Low Back Pain: Mechanical vs. Inflammatory Thomas A. Rennie, MD, FACR Rheumatology Associates of South Texas Disclosure • Dr. Rennie has disclosed that he is on the speaker’s bureau for Flexion Pharmaceuticals. Game Plan • Overview • Mechanical vs. Inflammatory Low Back Pain • Spondyloarthropathies – Ankylosing Spondylitis – Psoriatic Arthritis – Reactive Arthritis – Enteric Arthritis • Treatment Low Back Pain Overview • 31 million Americans have low back pain • Affects men and women equally • Average age of onset: 30 - 50 years old • Over 50% will have recurrence • 5-10% will develop chronic LBP Low Back Pain Overview • Accounts for 2-6% of visits to Primary Care Physicians – Ranks 2nd to upper respiratory symptoms • 80% of the population will experience back pain at some point in their lifetime • Leading cause of work-related disability worldwide – People older than 45 • Evidence for excessive imaging and surgery in U.S. Low Back Pain Overview • $50-100 billion annually • Direct costs – Office visits – Imaging – Labs – Treatment • Indirect costs: – Absenteeism: 20 million sick days – Loss of productivity – Employer health care – Worker’s compensation benefits – 85% of costs incurred by only 5-10% patients Causes of Low Back Pain • Mechanical • Inflammatory / Spondylarthritis – Degenerative disk disease – Ankylosing spondylitis – Degenerative joint disease • Non-radiographic axial spondyloarthropathy – Muscle strain – Psoriatic arthritis – Pregnancy – Reactive arthritis – Spondylolisthesis – Enteric arthritis – Spondylolysis – Fracture • Referred pain – Spinal stenosis – Abdominal aneurysm – Cholecystitis • Infiltrative – Nephrolithiasis – Cancer – Pancreatitis – Infection • Osteomyelitis • Abscess • Diskitis Why is it important to distinguish between inflammatory vs. mechanical low back pain? Inflammatory vs. Mechanical Back Pain FEATURE INFLAMMATORY MECHANICAL Morning stiffness > 1 hour ≤ 30 minutes Fatigue Significant Minimal Nocturnal pain Moderate Mild Activity ↓ symptoms ↑ symptoms Rest ↑ symptoms ↓ symptoms Systemic symptoms Yes No Inflammatory Back Pain • Do you have low back stiffness in the morning? • Does the back pain get worse or better with activity? • Does the pain wake you up at night? • Have you noticed increased fatigue? • Have you noticed any unexplainable weight loss? Spondyloarthropathies Screening Questions • Peripheral joint pain / arthritis • Acute diarrhea preceding the arthritis • Family history • History of STDs –AS • Urethritis or cervicitis preceding the –Psoriasis arthritis – Uveitis • Enthesitis – Reactive Arthritis – Achilles' tendinitis – Inflammatory bowel disease – Plantar fasciitis • Rashes • Alternating buttock pain •Psoriasis • Iritis / uveitis • Inflammatory bowel disease • Sausage digit / dactylitis – Recurrent diarrhea • Unexplainable weight loss – Hematochezia – Abdominal pain • History of GI infections Inflammatory Back Disease • Spondyloarthropathies – Ankylosing spondylitis • Non-radiographic axial spondyloarthropathy – Psoriatic arthritis – Reactive arthritis – Enteric arthritis • Crohn’s • Ulcerative colitis Ankylosing Spondylitis Ankylosing Spondylitis Epidemiology • Late adolescence – early adulthood • Onset after age 40 uncommon • Male:Female 3:1 • Manifestations in females less pronounced Physical Exam • Sacroiliac joint involvement – Pelvic compression – Gaenslen’s test – Patrick’s test • Progression of spinal disease / ankylosis – Schober’s test – Occiput to wall test – Chest expansion Sacroiliac Pain Pelvic Compression Test Sacroiliac Pain Patrick’s Test (FABER’s Test) Gaenslen’s Test Progression of Spine Disease / Ankylosis Schober’s Test Occiput-to-Wall Test Physical Exam • Peripheral arthritis: 30% of patients with AS – Hips and shoulders common – Rare involvement • Sternoclavicular • Temporomandibular • Cricoarytenoid • Symphysis pubis • Enthesitis – Ligamentous structures of the intervertebral discs – Achilles enthesitis / tendinitis – Plantar fasciitis Extra-articular Manifestations • Cardiac • Renal – Aortic insufficiency – Secondary amyloidosis – Aortitis – IgA Nephropathy – Pericarditis (10%) • Ocular • Neurologic – Anterior uveitis (25-30%) – Atlantoaxial subluxations • Pulmonary – Cauda equina syndrome – Upper lobe fibrosis • Osteoporosis – Restrictive lung disease Apical Pulmonary Fibrosis Audience Polling Question 1 How many white ankylosing spondylitis patients have a positive HLA-B27? 1. 10% 2. 50% 3. 75% 4. 90% Audience Polling Question 2 How many non-white patients have a positive HLA-B27? 1. 0-5% 2. 20-40% 3. 50-80% 4. 90-100% Audience Polling Question 3 A positive HLA-B27 is seen in approximately 8% of healthy white people. What percentage of this population will develop ankylosing spondylitis? 1. 2% 2. 20% 3. 75% 4. 