After reading this note you will be able to describe the clinical approach to spondyloarthritis, list the local risk factors, recognise key examination findings, interpret the basic investigations and outline the initial and definitive management plans – remembering to verify drug choices and dosing against the Kenya MoH guideline and your hospital formulary.
Definition
Spondyloarthritis (SpA) is a group of inter‑related inflammatory rheumatic diseases that primarily affect the axial skeleton (sacroiliac joints and spine) and may involve peripheral joints, entheses, skin, eyes and the gastrointestinal tract. The umbrella includes ankylosing spondylitis, psoriatic arthritis, reactive arthritis, enteropathic arthritis and undifferentiated spondyloarthritis.
Anatomy and physiology you need
| Structure | Relevance to SpA |
|---|---|
| Sacroiliac joints | First site of inflammation; pain radiates to buttocks, groin |
| Vertebral bodies & intervertebral discs | Inflammation → syndesmophyte formation → spinal rigidity |
| Entheses (tendon/ligament insertions) | Site of enthesitis, hallmark of SpA |
| HLA‑B27 presenting cells | Genetic predisposition; influences immune response |
| Gut‑associated lymphoid tissue | Microbial translocation may trigger reactive/enteropathic arthritis |
| Synovial membrane | Peripheral joint swelling when disease extends beyond axial skeleton |
Causes and risk factors
- Genetic: HLA‑B27 positivity (high prevalence in certain Kenyan ethnic groups)
- Infectious triggers:
- Chlamydia trachomatis (reactive arthritis)
- Salmonella, Shigella, Yersinia, Campylobacter (post‑enteric)
- Mycobacterium tuberculosis (TB‑associated sacroiliitis)
- HIV infection (immune dysregulation, higher prevalence of peripheral SpA)
- Autoimmune overlap: Psoriasis, inflammatory bowel disease (ulcerative colitis, Crohn’s)
- Environmental: Smoking (worsens axial disease), occupational heavy lifting (mechanical stress on entheses)
- Tropical co‑morbidities:
- Sickle cell disease (vascular occlusion may mimic enthesitis)
- Chronic malaria or other parasitic infections – may confound inflammatory markers
- Gender & age: Male predominance, onset typically before 45 years
Pathophysiology
Genetic susceptibility (HLA‑B27) → altered antigen presentation → abnormal immune activation → cytokine surge (TNF‑α, IL‑17, IL‑23) → inflammation of entheses & sacroiliac joints → bone erosion & new bone formation (syndesmophytes) → spinal rigidity and extra‑articular manifestations.
Clinical features
| Aspect | Key questions / findings | Why it occurs |
|---|---|---|
| Onset & duration | “When did the pain start? Was it sudden or gradual? Has it been continuous or intermittent?” | Inflammatory back pain often begins insidiously and persists >3 months; mechanical pain improves with rest. |
| Pain character | “Is the pain worse in the morning or after periods of inactivity? Does it improve with activity or showering?” | Cytokine‑driven inflammation causes stiffness that eases with movement; mechanical pain is activity‑related. |
| Morning stiffness | “How long does the stiffness last after getting out of bed?” | Stiffness >30 min is typical of axial spondyloarthritis (axSpA). |
| Peripheral joint involvement | “Do you have swelling, redness or pain in knees, ankles, hips, shoulders, or small joints?” | Enthesitis and synovitis are common extra‑axial manifestations. |
| Enthesitis | “Do you feel pain at the sites where tendons or ligaments attach to bone (e.g., heel, iliac crest, costochondral joints)?” | Inflammation at entheses is a hallmark of the spondyloarthritis spectrum. |
| Dactylitis | “Is any finger or toe uniformly swollen, giving a ‘sausage’ appearance?” | Diffuse synovitis of the entire digit reflects systemic inflammation. |
| Urogenital symptoms | “Any recent urethritis, cervicitis, or conjunctivitis?” | Reactive arthritis follows infections; mucocutaneous involvement is part of the triad. |
| Skin lesions | “Do you have pustular or scaly rash on palms/soles, or nail changes?” | Psoriatic arthritis is associated with psoriasis; nail pitting or onycholysis are clues. |
| Family history | “Any relatives with arthritis, psoriasis, inflammatory bowel disease (IBD) or known HLA‑B27?” | Strong genetic predisposition, especially HLA‑B27 positivity. |
| IBD symptoms | “Any chronic diarrhoea, abdominal pain, blood in stool?” | Enteropathic arthritis accompanies Crohn’s disease or ulcerative colitis. |
| Systemic features | “Fever, weight loss, fatigue?” | Active systemic inflammation may produce constitutional symptoms. |
| Trauma or infection history | “Recent gastrointestinal or genitourinary infection? Travel to malaria‑endemic area? HIV status?” | Reactive arthritis can be triggered by infections; HIV and TB can modify presentation. |
| Medication & comorbidities | “Current drugs, especially biologics, steroids, or antiretrovirals? Sickle‑cell disease?” | Certain drugs mask symptoms; sickle‑cell disease can cause vaso‑occlusive pain mimicking arthritis. |
Examination findings
- Reduced lumbar flexion (Schober test <5 cm) – reflects loss of spinal mobility from sacroiliac and vertebral inflammation.
