Endocarditis Flashcards
What is the usual cause of infective endocarditis
Streptococci or Negative Staphylococci
Symptoms of endocarditis
- Fever
- Heart murmur
- Glomerulonephritis
- Night Sweats
- Anaemia
How do negative staphylococci infect the body
Usually present in normal oral flora but make their way into the blood via dental surgery
What structures does endocarditis effect
- Valves with congenital or acquired defects (left side of the heart)
- Normal valves by S. pneumonia or S. aureus
- Prosthetic valves and pacemakers
Under what conditions can valid on the right side of the heart be infected
IV DRUG ADDICTS
Where is endocarditis most common
Developing countries
What gender does endocarditis effect the most
Males
Most common cause of endocarditis
S. aureus (IVDU, diabetes and surgery)
Pseudomonas aeruginosa
S. viridian’s dental problems
What are three characteristics of S. viridian’s that infect the endocardium
- Gram positive
- alpha haemolytic and
- optochin resistant
Risk factors that effect endocarditis
- IV drug use
- Poor dental hygiene
- Skin and soft tissue infection
- Dental treatment
- IV cannula
- Cardiac surgery
- Pacemaker
Pathophysiology
- Consequence of: presence of organisms in bloodstream and abnormal cardiac endothelium that facilitates adherence and growth
- Damaged endothelium promotes platelet and fibrin deposition which adheres to organisms leading to infected vegetation
What calves are commonly effected
Aortic and mitral valves
IV drug users are exceptions
Long-term effect on valves
Organisms can destroy them resulting in regurgitating or heart failure
How does poor dental hygiene result in endocarditis
- Bacteria in tooth plaque can cause gum disease = bleeding and inflammation of gums causing bacteria to enter bloodstream
Presentation of endocarditis
- New valve lesion
- Embolic events of unknown origin
- Sepsis of unknown origin
- Haematuria, glumerulonehritis
- Fever
How does infection by S.aureus effect development of endocarditis
Develops very quickly and illness feels worse
What can embolism of vegetations result in
Strokes, pulmonary embolisms
When should endocarditis be excluded as a diagnosis in patients
With heart murmur and a fever
Clinical manifestations of endocarditis
- Haemorrhages on nail beds
- Embolic skin lesions (black spots)
- Osler nodes (tender nodules in digits)
- laneway lesions (haemorrhages and nodules in the fingers)
- Roth spots (retinal haemorrhages with white or clear centres seen on fundoscopy
- Petechiae (small red/purple sports caused by bleeding in the skin)
How are embolic skin lesions caused
Infarcts causing bits of infective vegetation blocking small capillaries
How do we diagnose for Endocarditis
- 3 sets of blood cultures from DIFFERENT sites over 24hrs
- Take before antibiotics started
CRP + ESR raised
Normochromic/ normocytic anaemia
Neutrophilic
Urinalysis - haematuria
CXR - Cardiomegaly
ECG - long PR interval
Finally Echocardiograms
What is the advantage of TTE echocardiogram
Safe, non-invasive, no discomfort
Disadvantage of TTE
Poor images so low sensitivity but can identify vegetations (>2mm)
Does a negative TTE exclude infective endocarditis
no
Pros of TOE (tracheal oesophageal echo)
More sensitive, uncomfortable
BETTER AT DIAGNOSIS - exam answer
When do we use a TOE
Visualising mitral lesions and checking for development of aortic root abscess
Treatment of all types of endocarditis
Antibiotic for 4-6 weeks
treatment for non-staphylococcus bacteria
Penicillin (benzylpenicillin + gentamicin together to be strong enough the break cell walls)
Treatment for staphylococcus
Vancomycin
Rifampicin
Surgery to cure endocarditis
- Removing valves and inserting prosthetic ones
When is surgery used
- Infection can’t be cured with antibiotics
- Remove infected devices
- Remove large vegetations before they embolism
