Clinical Features And Diagnosis Of Infective Endocarditis
Symptomatology can be described under four groups:
- Features of subacute infection: This manifests as low-grade or high-grade intermittent or continuous fever, often associated with chills and rigor. Digital clubbing may develop within weeks and this may be painful. In some cases the symptoms may be non-specific. Even unexplained fatigue, anemia or resistance cardiac failure should draw attention to endocarditis. Splenomegaly develops and the organ is well palpable by the second week. A brownish pigmentation develops over the face and limbs café-au-lait pigmentation (meaning, coffee with milk).
- Hemodynamic changes: Destruction of a valve may result in valve rupture leading to the development of fresh murmurs, aggravation of existing murmurs and sudden cardiac failure. In some cases the vegetations obstruct the valves. The papillary muscles and the chordate tendinae may rupture giving rise to incompetence of the atrioventricular valves.
- Embolic Phenomena: The embolis are generally small though large fatal emboli may develop at times. Emboli produce several manifestations.
- Cutaneous embolism: This leads to painful red raised lesions called Janeway lesions more numeroud on the palms and soles.
- Nails: Splinted hemorrhages occur as longitudinal streaks under the nails.
- Spleen: Painful splenomegaly and splenic infarcts may develop.
- Peripheral Arteries: Occlusion of the arteries to the extremities gives rise to absence of peripheral pulses, claudication and distal pangrene.
- Central nervous system: The carotid or vertebral system may be involved giving rise to paralysis, convulsions, visual loss, aphasia and cerebella disturbances.
- Renal infarction: This condition causes hematuria and renal failure.
- Pulmonary embolism: Gives rise to pulmonary infarction, pleurisy and pleural effusion.
- Immunological disturbances: These lead to Vasculitis which manifests as Osler’s nodes (raised tender nodules on the pulps of the fingers), Roth’s spots (Circular hemorrhages with central white spots) seen on the conjunctiva and the retina and glomerulonephritis.
A high index of clinical suspicion is very essential for early diagnosis. In persons with congenital or acquired heart disease, fever, anemia, clubbing, refractory cardiac failure, changing murmurs, development of embolis or even vague illhealth should suggest the possibility of infective endocarditis. Infective endocarditis should be differentiated from activation of rheumatic fever, disseminated lupus erythematosus, drug toxicity and other prolonged fevers. Development of normocytic normochromic anemia, mild leukocytosis, elevation of ESR, proteinuria should strengthen the clinical diagnosis.
Echocardiogram can detect the vegetations clearly. Organism can be cultured from blood and this should be attempted in all cases. Blood is collected before exhibiting antimicrobial drugs. Five to six samples of blood should be collected at the commencement of fever and rigor and inoculated directly into special media and incubated aerobically and anerobically. The organisms are slow growers and therefore the cultures should be continued for 2-3 weeks. In doubtful cases, they should be subcultured. In many cases, mixed flora may be seen, or with treatment, the microbial flora may change. Hence repeart cultures should be done when treatment is prolongedor the progress is not fully satisfactory. Drug sensitivity of the organisms should be determined to assess the requirement of antibiotics. The organisms vary considerably in their drug sensitivity and therefore, prior assessment of the antibiotic requirement is of great value in ensuring successful therapy.
© 2014 Funom Theophilus Makama