Although subacute bacterial endocarditis (SBE) develops insidiously and has a slow progression over weeks to months, it is often aggressive. Usually, no evident portal of entry or source of infection can be found. The most common causative microorganism is streptococci (especially viridans, anaerobic, enterococci, microaerophilic, and non-enterococcal group D streptococci). SBE is less commonly caused by staphylococcus epidermidis and staphylococcus aureus. SBE is generally developed on abnormal valves after asymptomatic bacteremia resulting from gastrointestinal, genitourinary, or periodontal infections.

The initial symptoms are vague, including night sweats, malaise, fatigability, weight loss, anorexia, myalgia, dyspnea, and low-grade fever (< 39°C) [1]. Arthralgias and chills are possible. Valvular insufficiency features may be the first clue. Early in the course of the disease, ≤ 15% of patients have a murmur or fever but all eventually develop both. On physical examination, normal findings can be observed or fever, pallor, tachycardia, and change in a murmur or a new regurgitant type may be detected.

Approximately 35% of cases show CNS effects like transient ischemic attacks, stroke, or brain abscesses and subarachnoid hemorrhage due to mycotic aneurysm rupture. Potential renal emboli can result in flank pain. Splenomegaly and clubbing of fingers and toes may occur because of prolonged infection.

The four peripheral signs of endocarditis include:

• Roth spots: Retinal emboli that appear as oval or round hemorrhagic lesions on the retina with white centers on fundoscopic examination. Roth spots are also found in hypertension, vasculitis, diabetes mellitus, and intracranial hemorrhages [2]. Other ocular manifestations are retinal hemorrhages and infectious vitritis in embolic disease [3].
• Osler nodes: Painful subcutaneous and erythematous nodules on the digits tips. Osler nodes are one of the classic signs in late-phase SBE. However, they can be found in other conditions such as bacteremia, systemic lupus erythematosus, and disseminated gonococcal infection. Adequate intravenous antibiotics can resolve Osler nodes within 3 days [4].
• Janeway lesions: Small, erythematous, non-tender, or hemorrhagic macular lesions. They do not have an immunological origin and are present on the palms and soles [5].
• Splinter hemorrhages: Small vertical blood clots under nails. They can also be observed in scleroderma, systemic lupus erythematosus, rheumatoid arthritis, and trauma [6].

• Splenomegaly

  Findings compatible with both SBE and marantic endocarditis due to a B-cell lymphoproliferative disorder included an elevated ESR, and splenomegaly. Blood cultures eventually became positive during hospitalization. [ncbi.nlm.nih.gov]

  Splenomegaly and clubbing of fingers and toes may occur because of prolonged infection. [symptoma.com]

  It is characterized by a slow, quiet onset with fever, heart murmur, splenomegaly, and development of clumps of abnormal tissue, called vegetations, around an intracardiac prosthesis or on the cusps of a valve. [medical-dictionary.thefreedictionary.com]

  There can been present splenomegaly, tachycardia, petechiae on the skin occur in about 10-15% of patients usually appear in groups 2-3 days and fade away and disappear without a trace, mucous membranes, then finding on the fundus, bleeding beneath the [remedyland.com]

• Fever

  Fever, anaemia, splenomegaly and positive blood cultures for Gram-negative bacteria were found on admission. The fever resolved with antibiotic therapy on the third hospital day but he then developed hemiplegia and multifocal seizures. [ncbi.nlm.nih.gov]

  Early in the course of the disease, 15% of patients have a murmur or fever but all eventually develop both. [symptoma.com]

• Weight Loss

  The diagnosis of subacute bacterial endocarditis (SBE) is suggested by a history of an indolent process characterized by fever, fatigue, anorexia, and unexplained weight loss. [ncbi.nlm.nih.gov]

  The initial symptoms are vague, including night sweats, malaise, fatigability, weight loss, anorexia, myalgia, dyspnea, and low-grade fever ( 39 C). Arthralgias and chills are possible. Valvular insufficiency features may be the first clue. [symptoma.com]

  Long-term fever, weight loss, joint pain and muscle pain, fatigue and anemia. Heart murmur, petechiae, emboli phenomena. Blood culture is positive. [remedyland.com]

