Blocking a rash diagnosis: a rare case of infective endocarditis

Abstract

We report a case of a previously healthy, afebrile patient who presented with subacute bilateral lower extremity rash and complete heart block, which was later found to be secondary to infective endocarditis. His transoesophageal echocardiogram detected multiple vegetations and blood cultures were positive for Granulicatella adiacens, a nutritionally variant streptococcus that is a normal component of oral flora and thought to be responsible for approximately 5% of all cases of streptococcal endocarditis. Due to concerns for renal failure, the patient was treated with an unconventional regimen of ampicillin and ceftriaxone. He underwent a valve replacement and pacemaker placement and has done well since hospital discharge.

Background

Infective endocarditis (IE) is rare, occurring in 3–10 per 100 000 people annually. Staphylococcus aureus is the most common causative bacteria, accounting for 25%–30% of all cases.¹ Fever is often the presenting symptoms of patients with IE and diagnosis of IE is challenging in afebrile patients with no typical signs of infection. However, it is imperative that practitioners consider IE in patients who have rash and complete heart block (CHB). Delays in treatment could lead to severe complications such as valvular damage, septic emboli, mycotic aneurysms and brain abscesses.²

Here, we present a rare case of IE caused by Granulicatella adiacens. Given the atypical presentation of this patient and the dearth of case reports on G.adiacens endocarditis, we found it to be an interesting case to present.

Case presentation

An 82-year-old man with a history of hypertension and aeortic insufficiency presented to our institution with bradycardia and bilateral lower extremity rash. Eight months prior to presentation, he completed a prophylactic course of clindamycin after a dental implant procedure. Subsequently, the patient had an episode of Clostridium difficile diarrhoea that did not require hospitalisation. At presentation, he reported ankle oedema that began 2 weeks prior, followed by an erythematous, pruritic rash on his anterior shins. He denied fever, chills, chest pain, palpitations, dyspnoea or syncope. He initially presented to an urgent care facility for evaluation of the lower extremity oedema and rash, but was found to be bradycardic and thus, sent to the emergency department at our institution

On admission, he was bradycardic with a heart rate of 30 beats/min. He appeared well without distress. Cardiac exam revealed bradycardia with a faint diastolic murmur, loudest in the left upper sternal border. Lower extremities had trace ankle oedema with non-blanching, erythematous papules over the anterior shins (figure 1). Laboratories were significant for a haemoglobin of 84 g/L, creatinine of 0.0153 kg/m³, troponin of 0.0019 kg/m³, urine protein of 0.30 kg/m³, 13 urine red blood cells per high powered field and negative work up for autoimmune disorders. The patient had no history of alcohol, intravenous drug or tobacco use. His home medications included aspirin, amlodipine, valsartan and atorvastatin.

Figure 1.

Lower extremity purpuric rash. Pictures were taken day 3 of admission and had improved with antibiotics and topical therapies.

Investigations

Admission ECG revealed CHB (figure 2). Transthoracic echocardiogram demonstrated a tricuspid aortic valve with moderate mitral regurgitation and severe aortic insufficiency (figures 3 and 4). Based upon the ECG findings and valvular dysfunction on transthoracic echocardiogram, endocarditis was suspected by the electrophysiologist who recommended a transoesophageal echocardiogram (TOE) to exclude the possibility of infection prior to pacemaker placement. The patient was transferred to ICU for continuous monitoring, he continued to have CHB but he had no change in his vital signs. Subsequent TOE revealed multiple mobile vegetations consistent with endocarditis involving the right coronary and non-coronary cusps with a small aortic paravalvular abscess (figure 5). Blood cultures were positive for G. adiacens.

Figure 2.

ECG revealing complete heart block with a junctional escape rhythm.

Figure 3.

Transoesophageal echocardiogram two-dimensional image of long axis view of aortic valve and vegetation.

Figure 4.

Colour Doppler of transoesophageal echocardiogram of long axis view of severe aortic insufficiency.

Figure 5.

Transoesophageal echocardiogram with multiple mobile vegetations consistent with endocarditis involving the right coronary and non-coronary cusps with small aortic paravalvular abscess.

