Literature Review - Emergency Department Diagnosis of Infective Endocarditis Using Bedside Ultrasound

This week, instead of presenting a new case from our ED, we are going to highlight an interesting use of bedside cardiac ultrasound in the form of a case report that was published in the Critical Ultrasound Journal, February 2013.  The case report has not only the full article, but also helpful videos for teaching purposes.

Infective endocarditis typically presents with vague constitutional symptoms and is a challenging diagnosis to make in the ED.  The purpose of this article is to highlight the importance of maintaining high clinical suspicion in patients with predisposing factors such as IVDA, indwelling catheters, and known structural heart defects, as well as to demonstrate the utility of bedside sonography in making an earlier diagnosis which would facilitate more timely treatment.

CASE: 60 yo male with history of stage IIB rectal cancer presents to ED c/o progressive SOB.  Patient with h/o surgery/radiation for disease and still maintains an indwelling central venous catheter with a portal reservoir that was used for chemotherapy.  On presentation, patient is alert and oriented to name and place, but is ill-appearing and has difficulty answering questions.  

VS:  T 97.7F, HR 41 bpm, BP 84/53 mmHg, O2 sat 82% RA

PE:

  • Skin: indwelling catheter present to R chest wall poorly cared for but without overt signs of infection; large confluent purple macules on LE 
  • Pulm: rales b/l
  • Cardiac: 3/6 pan-systolic murmur best heard at LSB

 Labs:

  • WBC 26,000
  • Hb 6.9
  • Plt 17,000
  • Lactate 7.4
  • BUN/Cr: 68/1.55
  • UA: 50 rbc/hpf, no wbc, bacteria, casts

 Imaging:

  • CXR: central venous catheter tip visible in proximal superior vena cava
  • Transthoracic Echo (TTE)/bedside sono: large vegetation visualized on tricuspid valve (VIDEO CLIP); + regurgitation over the tricuspid valve (VIDEO CLIP); right atrial enlargement
  • CT chest: pulmonary consolidation, cavitary lesions suggestive of septic emboli; large filling defect near tricuspid valve suggesting large vegetation; patent foramen ovale
Image from Critical Ultrasound Journal

Image from Critical Ultrasound Journal

ED Course:

  • Fluid resuscitation
  • Blood cultures drawn immediately
  • Broad-spectrum abx started subsequent to blood cultures
  • Cardiology and CT surgery consulted 

 Hospital course:

  • Transesophageal Echo (TEE) confirmed  multiple bulky vegetations attached to tricuspid valve protruding into RA; significant tricuspid regurgitation and resultant right atrial dilation; patent foramen ovale
  • Patient deemed poor surgical candidate due to presence of multi-organ failure and overwhelming sepsis; patient died 2 weeks post admission from ED.  

Important Points from the Article

  1. Without the use of bedside sonography, the patient did not meet Duke’s criteria.  Based on the patient’s presentation, he satisfied only 3 minor criteria (predisposition 2/2 the indwelling catheter and vascular phenomenon in the form of arterial emboli and septic pulmonary infarcts); using bedside sono helped identify the tricuspid vegetation and regurgitation, which qualifies as a major criterion per Duke’s. 
  2. Although TTE is less sensitive than TEE in identifying endocarditis, studies have shown that vegetation size is directly correlated with complications and mortality, demonstrating the utility of TTE in indentifying larger vegetations.

Complications of infective endocarditis were 10% when vegetations were < 6mm; 50% for lesions 7-11mm; 100% for lesions > 15mm in size.