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PubMed This is a summary of 22 peer-reviewed journal articles Updated
Cardiology

The Great Masquerader: Recognizing the Many Faces of Endocarditis

At a Glance

Infective endocarditis (IE) is a serious heart infection that often mimics other illnesses. Symptoms range from classic high fevers and new heart murmurs to subtle signs like low-grade fevers, joint pain, skin bumps, and even strokes caused by traveling pieces of infection.

Infective endocarditis (IE) is often called “the great masquerader” because its symptoms can look like many other illnesses. While the “classic” signs involve a high fever and a new heart murmur, many patients experience a much more subtle or confusing start to the disease [1][2]. Recognizing these signs early is vital, as a delay in diagnosis is directly linked to an increased risk of serious complications and death [3].

The Traditional Signs vs. The Subtle Start

Classically, IE presents with a high fever and chills. However, in many cases—especially those that are “subacute”—the symptoms can be much more vague:

  • Persistent “Low-Grade” Fever: You may have a fever that comes and goes or never gets very high, often called a fever of unknown origin (FUO) [4][1].
  • Constitutional Symptoms: These include unexplained weight loss, night sweats, and a general feeling of exhaustion or “blah” (malaise) [5][6].
  • Atypical Pains: It is not uncommon for IE to cause prolonged back pain or joint pain, which can be mistaken for arthritis or general aging [5][7].

Emboli: When the Infection Travels

One of the most dangerous aspects of IE is when a piece of the vegetation (the infected growth on the valve) breaks off and travels through the bloodstream. This traveling fragment is called an embolus. Because these fragments are full of bacteria, they are often called septic emboli [8][9].

  • Stroke and Neurological Signs: A stroke (sudden weakness, numbness, or trouble speaking) can actually be the first sign of endocarditis for some patients [10][11].
  • Organ Damage: Emboli can travel to the spleen, kidneys, or liver, causing sharp pain and localized infections (abscesses) [12][13].
  • Heart Attacks: In rare cases, an embolus can even block the arteries supplying the heart itself, mimicking a heart attack [14][15].

The Immune System “Mask”

Sometimes, the body’s attempt to fight the infection creates a secondary reaction that mimics autoimmune diseases (where the body attacks itself). This happens because the immune system produces “immune complexes” that settle in different parts of the body:

  • Skin Manifestations: You might see Osler nodes (small, painful, purple-red bumps on the pads of fingers or toes) or Janeway lesions (painless red spots on the palms or soles) [16][17].
  • Kidney Issues: The immune reaction can cause inflammation in the kidneys (glomerulonephritis), leading to blood in the urine or decreased kidney function [16][18].
  • Eye Changes: Small hemorrhages in the retina of the eye, called Roth spots, can sometimes be seen by a doctor during an eye exam [19].

Why Misdiagnosis Happens

Misdiagnosis is common because these symptoms are so varied. A patient might see a dermatologist for a rash, a neurologist for a stroke, or a rheumatologist for joint pain—all without realizing the root cause is in the heart [5][20].

The danger is that if you are given antibiotics for a “minor” infection before blood cultures are taken, the antibiotics can “mask” the endocarditis, making it harder for doctors to find the bacteria and choose the right long-term treatment [21][22]. Maintaining a high index of suspicion—meaning always considering IE as a possibility when fever and other odd symptoms occur together—is the best way to ensure a timely diagnosis and better outcome [4][19].

