Enterococcus faecalis infective endocarditis arising from chronic rectal prolapse in the setting of spinal cord injury

Abstract

A 45-year-old man had recurrent presentations with pleuritic chest pain and shortness of breath. Four months prior, he had developed cauda equina syndrome from a spinal epidural abscess in the setting of intravenous drug use, complicated by lasting neurological deficits and a rectal prolapse. On his final presentation, blood cultures taken in the absence of antibiotics grew Enterococcus faecalis from multiple sets. A transoesophageal echocardiogram confirmed tricuspid valve endocarditis. He recovered well post-targeted long-term antibiotics. Endoscopy confirmed a chronic rectal prolapse with multiple ulcers and was hypothesised as the source of bacteraemia. He subsequently underwent perineal rectosigmoidectomy. This uncommon sequela of rectal prolapse highlights several issues, including the management of neurogenic bowel dysfunction following spinal cord injury and the importance of early prolapse recognition and management. Finally, appropriate collection of blood cultures and correct use of echocardiography are critical steps in investigating infective endocarditis.

Background

Infective endocarditis (IE) is a bacterial infection on the endocardial surface of the heart that can be caused by a number of different bacteria, but when caused by Enterococcus faecalis is often associated with large bowel pathology.^{1 2} IE due to a chronic rectal prolapse source has not been previously described in the literature.

A rectal prolapse is a protrusion of all rectal layers through the anus and is a rare event, occurring in 0.5% of the general population.^{3 4} There are three types, internal prolapse or internal intussusception, mucosal prolapse and full-thickness external rectal prolapse (ERP).^{3 4} Symptoms of ERP include a protruding mass which may or may not be reducible, pain, rectal bleeding, constipation and faecal incontinence.⁴ Commonly ulceration occurs due to mucosal congestion.^{3 4} Risk factors for rectal prolapse include vaginal deliveries, anatomical abnormalities, previous spinal cord injury (SCI) or surgery and female gender.^{3 4} Physical examination to differentiate internal from external prolapse and colonoscopy to exclude a lead point lesion are key in the workup of ERP.^3–7 Mainstay of treatment remains surgical with both intra-abdominal and perineal approaches.^4–7

Neurogenic bowel dysfunction (NBD) encompasses constipation, faecal incontience, abdominal distension and pain frequently experienced by patients with disorders of the central nervous system, including SCI.⁸ In patients with chronic SCI up to 95% report constipation, 75% experience episodes of faecal incontinence and 50% become dependent on others for toileting, all leading to a significant impact on quality of life.^9–11 Patients with NBD rely on multiple techniques from conservative methods to invasive in order to evacuate their bowels.⁸ Due to straining and assisted defecation rectal prolapse is more common among patients with SCI than the general population.¹²

Here, we present a unique case of a 45-year-old man with E. faecalis IE likely arising from a chronic rectal prolapse source following SCI.

Case presentation

A 45-year-old man had three presentations with pleuritic chest pain and shortness of breath. He had a history of intravenous heroin use, treated hepatitis C and was a current smoker. Four months prior, he had been admitted with cauda equina syndrome (CES) secondary to a methicillin-sensitive Staphylococcus aureus (MSSA) spinal epidural abscess in the setting of intravenous drug use. He was transferred to a tertiary neurosurgical centre where he underwent decompression and drainage of an abscess at the L5/S1 level. Persisting neurology and expansion of collection (T12-L1) necessitated further decompression. He subsequently developed lasting neurological deficits including urinary incontinence, weakness in both legs and constipation. Within a week of final decompression, a rectal prolapse was noticed in the setting of sustained straining to pass a bowel motion. At the time, he had no echocardiographic evidence of IE. He was eventually discharged on 6 months of oral flucloxacillin.

The three presentations with pleuritic chest pain and shortness of breath occured at 12, 19 and 21 weeks following discharge from spinal surgery. Prehospital symptom duration varied from 4 to 5 days. Cough, coryza and fever were absent in each instance. He denied any injecting drug use since spinal surgery and was on stable opioid replacement therapy with methadone. On each occasion, he was tachycardic, hypoxic, tachypnoeic, normotensive and afebrile. At each presentation, chest auscultation was relatively unremarkable, cardiac murmurs and peripheral stigmata of endocarditis were absent.

During his second admission, his rectal prolapse was reviewed by colorectal surgery. Since his spinal surgery, he described a reducible lump when bearing down to open bowels. Faecal incontience was absent though constipation was present and bright red blood on wiping was reported. He described intermittent oral macrogol use and digital evacuation to assist with daily incomplete bowel motions. On examination, no rectal prolapse was observed at rest and when asked to bear down. He was insensate and had reduced anal tone. As the prolapse was reducible, he was scheduled for an urgent outpatient colonoscopy.