  Infective Endocarditis SYMPTOMS Weakness Fatigue Weight loss Fever Chills Night sweats Anorexia Arthralgia 7. Infective Endocarditis SIGNS Petechial Hemorrhages Linear Hemorrhages Osler Nodes Janeway Lesions Retinal Hemorrhages Heart Murmur 8. [slideshare.net]

• Chills

  Arthralgias and chills are possible. Valvular insufficiency features may be the first clue. Early in the course of the disease, 15% of patients have a murmur or fever but all eventually develop both. [symptoma.com]

  Acute Bacterial Endocarditis Patients with acute or recent infection High temperature with chills, sweating, weakness Sudden changes or appearance of new murmurs The emergence embolism, petechiae and toxic effects General intoxication, an enlarged spleen [remedyland.com]

  Other symptoms include chills, weakness, cough, trouble breathing, headaches, aching joints, and loss of appetite. Emboli may also cause a variety of symptoms, depending on their location. [medical-dictionary.thefreedictionary.com]

  Infective Endocarditis SYMPTOMS Weakness Fatigue Weight loss Fever Chills Night sweats Anorexia Arthralgia 7. Infective Endocarditis SIGNS Petechial Hemorrhages Linear Hemorrhages Osler Nodes Janeway Lesions Retinal Hemorrhages Heart Murmur 8. [slideshare.net]

• Fatigue

  The diagnosis of subacute bacterial endocarditis (SBE) is suggested by a history of an indolent process characterized by fever, fatigue, anorexia, and unexplained weight loss. [ncbi.nlm.nih.gov]

  Long-term fever, weight loss, joint pain and muscle pain, fatigue and anemia. Heart murmur, petechiae, emboli phenomena. Blood culture is positive. [remedyland.com]

  Infective Endocarditis SYMPTOMS Weakness Fatigue Weight loss Fever Chills Night sweats Anorexia Arthralgia 7. Infective Endocarditis SIGNS Petechial Hemorrhages Linear Hemorrhages Osler Nodes Janeway Lesions Retinal Hemorrhages Heart Murmur 8. [slideshare.net]

  Acute bacterial endocarditis usually begins suddenly with a high fever, fast heart rate, fatigue, and rapid and extensive heart valve damage. [merckmanuals.com]

• Malaise

  Among the signs of subacute bacterial endocarditis are: Malaise Weakness Excessive sweat Fever It is usually caused by a form of Viridans group streptococcus bacteria that normally live in the mouth (Streptococcus mutans, mitis, sanguis or milleri).Other [en.wikipedia.org]

  The initial symptoms are vague, including night sweats, malaise, fatigability, weight loss, anorexia, myalgia, dyspnea, and low-grade fever ( 39 C). Arthralgias and chills are possible. Valvular insufficiency features may be the first clue. [symptoma.com]

  In addition, the patient reported a mild febrile illness with malaise and dysuria during the 3 weeks prior to presentation. Figure 1. [retinalphysician.com]

  Following symptoms can be present: sweating at night, chills, malaise, fatigue, anorexia, weight loss, vague muscle pain, redness and swelling of joints, sudden changes in the eyes, hemiplegia caused by cerebral embolism, pain abdomen, thorax, changes [remedyland.com]

• Clubbed Finger

  Obliteration in clubbed fingers of the diamond-shaped window normally produced when the dorsal surfaces of the corresponding finger of each hand are opposed (Schamroth sign) may useful for the identification of clubbing. [40] Complications Since clubbing [emedicine.medscape.com]

• Heart Disease

  AbP is given to patients with known rheumatic or other valvular heart disease by 98.9% of responders and to patients with known prosthetic heart valves by 81.5%. [ncbi.nlm.nih.gov]

  The subacute bacterial endocarditis is usually a rheumatic or congenital heart disease. [remedyland.com]

• Heart Murmur

  Its symptoms and signs are varied, and include fever, heart murmur, peripheral embolism, and heart failure. [ncbi.nlm.nih.gov]

