Evaluating a patient who develops Fever after getting admission to ICU.

1. FEVER IN AN ICU
PATIENT
DR.PRASANT.N

2. TABLE OF CONTENTS
• Introduction.
• Pathophysiology.
• Etiology
• Measurement of Temperature
• Approach to fever.
• Patient Evaluation
• Diagnostic Approach
• Differential Diagnosis
• Treatment

3. INTRODUCTION
• The American College of Critical Care Medicine and the Infectious
Diseases Society of America defined fever as a body temperature
of 38.3ºC (101ºF) or higher.
• Hyperthermia/hyperpyrexia refers to syndromes associated with a
high fever that often exceeds 41°C (105.8°F).
• Hyperthermia/hyperpyrexia syndromes are frequently noninfectious
in etiology (eg, environmental, pharmacologic, endocrine), can be
rapidly fatal, and their treatment differs from that of regular fever in
the ICU.

4. PATHOPHYSIOLOGY

5. ETIOLOGY
INFECTIOUS NON INFECTIOUS
Ventilator associated pneumonia Acalculous Cholecystitis
Catheter related blood stream infections Adrenal Insufficiency
Urosepsis Benign Post- operative Fever
Intra-abdominal infections Drug Fever
Surgical site infections Pancreatits
Diarrhoea Thyroid Storm
Sinus infections Transfusion reactions

6. MEASUREMENT OF TEMPERATURE
Peripheral temperature measurements
• Measured on the skin or mucus membranes
• Considered unreliable as influenced by environmental temperatures, mouth
breathing etc.
• Examples – oral temperature, axillary skin temperature
Core temperature measurements
• Not influenced by external factors.
• More accurately reflects temperature in the internal organs
• Examples – pulmonary, rectal, esophageal, urinary, tympanic.

7. APPROACH TO FEVER
TEMP > 38.3ºC (101ºF)
PATIENT CAME WITH
FEBRILE ILLNESS ?
PATIENT DEVELOPED
FEVER INSIDE THE ICU?
WHAT CAUSED THIS FEVER ?

8. CONTINUED…
PATIENT DEVELOPED FEVER AFTER ICU ADMISSION.
INFECTIOUS ? NON -INFECTIOUS ?

9. PATIENT EVALUATION.
• Be familiar with the patient’s history. Pay particular attention to
possible predisposing causes of fever.
• Perform a careful physical examination. Pay particular attention to
surgical wounds and vascular access sites.
• Obtain or review recent Chest X-ray , looking for evidence of new
infiltrates or effusions.
• Obtain appropriate laboratory studies.
• Patients receiving antibiotics for more than 3 days —>? C. difficile
toxin.

10. INFECTIOUS VS NON - INFECTIOUS FEVER
• Most noninfectious disorders usually do not lead to a fever> 38.9°C
(102°F).
• Therefore, if the temperature increases above this threshold, the
patient should be considered to have an infectious etiology as the
cause of the fever.
• However, patients with drug fever may have a temperature
>102°F.
• Similarly, fever secondary to blood transfusion maybe >102°F.

11. DIAGNOSTIC APPROACH
• Blood cultures are the only mandatory diagnostic tests in patients with a new
fever.
• Sputum.
Indicated for febrile patients with any of the following findings-: new sputum
production
a change in the color, amount, or thickness of their sputum.
a new or progressive pulmonary infiltrate.
an increased respiratory rate.
an increased minute volume; a decreased tidal volume;
decreased oxygenation.
needing more ventilatory support; or requiring more inspired oxygen.

12. • URINE .
Urinalysis and urine culture are indicated for febrile patients with
○ a urethral catheter.
○ urinary obstruction.
○ renal calculi.
○ recent genitourinary surgery or trauma, or neutropenia.

13. • CHEST IMAGING
• A chest radiograph is worthwhile in many patients with NEW
respiratory symptoms or signs.
• It may detect a new or progressive pulmonary infiltrate.
• Distinguish pneumonia from tracheobronchitis, or identify a
respiratory source of fever other than pneumonia or
tracheobronchitis .
• Computed tomography (CT) should be reserved for the clarification
of abnormal chest radiographic findings.

14. BLOOD CULTURES
• One blood culture is defined as a sample of 20–30 mL of blood drawn at
a single time from a single site, regardless of how many bottles or tubes
the laboratory may use to process the specimen.
• The sensitivity of Blood culture → obtaining the cultures before the
initiation of anti-infective therapy and the volume of blood drawn.
• At least one sample must be taken before initiation of anti- infective
therapy.
• In potentially septic patients with an intravascular catheter (in place >48
h) in whom a site of infection is not clinically apparent or a suspicion of
intravascular catheter-associated infection exists, at least one blood
culture set should be obtained from the catheter .