During each admission he had elevated white cell count (11.7×10⁹/L, 16.2×10⁹/L, 11.1×10⁹/L, respectively) and C reactive protein (159 mg/L, 155 mg/L, 156 mg/L, respectively). He also had a normal troponin I level. Urine culture collected on each admission yielded no growth. CT pulmonary angiogram on each admission excluded pulmonary embolus and showed migrating areas of consolidation. Two cavitating lesions in the left upper lobe from first admission were replaced by left upper lobe opacification and extensive hilar lymphadenopathy by the second admission. By the third admission, a new right-sided pleural effusion with right middle lobe consolidation had developed. All blood cultures in the first two admissions were unfortunately taken after antibiotic administration and had no growth and transthoracic echocardiography (TTE) also showed no vegetations. Based on this, he was treated for community acquired pneumonia with symptomatic response. In the final admission, cultures taken in the absence of antibiotics grew E.s faecalis sensitive to ampicillin. A transoesophageal echocardiogram (TOE) during his final admission identified a 1×1 cm vegetation on the tricuspid valve (figure 1).

Figure 1.

Transoesophageal echocardiogram—mid-oesophageal modified short axis view of right heart in two planes: tricuspid valve (green arrow) and vegetation (red arrow) with size marker.

The source of E. faecalis bacteraemia was hypothesised to be the rectal prolapse. He proceeded to have an inpatient colonoscopy. Examination under sedation revealed a 6 cm full-thickness rectal prolapse on testing with application of gentle traction using Babcock’s forceps. The mucosa was thickened with multiple deep erosions (figure 2). A lax chronically dilated sphincter complex was identified. No additional lesions were identified. Histology of a rectal biopsy showed benign rectal ulceration.

Figure 2.

Colonoscopy of rectal prolapse. (A) Full-thickness external rectal prolapse (ERP) (white arrow) with deep mucosal erosions (blue arrows) demontrated with Babcock’s Forceps. (B, C) Endoscopic views of rectum with deep mucosal erosions (blue arrows). (D) Endoscopic view of chronically inflammed and lax rectal mucosa (green arrows).

Subsequent video urodynamic studies confirmed bladder hyposensitivity and stress incontinence consistent with CES. Intermittent self-catheterisation was recommended by urology.

Differential diagnosis

In the first two presentations, the patient was managed as having community-acquired pneumonia because of his presentation with pleuritic chest pain and raised inflammatory markers. Investigations had excluded an acute coronary syndrome and pulmonary embolus. Given the cavitating lesions on CT and the history of injecting drug use, right-sided IE was also suspected. However, negative serial blood cultures, unfortunately obtained after antibiotic administration, and normal TTE was falsely reassuring. With rapid symptomatic improvement on antibiotics, community acquired pneumonia was diagnosed and the more invasive TOE was not pursued.

On the third presentation, appropriately collected blood cultures and a TOE confirmed the underlying pathology as IE. Multiple sources for E. faecalis were considered. Persistence from his spinal epidural abscess was unlikely given different offending organism (MSSA), negative TOE at the time of spinal epidural abscess diagnosis and long-term targeted antibiotic use with compliance. Absence of interval drug use, compliance with methadone and isolation of an enteric organism also made intravenous drug use less likely.

At this point, the ulcerated chronic rectal prolapse was considered a source. Identification of multiple deep erosions on the prolapsed mucosa was considered a likely portal of entry.

Treatment

The patient was commenced on 6 weeks of inpatient intravenous ampicillin 2 g four times per day with synergistic ceftriaxone 2 g two times per day, in accordance with European guidelines, to avoid the higher risk of adverse effects associated with the traditional regimen ampicillin plus gentamicin—specifically nephrotoxicity,¹³ vestibulotoxicity and cochleotoxicity.^{14 15} He had symptomatic relief and all repeat blood cultures showed no growth. A TOE performed 1 month following discharge revealed no valvular vegetations.

Although surgery is infrequently required for right-sided IE, in this case, surgery was not considered as the degree of valvular regurgitation did not warrant intervention and no further embolic events occurred while on medical therapy.¹³

Four months following discharge, the patient underwent perineal rectosigmoidectomy (Altemeier’s procedure) for his rectal prolapse. He had an unremarkable postoperative course and was discharged 4 days following procedure.

Outcome and follow-up

Four months following perineal rectosigmoidectomy, the patient was reviewed in the surgical outpatient clinic. There had been no recurrence of rectal prolapse nor any faecal incontinence reported.

Discussion

To the best of our knowledge, this is the first case of IE arising from a rectal prolapse source. In this case, a rectal prolapse developed 12 weeks prior to first presentation with IE. Prompt identification and management of the rectal prolapse following his SCI may have prevented development of IE.

