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Helicobacter pylori as a Reversible Cause of Treatment-Refractory Monoarthritis

Case Studies 6 min 137

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Created On: 01/07/2026

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Poster abstract

Reactive arthritis (ReA) is an inflammatory joint disease that occurs following an infection. Although gastrointestinal and genitourinary pathogens are common triggers, Helicobacter pylori (H. pylori) has rarely been reported as a causative organism.

A 19-year-old female presented with persistent inflammatory monoarthritis of the left knee for 5 months. Symptoms were not responsive to non-steroidal anti-inflammatory drugs (NSAIDs), intra-articular corticosteroid injection, methotrexate, and sulfasalazine. Further evaluation revealed active H. pylori infection. Following eradication therapy, joint symptoms resolved completely without further immunosuppressive treatment.

This case highlights H. pylori as a potentially reversible infectious trigger of treatment-refractory seronegative arthritis and emphasizes the importance of considering occult infections before escalating immunosuppressive therapy.

Complaints

The patient presented with musculoskeletal and gastrointestinal symptoms, including:

Left knee pain
Knee swelling
Tenderness around the joint
Morning stiffness
H. pylori infection
Epigastric discomfort
Nausea
Postprandial fullness

Anamnesis

Introduction

ReA is an inflammatory joint condition that develops after an infection at another site in the body. It occurs because the immune system reacts to the infection and may also affect the joints. It is mostly seen in young adults and is usually associated with gastrointestinal or genitourinary infections. Although H. pylori mainly affects the stomach, some studies suggest it may also trigger inflammatory conditions outside the digestive system.

This case is presented because identifying an unusual infectious trigger changed the patient's treatment and led to complete recovery.

Medical History

The patient first developed symptoms in August 2025. She denied:

Recent diarrheal illness
Gastrointestinal infection preceding arthritis
Urinary symptoms
Recent genitourinary infection

Past and family history revealed:

Remote history of H. pylori infection diagnosed several years earlier
No treatment for the previous H. pylori infection because she was asymptomatic
No personal or family history of psoriasis, inflammatory bowel disease, or spondyloarthritis

Examination

1. Physical Examination

Moderate left knee effusion
Periarticular warmth and tenderness
Pain-related limitation of joint movement
No skin rash, nail abnormalities, oral ulcers, or ocular inflammation
Normal examination of other peripheral joints
No evidence of axial involvement
Negative FABER (flexion, abduction, and external rotation) test

2. Laboratory Findings

C-reactive protein (CRP): 5 mg/L (mildly elevated)
Normal erythrocyte sedimentation rate (ESR), complete blood count, and complement levels
Negative antinuclear antibodies (ANA), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibodies, human leukocyte antigen B27 (HLA-B27)

3. Synovial Fluid Analysis

Approximately 20 mL aspirated on two occasions
White blood cell count: 15,000/µL with neutrophil predominance
No crystals identified
Gram stain, mycobacterial staining, fungal studies, and bacterial cultures negative
Findings consistent with sterile inflammatory synovitis

4. Imaging

Magnetic resonance imaging (MRI) of the left knee demonstrated:

Significant joint effusion
Active synovitis
No bone erosions, cartilage loss, enthesopathy

5. Additional Investigation

Positive urea breath test confirming active H. pylori infection

Treatment

Initial treatment focused on inflammatory arthritis management:

Intra-articular corticosteroid injection
Naproxen 500 mg twice daily
Methotrexate 15 mg weekly
Addition of sulfasalazine 1 g twice daily due to inadequate response

Despite escalation to combination disease-modifying antirheumatic drug (DMARD) therapy, symptoms persisted. Following confirmation of active H. pylori infection, all antirheumatic medications were discontinued. Standard 10-day eradication regimen was initiated with:

Amoxicillin 1 g two times daily
Clarithromycin 500 mg two times daily
Omeprazole 20 mg two times daily

Results

1. Clinical Outcomes

Progressive reduction in knee pain and morning stiffness
Complete resolution of arthritis by January 2026
No recurrence of symptoms during follow-up
Full recovery achieved without antirheumatic medication

2. Laboratory Outcomes

CRP decreased from 5 mg/L to 2 mg/L
ESR normalized to 6 mm/hour
Autoimmune serology remained negative

3. Follow-up Findings

At rheumatology review in February 2026:

No knee effusion
No warmth or synovitis
No evidence of recurrent arthritis
No extra-articular manifestations
Sustained remission maintained off all immunosuppressive therapy

The temporal relationship between H. pylori eradication and complete symptom resolution strongly supports an infection-associated ReA phenotype.

KEY LEARNING

H. pylori should be considered a potential trigger of seronegative inflammatory arthritis, particularly in unexplained or treatment-resistant cases.
Persistent monoarthritis that fails to respond to NSAIDs, corticosteroids, and conventional DMARDs warrants evaluation for occult infectious causes.
ReA associated with H. pylori may occur in HLA-B27-negative individuals and can present as isolated monoarthritis.
Successful eradication of H. pylori may result in complete remission of arthritis, potentially avoiding unnecessary long-term immunosuppressive or biologic therapy.
Incorporating H. pylori screening into the diagnostic workup of refractory inflammatory arthritis may identify a reversible and treatable underlying trigger.