Fever

Definition: Body temp >38.3°C (101°F) represents a fever and deserves further evaluation to search for an infection.

    • Core body temp can be 0.5°C (0.9°F) higher than oral temp, and 0.2°C to 0.3°C lower than rectal temp.

    • Normal body temp has a diurnal variation, with the nadir in the early morning between 4 - 8 AM and the peak in the late afternoon (4 and 6 PM).

    • Fever is a sign of inflammation, not infection. It is the result of inflammatory cytokines, which are endogenous pyrogens, that act on hypothalamus to elevate the body temp and set it at a higher point. Fever is an adaptive response that aids the host in defending against infection and other bodily insults.

Infection: most common cause in hospital.

    • Pneumonia, UTI, wounds, IV sites, Blood stream infections (The biggest group: 76 - 78%)

    • CNS, abdominal and pelvic inf. Consider immune status.

    • PE, DVT

    • Drugs

    • Neoplasm

    • CTD

    • Post-op atelectasis

    • Always check for sepsis and meningitis.

    • Endocarditis

Fever with relative bradycardia: Typhoid, Legionella pneumonia, Mycoplasma pneumoniae, ascending cholangitis, Plasmodium falciparum malaria with profound hemolysis.

Inf. causes of fever in the ICU: VW CARS

    • VAP, pneumonia

    • Wound inf.

    • C. difficle

    • Abd. abscess

    • Related to cath. and lines (CRBSI)

    • Sepsis/Sinusitis

Non inf. causes of fever in the ICU: PAID MAN

    • Pancreatitis/Pulmonary embolism

    • Adrenal insufficiency, thyrotoxicosis

      • Adrenal h'ge is a complication of DIC, anticoagulant therapy.

    • ARDS (50% develop pneumonia)

    • Ischemic bowel

    • DVT/Drug withdrawal. DVT common in trauma, post-op orthopedic surgery of hip and knee.

    • MI

    • Acalculous cholecystitis

    • Neoplasm

    • Most fevers that appear in the first 24-48 hours after surgery are most likely a result of the tissue injury sustained during the procedure.

    • Malignant hyperthermia characterized by muscle rigidity and hyperthermia, after halogenated IH anesthetics and depolarizing neuromuscular blockers (succinylcholine).

    • Hemodialysis. Due to contamination of HD equipment by endotoxins. BC ordered. Tx: empirically with Vancomycin + ceftazidime.

    • Fiberoptic bronchoscopy. Fever usually appears 8-10 hrs after procedure and it subsides spontaneously in 24 hours. Order BC only if fever does not subside after 24 hrs of procedure, or patient shows signs of sepsis (MS changes and hypotension).

    • Blood transfusion. Febrile reactions due to antileukocyte antibodies.

    • Spontaneous bacterial peritonitis in Pts on peritoneal dialysis, cirrhosis, and ascites.

Drug-Associated Fever in the ICU

    • Common offenders: Amphotericin, cephalosporins, penicillins, phenytoin, procainamide, quinidine.

    • Occasional offenders: Cimetidine, carabamazepine, hydralazine, rifampin, streptokinase, vancomycin

    • Drug induced hyperthermia syndromes: Malignant hyperthermia, neuroleptic malignant syndrome, serotonin syndrome.

SIRS/Sepsis

Not a Dx but and inflammatory response to clinical condtions: pancreatitis, infection, burns, trauma. Characterized by two or more of the following:

1. Fever > 38° C, >100.4°F or <96.8°F or <36° C.

2. HR >90

3. RR >20

4. PaCO2 <32 mmHg

5. WBC: >12,000/uL or <4000/uL or 10% immature (band) form.

These findings should occur in the absence of other known causes of these abnormalities.

FUO

H&P:

    • Travel, contact with sick persons, other exposures - STI, meds

    • How distressed does the patient look?

    • VS: repeat. Tachycardia is an expected finding with fever. Recheck BP

    • Skin rash, lesions, embolic phenomenon (endocarditis), wounds, decubiti.

    • Neurologic: mentation, photophobia, neck stiffness, Brudzinski's or Kernig's signs.

    • CVS: HR, JVD, skin temp and color. Any new murmurs? Capillary refill.

    • Lungs: Listen for crackles and breath sounds on both sides.

    • Abdomen: Assess for RUQ tenderness and bowel sounds, fluid accumulations.

    • Extremities: Check IV sites and signs of DVT or joint effusions.

