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A Case of Non-bacterial Thromboembolic Endocarditis

Authors: Captain William Dirkes (EM Resident Physician, Madigan Army Medical Center), Captain Joshua Kessler (EM Resident Physician, Madigan Army Medical Center), Lieutenant Colonel Jay Baker (EM Attending Physician, Madigan Army Medical Center), and Colonel Ian Wedmore (EM Attending Physician, Madigan Army Medical Center) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) & Justin Bright, MD (@JBright2021)

Introduction

A 59 year-old male presented to the emergency department with a chief complaint of difficulty concentrating and loss of vision. He had presented to the same facility the day prior for chest pain, chills, and a cough. During his prior visit, the patient underwent a chest x-ray which demonstrated a consolidation suggestive of a lobar pneumonia and was subsequently discharged home with a prescription for Azithromycin as well as instructions to follow-up with his primary care doctor. However, he was unable to fill his prescription. Upon attempting to drive home, the patient was pulled over by law enforcement because he was acting “delirious.” Despite the traffic incident, he was allowed to return home. The patient reported that once he arrived at home he began bumping into furniture, experiencing difficulty with concentration, and suffered vision loss. In addition, he continued to experience chills, chest pain, and shortness of breath. He denied experiencing any abdominal pain, dysuria, focal numbness or weakness, headache, hematuria, hematochezia or melena, speech disturbances, or a rash. His medical history included diabetes, hypertension, hyperlipidemia, and an unprovoked DVT (deep venous thrombosis) approximately 5 months prior. He denied any surgical history. His medications included Atorvastatin, Lantus, Metformin, Rivaroxaban, Sitagliptin, and Telmisartan. He reported smoking a ½ pack of cigarettes per day for the last 15 years, consuming alcohol occasionally, and denied any current or prior illicit drug use.

His initial vital signs in the emergency department were a blood pressure of 150/95, a heart rate of 106, a respiratory rate of 24, an oxygen saturation of 95% on room air, and a temperature of 97.8F, taken temporally. His physical exam demonstrated a male appearing his stated age, in no apparent distress but with mild tachypnea, diminished breaths sounds in the left posterior lung fields, and no cardiac murmurs on auscultation. His neurologic examination demonstrated that he was alert and oriented, but had intermittent periods of confusion and difficulty with recall during the interview. His speech was normal and his cranial nerves were grossly intact. He had a right hemianopsia on visual confrontation. He had full strength in all of his extremities and normal sensation to light touch. No dysmetria on finger-nose testing and heel-shin was normal.

He underwent a non-contrasted computed tomography (CT) scan of his head which demonstrated multifocal cortical abnormalities concerning for embolic infarcts with a dense left middle cerebral artery sign indicative of an evolving territorial infarct. A portable chest x-ray demonstrated a moderate left lung pleural effusion and prompted further imaging to characterize the lesion. A CT pulmonary arteriogram demonstrated a segmental pulmonary embolism of the right lower lung lobe with an enhancing mediastinal mass concerning for malignancy in addition to the already visualized left-sided pleural effusion. Abnormal laboratory findings included a white blood cell count of 10.4 and a platelet count of 58. The remainder of the CBC was unremarkable and his lactate, liver function tests, coagulation panel, troponin, and urinalysis were within normal limits. His electrocardiogram demonstrated a normal sinus rhythm with a rate of 85 beats/minute.

CT chest
segmental pulmonary embolism of the right lower lung lobe with an enhancing mediastinal mass concerning for malignancy in addition to the already visualized left-sided pleural effusion
ct head
multifocal cortical abnormalities concerning for embolic infarcts with a dense left middle cerebral artery sign indicative of an evolving territorial infarct.

He was admitted to the inpatient medicine service which included a neurology consultation. An inpatient MRI of his brain was obtained which demonstrated an acute ischemic infarct in the left parieto-occipital lobes. These findings were consistent with multiple chronic infarcts versus vasogenic edema possibly representing metastatic disease. A trans-esophageal echocardiogram demonstrated tricuspid vegetations. He was subsequently diagnosed with Non-Bacterial Thromboembolic Endocarditis (NBTE) and discharged home on the following day.

