Case vignette
A 20’s-year-old woman with a history of IVDU, HIV on Biktarvy, tricuspid valve endocarditis and MRSA bacteremia who presents with malaise, headache and weakness.
HR 143, BP 102/59, RR 22, SpO2 93% on 2L NC, T 37.8, 67kg
Physical exam notable for somnolence, diaphoresis and LUQ abdominal tenderness. You also note a holosystolic murmur at the parasternal left 5th intercostal space, flat, painless reddish-blue spots on her palms and soles, and reddish-brown lines under her fingernails and toenails.
Differential diagnosis includes: endocarditis, meningitis, pneumonia, bacteremia, traumatic injury, AIDS associated opportunistic infection.
What do you see in each view?
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Hyperdynamic, posterior mitral valve leaflet vegetation, small pericardial effusion
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Re-demonstrated mitral valve leaflet vegetation and small pericardial effusion
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Re-demonstrated mitral valve leaflet vegetation and hyperdynamic heart
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Flat IVC with >50% respiratory variation
What do you do next?
After performing bedside POCUS which shows a vegetation on the mitral valve, endocarditis rises to the top of your differential. You initially start fluids and initiate a septic work-up including blood cultures from 3 different sites, labs, and CT scans to assess for septic emboli. You also start broad spectrum antibiotics including ceftriaxone and vancomycin. You further consult cardiology and CTS. Ultimately the patient is admitted to the floor and the CT is remarkable for multiple embolic findings (brain, lungs, spleen, kidney, SMA occlusion). Initially, blood cultures are positive for gram positive cocci in clusters.
Teaching points
While it is true that the current AHA guidelines recommend TTE as the gold standard for diagnosing infective endocarditis, this case demonstrates how POCUS can help the ED physician expedite diagnoses in critically ill patients. The Duke Criteria for diagnosis of IE require two major criteria or one major and three minor criteria, with major criteria including “imaging findings highly suggestive of IE.” These imaging findings, such as vegetations or pendulum-like mass, can sometimes be detected on POCUS and lead to earlier consults and IE specific work-up/treatment including a TTE and antibiotics. Rapid diagnosis of IE is critical and delays in diagnosis have been associated with increased rates of complication and worse clinical outcomes, making POCUS a theoretically valuable tool for expediting care.
However, while case studies have demonstrated the utility of POCUS for detecting valvular vegetations, there is very little data assessing its sensitivity and specificity for diagnosing IE vs TTE. Current evidence shows that TTE only has a sensitivity of 40-66% and specificity of 94% for diagnosing IE with TEE having a higher sensitivity of 90-100% and similar specificity of 90-100%. One observational, cross-sectional, multicenter study from 2022 demonstrated a sensitivity of 77% and specificity of 94% for POCUS in detecting valvular vegetations in patients with bacteremia or candidemia. While further research is needed, this supports the idea that if endocarditis is suspected, in certain circumstances POCUS can help rule in the diagnosis and expedite treatment and appropriate work-up.
Sources:
1. López Palmero S, López Zúñiga MA, Rodríguez Martínez V, Reyes Parrilla R, Alguacil Muñoz AM, Sánchez-Yebra Romera W, Martín Rico P, Poquet Catalá I, Jiménez Guardiola C, Del Pozo Pérez A, Lobato Cano R, Lazo Torres AM, López Martínez G, Díez García LF, Parrón Carreño T. Point-of-Care Ultrasound (POCUS) as an Extension of the Physical Examination in Patients with Bacteremia or Candidemia. J Clin Med. 2022 Jun 23;11(13):3636. doi: 10.3390/jcm11133636. PMID: 35806920; PMCID: PMC9267352.
2. Wang A, Gaca JG, Chu VH. Management Considerations in Infective Endocarditis: A Review. JAMA. 2018 Jul 3;320(1):72-83. doi: 10.1001/jama.2018.7596. PMID: 29971402.
3. Baddour LM, Wilson WR, Bayer AS, Fowler VG Jr, Tleyjeh IM, Rybak MJ, Barsic B, Lockhart PB, Gewitz MH, Levison ME, Bolger AF, Steckelberg JM, Baltimore RS, Fink AM, O'Gara P, Taubert KA; American Heart Association Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease of the Council on Cardiovascular Disease in the Young, Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and Stroke Council. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association. Circulation. 2015 Oct 13;132(15):1435-86. doi: 10.1161/CIR.0000000000000296. Epub 2015 Sep 15. Erratum in: Circulation. 2015 Oct 27;132(17):e215. doi: 10.1161/CIR.0000000000000332. Erratum in: Circulation. 2016 Aug 23;134(8):e113. doi: 10.1161/CIR.0000000000000427. Erratum in: Circulation. 2018 Jul 31;138(5):e78-e79. doi: 10.1161/CIR.0000000000000594. PMID: 26373316.
4. Cohen A, Greco J, Levitus M, Nelson M. The use of point-of-care ultrasound to diagnose infective endocarditis causing an NSTEMI in a patient with chest pain. J Am Coll Emerg Physicians Open. 2020 Feb 6;1(2):120-123. doi: 10.1002/emp2.12004. PMID: 33000023; PMCID: PMC7493563.