7. Types of Bloodstream Infections
• Factors that contribute to the initiation of BSI are:
• Immunosuppression
• Use of broad spectrum antimicrobial agents
• Invasive procedures or extensive surgeries that allow the bacteria to
access the blood
• Prolonged survival of debilitated patients
8. Extravascular Bloodstream Infections
• The organisms multiply at the primary site such as lungs and are
drained by lymphatics and reach the bloodstream
• The organisms are either removed by the cells of the
reticuloendothelial system or they multiply more widely and thereby
causing septicemia
9. Portal of entry
• The most common portals of entry for bacteremia are the
genitourinary tract (25%),
• followed by respiratory tract (20%),
• abscesses (10%),
• surgical site wound infections (5%),
• biliary tract (5%
10.
11. • Sepsis Sepsis is defined as life-threatening organ dysfunction caused
by a dysregulated host response to infection
• SOFA score
• Sepsis is diagnosed by SOFA (Sepsis-related organ failure assessment)
score which in turn depends on six parameters.
• 1. Respiratory system—PaO2 /FiO2
• 2. Coagulation system—Platelet count
12. • 3. Liver—Serum bilirubin
• 4. Cardiovascular—Mean arterial pressure (MAP)
• 5. Central nervous system—Glasgow coma scale score
• 6. Renal—Serum creatinine and urine output
• Organ dysfunction can be identified as an acute change in the total
SOFA score ≥2 points following the infection
14. Septic shock
• It is a subset of sepsis in which underlying circulatory and cellular/
metabolic abnormalities are profound
• Patients with septic shock can be identified with a clinical construct of
sepsis with:
• Persisting hypotension requiring vasopressors to maintain MAP (mean
arterial pressure) ≥65 mm Hg and
• Serum lactate level >2 mmol/L (18 mg/dL) despite adequate volume
resuscitation
• Patients with septic shock have a mortality of >40% in contrast to
10%, for sepsis cases
15. FEVER OF UNKNOWN ORIGIN (FUO)
1. Fever ≥38.3°C (≥101°F) on at least two occasions
2.Duration of illness of ≥3 weeks
3. No known immunocompromised state
4. Diagnosis that remains uncertain after a thorough history-taking,
physical examination, and the following obligatory investigations
16. • ESR and CRP (C-reactive protein) level
• Platelet count, leukocyte count (total and differential), and
hemoglobin
• Electrolytes, creatinine, total protein, ferritin and protein
electrophoresis
• Enzymes such as alkaline phosphatase, alanine aminotransferase,
aspartate aminotransferase, lactate dehydrogenase, creatine kinase
• Antinuclear antibodies, and rheumatoid factor
17. • Urinalysis Culture: blood cultures (3 negative cultures) and urine
culture
• Radiology: Chest X-ray, abdominal USG
• Tuberculin skin test or interferon γ release assay
18. Etiology of FUO
• FUO has both infectious and non-infectious etiology.
• Infections (36%): This accounts for majority of FUO cases.
19. • Neoplasms (19%): For example, lymphoma, leukemia, myeloma,
renal, colon and liver cancers, etc.
• Non-infectious Inflammatory Diseases (19%): For example, connective
tissue disorders like rheumatoid arthritis, SLE (systemic lupus
erythematosus), etc.
• Miscellaneous Causes (19%):
• Granulomatous diseases
• Inherited and metabolic diseases
• Thermoregulatory disorders.
• Undiagnosed cases (7%).