Non-Bacterial Thromboembolic Endocarditis (NBTE)

NBTE is also known as Libman-Sacks Endocarditis or formerly, as Marantic Endocarditis. It is a rare condition, often diagnosed on autopsy, most often found between the fourth and eighth decades of life. [1, 2, 4] NBTE is the result of platelet and/or fibrin aggregation on a heart valve secondary to an underlying hypercoagulable state. Usually, the hypercoagulable state is induced by a metastatic process or rheumatologic condition such as Systemic Lupus Erythematosus (SLE), Anti-Phospholipid Syndrome, or Rheumatoid Arthritis. [1-3] These disorders are known to have a higher prevalence in female patient populations (approximately 5-9 times their male counterparts), more specifically in African American and Hispanic ethnicities. As such, the clinician should maintain a higher degree of suspicion when treating these patient populations. Unlike bacterial vegetations, the vegetations of NBTE are symmetric with a smooth or verrucoid texture and contain little evidence of polymorphonuclear leukocytes, microorganisms, or inflammation. The disease affects the heart valves with the following predilection: aortic valve > mitral valve > tricuspid valve > pulmonary valve. Clinically, the disease presents with embolic events including stroke, delirium, pulmonary embolism, renal/splenic infarction, acute myocardial infarction, digital ischemia, and/or rash. Because of the non-invasive nature of NBTE, clinical examination may or may not reveal a new cardiac murmur. An embolic stroke may be the initial presentation to suggest a diagnosis of NBTE and if the clinician is suspicious, an Echocardiogram should be obtained to assess for valvular lesions. Emergency Department management should include evaluation for Disseminated Intravascular Coagulation (obtaining coagulation panel, d-dimer, fibrinogen), as this complication has been found in 18% of cases of NBTE.

Treatment

Treatment of NBTE consists of anti-coagulation and therapy directed at the underlying metastatic process or rhematoogical condition. Unfractionated heparin should be the anti-coagulant employed as warfarin is less effective and has been associated with increased rates of thromboembolic events. Novel anticoagulants, such as Dabigatran, Apixaban and Rivaroxaban, should also be avoided as they have not been evaluated for use in this disease process. Surgical intervention may be considered in select cases where the risk-benefit ratio is favorable. Anticoagulation should be continued indefinitely, since recurrent thromboembolism has occurred in patients following its discontinuation. [5] The indications for surgical intervention in NBTE are similar to those in infective endocarditis, namely heart failure, valve rupture, and most commonly recurrent embolization despite anticoagulation. Follow-up should be considered on an individual basis. However, patients should be monitored for known complications of NBTE, specifically infective endocarditis and emobilzation despite anticoagulation. Additionally, Echocardiogram 6 weeks to 3 months after initiation should be considered to follow the progression or resolution of valvular vegetations. Prognosis is generally grim despite anticoagulation due to the underlying predisposing medical condition rather than NBTE itself; a strong association between advanced malignancy and NBTE has been demonstrated in retrospective studies. Similarly, in patients with SLE, a longitudinal, cross-sectional study reports poor outcomes due to recurrent embolic events (25%), cognitive disability (24%) and death (9%). [6]

References/Further Reading

  1. el-Shami, K, Griffiths, E, and Streiff, M. Nonbacterial Thrombotic Endocarditis in Cancer Patients: Pathogenesis, Diagnosis, and Treatment. The Oncologist. 2007;12:518-23.
  2. Deppisch LM, Fayemi AO. Non-bacterial thrombotic endocarditis: Clinicopathologic correlations. Am Heart J 1976;92:723–729.
  3. Eiken PW, Edwards WD, Tazelaar HD, McBane RD, Zehr KJ (2001).“Surgical pathology of nonbacterial thrombotic endocarditis in 30 patients, 1985–2000”. Mayo Clin. Proc.76 (12): 1204–12. doi:4065/76.12.1204. PMID 11761501.
  4. Lopez JA, Ross RS, Fishbein MC, SIegel JC. Nonobacterial thrombotic endocarditis: a review. AM Heart J 1987; 113:773.
  5. Rogers LR, Cho ES, Kempin S et al. Cerebral infarction from non-bacterial thrombotic endocarditis: Clinical and pathological study including the effects of anticoagulation. Am J Med 1987;83:746 –756.
  6. Roldan CA, Qualis CR, Sopko KS, SIbbit WL Kr. Transthoracic versus tranesophageal echocardiography for detection of Libman-Sacks endocarditis: a randomized controlled study. J Rheumatol 2008; 35:224.

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