- Chest expansion <2.5 cm – costovertebral joint involvement limits thoracic expansion.
- Positive FABER/Patrick test – pain over sacroiliac joint suggests sacroiliitis.
- Enthesitis at Achilles, plantar fascia, tibial tuberosity – tender swelling at entheses indicates active disease.
- Peripheral synovitis (warm, swollen joints) – indicates extra‑axial spread.
- Dactylitis (uniform swelling of a digit) – characteristic of psoriatic or undifferentiated spondyloarthritis.
- Uveitis (red eye, photophobia) – acute anterior uveitis is strongly associated; requires slit‑lamp exam.
- Skin lesions (psoriatic plaques, keratoderma blennorrhagicum) – point toward psoriatic or reactive forms.
- Abdominal tenderness or diarrhoea – suggests concurrent IBD.
Differential diagnosis
| Condition | Points toward it | What separates it from spondyloarthritis |
|---|---|---|
| Mechanical low back pain | Improves with rest, no morning stiffness, clear precipitating event | Lack of inflammatory features, normal sacroiliac imaging |
| Rheumatoid arthritis | Symmetrical small‑joint polyarthritis, positive rheumatoid factor/anti‑CCP | No axial involvement, seropositivity, erosive changes on hands |
| Ankylosing spondylitis vs. Diffuse idiopathic skeletal hyperostosis (DISH) | Age >50, flowing ossification of anterior longitudinal ligament | DISH spares sacroiliac joints, no HLA‑B27 association |
| Septic arthritis | Acute mono‑arthritis, fever, high inflammatory markers, positive joint aspirate culture | Infectious etiology, rapid joint destruction |
| Osteitis condensans ilii | Young females, bilateral symmetric sclerosis of iliac side of sacrum, no erosions | Absence of erosive sacroiliitis, usually asymptomatic |
| HIV‑associated arthritis | HIV positive, may have asymmetric oligoarthritis, may coexist with enthesitis | Often seronegative, may improve with antiretroviral therapy |
| Tuberculous spondylitis (Pott disease) | History of TB, constitutional symptoms, vertebral body collapse on imaging | Predominant vertebral destruction, paravertebral abscess, positive TB tests |
Investigations
| Test | What it answers | Interpretation |
|---|---|---|
| HLA‑B27 typing | Genetic predisposition | Positive supports axSpA but not diagnostic alone |
| Plain radiograph of sacroiliac joints | Structural changes (erosions, sclerosis, ankylosis) | Bilateral sacroiliitis grade ≥2 confirms radiographic axSpA |
| MRI sacroiliac joints | Active inflammation (bone marrow edema) | Early sacroiliitis before radiographic changes |
| CRP / ESR | Inflammatory activity | Elevated in active disease; guides treatment response |
| Complete blood count | Anemia, leukocytosis | Anemia of chronic disease common; leukocytosis may suggest infection |
| Uveitis slit‑lamp exam | Ocular involvement | Acute anterior uveitis supports spondyloarthritis |
| Stool PCR / culture for enteric pathogens | Reactive trigger | Positive after recent diarrhoea suggests reactive arthritis |
| HIV test | Co‑infection risk | Positive influences management and prognosis |
| TB screening (GeneXpert, chest X‑ray) | Latent/active TB | Important before initiating biologics |
| Serology for rheumatoid factor / anti‑CCP | Exclude RA | Negative supports spondyloarthritis |
Diagnosis and severity
Diagnostic classification (per international criteria adapted to our setting):
- Axial disease – requires either radiographic sacroiliitis (≥grade 2 bilaterally or ≥grade 3 unilaterally) or MRI evidence of active sacroiliitis plus at least two of:
- Age at onset <45 years
- Persistent inflammatory back pain >3 months
- Good response to NSAIDs
- HLA‑B27 positivity
- Family history of spondyloarthritis
- Peripheral disease – presence of ≥1 of: peripheral arthritis, enthesitis, dactylitis, or extra‑articular features (uveitis, IBD, psoriasis) with supporting seronegative status.
