Infectious arthritis
Lyme arthritis

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 9 July 2018, last major update March 2013

Copyright: (c) 2002-2017,, Inc.

PubMed Search: Chronic Lyme disease [title]

Cite this page: Shankar, V. Lyme arthritis. website. Accessed August 15th, 2018.
Definition / general
  • Due to infection with Borrelia burgdorferi, a spirochete transmitted by Ixodes tick; joints affected weeks to years later
  • Causes chronic arthritis of large joints with pannus formation in 10%
  • Also affects skin, heart, nervous system
  • Precise pathophysiology of disease unknown but involves intricate network of vector, bacterial and host factors (Clin Vaccine Immunol 2008;15:21)
  • "Amber theory": disease due to infection of structures close to joint space, followed by entry of nonviable bacteria and debris into joint space, eliciting inflammatory response (Clin Rheumatol 2012;31:989)
Clinical images

Images hosted on other servers:

Erythema migrans skin lesion


Bullseye rash

Lyme arthritis of right knee

Microscopic (histologic) description
  • Chronic papillary synovitis with hyperplasia, fibrin deposition, mononuclear cell infiltrates, onion skin thickening of arterial walls; resembles rheumatoid arthritis
  • Perineuritis may be present
Microscopic (histologic) images

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Borrelia burgdorferi

Borrelia spirochetes identified on silver stain

Positive stains
  • Silver stain highlights bacteria
Electron microscopy description
  • Surface fibrin-like material, thickened synovial lining cell layer, evidence of vascular injury, Borrelia-like structures in synovial membranes and some synovial fluid cell samples (Hum Pathol 1996;27:1025)