INFECTIVE ENDOCARDITIS Flashcards
DEFINITION OF INFECTIVE ENDOCARDITIS.
THE INFECTION OF THE ENDOCARDIAL SURFACE OF THE HEART, THE INFECTION OF ONE OR MORE HEART VALVES OR THE INFECTION OF THE INTRACARDIAC DEVICES.
EPIDEMIOLOGY OF IE.
- UNCOMMON DISEASE
- A/W PUO
- FATAL IF UNTREATED
- IN DEVELOPING COUNTRY, ALWAYS OCCUR IN INDIVIDUALS AGE 20-40 YEARS OLD
- STAPHYLOCOCCUS SPP - COMMON CAUSE OF IE IN HEALTH CARE COMMUNITIES.
- STREPTOCOCCUS SPP - COMMON CAUSE OF IE IN PRE EXISTING STRUCTURAL HEART DISEASE
- COMMONLY AFFECT THE NATIVE VALVE, MAINLY THE LEFT SIDE OF THE HEART AND MITRAL VALVE USUALLY GET AFFECTED.
PATHOGENESIS OF IE.
- DAMAGED TO THE ENDOCARDIUM OF THE HEART WHICH CAN BE D/T TRAUMA, TURBULENCE OR PREVIOUS HX OF RHD.
- THIS WILL CAUSE THE DEPOSITION OF THE PLATELETS AS WELL AS FIBRINS TO OCCUR IN THE HEART.
- OVER TIME, IT WILL FACILITATE THE COLONIZATION OF THE BACTERIA IN THE DEPOSITION OF THE PLATELETS AND FIBRINS AREA (NIDUS) RESULTING IN TRANSIENT BACTEREMIA.
- HENCE, BACTERIA WILL RECRUIT MORE PLATELETS FROM THE CIRCULATION INCLUDING PLATELET ACTIVATION AND PLATELET AGGREGATION.
- D/T PLATELET AGGREGATION, THE COLLECTION WILL BECOME BIGGER AND THIS WILL LEAD TO VEGETATION.
RISK FACTOR OF IE
- HOST FACTOR (HEARTS DEFECT)
- CONGENITAL
- MVP, BAV, VSD - ACQUIRED
- CRHD
- PROSTHESIS
DEGENERATIVE VALVE SCLEROSIS
RISK FACTOR OF IE
- HOST FACTOS (BACTEREMIA)
- REPEATED EXPOSURE (IVDU)
- REPEATED EXPOSURE DURING DENTAL PROCEDURES (FLOSSING)
- OTHER SOURCES OF INFX ELSEWHERE
- DURING INVASIVE PROCEDURE (HAEMODYLASIS, DM, IMMUNOSUPPRESED PT)
RISK FACTOR OF IE
- BACTERIAL FACTORS
- ABLE TO ADHERE TO DAMAGED VALVE -> LOCAL PROCOAGULANT ACTIVITY TRIGGERED -> NURTURE THE INFECTED VEGETATION IN WHICH THEY CAN SURVIVE (S. AUREUS. STREPTOCOCCUS SPP, ENTEROCOCCUS SPP.)
- EQUIPPED WITH NUMEROUS SURFACE DETERMINANTS THAT MEDIATE THE ADHERENCE TO THE HOST MATRIX MOLECULES PRESENT ON DAMAGED VALVES (HAVE FIBRONECTIN BINDING PROTEINS ON THEIR SURFACE IN S. AUREUS) THAT CAN TRIGGER PLATELET XTIVATION.
- ESCAPE COMPLEMENT.
RISK FACTOR OF IE
- BACTERIAL FACTORS
- ESCAP HOST DEFENSE
- FORM BIOFILM THAT SHIELD THE ORGANISM FROM BEING ELIMINATED BY THE HOST DEFENCE AND DIMINISHED THE EFFICACY OF PHAGOCYTOSIS.
- CONTAINS VIRULENCE FACTORS SUCH AS EXOPROTEIN HEMOLYSIS, DNASE , PROTEASE, FIBRINOLYSIN
EXAMPLE OF HACEK BACTERIA
- KINGELLA
- HAEMOPHILUS
- CARDIOBACTERIUM
EXAMPLES OF ZOONOTIC ENDOCARDITIS.
- COXIELLA BURNETTI
- BRUCELLA
- BARTONELLA HENSELAE
- CHLAMYDIA PSITTACI
EXAMPLES OF RARE GRAM NEGATIVE BACTERIA
- LEGIONELLA SPP
- MYCOPLASMA SPP
- ACINETOBACTER SPP
- PSEUDOMONAS AERUGINOSA
NON CANDIDA FUNGUS
ASPERGILLUS
CANDIDA
LABORATORY SIGNS OF INFX
- INCREASE IN INFLAMMATORY MARKERS - CRP/ESR
- INCREASE IN WHITE CELL COUNT
- REDUCE HB
MICROBIOLOGICAL DIAGNOSIS
IDEALLY 3 SEPERATE SAMPLES OF BLOOD SHOULD BE COLLECTED WITHIN 24 HOURS PERIOD AND BEFORE ANTIMICROBIAL THERAPY IS ADMINISTERED TO ISOLATE THE CAUSATIVE ORGANISM AND TO PERFORM ANTIBIOTIC SUSCEPTIBILITY TESTS SO THT OPTIMUM THERAPY CAN BE PRESCRIBED
SPECIMEN THT CAN BE USED FOR DIAGNOSIS
BLOOD
URINE
RESECTED VALVULAR TISSUE/ EMBOLIC FRAGMENTS
TEST/ INVESTIGATIONS THT CAN BE DONE FOR DIAGNOSIS
CULTURE
ELISA
ELECTRON MICROSCOPE
PCR
