Fever in the ICU

1
Fever in the ICU

• Simranjit Singh Galhotra, MD, MBA
• George Washington University
• Fellow, Pulmonary and Critical Care Medicine
• January 1998

2
Fever, A Little History

• Hippocrates recognized fever as a beneficial sign
  during infection
• Thomas Sydenham (1624-1689), English physician
  Fever is Natures engine which she brings into
  the field to remove her enemy.
• Fever therapy used in many societies world-wide

3
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

4
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

5
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

6
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 101-20, 1996
7
Nosocomial Fevers

• Hospital-acquired fevers occur in one-third of
  all medical inpatients
• Nosocomial fevers even more common in the ICU

8
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

9
Diagnostic Approach

• Fever is a non-specific sign seen in inflammatory
  processes that may be
• infectious
• noninfectious, including neoplastic
• The 102º Rule

10
Temp lt 102º

• Acute cholecystitis
• Acute MI
• Dresslers Syndrome
• Thrombophlebitis
• GI bleed

• Acute pancreatitis
• Pulmonary embolism or infarct
• Viral hepatitis
• Uncomplicated wound infection

11
Temp ³ 102º

• Cholangitis
• Suppurative phlebitis
• Pericarditis
• Septic pulmonary embolism
• Pancreatic abscess

• Non-viral liver disease drug fever,
  leptospirosis
• Complicated wound infection
• Bowel infarction

12
Causes of Fever in the ICU

• SIRS
• Intravenous-line infections
• Nosocomial pneumonia
• Nosocomial sinusitis
• Intraabdominal infections

• Urinary catheter-associated bacteriuria
• Drug fever
• Post-operative fever
• Neurosurgical causes

13
Systemic Inflammatory Response Syndrome

• Definition of SIRS
• T gt 38ºC or lt 36ºC
• HR gt 90
• RR gt 20 or pCO2 lt 32
• WBC gt 12 or lt 4

14
SIRS

• Often noninfectious etiology found
• Pulmonary embolism
• Myocardial infarction
• Gastrointestinal bleed
• Acute pancreatitis
• Cardiopulmonary bypass

15
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 3271062-8, 1992
16
Intravenous-line Infections

• Look for local signs of infection present in lt
  50
• Remove line if no other source and T gt 102º

17
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 gt 3 days

Cobb DK. NEJM 3271062-8, 1992
18
Scheduled Replacement?

• Four groups
• 1 replaced q 3 days with a new stick
• 2 replaced every 3 days over guidewire
• 3 replaced only if clinically indicated
  (fever, mechanical complications) with new
  stick
• 4 replaced only if clinically indicated over
  guidewire

19
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

20
Scheduled Replacement?

• No support for changing lines every 3-5 days
  change only if unexplained fever or catheter
  malfunction occurs
• Concurs with CDCs Guideline for Prevention of
  Intravascular Device-Related Infections. Am J
  Infect Control 199624262-293

21
Nosocomial Pneumonia

• Almost all cases occur in mechanically ventilated
  patients
• Signs are
• fever
• leukocytosis
• purulent tracheal secretions
• new or worsening infiltrates on CXR

22
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

23
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

24
Nosocomial Sinusitis

• Fever and leukocytosis often present
• Purulent nasal discharge often lacking
• Common in trauma and neurosurgical units

25
Nosocomial Sinusitis

• Risk factors
• 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

26
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 post-operative period

27
Intra-abdominal Infections

• Suspect antibiotic-associated colitis due to
  Clostridium difficile in patients on
  broad-spectrum 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

28
Catheter-Associated Bacteriuria

• Foley catheters
• Result in acquisition of bacteriuria
• Nearly always represents colonization, not
  infection
• Pyuria often accompanies CAB, mimicking a UTI

29
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

30
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

31
Drug Fever

• On physical patient looks inappropriately well
  for degree of fever
• fever usually 102º to 104º
• relative bradycardia
• 5-10 have rash

32
Drug Fever

• Lab tests show
• leukocytosis with left shift
• eosinophils on peripheral smear (common)
• eosinophilia (low-grade)
• elevated ESR
• mildly elevated AP, AST, ALT

33
Common Causes of Drug Fever

• Antibiotics
• Sleep medications
• Antiepileptics
• Stool Softeners
• Diuretics

• Antihypertensives
• Antidepressants
• Antiarrhythmics
• NSAIDs

34
Rare Causes of Drug Fever

• Digoxin
• Steroids
• Diphenhydramine
• Aspirin
• Vitamins
• Aminoglycosides
• Tetracyclines

• Erythromycins
• Chloramphenicol
• Vancomycin
• Imipenim
• Quinolones

35
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 6273, 1985
36
Postoperative Fever

• Garibaldi found that 72 of fevers within the
  48º after surgery were non-infectious
• Wound, urinary tract, and respiratory infections
  occur later than 48º

Garibaldi RA. Infect Control 6273, 1985
37
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

38
Fever in Neurosurgical Patient

• Most important causes are
• Wound infection
• Meningitis, an infrequent post-op complication,
  especially after open-head trauma

39
Fever in Neurosurgical Patient

• Commonest clinical entity is posterior fossa
  syndrome
• 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

40
Causes of High Fever (³ 106º)

• 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)

41
Causes of High Fever (³ 106º)

• Malignant hyperthermia
• Rare genetic disorder, probably autosomal
  dominant
• Incidence 115,000 in kids less in adults
• Hypercatabolic reaction to anesthetic drugs
• Sustained muscle contraction -gt excess heat
• Tachycardia occurs in gt90 of pts within 30
  minutes
• Treated with dantrolene mortality 7

42
Causes of High Fever (³ 106º)

• 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

43
Summary

• 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