Early prolapse repair is imperative to avoid complications. Progressive increase in size of ERP weakens the sphincter complex increasing the risk of incontinence and rectal incarceration.⁴ Although not fully understood, ulceration may develop due to local trauma from self-digitation, local ischaemia from venous congestion and abnormal contraction of the puborectalis causing rectal compression.^{16 17} In 10%–15% of cases, these present as a solitary anterior rectal ulcer.^{5 7} American, Dutch and Italian guidelines recommend full history and examination to identify predominant symptoms (including faecal incontinence), and to confirm the presence and length of ERP.^5–7 In this case, although history was highly suspicious for an ERP, it was not visualised on examination and this may have delayed intervention. One guideline recommendation is to use photography by the patient to confirm ERP is present.⁵ The presence of urinary incontinence warrants investigation for multivisceral prolapse and requires a multidisciplinary approach.^5–7 In our case, the patient was reviewed by a urological continence team and video urodynamics confirmed absence of bladder prolapse. As in this case, preoperatively all patients need to undergo colonoscopy and anoscopy to rule out a lead point (ie, mass) or other concerning lesions.^5–7

In the majority of cases, ERP requires surgery varying from intra-abdominal to perineal approaches. However, there is a lack of consensus regarding the best operation.¹⁸ A 2015 Cochrane review of 15 randomised control studies comparing operative approaches for ERP was unable to show superiority of one procedure over another.¹⁸ Most guidelines make a weak recommendation for intra-abdominal approach with rectal fixation as a firstline for ERP.^{5 6} However, they all acknowledge that choice of procedure needs to take co-morbidities, symptoms and operator expertise into account.^5–7 A perineal rectosigmoidectomy is recommended when the prolapse is large (usually >5 cm).^{5 7} It involves full-thickness resection of prolapsed rectum and a coloanal anastomosis.⁴ In this case, perineal rectosigmoidectomy was performed due to operator preference, size of prolapse (6 cm) and to avoid synthetic material which may act as a nidus for infection. Earlier implementation of the above guidelines may have avoided ERP progression, ulceration and subsequent IE.

The case also highlights the importance of managing NBD following SCI. In this case, rectal prolapse occured when straining to pass a bowel motion shortly following spinal surgery. SCI occured at the L5/S1 level from compression of the cauda equina (L3–S5 spinal nerves). Here the pattern of NBD is lower motor neuron with injury below the conus medullaris (L1–2) characterised by an areflexic bowel with an atonic external anal sphincter, resulting in slow-transit constipation and increased risk of faecal incontinence.^19–22 Early management of NBD post-SCI may have avoided development of rectal prolapse. In acute SCI with lower motor neuron involvement, initiating treatment is recommended within 24 hours of admission with manual rectal evacuation to prevent overdistension.²³ Subsequently, guidelines suggest an individualised approach with initial assesment of NBD symptoms using validated questionnaires.^{19 22–24} Conservative approaches, although supported by only low levels of evidence, are initially recommended with approaches that include dietary modifications, scheduled defecation, medications and assistive techniques.^{19 22–25} In this case, minimising constipating medications like methadone, using a low fibre diet, multiple regular oral laxatives and scheduled defecation may have improved slow-transit constipation.^{19 22–25} In addition to digital evacuation, transanal irrigation is strongly recommended for constipation in SCI.^{19 22–26} These techniques employed early post-SCI may have avoided prolapse occurrence.

The diagnosis of IE was delayed by inappropriate blood culture collection and reliance on TTE. The 2015 American and European guidelines use the Modified Duke criteria to guide diagnosis of IE.^{13 27 28} A micro-organism consistent with IE, such as E. faecalis, demonstrated on two separate blood cultures is a major criterion for possible IE.²⁸ A best practice statement from the 2016 International Guidelines for Surviving Sepsis and Septic Shock recommends for at least two sets of blood cultures (aerobic and anaerobic) prior to antimicrobial therapy if there is no substantial delay.²⁹ Obtaining blood cultures following antimicrobial therapy is associated with a significant loss of pathogen detection.³⁰ In the first two admissions, blood cultures were only taken post antibiotic administration and prevented earlier identification of E. faecalis. In addition, echocardiogram evidence for IE (including a vegetation on valve) is another major criterion for IE.^{13 27 28} However, TTE was negative in the first two admissions despite clinical suspicion for IE. In this instance, guidelines recommend a TOE owing to its higher sensitivity (90%–100%) and specificity (>90%) for detecting vegetations on native valves.^{13 27 31}

Learning points.

• Neurogenic bowel dysfunction is common following spinal cord injury, and management is essential to preventing complications like rectal prolapse.

• External rectal prolapse requires prompt identification and management to improve quality of life and prevent complications including infective endocarditis.

• Collection of serial blood cultures prior to antibiotic administration and use of transoesophageal echocardiography are critical diagnostic steps in cases of suspected infective endocarditis.