  Heart murmurs can be considered irrelevant when it comes to infections tricuspidalis valves and valvular pulmonary artery. However, with repeated pulmonary infarction due to pneumonia, heart murmurs can be very characteristic signs. [remedyland.com]

  About 90 percent of patients will have heart murmurs, but murmurs may be absent in patients with right-sided heart infections. A changing murmur is common only in acute endocarditis. [healthcentral.com]

  It is characterized by a slow, quiet onset with fever, heart murmur, splenomegaly, and development of clumps of abnormal tissue, called vegetations, around an intracardiac prosthesis or on the cusps of a valve. [medical-dictionary.thefreedictionary.com]

• Tachycardia

  On physical examination, normal findings can be observed or fever, pallor, tachycardia, and change in a murmur or a new regurgitant type may be detected. [symptoma.com]

  Heart murmur is present in approximately 80-90% of patients, and in subacute bacterial endocarditis is more frequent up to 95% and it is accompanied by tachycardia and other signs of aggravated heart failure. [remedyland.com]

  There may also be a rapid heartbeat (tachycardia). Individuals with prosthetic valvular endocarditis may develop abscesses on or near the valves. Bacteria may also grow in the heart and obstruct the flow of blood through it. [rarediseases.org]

  […] glomerulonephritis ;, Osler nodes Therapeutic consequences Lack of valve vascularization requires antibiotic treatment for several weeks References: [14] [15] [6] [16] Clinical features Course of disease Constitutional symptoms Fever and chills ( 90% of cases), tachycardia [amboss.com]

  Löffler's endocarditis, Löffler's parietal fibroplastic endocarditis endocarditis associated with eosinophilia, marked by fibroplastic thickening of the endocardium, resulting in congestive heart failure, persistent tachycardia, hepatomegaly, splenomegaly [medical-dictionary.thefreedictionary.com]

• Systolic Murmur

  In addition to the general symptoms of infective endocarditis, there may be a heart murmur from blood flowing backward through a defective valve (regurgitative murmur) or a murmur suggestive of blood outflow obstruction (systolic murmur). [rarediseases.org]

• Diastolic Murmur

  murmur ; loudest at the left sternal border Signs of progressive heart failure ( e.g., dyspnea, edema ) Signs of acute cardiac decompensation ( pulmonary edema ) Arrhythmias Extracardiac manifestations These manifestations are mainly caused by bacterial [amboss.com]

• Recent Dental Work

  The patient denied recent dental work and was on no medications at that time. On admission, his body temperature was 38 C and pulse was 105 bpm. Abnormal physical findings included bibasal lung crackles and bilateral lower extremity pitting edema. [bmcnephrol.biomedcentral.com]

• Janeway Lesion

  A case is reported with splinter hemorrhages and Janeway lesions, resulting from an infected radial artery catheter. [ncbi.nlm.nih.gov]

  Janeway lesions: Small, erythematous, non-tender, or hemorrhagic macular lesions. They do not have an immunological origin and are present on the palms and soles. Splinter hemorrhages: Small vertical blood clots under nails. [symptoma.com]

  See also bacterial endocarditis, endocarditis, Janeway lesion. observations The infected vegetations may separate from the valve or prosthesis and form emboli. [medical-dictionary.thefreedictionary.com]

  On physical exam, there may be conjunctival hemorrhages, splinter hemorrhages, Janeway lesions (nontender hemorrhagic macules and papules on the palms), Osler nodes (painful erythematous nodules located on the fingertips), or Roth spots (pale lesions [visualdx.com]

  Infective Endocarditis SIGNS Petechial Hemorrhages Linear Hemorrhages Osler Nodes Janeway Lesions Retinal Hemorrhages Heart Murmur 8. Infective Endocarditis Outcome Fatal 10-70% of cases 9. [slideshare.net]

• Splinter Hemorrhage

  SBE manifests many skin findings including petechiae, splinter hemorrhages of the nails, Osler's and laneway lesions, clubbing of the fingers, and findings suggestive of angiitis. [ncbi.nlm.nih.gov]

  Splinter hemorrhages: Small vertical blood clots under nails. They can also be observed in scleroderma, systemic lupus erythematosus, rheumatoid arthritis, and trauma. [symptoma.com]