    • Lines, drains, dressings, wounds: IV lines, Foley cath, NGT

    • Neutropenic patient/immunocompromised:

Lab/Dxtic:

CBC, BC (two sets from two different sites), CMP, UA and Cx, sputum culture and GS, CXR, LP if meningitis is suspected. Consider C. difficile stool cultures. If probability of septicemia is high as CRBSI or endocarditis, at least 3 venipuncture sites are recommended for blood cultures. If the patient has received antimicrobial agents within the past few weeks, at least four venipuncture sites are recommended.

Common pathogenic organisms identified in nosocomial infections:

    • S. aureus

    • Pseudomonas aeruginosa

    • C. albicans

    • Pneumonia: ventilator dependent patient, new infiltrate on CXR, fever, leukocytosis, and purulent tracheal secretions. S. aureus, Pseudoomonas, Klebsiella

    • UTI: fever, indwelling cath for more than a few days. Positive urine culture in chronically catheterized patients is not always an evidence of infection. The demonstration of pyuria by gram stain or LE dipstick test (for detection of granulocytes in urine) can help to identify patients with significant bacteriuria.

    • Catheter sepsis: Indwelling catheter x 48 hours, fever, or purulence found at the catheter insertion site. If a patient appears toxic, or there is purulence at the catheter site, remove the catheter, send the tip for semiquantitative cultures. This must be combined with a blood culture obtained from a distant venipuncture site. If the patient is not seriously ill and there is no purulence at the catheter insertion site, the catheter can be left in place. In this case one blood sample is obtained through the catheter and a second blood sample should be obtained from a distant venipuncture site: both samples should be submitted for quantitative blood cultures.

    • Surgical wounds: clean (abdomen and throax unopened), contaminated (abdomen or chest opened) and dirty (direct contact with pus or bowel contents). Wound infection typically appear 5-7 days postop. Necrotizing wound infections are produced by Clostrida or beta-hemolytic streptococci. Evident in the first few postoperative days. Often marked edema, skin may have crepitus and fluid-filled bullae. Spread to deeper structures is rapid and produces progressive rhabdomyolysis and myoblobinuric renal failure. Treatment involves extensive debridement and IV PCN.

    • Paranasal Sinusitis: Purulent drainage from the nares may be absent. Dx suggested by radiographic features of sinusitis (opacification of involved sinsuses). X-ray (occipitomental view or Waters view) can be obtained at the bedside. CT scans are reserved only for cases where the portable sinus film are of poor quality. 30 - 40% of patients with radiographic evidence of sinusitis do not have an infection documented by culture of aspirated material from the involved sinus. Radiographic evidence of sinusitis is not sufficient for the diagnosis of purulent sinusitis. The diagnosis must be confirmed by sinus puncture and isolation of pathogens by quantitative culture (>103 CFU/mL). Pseudomonas aeruginosa, S. aureus and yeasts

Tx:

    • Rule out hemodynamic instability. Review meds and obtain cultures. Give antipyretics. Ensure IV access and consider maintenance fluids for insensible losses.

    • The only clinical situation where reduction of fever is justified is in the early period following ischemic brain injury. Antipyretic therapy is mandatory for fever associated with ischemic stroke.

    • Empiric ABx therapy: Given in the following situations.

      • When the likelihood of infection is high.

      • When there is evidence of severe sepsis or severe organ dysfunction (e.g., depressed consciousness, progressive hypoxemia, hypotension, metabolic acidosis, or decreasing urine output).

      • When the patient is immunocompromised (e.g. neutropenia).

      • MRSA: vancomycin

      • VRE: linezolid

      • Gram negative inf: carbapenem (imipenem cilastatin or meropenem)

      • Pseudomonas: ceftazidime, cefepime or ticarcillin clavulanate or pipericilin tazobactam.

    • Consider ABX. If Pt is hemodynamically stable, immunocompetent, not toxic appearing, with no clear source of infection, it may be prudent to withhold ABX and recheck cultures.

    • Pt. with fever and hypotension require broad-spectrum ABX and IV fluids or pressors to manage the hypotension. Septic shock is an emergency.

    • Pts with fever and neutropenia require broad-spectrum ABX and often need soluble beta-lactam coverage.

    • Pts with fever and meningitis sx require ABX immediately. Do not wait for LP kit. Give the ABX then approach the LP.

    • Consider changing or removing Foley catheters and any indwelling IV sites.

    • Antipyretic drugs: PGE synthesis inhibition (ASA, APAP, NSAIDs)