Abstract

A rare instance of infective endocarditis by Streptococcus viridans and Lactobacillus spp in an elderly patient with advanced colorectal cancer, leading to an aortic valve abscess, infectious emboli, and stroke. Our hypothesis is the gastrointestinal tract served as the probable entry route for the bacteria.

Keywords: Lactobacillus; Infectious emboli; Stroke; Streptococcus viridans; Aortic valve abscess.

Abbreviations: TTE: Transthoracic Echocardiogram; TEE: Transesophageal Echocardiogram; AR: Aortic Regurgitation; IE: Infective Endocarditis; CT: Computed Tomography; CTA: Computed Tomography Angiography; MRI: Magnetic Resonance Imaging; ESC: European Society of Cardiology; IDU: Intravenous Drug Use.

Citation: Ukenenye E, Stojanović N, Kahn A, Nigussie B, Gunsburg D, et al. Polymicrobial Infective Endocarditis with Stroke in a Patient with Metastatic Colorectal Cancer. SciBase Cardiol. 2024; 2(2): 1011.

History of presentation

This is a case of a 72-year-old African-American male who presented with new onset left facial droop, slurred speech, and left-sided hemiparesis that started on the day of presentation. Physical examination confirmed these complaints and was notable for cachexia.

• To detect the possible clinical features and presentation of polymicrobial infective endocarditis in colorectal cancer patients.

• To appreciate the possible imaging findings in polymicrobial infective endocarditis and its complications.

Past medical history

Hypertension

Cerebrovascular accident (2018) without residual deficits

Differential diagnosis

Stroke

TIA

Brain mass

Seizures

Investigations

Computed Tomography (CT) brain was negative for acute intracranial hemorrhage, mass effect, and infarct. CT Angiography (CTA) brain reported Right M2 superior division occlusion (Figure 1) confirmed with an MRI, which identified an MCA infarct.

CTA abdomino-pelvic was done for rectal bleeding and it highlighted descending colon wall thickening and multiple liver masses. Carcinogenic Embryonic Antigen was 258 ng/mL (0.0-4.7 ng/mL). Liver biopsy sample and immunostaining showed a positive reaction for CDX2, CK20, and villain; and a negative reaction for CK 7, consistent with metastatic colonic adenocarcinoma.

The patient became febrile and the first blood culture sets grew Streptococcus viridans (anaerobic bottles) and Lactobacillus species (aerobic bottles). Three additional sets of blood cultures drawn 30 minutes apart resulted in the same findings. Transthoracic echocardiography revealed a poorly visualized aortic valve, valve leaflets mildly thickened with mild regurgitation, and hyperdynamic left ventricular systolic function. Transesophageal Echocardiography (TEE) demonstrated 1 cm mobile vegetation in the aortic valve with leaflet perforation, abscess, and severe Aortic Regurgitation (AR) as shown in Figures 2 and 3.

Discussion

IE is a life-threatening condition that is mostly caused by bacterial but sometimes fungal or even non-infectious causes that remain a clinical challenge due to variable clinical presentation that requires a high index of suspicion.

The initial clinical assessment should include evaluating for risk factors (Table 1).

Table 1: Infective endocarditis risk factors.

Our patient had a risk factor of relative immunosuppression in the setting of active stage four gastrointestinal malignancy.

Fever (77.7%), cardiac murmur (64.5%), congestive heart failure (27.2%), embolic complications (25.3%), and cardiac conduction abnormalities (11.5%) are the most common IE clinical manifestations [1-6]. Atypical presentation is common in elderly or immunocompromised patients [7]. Our patient was admitted with acute neurological symptoms indicative of embolic complications stemming from IE, accompanied by fever and a newly observed murmur associated with AR. A significant aspect of this case is the patient’s cancer-related cachexia and frailty, which might account for the absence of typical clinical indicators of IE until the onset of embolic complications.

The most recently validated modified diagnostic criteria of IE were provided in the 2023 European Society of Cardiology (ESC) modified diagnostic criteria of IE (see Table 2). Definitive IE was classified if at least two major criteria, one major and at least three minor criteria, or five minor criteria were met.

Table 2: Major diagnostic criteria for infective endocarditis.

The minor criteria as per the 2023 ESC, modified diagnostic criteria of IE, are listed in Table 3 below:

Table 3: Minor diagnostic criteria for infective endocarditis.

The minor criteria as per the 2023 ESC, modified diagnostic criteria of IE, are listed in Table 3.

As per the 2023 ESC modified diagnostic criteria of IE, our patient fulfilled the criteria for definite IE.

The Transthoracic Echocardiography (TTE) report prompted Transesophageal Echocardiogram (TEE) to be conducted. TEE showed a large left coronary cusp vegetation of 10 mm with an estimated size of 4 mm that was missed by TTE, as well as an aortic valve abscess and possible fistula formation. Vegetation characteristics and size, perivalvular complications (abscess, pseudoaneurysm, and dehiscence of the valve), intracardiac fistula, and leaflet perforation are the main echocardiographic findings for the diagnosis and evaluation of local complications of IE.

Surgical intervention was initially considered. However, considering the patient’s stage four colorectal cancer, cachexia, and dire prognosis, the patient and family agreed to a do-not-resuscitate and do-not-intubate status. This case underscores the importance of weighing all factors and adopting a personalized treatment strategy to manage complex health conditions. The elderly, as a fragile subgroup of the patient, have more comorbidities, underuse of curative cardiac procedures, and higher mortality of IE when compared to younger patients [8].

Aminoglycosides such as gentamicin synergize with cell wall inhibitors for bactericidal activity. They help shorten the duration of therapy and more successfully eradicate microorganisms [6]. The patient received prolonged intravenous antibiotics. Subsequent blood cultures all returned negative.

Polymicrobial IE among patients with IE is unusual (< 5%). Over half of these patients had a prosthetic heart valve, and fewer than half had a history of Intravenous Drug Use (IDU). The most common pathogens were Enterococcus, coagulase-negative staphylococci, and Candida [9]. Polymicrobial IE is associated with IDU and is otherwise rare [10]. Our patient had no history of IDU. Our hypothesis suggests that the gastrointestinal tract served as the probable entry route for both bacteria, facilitated by the breakdown of the gastrointestinal barrier with active colorectal cancer and weakened immune system in an elderly cachectic patient. The patient was previously unaware of his colorectal cancer diagnosis, which was inadvertently discovered following the initiation of rectal bleeding. This unforeseen complication arose after the commencement of anticoagulation and antiplatelet therapies.

Follow-up: Not applicable (our patient died during this admission).

Conclusion

In summary, this report documents IE atypical presentation in an immunocompromised elderly patient with metastatic colorectal cancer, showcasing the unique challenge of diagnosing and managing IE with dual microorganisms. The case underscores the possible critical role of compromised gastrointestinal integrity and diminished immune function in the pathogenesis of this condition. This case also highlights the necessity of considering a broad range of potential etiologies in IE and the value of personalized care in managing such intricate medical scenarios.

Disclosures: The authors have nothing to disclose.

Funding: There was no funding.

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