Common questions in this guide

Why is infective endocarditis hard to diagnose?
Infective endocarditis is often called 'the great masquerader' because its symptoms, such as low-grade fevers, joint pain, and fatigue, mimic many other common illnesses. This wide variety of symptoms can lead patients to see different specialists before a heart infection is finally suspected.
Can a heart infection cause a stroke?
A piece of the infected growth on the heart valve, known as a septic embolus, can break off and travel through the bloodstream to the brain. Because of this, a stroke can actually be the first noticeable sign of endocarditis for some patients.
What are Osler nodes and Janeway lesions?
These are specific skin changes caused by your immune system reacting to the heart infection. Osler nodes are small, painful, purple-red bumps on the pads of the fingers or toes, while Janeway lesions are painless red spots that appear on the palms or soles.
Can endocarditis cause back or joint pain?
Yes, atypical pains like prolonged back pain or joint pain are surprisingly common with infective endocarditis. Because these symptoms do not seem related to the heart, they are often mistaken for arthritis or the effects of general aging.
How do antibiotics affect an endocarditis diagnosis?
Taking antibiotics for a different issue before your doctor takes blood cultures can temporarily hide or 'mask' the endocarditis bacteria. This makes it much harder to definitively diagnose the condition and choose the right long-term treatment.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Given that some of my symptoms look like an autoimmune issue, what specific tests can definitively rule out endocarditis?
  2. 2.Could the neurological or organ symptoms I experienced be related to an 'embolic event' from the heart?
  3. 3.If my blood cultures were negative, could previous antibiotic use be masking a heart infection?
  4. 4.Is my current back pain or joint pain a secondary symptom of the infection?
  5. 5.How does the size of the vegetation on my valve affect my risk for a stroke or other emboli?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (22)
  1. 1

    Infective endocarditis as a complication of longstanding ventriculoatrial (VA) shunt: the importance of suspicion and early investigation in patients with VA shunt and pyrexia of unknown origin.

    Sun R, Warwick R, Harrisson S, Bandla N

    BMJ case reports 2021; (14(1)) doi:10.1136/bcr-2020-237161.

    PMID: 33462007
  2. 2

    A Case of Infective Endocarditis Associated With Patent Ductus Arteriosus in Which PET/CT Was Useful for Diagnosis.

    Miyagami T, Kushiro S, Arikawa M, et al.

    Clinical nuclear medicine 2022; (47(9)):832-833 doi:10.1097/RLU.0000000000004296.

    PMID: 35695706
  3. 3

    Delayed Diagnosis of Infective Endocarditis-Analysis of an Endocarditis Network.

    Saha S, Zauner B, Kaiser R, et al.

    Journal of clinical medicine 2026; (15(3)) doi:10.3390/jcm15030924.

    PMID: 41682607
  4. 4

    Multivalvular infective endocarditis due to streptococcus pluranimalium in a young patient with bicuspid aortic valve.

    Zúñiga-Espinosa JE, Peralta-Amaro AL, Tejada-Ruíz MI, et al.

    Oxford medical case reports 2025; (2025(9)):omaf156 doi:10.1093/omcr/omaf156.

    PMID: 40979811
  5. 5

    Subacute Infective Endocarditis Misdiagnosed as Polymyalgia Rheumatica: A Case Report.

    Rahim Z, Eftekhar A

    Cureus 2025; (17(10)):e94516 doi:10.7759/cureus.94516.

    PMID: 41246729
  6. 6

    Simultaneous Multifocal Intracranial Haemorrhages Associated with Staphylococcus Aureus Endocarditis: A Plausible Role for Diclofenac Administration.

    Tvito A, Rokach A, Ben-David E, et al.

    European journal of case reports in internal medicine 2023; (10(10)):004044 doi:10.12890/2023_004044.

    PMID: 37789977
  7. 7

    A Case Report of Subacute Infective Endocarditis Presenting With Extreme Weight Loss, Aortic Regurgitation, and Splenic Infarct.

    Rahman A, Rogers P, Piasecki JB, Frederick J

    Cureus 2024; (16(5)):e59866 doi:10.7759/cureus.59866.

    PMID: 38854221
  8. 8

    Evaluation of parameters predicting in-hospital mortality and septic embolisms in patients with infective endocarditis.

    Tatlı Kış T, Kış M, Güzel T, Mermutluoğlu Ç

    Postepy w kardiologii interwencyjnej = Advances in interventional cardiology 2024; (20(4)):480-486 doi:10.5114/aic.2024.145171.

    PMID: 39896998
  9. 9

    Infective endocarditis complicated by embolic events: Pathogenesis and predictors.