Severity grading (clinical and imaging):
| Domain | Mild | Moderate | Severe |
|---|---|---|---|
| Pain & function | BASDAI <3, normal daily activities | BASDAI 3–5, occasional limitation | BASDAI >5, major activity restriction |
| Spinal mobility | Normal Schober, chest expansion >2.5 cm | Reduced Schober 3–4 cm, chest 1.5–2.5 cm | Schober <3 cm, chest <1.5 cm |
| Radiographic damage | No syndesmophytes, isolated sacroiliitis | Isolated syndesmophytes, partial ankylosis | Extensive syndesmophytes, bamboo spine |
| Extra‑articular | None or isolated uveitis | Recurrent uveitis, mild IBD | Chronic uveitis, active IBD, severe psoriasis |
| Inflammatory markers | Normal CRP/ESR | Mildly elevated | Persistently high |
Severity guides therapy: mild disease may be managed with NSAIDs and physiotherapy; moderate to severe disease warrants escalation to disease‑modifying agents (TNF‑α inhibitors, IL‑17 inhibitors) after screening for infections and TB. Regular reassessment using BASDAI, functional scores, and imaging monitors progression and treatment response.
Management
| Phase | Goal | Key actions | Monitoring / safety |
|---|---|---|---|
| Immediate stabilisation | Relieve severe pain, protect function, rule out red‑flag infection | • High‑dose NSA NSAID (e.g., ibuprofen, naproxen) unless contraindicated <br>• Short course oral glucocorticoid if acute sacroiliitis or peripheral flare and NSAID not tolerated <br>• Analgesia with paracetamol or weak opioid if needed <br>• Assess for active TB, HIV, hepatitis before long‑term immunosuppression | • Vital signs, GI tolerance, renal function, liver enzymes <br>• Screen for latent TB (IGRA or Mantoux) and hepatitis B/C |
| Definitive treatment | Control inflammation, prevent structural damage, maintain mobility | • NSAID continued as first‑line long‑term therapy <br>• TNF‑α inhibitor (e.g., etanercept, adalimumab, infliximab) if inadequate response to NSAID after 3–6 months or high disease activity <br>• IL‑17 inhibitor (e.g., secukinumab) as alternative when TNF‑α blocker fails or is contraindicated <br>• Sulfasalazine for predominant peripheral arthritis <br>• Physical therapy: daily stretching, posture training, core strengthening <br>• Patient education: smoking cessation, weight control, ergonomic advice | • Disease activity scores (BASDAI, ASDAS) every 3 months <br>• Laboratory safety: CBC, LFT, renal panel, CRP/ESR <br>• Infection surveillance: repeat TB screen if on biologic > 12 months, monitor for opportunistic infections <br>• Ophthalmology review if uveitis symptoms |
| Long‑term follow‑up | Detect complications, adjust therapy, ensure adherence | • Clinic visit every 6 months (more often if on biologic) <br>• Imaging (pelvic X‑ray or MRI) every 2–3 years to assess radiographic progression <br>• Bone density scan every 5 years or earlier if steroids used <br>• Vaccinations: influenza annually, pneumococcal, hepatitis B, HPV; avoid live vaccines while on biologics | • Document adverse events, especially infections, hepatic or hematologic toxicity <br>• Review vaccination status before initiating biologics |
Contra‑indications / safety notes
- Active untreated infection (including TB, hepatitis B reactivation) → postpone biologic.
- Severe uncontrolled heart failure → avoid NSAID high‑dose and certain TNF blockers.
- Pregnancy: NSAID after first trimester, sulfasalazine relatively safe; biologics generally avoided unless disease is severe.
- Renal insufficiency → prefer COX‑2 selective NSAID at lowest effective dose, monitor creatinine.
Complications and prognosis
- Structural damage: Ankylosis of the spine, leading to reduced chest expansion and restrictive lung pattern.
- Uveitis: Acute anterior uveitis in up to 30 %; may be first manifestation.
- Peripheral enthesitis/arthritis: Can cause tendon rupture or chronic pain.
- Cardiovascular disease: Accelerated atherosclerosis; monitor lipid profile and blood pressure.
- Osteoporosis: Chronic inflammation and reduced mobility increase fracture risk.
- Gastro‑intestinal bleeding: From long‑term NSAID use; use gastro‑protective agents when risk factors present.
- Infection: Biologic therapy raises risk of bacterial, fungal, and viral infections; screen and vaccinate.