Differential diagnosis

Iatrogenic CHB

IE

Antineutrophil cytoplasmic antibody-associated vasculitis

Amyloidosis

Sarcoidosis

Angiosarcoma

Treatment

The patient’s CHB was thought to be secondary to para-aeortic abscess damage to the atrioventricular node. Therefore, during the admission, the patient underwent tissue aortic valve replacement and pacemaker placement. Operative aortic valve cultures were positive for G. adiacens. Ceftriaxone and ampicillin were initiated during the admission and continued postdischarge for a total of 6 weeks. This unconventional antibiotic regimen was chosen given concern for the patient’s fluctuating renal function and advanced age.

Outcome and follow-up

Four weeks after discharge, the patient was doing well and undergoing physical therapy. The rash had completely resolved by 2 weeks postdischarge. He continued with his antibiotic therapy and was scheduled for follow-up with cardiology and infectious disease specialists.

Discussion

This patient presented to our hospital with few signs and symptoms suggestive of IE, but was ultimately found to have culture proven, G. adiacens positive endocarditis. Both his initial presentation and causative organism are not well described in the literature.

It is rare that patients with IE are afebrile, as 80%–90% of cases present with a fever.^{1 3} Our patient presented with CHB and a lower extremity skin rash consistent with cutaneous purpura. Cutaneous purpura is the most common skin manifestation of IE, but the prevalence varies from 8%–40% and is often accompanied by other signs of infection.⁴ Despite few case reports in which endocarditis presents as heart block without other sequelae, our patient was found to have CHB prior to diagnosing IE. CHB was thought to be secondary to atrioventricular nodal damage due to the paravalvular abscess. New or changing cardiac conduction anomalies are found in approximately 10%–25% of all cases of IE with CHB seen in only 2%–4% of all cases.^5–8

The patient’s blood cultures and aortic valve histopathology revealed G. adiacens, an unusual cause of IE. G. adiacens is a fastidious organism that is considered a nutritionally variant streptococcus, associated with normal oral flora. It is thought to account for approximately 5% of all streptococcal endocarditis, however it is likely underdiagnosed.² Given the concern for worsening renal function, our patient was treated unconventionally with ampicillin and ceftriaxone, instead of the suggested synergistic regimen of a β-lactam antibiotic and an aminoglycoside. According to guidelines, there is no data available for this combination of treatment for G. adiacens endocarditis.⁹

Despite feeling well, our patient had a G. adiacens endocarditis with a paravalvular abscess causing CHBand a rash, which ultimately led him to seek medical attention. IE diagnosis is often delayed or even missed in the absence of typical clinical features such as fever. The presence of prior aortic insufficiency was an additional confounder in this case that lead to devaluing the presence of murmur and possible diagnosis of endocarditis. Our case reveals the importance of historical and diagnostic evaluation of endocarditis in patients with atypical presentations such as skin manifestations (purpura) and conduction abnormalities, which may suggest myocardial or paravalvular extension.¹

Patient’s perspective.

I noticed my feet and ankles were swollen and my lower legs were covered in a rash. We iced the ankles, and tried cortisone on the legs to reduce the itching. My daughter decided to take me urgent care the following morning to have a doctor take a look. After taking my blood pressure and heart rate, the doctor strongly suggested we go straight to the emergency room. She said we needed to make sure I was not in heart or renal failure. I did not feel sick, but we went anyway. We saw a parade of doctors who originally thought I needed a pacemaker. After several hours, I was told that my blood work showed I needed to be admitted to the hospital due to an infection in my heart. I was completely blindsided by this diagnosis because I had not felt ill. I was admitted on Saturday afternoon and on the following Tuesday I was scheduled for open-heart surgery to replace two heart valves. Two days postoperation, a pacemaker was put in. As an octogenarian, I had lived a relatively healthy life for most of my adult life. This need for surgery was a complete surprise. Recovery was intense with all the antibiotics I was prescribed, however, 7 weeks later, I am feeling good and the cardiologist and surgeon have said I have made great progress. I am thankful for the care I received and am hopeful for continued health and strength for years to come.

Learning points.

• Complete heart block can be a presenting finding of infective endocarditis (IE).

• Patients with purpura should be evaluated for IE in the setting of new cardiac conduction abnormality.

• Ampicillin and ceftriaxone is an unconventional regimen for IE, but possibly effective treatment of Granulicatella adiacens in patients with acute and chronic renal failure.