The Department of Rheumatology, Dudley Group of Hospitals NHS Trust, The Guest Hospital, Tipton Road, Dudley, West Midlands DY1 4SE,
1 The Highfield Rheumatology Unit and
2 The Department of Radiology, Worcestershire Acute Hospitals NHS Trust, Newtown Road, Worcester, Worcestershire, UK
SIR, A 39-yr-old male was admitted with synovitis of his right knee and left elbow. He had a complicated past medical history starting 10 yr earlier when he developed acute vertigo and bilateral sensorineural deafness. A cause for the deafness was not found but the possibility of autoimmune-mediated hearing loss was considered. Three years prior to the current admission he had an episode of scleritis successfully treated at a second hospital with systemic steroids. Eighteen months after his eye problems he was admitted to a third hospital with acute synovitis of his left knee, fever and weight loss. A presumptive diagnosis of septic arthritis was made. Synovial fluid aspiration and synovial biopsy did not grow any organisms or show any granuloma. His inflammatory markers were elevated with an erythrocyte sedimentation rate (ESR) of 70 mm/h and a C-reactive protein (CRP) of 124 mg/dl. His knee symptoms subsided over a couple of weeks. He was lost to follow-up but presented as an emergency to the third hospital, 3 months before the current admission, with chest pain and first-degree atrioventricular (AV) node heart block. He rapidly went on to develop complete AV block requiring insertion of a permanent pacemaker. Serological studies for virus, atypical bacteria and spirochaete infections were negative. A transthoracic echocardiogram (TTE) was normal. His inflammatory markers were elevated with a CRP of 191 mg/dl and ESR of 108 mm/h, but he was discharged home with no cause for his heart block established.
Investigations during the current admission revealed a normal full blood count, serum electrolytes and liver function tests. The ESR was elevated at 98 mm/h and CRP at 140 mg/dl. Autoantibody testing was negative, serum angiotensin-converting enzyme (ACE) was normal and a full atypical serology screen including Borrelia burgdorferi and Chlamydia spp. was negative. Synovial fluid aspiration and culture failed to grow any organisms. A clinical diagnosis of Cogan's syndrome (CS) was made. Repeat echocardiograms (transthoracic and transoesphageal) revealed moderate mitral and aortic regurgitation, dilation of the aortic ring at 4 cm and left ventricular dysfunction. Diffuse dilation of the ascending thoracic aorta was shown on a CT angiogram (Fig. 1). He was treated with intra-articular and oral steroids and methotrexate, and had a dramatic clinical and biochemical response with his ESR and CRP falling to 46 and 22, respectively. Three months later he remained well and a repeat CT angiogram did not show any further changes. The patient provided signed consent for the publication of his case details.
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The first cardiovascular abnormality in our case was the development of AV block and to our knowledge this is the first report of AV block occurring in CS. The atrioventricular node sits high in the intraventricular septum close to the aortic valve and is vulnerable to valve pathology. A small number of case reports have described AV block in Takayasu's arteritis [5, 6]. Naitoh et al. [5] attributed the AV node dysfunction in Takayasu's arteritis to a myocarditic process caused by infiltration of the interventricular septum and AV node by the arteritis. Naitoh et al.'s patient was treated promptly with corticosteroids with resolution of the AV block and inflammatory response supporting an inflammatory cause for the AV block. Yokoi et al. [6] describe post-mortem findings of fibrotic infiltration of the AV node and conducting system in a lady with a long history of Takayasu's arteritis and recent onset of AV block. The AV block in this case was felt to be due to acquired autoimmunity involving the cardiac conduction system.
In our case no cause for the AV block was found, but his inflammatory markers were significantly raised at the time of developing AV block and suggested ongoing inflammation. Although initial cardiovascular investigations were normal, 3 months later clear evidence of aortic dilatation and aortic valve and LV dysfunction was demonstrated. We believe that underlying aortitis had spread to involve the interventricular septum and AV node causing the AV block. Other rheumatic conditions that can cause AV block include sarcoidosis [7, 8] and, rarely, systemic lupus erythematosus (SLE) [8, 9]. Many of the clinical features in this case can also be found in sarcoidosis, such as eye inflammation, joint disease and occasionally deafness; however, no granuloma were detected on synovial biopsy, serum ACE levels were consistently normal and the hearing loss suffered in our patient was typical of that described in CS. A diagnosis of sarcoidosis was therefore considered unlikely. AV block has been reported in SLE, but the man in our case had no other features suggestive of SLE.
Treatment with corticosteroids and methotrexate has helped symptomatically in this man and has appeared to stabilize the aortic changes, although long-term follow-up with echocardiograms and CT angiograms is required. With hindsight, treatment with corticosteroids at the time AV block developed may have halted or reversed the AV node dysfunction. No impact on the cardiac conduction has been observed since immunosuppression was commenced 4 months after development of AV block.
This is the first report of AV block in CS. Although rare, AV block is potentially fatal and any episodes of syncope or bradycardia should be investigated thoroughly in this group of patients.
Conflict of interest
The authors have declared no conflicts of interest.
Notes
Correspondence to: N. Erb. E-mail: Nicola.Erb{at}dudleygoh-tr.wmids.nhs.uk
References