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2. Fever, A Little History. Hippocrates recognized fever as a beneficial sign during infectionThomas 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 world-wide. 3. Fever, Late 1800s. Liebe
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1. Fever in the ICU Simranjit Singh Galhotra, MD, MBA
George Washington University
Fellow, Pulmonary and Critical Care Medicine
January 1998
2. 2 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 world-wide
3. 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. 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. 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. 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
7. 7 Nosocomial Fevers Hospital-acquired fevers occur in one-third of all medical inpatients
Nosocomial fevers even more common in the ICU
8. 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. 9 Diagnostic Approach Fever is a non-specific sign seen in inflammatory processes that may be
infectious
noninfectious, including neoplastic
The “102º Rule”
10. 10 Temp < 102º Acute cholecystitis
Acute MI
Dressler’s Syndrome
Thrombophlebitis
GI bleed Acute pancreatitis
Pulmonary embolism or infarct
Viral hepatitis
Uncomplicated wound infection Helps avoid needless antibiotic therapyHelps avoid needless antibiotic therapy
11. 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 Helps avoid needless antibiotic therapyHelps avoid needless antibiotic therapy
12. 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. 13 Systemic Inflammatory Response Syndrome Definition of SIRS
T > 38ºC or < 36ºC
HR > 90
RR > 20 or pCO2 < 32
WBC > 12 or < 4 Circulating inflammatory cytokines have been found that initiate a SIRS in CPBCirculating inflammatory cytokines have been found that initiate a SIRS in CPB
14. 14 SIRS Often noninfectious etiology found:
Pulmonary embolism
Myocardial infarction
Gastrointestinal bleed
Acute pancreatitis
Cardiopulmonary bypass
15. 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%
16. 16 Intravenous-line Infections Look for local signs of infection: present in < 50%
Remove line if no other source and T > 102º
17. 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 > 3 days Randomized controlled trial at UVA from 10/88 to 1/90 all patients admitted to the ICU who needed triple-lumen central venous catheters or pulm-artery catheters inserted via SC or IJ for more than 3 days.
Four groups:
1 replaced every 3 days with a new stick
2 replaced every 3 days over a guidewire
3 replaced only if clinically indicated (fever, mechanical complications) with new stick
4 replaced only if clinically indicated (fever, mechanical complications) over a guidewire
Total 160 pts andRandomized controlled trial at UVA from 10/88 to 1/90 all patients admitted to the ICU who needed triple-lumen central venous catheters or pulm-artery catheters inserted via SC or IJ for more than 3 days.
Four groups:
1 replaced every 3 days with a new stick
2 replaced every 3 days over a guidewire
3 replaced only if clinically indicated (fever, mechanical complications) with new stick
4 replaced only if clinically indicated (fever, mechanical complications) over a guidewire
Total 160 pts and
18. 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. 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. 20 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 Device-Related Infections. Am J Infect Control 1996;24:262-293
21. 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. 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. 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. 24 Nosocomial Sinusitis Fever and leukocytosis often present
Purulent nasal discharge often lacking
Common in trauma and neurosurgical units
25. 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. 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. 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. 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. 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. 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. 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. 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. 33 Common Causes of Drug Fever Antibiotics
Sleep medications
Antiepileptics
Stool Softeners
Diuretics Antihypertensives
Antidepressants
Antiarrhythmics
NSAIDs
34. 34 Rare Causes of Drug Fever Digoxin
Steroids
Diphenhydramine
Aspirin
Vitamins
Aminoglycosides
Tetracyclines Erythromycins
Chloramphenicol
Vancomycin
Imipenim
Quinolones
35. 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
36. 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
37. 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. 38 Fever in Neurosurgical Patient Most important causes are
Wound infection
Meningitis, an infrequent post-op complication, especially after open-head trauma Wound infection and meningitis are the most important causes.
Post-op bacterial meningitis is an infrequent complication, especially after open-head trauma
The commonest clinical entity confused with post-neurosurgical meningitis is posterior fossa syndrome--stiff neck, low CSF glucose, protein elevated, and mostly PMNs. Can occur after any intracranial procedure; sx due to blood in CSF. Cx are (-) and decrease in meningeal sx as the RBCs decrease over time.
Central fever may be caused by any intracranial space-occupying lesion or trauma, esp. if it affects the base of the brain or hypothalamus. Are usually very high.Wound infection and meningitis are the most important causes.
Post-op bacterial meningitis is an infrequent complication, especially after open-head trauma
The commonest clinical entity confused with post-neurosurgical meningitis is posterior fossa syndrome--stiff neck, low CSF glucose, protein elevated, and mostly PMNs. Can occur after any intracranial procedure; sx due to blood in CSF. Cx are (-) and decrease in meningeal sx as the RBCs decrease over time.
Central fever may be caused by any intracranial space-occupying lesion or trauma, esp. if it affects the base of the brain or hypothalamus. Are usually very high.
39. 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. 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. 41 Causes of High Fever (³ 106º) Malignant hyperthermia
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%
42. 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. 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