  Osler's nodes, petechiae, Roth's spots, and splinter hemorrhages under the fingernails are common manifestations of blood-borne metastases of these emboli. [medical-dictionary.thefreedictionary.com]

• Petechiae

  SBE manifests many skin findings including petechiae, splinter hemorrhages of the nails, Osler's and laneway lesions, clubbing of the fingers, and findings suggestive of angiitis. [ncbi.nlm.nih.gov]

  In these cases, the changes are masked and as the first warning sign, suddenly embolism, then petechiae, unexpected heart failure, altered murmur or high temperature can occur. [remedyland.com]

  […] developed dehiscence of a prosthetic valve New valvular regurgitation Minor criteria Predisposing cardiac disease Intravenous drug abuse Fever 38 C Vascular phenomena: arterial embolism, pulmonary septic embolism, mycotic aneurysm, intracranial hemorrhage, petechiae [symptoma.com]

  Osler's nodes, petechiae, Roth's spots, and splinter hemorrhages under the fingernails are common manifestations of blood-borne metastases of these emboli. [medical-dictionary.thefreedictionary.com]

• Skin Rash

  Call your doctor if you have any of these signs of an infection: Fever over 100 F(38.4 C) Sweats or chills, particularly night sweats Skin rash Pain, tenderness, redness or swelling Wound or cut that won't heal Red, warm or draining sore Sore throat, [my.clevelandclinic.org]

  Other signs and symptoms include poor appetite, feeling weak or tired, joint pains, skin rashes, and changes in the nature of a previously present heart murmur. [csun.edu]

  However, the patient returned to our hospital 1 year later with intermittent bilateral lower extremity edema and skin rashes. On admission, his vitals were normal with the exception of mild blood pressure elevation (150/80 mmHg). [bmcnephrol.biomedcentral.com]

• Palpable Purpura

  The case of a patient who had palpable purpura on his lower extremities due to Lactobacillus-caused subacute bacterial endocarditis is reported. Histologic examination of the purpuric lesions demonstrated a leukocytoclastic angiitis. [ncbi.nlm.nih.gov]

  Palpable purpura may also be seen. Imaging may reveal septic pulmonary infarcts, mycotic aneurysms, and stroke. [visualdx.com]

  Physical examination revealed palpable purpura, mild hypertension, hepatosplenomegaly, and a holosystolic cardiac murmur (Levine 2/6). Echocardiography showed tricuspid valve vegetations with moderate to severe regurgitation. [bmcnephrol.biomedcentral.com]

• Retinal Hemorrhage

  Other ocular manifestations are retinal hemorrhages and infectious vitritis in embolic disease. Osler nodes: Painful subcutaneous and erythematous nodules on the digits tips. Osler nodes are one of the classic signs in late-phase SBE. [symptoma.com]

  hemorrhage and a vitreous inflammatory response leading to a mild decrease in VA. [retinalphysician.com]

  Infective Endocarditis SIGNS Petechial Hemorrhages Linear Hemorrhages Osler Nodes Janeway Lesions Retinal Hemorrhages Heart Murmur 8. Infective Endocarditis Outcome Fatal 10-70% of cases 9. [slideshare.net]

The diagnosis of endocarditis is challenging since the presentation varies from case to case. The symptoms of SBE can take several weeks or months to develop while some patients show symptoms acutely after a few days [7].

Laboratory studies may show anemia, leukocytosis, elevated erythrocyte sedimentation rate (ESR), and microscopic hematuria. Although, bacterial endocarditis can be present in the absence of these findings [8].

If endocarditis is suspected, three sets of blood cultures (20 mL each) must be obtained from a separate new venipuncture site within 24 hours.

Echocardiography should be performed. Transthoracic echocardiography (TTE) is usually preferred since it is less costly and non-invasive compared to transesophageal echocardiography (TEE).

The definite diagnosis of infective endocarditis is done when microorganisms are cultured or observed histologically after being obtained from endocardial vegetations during embolectomy, cardiac surgery, or autopsy. Since this is not always possible, diagnostic criteria called revised Duke's criteria has been established with a specificity and sensitivity of more than 90%.

