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Non-bacterial thrombotic endocarditis andsubclinical myopericarditis in a patient withadvanced rectal cancerMuzzammil Ali
Heart of England FoundationTrust, Birmingham, UK
Correspondence toDr Muzzammil Ali,[email protected]
Accepted 23 September 2015
To cite: Ali M. BMJ CaseRep Published online:[please include Day MonthYear] doi:10.1136/bcr-2015-212820
DESCRIPTIONA 57-year-old man presented to the surgical assess-ment unit, with rectal pain. He had a 6-weekhistory of painless rectal bleeding and 45 kg ofweight loss. On examination, he had a circumferen-tial exophytic rectal mass.Blood results showed a microcytic anaemia with
an inflammatory picture. A CT of the thorax,abdomen and pelvis, revealed an invasive rectalmass (figure 1) and foci of left renal infarction(figure 2). MRI staging was T4N2M0 (figure 3).The preoperative ECG for a palliative
de-functioning end-colostomy showed T-waveinversion in the anterolateral leads (figure 4).Troponin-I was positive at 1437 ng/L without anyclinical features of myocardial ischaemia. To investi-gate this, a transthoracic echocardiogram (TTE)
was performed. This showed a 13×8 mm mobilevegetation on the anterior mitral valve (figure 5).There were no stigmata of infective endocarditisand the modified Duke criteria were not satisfied asblood cultures were negative.1 Culture-negativeendocarditis was thereafter excluded.A cardiac MRI was subsequently performed,
which revealed left ventricular myopericarditis(figure 6). This explained the positive troponin-Iresult. However, work up for this wasunremarkable.Differentials of non-infectious cardiac lesions
were then considered. The hypercoagulable state inmalignancy coupled with renal embolic phenomenamade non-bacterial thrombotic endocarditis(NBTE) the definitive diagnosis (figure 7). Heparinreduces thrombus size and the incidence of
Figure 1 CT of the thorax, abdomen and pelvisrevealing a large rectal mass (*) with areas of localperforation evidenced by pre-sacral gas outside of thebowel wall (arrows).
Figure 2 CT of the thorax, abdomen and pelvisrevealing a large focus of hypodensity in the left renalparenchyma (*) indicative of left renal infarction.
Figure 3 MRI of the abdomen and pelvis illustratingthe large invasive rectal mass staged as T4N2M0.
Figure 4 Preoperative ECG with diffuse T-waveinversion in the anterolateral leads.
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Figure 7 Pathophysiology ofnon-bacterial thrombotic endocarditisby applying Virchow’s Triad; the threefactors of hypercoagulability,endothelial damage and abnormalblood flow in advanced malignancycontribute to the formation of a sterilevegetation on a normal cardiac valve(TNF, tumour necrosis factor; IL,interleukin).
Figure 6 Cardiac MRI showingglobal late gadolinium enhancementwithin the anterior, mid and apical leftventricular (LV) segments indicative ofmyopericarditis.
Figure 5 Initial transthoracicechocardiogram. (A) A 13×8 mmmobile mass on the anterior mitralvalve leaflet (arrow), which liesbetween the left ventricle (LV) and leftatrium (LA). (B) Large regurgitant jet ofblood (blue) from the LV to the LA,indicative of mitral regurgitation.
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thromboembolic recurrence in NBTE.2 Therefore, therapeuticlow-molecular-weight heparin (LMWH) was started. There waslittle change in the patient’s bleeding.
A TTE repeated 4 weeks later showed that the vegetation wasnon-existent with no evidence to suggest embolisation (figure 8).Postoperative histopathological analysis of the rectal biopsyshowed well-differentiated rectal squamous cell carcinoma(figure 9). The patient was discharged on lifelong LMWH.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
REFERENCES1 Horstkotte D, Follath F, Gutschik E, et al. Guidelines on prevention, diagnosis and
treatment of infective endocarditis executive summary; the task force on infectiveendocarditis of the European society of cardiology. Eur Heart J 2004;25:267–76.
2 el-Shami K, Griffiths E, Streiff M. Nonbacterial thrombotic endocarditis in cancerpatients: pathogenesis, diagnosis, and treatment. Oncologist 2007;12:518.
3 Tattevin P, Watt G, Revest M, et al. Update on blood culture-negative endocarditis.Med Mal Infect 2015;45:1–8.
Figure 8 Transthoracicechocardiogram 4 weeks after theinitiation of low-molecular-weightheparin. (A) Non-existence of theprevious thrombus with a normallyfunctioning mitral valve. (B) Mildmitral regurgitation (blue).
Figure 9 Rectal biopsy showing a well-differentiated squamous cellcarcinoma. 1: Normal epidermis composed of uniform and regularlyspaced squamous cells; 2: infiltrative island of squamous cells withenlarged atypical nuclei, mitotic activity and disorder indicative ofsquamous cell carcinoma.
Learning points
▸ Myopericarditis describes a primary pericarditic syndromewith minor myocardial involvement. Viral infections are themost common cause. Most cases present subclinicallywithout a defined aetiological agent found. The diagnosis isbased on elevated serum cardiac markers in the absence ofanother cause, and evidence of myocardial inflammation oncardiac MRI, or new left ventricular (LV) systolic dysfunctionon echocardiography. There are a variety of atypical ECGchanges possible. Treatment is largely conservative.
▸ When a valvular mass is found on a transthoracicechocardiogram, infective endocarditis (IE) must first be ruledout by applying the modified Duke criteria. If blood culturesremain persistently negative, culture-negative endocarditis(CNE) must then be ruled out by considering prior antibioticexposure and intracellular fastidious bacteria—Bartonellaspp, Coxiella burnetti and Tropheryma whipplei.3 If CNE andby extension systemic infection are excluded, this effectivelyindicates that the said mass is sterile.
▸ Non-bacterial thrombotic endocarditis (NBTE) is rare and ismost commonly diagnosed on post mortem. It ischaracterised by the deposition of aseptic thrombi onnormal cardiac valves. In 80% of cases, malignancy is theunderlying aetiology. There are no pathognomonic featuresas patients are usually asymptomatic. The antemortemdiagnosis is by first excluding IE and CNE, and, thereafter,by contextualising the cardiac vegetation against thepatient’s background. In patients with advanced cancer,cardiac vegetations in the absence of systemic infectionprovide strong evidence to diagnose NBTE. Definitivetreatment includes antitumour therapy and indefinitesystemic anticoagulation with unfractionated orlow-molecular-weight heparin. Vitamin K antagonists suchas warfarin are less effective in preventing thromboembolicrecurrence.
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