Septic arthritis due to non-tuberculous mycobacterium without effusion

https://doi.org/10.1016/j.ajem.2020.09.043Get rights and content

Abstract

Septic arthritis is an important but difficult to make diagnosis that leads to significant morbidity and mortality. Joint effusion is generally accepted to be a highly sensitive finding in septic arthritis; however, final diagnosis requires synovial fluid studies. Without a significant joint effusion, it is difficult to obtain synovial fluid. In this case report, we describe the presentation and diagnosis of septic arthritis in the first MTP due to mycobacterium chelonae in a 69 year old man with a history of gout and immunosuppression due to a heart transplant. There was notably no significant effusion in the joint on clinical examination or bedside ultrasound. As the patient was immunosuppressed, arthrocentesis was performed under ultrasound guidance. A needle was clearly visualized in the joint; however, minimal synovial fluid was obtained. The fluid grew Mycobacterium chelonae in culture. Subsequent joint washout revealed purulent synovial fluid that grew out the same bacteria. This case emphasizes the importance of obtaining synovial fluid to evaluate for septic arthritis, even when joint effusion is absent. Ultrasound guidance can facilitate this.

Introduction

Septic arthritis is an important diagnosis that can result in significant morbidity related to joint destruction, loss of function, and systemic illness [1,2]. Increased incidence is observed in patients with underlying joint disease [3,4], patients with joint prostheses, and immunosuppressed patients. Fungal and atypical mycobacterial infections are less common than gram negative or positive bacterial infections, and they may be more likely in patients with underlying risk factors [[5], [6], [7]]. Although uncommon, this remains a critical diagnosis for the emergency physician to make.

Synovial fluid studies are considered the gold standard for diagnosis [[8], [9], [10]]. Arthrocentesis is often performed by emergency physicians to obtain synovial fluid for analysis. Ultrasound guidance may facilitate arthrocentesis.

Section snippets

Case report

A 69 year old male with a history of heart transplant 5 months prior presented to the emergency department for evaluation of worsening leukocytosis on outpatient laboratory studies. His postoperative course had been complicated by sternal wound infection. His mycophenolate mofetil was resumed about 5 weeks prior to presentation. Within a week after this, he noted pain and swelling of his left foot. He reported no systemic signs of infection. He was initially monitored with outpatient labs and

Discussion

This case report highlights the potential for septic arthritis despite the absence of joint effusion. In general, effusion is considered a highly sensitive finding in septic arthritis, 92% in some sources [8,12], but there is little data evaluating this finding systematically. As joint effusion is so often expected in septic arthritis, the absence of an effusion may falsely provide reassurance that septic arthritis is not present. In this case, the high pretest probability of septic arthritis

Declaration of Competing Interest

Dr. Theyyunni reports grants from GE Healthcare, grants from Department of Defense, outside the submitted work.

Author contributions

VL was the primary author of this manuscript including conceptualization, investigation, and writing – original draft. NT served as senior author, providing supervision, writing – review and editing, and resources.

References (18)

There are more references available in the full text version of this article.

Cited by (1)

View full text
© 2020 Elsevier Inc. All rights reserved.