Cardiovascular Diseases

Infective endocarditis

Definitions, general information
Microbial infection of a heart valve (native or prosthetic ) or endothial lining of the heart or blood vessles or congenital defect. Commonly caused by bacteria ,rarely by other like fungi. Most often involving aortic and mitral valves

Definitions, general information- continued

3-10/100 000/year Median age has increased from 30-40 to 47-69 yrs More common in women The viridans group of streptococci is the most common pathogen in developing countries Staphylococcus aureus is the most common pathogen in developed countries.

Pathophysiology

Typicaly occur on preexisting endocardial damage(high jet pressure like VSD ,AR,MR)That attract the fibrin and platlets accumalation which favour colonization of blood borne bacteria – VEGITATIONSAs infection established Veg. enlarge or causing destruction or extension –AbscessExtracardiac manfestations due to Emboli (Emboli can break off vegetations causing abscesses at distant sites) or Immune complex depositions

More common lesions now: Mitral valve prolapse Degenerative calcific valvular stenosis Bicuspid aortic valve Prosthetic valves Congenital defects

Microbiology

The viridans group of streptococci (Streptococcus mitis, Strep. sanguis) are commensals in the upper respiratory tract that may enter the blood stream on chewing or teeth-brushing, or at the time of dental treatment, Others including Enterococcus faecalis,. and Strep. bovis, may enter the blood from the bowel or urinary tract. Staph. aureus has now overtaken streptococci as the most common cause of acute endocarditis Other like Coxiella burnetii, HACEK,Brucella ,fungi.



Clinical symptoms – when to suspectSubacute endocarditis This should be suspected when a patient with congenital or valvular heart disease develops a persistent fever. Unusual tiredness, night sweats or weight loss, or develops new signs of valve dysfunction or heart failure. Less often, it presents as an embolic stroke or peripheral arterial embolism. Other features include purpura and petechial haemorrhages in the skin and mucous membranes, and splinter haemorrhages under the fingernails or toe nails. Osler’s nodes are painful tender swellings at the fingertips that are probably the product of vasculitis; they are rare. Digital clubbing is a late sign. Roth spots, glomerulonephritis – up to 30% of patientsThe spleen is frequently palpable

Splinter Haemorrhages

Osler Nodes

Janeway Lesions

Roth Spots


Acute endocarditis This presents as a severe febrile illness with prominent and changing heart murmurs and petechiae Embolic events are common, and cardiac or renal failure may develop rapidly.

Diagnosis

Duke criteria
Major criteria
Blood culture positive for typical IE-causing microorganism Evidence of endocardial involvement
Minor criteria
Predisposition – heart condition or i.v. drug abuseFever – temp. >38 °CVascular phenomena – arterial emboli etc.Immunologic phenomena – glomerulonephritis, Osler’s nodes, Roth’s spotsMicrobiological evidence – positive blood cultures but do not meet major criteria Diagnosis 2 major criteria 1 major and 3 minor 5 minor criteria

Blood cultures

Always before starting antibiotics.Always triple samples – aerobe, anaerobe and mycotic , 10 ml each.Three sets of samples required.

Echocardiography

Transthoracic (TTE) and transoesophageal (TEE). Echocardiography is key for detecting and following the progress of vegetations, for assessing valve damage and for detecting abscess formation.

Other investigations

Elevation of the ESR, a normocytic normochromic anaemia, and leucocytosis are common The ECG may show the development of AV block. The chest X-ray may show evidence of cardiac failure and cardiomega ly. GUE Hematuria

Treatment basics

Sucess relies on eradication of pathogen Bactericidal regiment should be used Drug choice due to pathogen Surgery is used mainly to cope with structural complications

Treatment basics - continued

A multidisciplinary approach, with cooperation between the physician, surgeon and microbiologist. Empirical treatment depends on the mode of presentation, the suspected organism, and whether the patient has a prosthetic valve or penicillin allergy If the presentation is acute, flucloxacillin and gentamicin are recommended, while for a subacute or indolent presentation, benzyl penicillin and gentamicin are preferred


Those with penicillin allergy, a prosthetic valve or suspected meticillin-resistant Staph. aureus (MRSA) infection, triple therapy with vancomycin, gentamicin and oral rifampicin should be consideredSURGERY indicated :Heart failure due to valve damage • Failure of antibiotic therapy (persistent/uncontrolled infection) • Large vegetations on left-sided heart valves with evidence or ‘high risk’ of systemic emboli • Abscess format

Complications

Congestive heart failure Most common complication Main indication to surgical treatment ~60% of IE patients Uncontrolled infection Persisting infection Perivalvular extension in infective endocarditis Systemic embolism Brain, spleen and lungs 30% of IE patients May be the first symptom


Complications - continued
Neurologic events Acute renal failure Rheumatic problems Myocarditis

Prophylaxis

First and most important – proper oral hygieneRegular dental reviewAntibiotics only in high-risk group patients1. Prosthetic valve or foreign material used for heart repair.2. History of IE3. Congenital heart disease Cyanotic without correction or with residual lickeageCHD without lickeage but up to 6 months after surgeryUse amoxycilin or ampicylin 30-60 min prior to intervention.