Prognosis is variable; early diagnosis and aggressive NSAID/biologic therapy can halt radiographic progression and preserve function. Delayed treatment is associated with higher rates of spinal fusion and disability.
High‑yield exam points
- Look‑alike conditions: Diffuse idiopathic skeletal hyperostosis (DISH) – flowing ossifications without sacroiliitis; rheumatoid arthritis – symmetrical small‑joint erosions, no enthesitis.
- Common wrong first step: Starting disease‑modifying antirheumatic drug (DMARD) such as methotrexate before NSAID trial; DMARDs are ineffective for axial disease.
- Bedside examiner questions:
- “What feature of the Schober test indicates reduced lumbar flexion?”
- “How does enthesitis differ from tendonitis on examination?”
- “Why must you screen for latent TB before a TNF‑α inhibitor?”
- “What is the significance of a positive HLA‑B27 in this patient?”
Clinical case
Case: 28‑year‑old male construction worker presents with 8 months of progressive low‑back pain, worse at night and improves with exercise. He reports morning stiffness lasting > 45 min, occasional heel pain, and a recent episode of red‑eye pain lasting 2 days. Physical exam shows reduced lumbar flexion (Schober 3 cm), tenderness at the left Achilles insertion, and bilateral sacroiliac tenderness. HLA‑B27 is positive; pelvic X‑ray shows bilateral sacroiliitis grade II.
Questions
- What is the next best step in management?
Answer: Initiate a full‑dose NSAID and refer for physiotherapy while arranging baseline labs and TB screening before considering biologic therapy.
- Which extra‑articular manifestation in this patient requires urgent referral?
Answer: Anterior uveitis – refer to ophthalmology promptly to prevent visual loss.
- If the patient fails NSAID therapy after 4 months, which class of drug is the preferred next option?
Answer: A tumor necrosis factor‑α inhibitor, provided infection screening is negative.
Practice questions
Question 1
A 32‑year‑old woman with a 6‑month history of inflammatory back pain has a normal pelvic X‑ray but MRI shows bone marrow oedema at the sacroiliac joints. She is HLA‑B27 positive. What is the most appropriate next step?
A. Start sulfasalazine
B. Begin high‑dose NSAID and arrange physiotherapy
C. Immediate TNF‑α inhibitor
D. Order a CT scan of the spine
Answer: B. Begin high‑dose NSAID and arrange physiotherapy
Explanation: NSAID is first‑line for axial disease; MRI confirms active sacroiliitis, but biologics are reserved for NSAID‑refractory cases.
Question 2
A patient on a TNF‑α inhibitor for ankylosing spondylitis develops a persistent cough and night sweats. Which investigation should be performed first?
A. Sputum culture
B. Chest X‑ray
C. IGRA (interferon‑gamma release assay)
D. Bronchoscopy
Answer: C. IGRA (interferon‑gamma release assay)
Explanation: Reactivation of latent TB is a key safety concern; IGRA is the preferred screening tool before continuing biologic therapy.
Question 3
Which feature distinguishes enthesitis of spondyloarthritis from a simple tendon strain?
A. Pain improves with rest
B. Swelling localized to the tendon belly
C. Point tenderness at the insertion site with pain on passive stretch of the muscle
D. Presence of joint effusion
Answer: C. Point tenderness at the insertion site with pain on passive stretch of the muscle
Explanation: Enthesitis is characteristically painful at the bone‑tendon insertion and worsens with stretching of the attached muscle.
Question 4
A 45‑year‑old man with known ankylosing spondylitis presents with acute anterior eye pain, photophobia, and blurred vision. What is the immediate management?
A. Oral NSAID only
B. Topical steroid eye drops
C. Urgent ophthalmology referral for systemic steroids
D. Observation for 48 hours
Answer: C. Urgent ophthalmology referral for systemic steroids
Explanation: Acute anterior uveitis requires prompt ophthalmology input; systemic steroids are often needed to control inflammation.
Question 5
Which of the following is a contraindication to initiating a COX‑2 selective NSAID in a patient with spondyloarthritis?
A. Controlled hypertension
B. History of peptic ulcer disease without current NSAID use
C. Mild chronic kidney disease (eGFR 55 ml/min)
D. Active hepatitis B infection
Answer: D. Active hepatitis B infection
Explanation: Active viral hepatitis is a contraindication to NSAID use due to risk of hepatic injury; the other conditions are relative cautions but not absolute contraindications.
Drafted with AI assistance from standard references and reviewed for structure. Check details against your lecture notes and the Kenya MoH guideline.