Fluorodeoxy glucose-positron emission tomography as a useful
diagnostic tool for reactive arthritis
Kiyoshi Shikino, MD, PhD, Yuta Hirose, MD–︎, Masatomi
Ikusaka, MD, PhD
Department of General Medicine, Chiba University Hospital
1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba 260-8677, Japan
Funding: None.
Conflicts of Interest : None.
Authorship: All authors had access to the data and a role in
writing the manuscript.
Acknowledgments: NA.
Article type: Images in Clinical Medicine
Running head: FDG-PET/CT for reactive arthritis
Text word count: 532 words
Number of figures: 2
References: 2
Corresponding author: Kiyoshi Shikino
Department of General Medicine, Chiba University Hospital
1-8-1, Inohana, Chuo-ku, Chiba-city, Chiba 260-8677, Japan
Tel: +81-43-224-4758
Fax: +81-43-224-4758
E-mail:kshikino@gmail.com
Key words : FDG-PET/CT; reactive arthritis
Key Clinical Message: FDG-PET/CT can reveal abnormal
accumulation at the affected joints and enthesitis, suggesting reactive
arthritis.
In December 2014, a 46-year-old man was referred to our hospital with a
1-month history of acute polyarthralgia. Arthralgia acutely appeared in
the metacarpophalangeal (MP) joint of the hallux, and it consecutively
spread to the left foot joint, right knee joint, lumbar region, left
shoulder joint, MP joint of the left thumb, and distal interphalangeal
(DIP) joint of the right middle finger. He had no medical or family
history. Physical examination showed: body temperature, 37·6°C; blood
pressure, 114/65 mmHg; and pulse rate, 100 beats/min. His affected
joints showed swelling, redness, warmth, and tenderness. Laboratory
examination showed high liver enzyme (aspartate transaminase level, 42
U/L; alanine transaminase level, 116 U/L) and C-reactive protein levels
(4·0 mg/dL). The rheumatoid factor and anti-nuclear antibody were
negative. The urine white blood cell (WBC) was 2+, and the
nitrite and culture were
negative. Synovial
fluid from the right knee indicated a WBC count of 14,600/μL. A culture
of the general and acid-fast bacteria was negative. Articular
radiography showed no bone destruction. Fluorodeoxyglucose-positron
emission tomography (FDG-PET/CT) showed abnormal accumulation at the
affected joints and enthesitis (arrow) of the left shoulder joint
(Figure 1). We suspected reactive arthritis from the history of acute
onset and progressive oligoarthritis with enthesitis. After asking
detailed questions, the patient admitted to being sexually active with
multiple partners, which he first denied, and reported feeling slightly
painful urination about 1 week before joint pain. Polymerase chain
reaction (PCR) of Chlamydia trachomatis from urethra secretion
was positive. PCR of Neisseria gonorrhoeae and the serum HIV
antibody were negative. Reactive arthritis due to C· trachomatiswas diagnosed. We started azithromycin (1 g orally) for chlamydial
urethritis and
non-steroidal anti-inflammatory drugs for arthritis. Urinalysis improved
but the improvement of arthritis was insufficient. We systemically
administered a glucocorticoid, and his symptom resolved for 1 month. We
confirmed that C· trachomatis was negative, and he had no
recurrence of arthritis in January 2021.
Reactive arthritis is classified as seronegative spondyloarthritis.
Acute oligoarthritis develops 1–4 weeks after a previous infection.
Reactive arthritis affects younger individuals 20–40 years and mostly
men (ratio of men to women, 2:1 and 3:1).1 The onset
is acute compared with other seronegative types of spondyloarthritis,
and the symptoms were completed within about 2 weeks. Arthritis occurs
frequently in the lower limbs, and the knee joint is mostly
affected.1 Urinary tract infections (e·g·, C·
trachomatis) and intestinal infections (e·g·, Campylobacter
jejuni, Salmonella enteritidis, and Yersinia
enterocolitica) are common causative agents, and previous urethritis or
diarrhea is a diagnostic indicator.2 In cases of
chlamydial urethritis, detailed questions are important because patients
do not disclose their sexual activity, and chlamydial urethritis is
oligosymptomatic. It is essential to perform examination and treatment
of sexually transmitted disease (STD) when patients have arthritis
symptoms that need hospital visits, in order to prevent the patient from
spreading the STD.
Only two studies have performed FDG-PET/CT to diagnose reactive
arthritis.3,4 Enthesitis is a feature of reactive
arthritis,3 and magnetic resonance imaging (MRI) and
ultrasonography are often performed to detect enthesitis. FDG-PET/CT is
more sensitive than MRI and the findings obtained are not affected by
its technique compared with ultrasonography findings. FDG-PET/CT is
expensive but useful for diagnosing difficult cases of reactive
arthritis.