Arthritis
Arthritis means inflammation of joints. Joint inflammation (redness or heat and swelling) is a sign and joint pain is a symptom. Arthritis is a common term used for any joint inflammation. There are more than 100 types of arthritis and related conditions. It can affect all age group, sex and races, arthritis is the leading cause of disability in America. Women and old age group individuals are affected most commonly.

Common symptoms of Arthritis
1. Joint pain
2. Swelling around the joint
3. Redness or hot joint (warmth)
4. Limited range of motion
5. Stiffness of the joint

These symptoms may be mild, moderate or severe. Symptoms may be persistent or come and go, when it gets progressively severe then it is difficult to move the joints or inability to move the joint or inability to walk.

Types of arthritis

There are more than 100 types of arthritis and related conditions, but most common types of arthritis are
Osteoarthritis
Rheumatoid arthritis
Gout

It is a vast topic so first I want to tell you about commonest type of arthritis “Osteoarthritis”

Osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis. Most commonly it is associated with ageing and the major cause of joint pain in older people. Osteoarthritis is characterized by focal loss of articular cartilage, subchondral osteosclerosis, osteophyte formation or bone hypertrophy. Joint involvement in Osteoarthritis follows a characteristic pattern Hip joint, knee-joint, joints in hands, neck and then spine. Knee and hip-joint involvement are most common in women with age group 45 to 65.

Pathophysiology

Normal joints have little friction with movement and do not wear out with overuse or trauma. In joints cartilage has the very important role which is made up of matrix or fluid (around 80%), solid phase collagen and protein (around 18%) and cells (chondrocytes around 1-2%). Under normal condition there is a balance between matrix and enzymatic activities of cartilage in dynamic remodeling of collagen but in osteoarthritis increase degradation of major structural components of cartilage occurs because of overexpression of degrading enzymes leads to loss of collagen and proteoglycans from matrix, which makes cartilage more vulnerable to load bearing injury.

Because of this slow destruction of cartilage in the form of fibrillation/fissuring occurs which leads to vertical cleft formation, chondrocytes death and thus leads to decreased cartilage thickness which is usually focal and mainly affects the weight-bearing joints.

Loss of cartilage leads to sclerotic bone formation and often deposition of calcium pyrophosphate and calcium phosphate crystals in the abnormal cartilage.

Subchondral bone stiffens, then undergoes infarction, and develops subchondral cysts. Fibrocartilage is produced at the joint margin, which undergoes endochondral ossification to form osteophytes. Bone remodeling and cartilage thinning slowly alter the shape of the OA joint, increasing its surface area.
In attempt to repair bone and stabilize the joint subchondral sclerosis and osteophytes formation occurs. The synovium undergoes variable degrees of hyperplasia, and inflammatory changes which causes synovial fluid less viscous with greater volume, although to a much lesser extent than in RA and other inflammatory arthropathies.

In simple words osteoarthritis is a process of progressive cartilage matrix degradation to which an ineffectual attempt at repair is made.

Risk factors in Osteoarthritis
1. Heredity – Osteoarthritis associated with heredity and some genetic factors.
2. Gender – Women more commonly have osteoarthritis than man. The cause behind this may be associated with hormones and sex hormones.
3. Obesity – Obesity is a very important risk factor in osteoarthritis, so most common joint involvement in obese women is knee and hip (weight bearing joints)
4. Age – Age is most consistently identified risk factor of Osteoarthritis. More commonly men after 50 and women after 40 may suffer with osteoarthritis.
5. Trauma – Repetitive injury may cause cartilage destruction and related injuries may lead to osteoarthritis.
6. Occupation – Farmers, sport and some occupation related to repetitive friction on joints may also cause osteoarthritis.

Signs and Symptoms
The main presenting symptoms are pain and restriction of movement of involved joint. The cause of pain in osteoarthritis is not completely understood but may be because of weight-bearing and pressure on joints so commonly cause “Night pain”.
 Pain may be gradual and slow in onset and may become consistent after long time.
 Pain may be variable or intermittent ( some days are pain-free, good days but some are bad days with pain)
 Pain is mostly related to activity, movement or weight-bearing (standing or walking for long time or most of the time in a day), relieved by rest.
 Usually only one or few joints painful.

Signs
• Restricted movement of joint due to stiffening of joint, capsular thickening and bone hypertrophy
• Palpable, sometimes patient can also hear sound (crepitus) during movement of joint due to rough articular surface.
• Bony swelling around joint margins.
• Deformity, without instability
• Tenderness on palpation at joint line.
• Surrounding muscle weakness
• Synovitis usually mild.

