Chapter 3 - Principles of Infectious Disease and Fever in Acute Care Flashcards
Basic bacterial cell properties
- bacteria are their own organism
- unlike human cells that have a cell membrane, bacterial cells have a cell wall
- dependent on protein synthesis and DNA replication
Basic viral cell properties
- viruses must utilize a human host
- virus attaches to the cell membrane and injects nucleic acid (DNA or RNA) into the cell → virus nucleic acid replication using host → new viruses and destruction and host cell
3 primary targets of antibiotics
- the cell wall, “bactericidal”
- bacterial protein synthesis, “bacteriostatic”
- bacterial DNA replication, “bacteriostatic”
2 main properties of antivirals
- block entry of virus into host cell (ex: antiviral prophylaxis)
- work in the host cell to deactivate the virus
Normal WBC count
4,000-11,000
The WBC Differential: Neutrophil
- role: destroy bacteria
- normal range: 57-67%
The WBC Differential: Lymphocytes
- role: destroy viruses
- normal range: 22-33%
The WBC Differential: Monocytes
- role: clear cellular debris
- normal range: 3-7%
The WBC Differential: Eosinophils
- role: combat allergens/parasites
- normal range: 1-3%
The WBC Differential: Basophils
- role: undetermined, role in anaphylaxis
- normal range: 0-1%
The WBC Differential: Bands (immature neutrophils)
- 3-5% of total neutrophils count
- bands are like teenagers: if you see a large number congregating somewhere, something bad is happening (> 10% bands)
Non-infectious causes of fever
- Autoimmune
- Inflammatory
- Drug reaction
Infectious causes of fever
- Bacterial (most common cause of fever in acute care setting)
- Viral
- Fungal (more common in immunocompromised patients)
- Rickettsial
- Parasitic
Most common causes of post-op fever
- volume contraction (dehydration)
- atelectasis
Bacterial post-op fever
Common findings • Fever • Leukocytosis with neutrophilia • Surgical site drainage Diagnostic workup • Evaluate for point of invasion • Blood cultures • Wound cultures • UA with culture Treatment • ANTIBIOTICS ONLY WITH SIGNS OF BACTERIAL INFECTION • Remove offending items (Foley, lines, etc.)
Volume contraction (dehydration) post-op fever
Common findings
• Azotemia
• Decreased skin turgor (except in elderly)
• Decreased PO intake/inadequate IV hydration
Diagnostic Workup
• Metabolic panel
• Determine estimated blood loss and replacement
• Evaluate intake and output
• Urine output = most reliable indicator of perfusion
Treatment
• Isotonic IV fluids and increase PO fluid intake
Atelectasis post-op fever
Common findings • Atelectasis present on CXR • Lack of incentive spirometer use • Cough • SOB • Decreased lung sounds Diagnostic workup • Evaluate use of incentive spirometer • Diagnosis of exclusion • May consider a CXR Treatment • Encourage incentive spirometer • OOB to chair and ambulation • Educate on splinting • Evaluate medication use that decrease respiratory drive (i.e., narcotics)
Risks vs. benefits of fever: Risks
- Doubles caloric requirement
- Increases myocardial O2 requirement by 15%
- Uncomfortable
- Inhibits mobility
- Teratogenic (harmful to fetus)
- Rapid elevation → seizure (most common in children)
Risks vs. benefits of fever: Benefits
- Kills or reduces replication in most infectious organisms
- Enhances the inflammatory response
- Improved outcomes and survival in animal studies and pediatrics
Contraindications to Fever
- Myocardial disease – ↑ myocardial O2 requirements
- Pregnancy – teratogenicity of fever
- Elderly (caution) – double caloric requirements in those already at risk for malnutrition
General Principles on Treatment of Fever
- Antibiotics only when evidence of bacterial infection is present (neutrophilia, drainage, positive cultures)
- Antibiotic therapy starts with broad spectrum (based on likely cause of infection) and then narrow spectrum (based on culture results)
- Antipyretics only when metabolic costs of fever outweigh risks
- If the patient can tolerate the fever, consider lowering the temperature vs. eliminating the fever completely
Common symptom complex of a UTI
- dysuria
- urgency
- frequency
Complicated UTI/pyelonephritis vs. uncomplicated UTI
complicated UTI/pyelonephritis is positive for CVA tenderness, fever, nausea, and/or vomiting
Diagnostic workup for an uncomplicated
Consider a UA with culture and susceptibilities
Diagnostic workup for a complicated UTI/pyelonephritis
- UA with culture and susceptibilities
- CBC and blood culture
Outpatient treatment of an uncomplicated UTI
- TMP-SMX (bactrim) DS 1 tab PO twice daily for 3 days (if local resistance < 20%)
- Nitrofurantoin (Macrobid) 100 mg PO twice daily for 5 days (if sulfa allergy or local resistance to TMP-SMX > 20%)
Outpatient treatment of a complicated UTI/pyelonephritis
- Ciprofloxacin 500 mg PO twice daily or 1000 mg PO daily for 5-7 days or levofloxacin (Levaquin) 750 mg PO daily for 5-7 days
- Ceftriaxone (Rocephin) 1g IM (if local fluroquinolone resistance is > 10% or patient can’t take fluroquinolones)
Inpatient treatment of complicated UTI/pyelonephritis
- Ciprofloxacin 400 mg IV twice daily or levofloxacin (Levaquin) 750 mg IV daily for 5-7 days
- alternative regimens: 3.375 mg IV q4-6h for 14 days