are the anatomical structures where two bones articulate between each other. A
tissue called ‘articular cartilage’ covers the articulating bone surfaces. Itsfunction
is to prevent friction between bone surfaces. The joint is encased in a capsule
separating it from the surrounding fat, muscle, and
skin. Inside the capsule, there is a
layer called synovium which helps in
lubricating the joint by producing a fluid called ‘synovial fluid’.
Roughly, we could classify the joints in our body to Small Joints (joints of the fingers and toes), Large Joints (joints of the shoulder, hip, and knee) and Axial Joints (joints of the vertebral column).
Arthritis is a term used to describe inflammation within a joint. The inflamed joint will appear swollen, warm, reddened, and painful. Arthritis can be caused byinfections, autoimmune diseases, anddegenerative diseases, among other reasons. Arthritis may affect these joints in varyingpatterns. We can classify arthritis according to the number of joints involved.
1. Monoarthritis:Inflammation of any single joint
2. Oligoarthritis:Inflammation of < 4 joints
3. Polyarthritis: inflammation of > 5 joints
Arthritis has also been classified according to the duration of the disease into Acute and Chronic arthritis. Arthritis is said to be chronic if the duration of it is more than six weeks. Arthritis may sometimes lead to permanent loss of the normal anatomy of the joint, leading to serious physical dysfunction. These types of arthritis are called ‘Deforming Arthritis’.
I. INFECTIOUS ARTHRITIS
Infectiousarthritis isone of the most common forms of arthritis andis called ‘Septic Arthritis’. Children are particularly prone to infectious arthritis, but it could also affect adults. Septic Arthritis is most commonly caused by bacteria such as Staphylococci and Streptococci. Other infectious organisms, such as various viruses (Chikungunya, Rubella), Mycobacterium Tuberculosis, and fungi,can also cause septic arthritis. Patients usually presenta sudden onset of arthritis, involving mostly the large joints. The diagnosisis usually confirmed by extracting the fluid from the joint using a needle forculturing. Infectious arthritis is treated using antimicrobial drugs dependingon the organism infecting the joints.
II. AUTOIMMUNE DISEASES
Autoimmune diseases occur when the body’s immunity turnsagainst its organs. There are various types of autoimmune arthritis:
It is the most common type of autoimmune disease-causing arthritis. Patients present with symmetrical arthritis, involving both small and large joints of both the upper and lower limbs. Diagnosis is made by using this pattern of disease. Blood investigations,such asRheumatoid Factor and Anti-CyclicCitrullinated Peptide antibody (ACCP), may help in making diagnosis and prognosis.
It is the second most common autoimmune disease,causing arthritis after Rheumatoid arthritis. These patients also present joint impairmentsimilar toRheumatoid arthritis, but they have additional symptoms, such as dryness of the mouth and eyesand swelling of the salivary and lacrimal glands.
Systemic Lupus Erythematosus (SLE)
It is a severe form of autoimmune disease affecting multiple organs. Patients may present with polyarthritis along with other symptoms, such as hair loss, oral ulcers, recurrent fever, skin rashes, swelling of the feet and legs, and bleeding. Blood investigations, such as ANA (Anti-Nuclear Antibody), dsDNA (antibodies to double-stranded DNA), and checking the level of blood components like Complements (C3 and C4), will help in making adiagnosis. Other tests, including various blood/imaging tests and biopsies, are used to identify organ involvement.
Mixed Connective Tissue Disease
Patients present with arthritis, pain in muscles with weakness, and a bluish discolouration with paininthe fingers. It is usually a non-deforming type of arthritis.
It is a type of arthritis where the axial joints of the body are affected significantly. Patients typically manifest lower back pain present during rest and arerelieved by activity. These patients are likely to presentthe involvement of other large or small joints. They can also have nonarticular manifestations such as skin disease (Psoriasis), pain and redness in the eye (uveitis), and blood in stools (inflammatory bowel disease). Genetic testing helps in diagnosis of Spondyloarthritis.
The therapeutic armamentariums for Arthritis associated with autoimmune diseases have expanded over the years. Drugs, including Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), corticosteroids, Disease-ModifyingAntirheumatic Drugs (DMARDs), Anti-Cytokine therapies, and monoclonal antibodies among others, are used to treat autoimmune diseases.
III. CRYSTAL ARTHROPATHIES
These are diseases of the joint caused by deposition of crystals. Most common among them is gout. Gout is caused by deposition of monosodium urate crystals in the joints. Patients usually turn upwith episodes of arthritis separated by asymptomatic periods. These patients are prone to developing renal stone and renal diseases. Other crystal-induced disease includes Calcium Pyrophosphate Deposition disease and Basic Calcium Phosphate Deposition disease. These diseases are treated by NSAIDs, colchicine, uric acid lowering drugs, DMARDs, etc.
Osteoarthritis predominantly affects the elderly population. Females are more prone to osteoarthritis. This type of arthritis has been found to be associated with wear and tear of joints. Joints symptoms are related to activity and advanced stages of the disease canmake one completely disabled. Early detection and prevention of progression may help in alleviating the morbidity related to osteoarthritis.
V. ARTHRITIS AFFECTING CHILDREN
Children can also be affected by arthritis. Childhood arthritis is mostly due to infections such as bacteria or viruses. There are some forms of arthritis in children where it is indirectly related to infection. Some examples are Acute Rheumatic Fever and Post Streptococcal Reactive Arthritis; both are related to infection by Streptococcus. Autoimmune diseases, such as SLE andIdiopathic Inflammatory Myopathies, can affect children and cause arthritis.
Rare forms of arthritis are also seen in children where the exact cause and mechanism of disease is not known; these are called Juvenile Idiopathic Arthritis. Various treatment modalities found useful in treating adult arthritis can also be beneficially usedto treatchildhood arthritis.
Clinical Immunology and Rheumatology is a field of medicine that helpsdiagnose and manageautoimmune inflammatory rheumatic disorders.
In patients with symptoms related to joints, unexplained musculoskeletal symptoms, or suspected autoimmune diseases, prompt referral to this specialty for disease detection and treatment may help to improve the quality of life and prevent damage that can occur due to uncontrolled disease activity.