDs
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Rare Causes of Drug Fever
Digoxin
 Steroids
 Diphenhydramine
 Aspirin
 Vitamins
 Aminoglycosides
 Tetracyclines

Erythromycins
 Chloramphenicol
 Vancomycin
 Imipenim
 Quinolones

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Postoperative Fever
 Fever
common post-operatively
 Most episodes noninfectious
 Probably due to intraoperative tissue
trauma with subsequent release of
endogenous pyrogens into the
bloodstream
*Garibaldi RA. Infect Control 6:273, 1985
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Postoperative Fever
 Garibaldi*
found that 72% of fevers
within the 48º after surgery were noninfectious
 Wound, urinary tract, and respiratory
infections occur later than 48º
*Garibaldi RA. Infect Control 6:273, 1985
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Postoperative Fever
Empiric antibiotics should be withheld in
patients with fever within 48º of surgery if they
lack a specific diagnosis after thorough
evaluation
 Continuing perioperative prophylactic
antibiotics does not prevent infection, only
selects for resistant organisms

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Fever in Neurosurgical Patient
 Most


important causes are
Wound infection
Meningitis, an infrequent post-op
complication, especially after openhead trauma
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Fever in Neurosurgical Patient
 Commonest
clinical entity is posterior
fossa syndrome


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
stiff neck, low CSF glucose, elevated
protein, mostly neutrophils
Can occur after any intracranial procedure
Symptoms due to blood in CSF
Culture negative, and symptoms subside as
RBCs decrease over time in CSF
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Causes of High Fever (º)
Central fevers
 intracranial hemorrhage, head trauma,
infection, malignancy
 especially if the base of the brain or
hypothalamus affected
 Infusion-related sepsis (contaminated infusate)
 Rarely, bacterial infection
 Drug fever (usually 102º to 106º)

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Causes of High Fever (º)

Malignant hyperthermia

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Rare genetic disorder, probably autosomal
dominant
Incidence 1:15,000 in kids; less in adults
Hypercatabolic reaction to anesthetic drugs
Sustained muscle contraction -> excess heat
Tachycardia occurs in >90% of pts within 30
minutes
Treated with dantrolene; mortality ~7%
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Causes of High Fever (º)
 Malignant



neuroleptic syndromes
Confusion, hyperthermia, muscle stiffness,
autonomic instability
Drugs implicated: phenothiazines,
thioxanthines, butyrphenones-antipsychotics, tranquilizers, and antiemetics
Dantrolene or bromocriptine, a dopamine
agonist, effective in uncontrolled studies
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Summary

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Fever in the ICU can have many infectious and
noninfectious etiologies
Crucial to identify the precise cause as some of the
conditions in each groups are life-threatening, while
others require no treatment
“Routine fever work-up” not cost-effective
If initial evaluation shows no infection, antibiotics
should be withheld
Empiric antibiotics may be started in the unstable
patient, but stopped if infection is not evident later
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