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Questions and Answers
What is the primary difference between sepsis and severe sepsis?
What is the definition of bacteremia?
What is the key factor in differentiating septic shock from severe sepsis?
What is the recommended time frame for administering broad-spectrum IV antibiotics?
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What is the purpose of obtaining cultures prior to administering antibiotics?
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What is the definition of SIRS?
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What is the recommended initial fluid resuscitation for hypotension or lactate >36 mg/dL?
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What is the criteria for SIRS?
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What is the indication for administering vasopressors?
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What is the preferred specimen for isolation of nontyphoidal Salmonella species?
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In patients who received antibiotic therapy prior to hospitalization, which specimen may still be positive for Salmonella?
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What is a common hematological finding in patients with typhoid fever?
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What is the significance of a high sedimentation rate in salmonellosis?
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What is the recommendation for antibiotic use in uncomplicated nontyphoidal Salmonella gastroenteritis?
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What is the purpose of imaging studies in patients with salmonellosis?
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What is the significance of eosinophilia in patients with salmonellosis?
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What is the common liver function abnormality seen in salmonellosis?
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What is the preferred specimen for isolation of S. typhi or S. paratyphi?
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What is the significance of thrombocytopenia in salmonellosis?
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Study Notes
Infection
- Infection is the presence of microorganisms in normally sterile host tissue.
- Bacteremia is the presence of viable bacteria in the blood.
Spectrum of Infection
- Sepsis is the systemic response to infection.
- Severe sepsis is sepsis associated with organ dysfunction, hypoperfusion, or hypotension.
- Septic shock is sepsis with hypotension despite adequate fluid resuscitation, and perfusion abnormalities.
SIRS (Systemic Inflammatory Response Syndrome)
- SIRS is an exaggerated systemic inflammatory response to a variety of severe clinical insults.
- It is manifested by 2 or more of the following conditions:
- Temperature >38 °C or <36 °C
- Heart rate >90 beats/min
- Respiratory rate >20 breaths/min
- White blood cell count (WBC) >12,000 (Leukocytosis) or <4,000
- Blood glucose >2 mmol/L
Management of Sepsis
- Obtain cultures (blood, urine, sputum, etc.) prior to administration of antibiotics.
- Administer broad-spectrum IV antibiotics within 1 hour.
- Initial fluid resuscitation of 30 mL/kg crystalloid for hypotension or lactate >36 mg/dL (≥4 mmol/L).
- Use vasopressors if Mean Arterial Pressure (MAP) is <65 mmHg.
Typhoid Fever
- Typhoid fever can have varying clinical courses, ranging from mild to severe, with 10-15% of patients developing severe disease.
- The incubation period is typically 10-14 days, and symptoms include prolonged low-grade fever, dull frontal headache, malaise, myalgia, dry cough, anorexia, and nausea.
- The fever may progress in a stepwise manner to become persistent and high-grade by the end of the second week, lasting up to 4 weeks if left untreated.
- Relative bradycardia at the peak of the fever is an indicator of typhoid fever, although this finding is not universal.
- Rose spots develop on the back, arms, and legs in up to 25% of cases late in the first week of fever.
- Other symptoms include coated tongue, alteration of bowel habits, tender abdomen, and hepatosplenomegaly.
Other Presentations of Salmonella Infection
- Urolithiasis or structural abnormalities and immunosuppressive therapy predispose to Salmonella urinary tract infections.
- Relapses can occur, even with appropriate therapy, and the relapse rate is significantly higher in immunosuppressed patients with Salmonella bacteremia.
Diagnosis
- Blood culture is 80-100% accurate in detecting bacteremia.
- Bacteria appear in the bloodstream within 14 days, facilitating secondary metastatic foci.
- Gallbladder infection can lead to long-term carriage of S typhi or S paratyphi in bile and secretion to the stool.
Transmission
- Salmonella is transmitted through consumption of contaminated foods, including beef, poultry, eggs, fruits, vegetables, dairy products, and shellfish.
- Meat can become infected with Salmonella during production, when bacteria from animal intestines transfer onto meat due to careless processing or improper hygiene.
Causes
- The 7 most commonly isolated Salmonella strains causing human disease reported to the CDC in 2007 include S enteritidis, S typhimurium, S enteritidis heidelberg, S enteritidis newport, S enterica serotype Javiana, S enterica serotype I 4,5,12:i:, and S enteritidis montevideo.
- Enteric fever is caused by S typhi and S paratyphi.
Laboratory Diagnosis
- Freshly passed stool is the preferred specimen for isolation of nontyphoidal Salmonella species.
- PCR is performed, and bone marrow aspirate and culture are superior to blood culture.
- In patients who received antibiotic therapy prior to hospitalization, bone marrow aspirate may still be positive for Salmonella even if blood culture results are negative.
Laboratory Findings
- WBC count is usually within the reference range, but approximately one-fourth of patients with typhoid fever are leukopenic, neutropenic, or anemic.
- Thrombocytopenia is neither universal nor diagnostic.
- Eosinophilia should prompt a search for concomitant parasitic infection.
- Mild hepatocellular liver function abnormality is common.
Imaging Studies
- Radiologic findings in salmonellosis are nonspecific.
- Patients older than 50 years with nontyphoid Salmonella bacteremia should undergo clinical assessments such as CT or MRI to rule out concurrent vascular infections.
Treatment
- Salmonella gastroenteritis is usually a self-limiting disease.
- Fluid and electrolyte replacement may be indicated in severe cases.
- Antibiotics are not routinely used to treat uncomplicated nontyphoidal Salmonella gastroenteritis and are reserved for patients with severe disease or those who are at a high risk for invasive disease.
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Description
This quiz tests your knowledge on sepsis and septic shock, including the definition, spectrum, and clinical manifestations of infection.