90% Laboratory Data •HLA –B27 – 90% of white AS patients – 50-80% of non-white patients – 8% healthy whites • 2% will develop AS • 15 – 20% if they have a 1st degree relative with AS – 3% healthy North American Blacks • ESR and CRP – Elevated in 70% of patients with AS – Normal ESR and/or CRP does not exclude the presence of clinically active AS Radiographic Findings • Sacroiliitis – Bilateral and symmetric – Involves lower 2/3 of SI joints – Earliest changes on the iliac side of the SI joint • Sclerosis • Pseudo-widening • Erosions • Complete ankylosis / fusion – If x-rays are normal •MRI Radiographic Findings • Spinal disease – Shiny corners – Squaring of the vertebrae – Ossification of the outer layers of the annulus fibrosis – Syndesmophytes •Thin • Marginal – Fusion of the vertebral body • Bamboo spine Radiographic Findings Enteric Arthritis Enteric Arthritis Epidemiology • Any age • Male = Female ULCERATIVE COLITIS CROHN’S DISEASE Peripheral arthritis 10% 20% Sacroiliitis 15% 15% Sacroiliitis/spondylitis 5% 5% Physical Exam Peripheral Arthritis Ulcerative Colitis Crohn’s Disease Shoulder 20% 20% Elbow 30% 10% Wrist 15% 15% MCP 25% 10% Hip 20% Knee 70% 80% Ankle 50% 40% MTP / Toes 10% Extra-intestinal Manifestations • Pyoderma gangrenosum (< 5%) • Aphthous stomatitis (< 10%) • Acute anterior uveitis ( 5 – 15%) • Erythema nodosum (< 10%) Frequency of HLA-B27 in IBD ULCERATIVE COLITIS CROHN’S DISEASE Sacroiliitis/spondyliti 70% 55% s Peripheral arthritis Same as normal Same as normal healthy control healthy control population population Laboratory Data • ESR and CRP elevated • ANA and RF negative • Iron deficiency anemia • Leukocytosis • Thrombocytosis • pANCA in 50 – 60% of UC patients Radiographic Findings • Same findings as with AS – Bilateral symmetric sacroiliitis – Bamboo spine • Activity of inflammatory spine disease does not correlate with IBD activity Psoriatic Arthritis Psoriatic Arthritis Epidemiology • 35 – 50 years old • Juvenile psoriatic arthritis: 9 – 12 years • Prevalence – Any arthritis: Male:Female 1:1 – Spinal involvement: Male:Female 3:1 • Less than 30% of patients with psoriasis will develop arthritis • Psoriasis precedes arthritis: 67% • Arthritis precedes psoriasis: 33% Occult Psoriasis • Umbilicus •Scalp • Anus / cleft of the buttocks •Ears Psoriatic Arthritis Subtypes SUBTYPE PERCENTAGE TYPICAL JOINTS Asymmetric 15-20% DIPs, PIPs, MCPs, MTPs, Knees, Hips, oligoarticular Ankles Predominant DIP 2-5% DIPs Involvement Arthritis Mutilans 5% DIPs, PIPs Polyarthritis (RA like) 50-60% MCPs, PIPs, Wrists Axial 2-5% Sacroiliitis, Spondylitis Clinical Features Associated with Subtypes • Asymmetric oligoarthritis: Dactylitis • Predominant DIP involvement: Nail changes • Arthritis mutilans: Osteolysis • “RA” like disease: Fusion of wrists • Axial involvement: Asymmetric sacroiliitis Asymmetric oligoarthritis: Dactylitis Predominant DIP Involvement: Nail Changes Arthritis Mutilans: Osteolysis Laboratory Data • ESR and CRP may be elevated • ANA, RF and CCP typically negative – Positive RF in 5 – 10% of patients – Positive CCP in 8 - 16% • Anemia Radiographic Data • Sacroiliitis – Unilateral – Asymmetric • Spinal disease – Asymmetric involvement – Syndesmophytes • Large • Non-marginal Radiographic Data Audience Polling Question 4 1. Normal 2. Ankylosing spondylitis 3. Degenerative arthritis 4. Psoriatic arthritis Audience Polling Question 5 1. Normal 2. Ankylosing spondylitis 3. Degenerative arthritis 4. Psoriatic arthritis Audience Polling Question 6 1. Normal 2. Ankylosing spondylitis 3. Degenerative arthritis 4. Psoriatic arthritis Audience Polling Question 7 1. Normal 2. Ankylosing spondylitis 3. Degenerative arthritis 4. Psoriatic arthritis Radiographic Data Radiographic Data Reactive Arthritis Reactive Arthritis Epidemiology • 20 – 40 years of age • Enterogenic: Male = Female – Campylobacter – Salmonella – Shigella – Yersinia • Urogenital: Male > Female – Chlamydia trachomatis – Ureaplasma urealyticum Sacroiliitis / Spondylitis • Similar to psoriatic arthritis – Sacroiliitis: Unilateral or asymmetric – Spondylitis: Nonmarginal syndesmophytes • 5% of patients with reactive arthritis develop x-ray changes in the SI joints Peripheral Arthritis • Asymmetric • Oligoarticular • Joints involved – Knees –Ankles – Feet –Wrists – Digits • Enthesitis Extra-articular Manifestations • Low-grade fever • Urethritis • Sterile conjunctivitis – Sterile • Anterior uveitis – Infectious • Colitis • Prostatitis – Infectious • Salpingitis – Sterile • Vulvovaginitis • Heart block • Keratoderma blennorrhagicum • Pericarditis • Circinate balanitis • Painless oral ulcers Keratoderma Blennorrhagicum Circinate Balanitis Laboratory Data • Many patients are HLA-B27 (-) • HLA-B27 (+) correlates with increased disease – Severity – Chronicity – Frequency