Osteoarthritis can be localized; only in one joint or it can be generalized.
Joints commonly affected in generalized osteoarthritis are
• Distal interphalangeal (DIP) and proximal interphalangeal (PIP) joints (causing Heberden and Bouchard nodes)
• Thumb carpometacarpal joint
• Intervertebral disks and zygapophyseal joints in the cervical and lumbar vertebrae
• First metatarsophalangeal joint
• Hip
• Knee

Generalized nodal OA has a very strong genetic component; the daughter of an affected mother has a 1 in 3 chance of developing nodal OA herself. People with nodal OA are at increased risk of OA at other sites, especially the knee.

Knee OA
Usually involve patellofemoral and medial tibiofemoral compartment but may affect the whole joint.
The pain is usually at anterior and medial side, posterior knee pain suggests popliteal cyst (Baker’s cyst).

Hip OA
Targets the superior aspect of joint, usually unilateral and involvement of superolateral femoral head makes it worse with poor prognosis. The central or medial osteoarthritis is less common with good prognosis and confined to women.

Spine OA
The cervical and lumbar spine are predominantly targeted by OA, and referred to as cervical spondylosis and lumbar spondylosis, respectively. The typical presentation is with pain localized to the low back region or the neck, although radiation of pain to the arms, buttocks and legs may also occur due to nerve root compression. Pain is typically relieved by rest and worse by movement.

Erosive OA
Typically patients with hand OA who have a more prolonged symptom phase, more overt inflammation, more disability and worse outcome than those with nodal OA.

Investigations

X- RAY – Plain X ray of the affected joint is performed, typical features of Osteoarthritis can be seen like narrowing of joint space, bone remodeling, subchondral cyst formation or effusion.
In case of spine osteoarthritis to see the nerve compression MRI should be performed.
Routine biochemistry, hematology and autoantibody tests are usually normal.
Synovial fluid analysis required to rule out other related disorder.

Management
1. Education and supportive measures
2. Pharmacotherapy

1. Education and supportive measures

It is very important to know the nature of condition, so you can ask to your physician in detail about the condition. Knowledge about the risk factors and treatment is also very important.

Weight loss – If patient is overweight than weight reduction is very important to relieve pain specially in lower limbs because weight bearing joints are more prone to get osteoarthritis.
Exercise – Exercise has beneficial effects in OA, including both strengthening and aerobic exercise, preferably with reinforcement by physiotherapist. Aquatic exercises also recommended to relieve the stress.
Shock-absorbing footwear, pacing of activities, use of a walking stick for painful knee or hip OA, or provision of built-up shoes to equalize leg lengths can all improve symptoms.
Change in lifestyle also recommended, taking rest for few minutes in between work.

2. Pharmacotherapy

If symptoms do not respond to general and supportive measures than analgesics and anti-inflammatory drugs should be use.
Topical NSAIDS can be use first but for patients who are symptomatic for long time oral analgesic (NSAID) and then capsaicin should be use.
In severe cases sometimes opioids can be use.
Corticosteroid injection
Intraarticular corticosteroid injections are very effective in treatment of knee osteoarthritis. Duration of effect may be three to six months, so in constant and severe pain repetitive injections can be given depending upon preparation.
Chondroitin and glucosamine
Chondroitin sulphate and glucosamine sulphate have been used alone and in combination for the treatment of knee OA.
Hyaluronan injections
In knee OA, intra-articular injection of one of several forms of hyaluronan (polymers of hyaluronate), usually given as a course of weekly injections for 3–5 weeks, may give modest pain relief for several months. But because of repetitive injections and low efficacy these are usually not recommended.

Surgery

Surgery should be considered for patients with OA whose pain, stiffness and reduced function impact significantly on their quality of life and are refractory to other treatments. Total joint replacement surgery is by far the most common surgical procedure for patients with OA. Surgery is indicated when there is significant structural damage on X-ray and functional impairment affecting the quality of life and if all nonsurgical measures fail. Surgical options include arthroscopy, osteotomy and arthroplasty.

Coming up next – Crystal induced arthritis /Gout

Please note: Any medical information published on this website is not intended as a substitute for informed medical advice and you should not take any action before consulting with a health care professional.

Content source – Davidson’s Principles and Practice of Medicine
http://www.merckmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/joint-disorders