    Hu W, Wang X, Su G

    Clinical cardiology 2021; (44(3)):307-315 doi:10.1002/clc.23554.

    PMID: 33527443
  10. 10

    Stroke in Patients with Infective Endocarditis: A 15-Year Single-Center Cohort Study.

    Cao GF, Liu W, Bi Q

    European neurology 2018; (80(3-4)):171-178 doi:10.1159/000495149.

    PMID: 30485851
  11. 11

    MRI versus CT in the detection of brain lesions in patients with infective endocarditis before or after cardiac surgery.

    Vitali P, Savoldi F, Segati F, et al.

    Neuroradiology 2022; (64(5)):905-913 doi:10.1007/s00234-021-02810-y.

    PMID: 34647143
  12. 12

    Infective Endocarditis Following Post-COVID Organizing Pneumonia Complicated by Multiple Splenic Abscesses and Glomerular Nephritis.

    Jazeer M, Pakkiyaretnam M

    Cureus 2023; (15(9)):e45860 doi:10.7759/cureus.45860.

    PMID: 37881375
  13. 13

    Multivalvular Endocarditis With Abscess: A Wild Goose Chase.

    Abuso S, Rubin L, Geraghty B, et al.

    The Pediatric infectious disease journal 2022; (41(7)):e296-e299 doi:10.1097/INF.0000000000003544.

    PMID: 35389950
  14. 14

    Multidisciplinary Perspectives of Challenges in Infective Endocarditis Complicated by Septic Embolic-Induced Acute Myocardial Infarction.

    Stamate E, Ciobotaru OR, Arbune M, et al.

    Antibiotics (Basel, Switzerland) 2024; (13(6)) doi:10.3390/antibiotics13060513.

    PMID: 38927180
  15. 15

    An unusual case of infective endocarditis with acute limb ischemia and cardiac embolism.

    Daoud N, Malikayil K, Regalla D, Alam M

    IDCases 2021; (25()):e01201 doi:10.1016/j.idcr.2021.e01201.

    PMID: 34189046
  16. 16

    Infective endocarditis - why should rheumatologists be aware?

    Samões B, Fonseca D, Guerra M, et al.

    Acta reumatologica portuguesa 2021; (46(1)):77-81.

    PMID: 33820896
  17. 17

    A Case of Aortic Valve Infective Endocarditis with Dermatological Findings of Infective Endocarditis.

    Sachdeva AS, Gomez JO, Wattanakit K

    Cureus 2022; (14(3)):e23044 doi:10.7759/cureus.23044.

    PMID: 35419246
  18. 18

    Bacterial Endocarditis Presenting as Leukocytoclastic Vasculitis.

    El Chami S, Jibbe A, Shahouri S

    Cureus 2017; (9(7)):e1464 doi:10.7759/cureus.1464.

    PMID: 28936376
  19. 19

    Native-Valve Infective Endocarditis.

    Chambers HF, Bayer AS

    The New England journal of medicine 2020; (383(6)):567-576 doi:10.1056/NEJMcp2000400.

    PMID: 32757525
  20. 20

    Beyond the Surface: Cutaneous Vasculitis as a Sign of a Fatal Underlying Condition.

    Elaribi S, Ponnambath N

    Cureus 2025; (17(9)):e91953 doi:10.7759/cureus.91953.

    PMID: 41084712
  21. 21

    Factors associated with delayed diagnosis of infective endocarditis: A retrospective cohort study in a teaching hospital in Japan.

    Nishiguchi S, Nishino K, Kitagawa I, Tokuda Y

    Medicine 2020; (99(30)):e21418 doi:10.1097/MD.0000000000021418.

    PMID: 32791760
  22. 22

    Assesment of the Duke criteria for the diagnosis of infective endocarditis after twenty-years. An analysis of 241 cases.

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This page is for informational purposes only and does not replace professional medical advice. Always consult your healthcare provider if you suspect a heart infection or experience unexplained fevers and symptoms.

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