For a definite clinical diagnosis: 2 major criteria are needed, or 1 major and 3 minor criteria, or 5 minor criteria.
For a potential clinical diagnosis: 1 major criterion and 1 minor criterion are needed, or 3 minor criteria.

Major criteria

1. 2 positive blood cultures for typical microorganisms causing endocarditis
2. 3 positive blood cultures for microorganisms that are consistent with endocarditis
3. Serologic evidence of Coxiella burnetii infection (or 1 positive blood culture)
4. Evidence of endocardial involvement on echocardiography:

• Oscillating intracardiac vegetative mass on a valve, or on the supporting structures, in the path of regurgitant jets, or on implanted material without other anatomic explanation
• Cardiac abscess
• Newly developed dehiscence of a prosthetic valve
• New valvular regurgitation

Minor criteria

1. Predisposing cardiac disease
2. Intravenous drug abuse
3. Fever ≥38° C
4. Vascular phenomena: arterial embolism, pulmonary septic embolism, mycotic aneurysm, intracranial hemorrhage, petechiae on the conjunctiva, Janeway lesions
5. Immunologic phenomena: glomerulonephritis, Osler nodes, Roth spots, positive rheumatoid factor
6. Microbiological evidence of infection that is consistent with but not meeting major criteria
7. Serologic evidence of infection with organisms consistent with causing endocarditis

• Elevated Sedimentation Rate

  Blood tests show signs of inflammation such as an elevated sedimentation rate,while anemia and blood cells in the urine are often present. The most important diagnostic test for endocarditis involves a positive blood culture. [csun.edu]

• Blood Culture Positive

  Diagnosis 5.1 Clinical features 5.2 Laboratory findings 5.3 Imaging techniques 5.3.1 Echocardiography 5.3.2 Multislice computed tomography 5.3.3 Magnetic resonance imaging 5.3.4 Nuclear imaging 5.4 Microbiological diagnosis 5.4.1 Blood culture–positive [escardio.org]

  positive for infectious organisms Blood cultures that are positive for microorganisms, which are taken 12 hours apart 3 blood cultures positive on separate occasions that are taken at least 1 hour apart Abnormalities in echocardiogram showing either a [dovemed.com]

  The criteria combine the clinical, microbiologic, pathologic, and echocardiographic characteristics of a specific case [2] : Major blood culture criteria for IE include the following: Two blood cultures positive for organisms typically found in patients [emedicine.medscape.com]

1. Mylonakis E, Calderwood SB. Infective endocarditis in adults. N Engl J Med. 2001;345:1318–30. doi: 10.1056/NEJMra010082.
2. Fred HL. Little black bags, ophthalmoscopy, and the Roth spot. Tex Heart Inst J. 2013;40:115–6.
3. Habib G, Hoen B, Tornos P, et al. Guidelines on the prevention, diagnosis, and treatment of infective endocarditis (new version 2009): The task force on the prevention, diagnosis, and treatment of Infective Endocarditis of the European society of Cardiology (ESC). Eur Heart J. 2009;30(19):2369-413.
4. Jackson TL, Eykyn SJ, Graham EM, Stanford MR. Endogenous bacterial endophthalmitis: a 17-year prospective series and review of 267 reported cases. Surv Ophthalmol. 2003;48:403–23. doi: 10.1016/S0039-6257(03)00054-7.
5. Farrior JB, Silverman ME. A consideration of the differences between a Janeway’s lesion and an Osler’s node in infectious endocarditis. Chest. 1976;70:239–43. doi: 10.1378/chest.70.2.239.
6. Robertson JC, Braune ML. Splinter haemorrhages, pitting, and other findings in fingernails of healthy adults. Br Med J. 1974;4:279–81. doi: 10.1136/bmj.4.5939.279.
7. Luttenberger K, DiNapoli M. Subacute bacterial Endocarditis. J.Nurse Pract. 2011;36(3):31–38. doi:10.1097/01.npr.0000393971.15598.0c.
8. Cunha BA, Gill MV, Lazar JM. Acute infective endocarditis. Diagnostic and therapeutic approach. Infect Dis Clin North Am. 1996;10:811–34.