2025 results
HACEK is the acronym commonly used to describe and help doctors to remember a group of
fastidious Gram-negative ... which can also cause ... endocarditis is caused ... endocarditis is caused ... #Diagnosis #InfectiousDiseases
Causes of blood culture negative infective endocarditis

Bartonella spp, Brucella spp, Coxiella burnetii, Chlamydia spp, Tropheryma whipplei,
Causes of blood ... culture negative ... #differential #diagnosis ... #negative #Endocarditis ... #InfectiousDiseases
Transplant Infections Timeline
Pre-transplant:
 • Common bacteria (endogenous): Staphylococci (skin), Gram-negative bacilli (gut)
 • Viruses: HSV (reactivation)
Engraftment:
Staphylococci (skin), Gram-negative ... Staphylococci (skin), Gram-negative ... #differential #diagnosis ... #causes #infectiousdiseases
Causes of Culture Negative Abscess - Differential Diagnosis Framework
Consider prior antibiotics as a cause of a
Causes of Culture ... - Differential Diagnosis ... antibiotics as a cause ... #Differential #Diagnosis ... #InfectiousDiseases
Blood Culture-Negative Infective Endocarditis (BCNIE)
Definition: No etiology found after 3 separate blood cultures remain negative for
Blood Culture-Negative ... but important causes ... BCNIE Diagnostic ... #Endocarditis #diagnosis ... differential #workup #infectiousdiseases
Endocarditis - Overview and Differential Diagnosis Framework

Who?
Infectious:
• Pre-existing valvular disease
• Prosthetic valve
• Congenital heart disease
• IV
and Differential Diagnosis ... aureus, Coagulase-negative ... staphylococci Culture Negative ... Septic emboli cause ... #cardiology #infectiousdiseases
Microorganisms Responsible for Infective Endocarditis

Native valves:
 - Streptococcus viridans 
 - Enterococci 
 - Other streptococci
epidermidis - Gram-negative ... ) - Culture negative ... Enterococci - Gram-negative ... Bacteria #Pathogens #Diagnosis ... #Differential #InfectiousDiseases
Causes of Relative Bradycardia - Note the propensity for intracellular organisms.
Infectious: 
Legionella, Psittacosis, Q fever, Typhoid
Causes of Relative ... Drug fever #relative ... #bradycardia #Causes ... #differential #diagnosis ... #infectiousdiseases
Endocarditis Algorithm - Infective vs Noninfective Causes
Noninfective:
 • Malignancy
 • Autoimmune disease
 • Systemic infection
Native Valve
vs Noninfective Causes ... HACEK • Culture-negative ... epidermidis • Gram-negative ... #Noninfective #Causes ... #Differential #Diagnosis
Important Biostatistics and Epidemiology Equations

Sensitivity = TP / (TP + FN) = true positives / disease
FP + TN) = true negatives ... all positives Negative ... / all negatives ... Specificity) Negative ... #calculations #diagnosis