15. DIFFERENTIAL DIAGNOSIS.
1 )Ventilator Associated Pneumonia:
• Mechanical ventilation for more than 48 hours develops a fever.
• New or progressive pulmonary infiltrates.
• Leukocytosis
• Purulent tracheobronchial secretions.
Signs:
increased respiratory rate,
• Increased minute volume
• Decreased tidal volume,
• Decreased oxygenation, or
• The need for more ventilatory support or inspired oxygen

16. 2) Catheter Related Blood Stream Infection:
• Fever without localizing symptoms or signs.
• Cellulitis at the site of insertion.
• Purulent drainage from the insertion site.
• Sepsis (fever, tachycardia, tachypnea, leukocytosis).

17. • Catheter Associated Urinary Tract Infection ( CAUTI:
They may also present with symptoms and signs of cystitis (fever,
suprapubic pain, hematuria, pyuria).
pyelonephritis (fever, chills, flank pain, costovertebral angle
tenderness, nausea, and vomiting)
Urosepsis.

18. Diarrhea in ICU:
Most common : Clostridium difficile
Pseudomonas
Clostridium septicum.
• Commonly seen with : Clindamycin , 3rd generation
cephalosporins, flouroquinolones.
• Symptoms usually begin during or shortly after antibiotic therapy.
• Neutrophilia and increased Fecal leucocytes.

19. Sinusitis:
• Nasotracheal and nasogastric tubes are risk factors.
• Maxillary sinus is commonly affected.
• Major Criteria:
Cough with purulunt discharge from nose.
Minor Criteria:
Facial pain , Headache, Earache, fever, malodorous breath , sore throat.
Diagnosis:
Drainage of the pus and culture.
CT scan will be required to identify opacification or fluid levels.

20. Drug Fever
• Hypersensitivity reaction
• Local inflammation at the site of administration : Amphotericin B,
erythromycin ,KCl, sulfonamides.
• Drugs or their delivery systems may contain pyrogens or microbial
contaminants
• Stimulation of heat production e.g. thyroxine
• Limit heat dissipation e.g., atropine
• Alter thermoregulation e.g., phenothiazines, antihistamines
antiparkinson drugs.

21. • Febrile transfusion reactions:
• More common following platelet transfusion
• Usually begin within 30 min to 2 h after a blood-product transfusion
• The fever generally lasts between 2 to 24 h and may be preceded
by chills.
• An acute leukocytosis lasting up to 12 h occurs commonly.

22. PROCALCITONIN
• May be particularly useful in distinguishing bacterial from other forms of
infection.
• Trends in concentrations over time are again of more value than single
measurements.
• Mortality rates were lower in patients whose PCT concentration
decreased by more than 50% in 72 h than in those in whom levels
decreased by less than 50% (12.2 vs 29.8%; p = 0.007).
• Measurement of procalcitonin levels can be used to support shortening
the duration of antimicrobial therapy in sepsis patients (weak
recommendation, low quality of evidence).
• Decisions on initiating, altering, or discontinuing antimicrobial therapy
should never be made solely on the basis of changes in any biomarker,
including procalcitonin.

24. EMPIRICAL ANTIBIOTICS
TREATMENT OF FEVER
• When clinical evaluation suggests that infection is the cause of
fever, empirical antimicrobial therapy should be instituted as soon
as possible after cultures are obtained, especially if the patient is
seriously ill or deteriorating.
• Initial empirical antibiotic therapy should be directed against likely
pathogens, as suggested by the suspected source of infection, the
patient risk for infection by multidrug-resistant pathogens, and local
knowledge of antimicrobial susceptibility pattern.

25. • Relative risk- benefits should be evaluated in individual patients
• Treat with acetaminophen if:
• Temperature > 39°C CNS insult such as CVA Poor
cardiorespiratory reserve such as CHF, CAD
• External cooling useful in cases of hyperthermia rather than fever.

26. TAKE HOME MESSAGE
• Appropriately obtained temperature >38.3° should prompt clinician
to take appropriate diagnostic tests
• Fever has no one to one relation with infection Fever has no one to
one relation with infection
• Consider infectious and non infectious causes.
• Appropriate microbiological and imaging studies
• Empirical antibiotics within 1 hr of identifying sepsis
• Treatment of fever is recommended if deemed essential