Differential Diagnosis for 73 year old female with CHF, COPD, and Positive Blood Cultures for Staph Epidermidis

• Single most likely diagnosis:
  • Contaminant: This is the most likely diagnosis because Staphylococcus epidermidis is a common skin commensal and frequent contaminant of blood cultures, especially when the patient does not exhibit signs of infection such as fever.
• Other Likely diagnoses:
  • True Infection - Staph Epidermidis Bacteremia: Although less likely due to the absence of fever, it's possible that the patient has a true infection, especially if the organism is known to cause infections in certain contexts (e.g., prosthetic valves, indwelling catheters). The lack of fever does not rule out infection, especially in elderly or immunocompromised patients.
  • Catheter-Related Bloodstream Infection (CRBSI): If the patient has an indwelling catheter, Staph epidermidis could be causing a CRBSI, which might not always present with fever, especially in the early stages.
• Do Not Miss diagnoses:
  • Endocarditis: Although Staph epidermidis is less commonly associated with endocarditis compared to Staph aureus, it can still cause this condition, especially in patients with prosthetic valves. Endocarditis can be silent and not always present with the classic signs of infection.
  • Prosthetic Device Infection: If the patient has any prosthetic devices (e.g., prosthetic joints, pacemakers), Staph epidermidis could be infecting these devices, which might not always cause systemic signs of infection like fever.
• Rare diagnoses:
  • Staph Epidermidis Infective Endarteritis: A rare condition where the infection involves the arterial walls, potentially leading to severe complications like embolic events or rupture of the artery.
  • Device-Associated Infection (other than catheters): Infections associated with other medical devices (e.g., prosthetic heart valves, intrauterine devices) are rare but possible causes of Staph epidermidis bacteremia without fever.