Your hands can be easily affected by joint problems, especially arthritis. When it comes to hand arthritis, the fingers and thumbs are often the first to complain with dull pain, morning stiffness, or a feeling of weakness when gripping.
Understanding the structure of the joints in the fingers, correctly identifying the types of arthritis and accompanying symptoms is an important step to help patients promptly detect and intervene, avoiding long-term damage.
Finger Joint Structure
Each finger has three main joints:
- Metacarpophalangeal joint (MCP): located at the point where the finger joins the hand, is the main place to flex and extend when making a fist.
- Proximal interphalangeal joint (PIP): joint in the middle of the finger.
- Distal interphalangeal joint (DIP): joint closest to the tip of the finger.
- For the thumb: The most commonly affected joint is the metacarpophalangeal joint (CMC), located at the base of the thumb, which allows the thumb to move in multiple directions, helping to grasp objects.
What is the most common type of arthritis?
The two most common types of arthritis that affect the fingers and thumb are:
1. Osteoarthritis (OA)
This is the most common form of arthritis and is mainly degenerative. In OA, the cartilage covering the ends of bones gradually wears away, causing the bones in the joint to rub directly against each other, causing pain and limited movement. The body responds by creating small bone spurs, causing the fingers to swell, deform, and develop lumps, also known as ganglions.
These bone spurs can appear at different joints, in no clear pattern, causing the fingers to swell, become bumpy, or become crooked. In OA, the DIP and CMC joints are the two most commonly affected joints, but the PIP joint can also be affected.
Symptoms of OA in the fingers/thumbs:
- Pain when moving the joint
- Stiffness, especially in the morning
- Mild swelling and palpable bony lumps
- Limited ability to move or bend or extend the fingers
- Bent or deformed fingers over time
2. Rheumatoid Arthritis (RA)
Unlike OA, RA is an autoimmune disease, where the immune system mistakenly attacks the lining of the joints, causing inflammation and destruction of the joint structure. RA often starts in the small joints of the hands, including the MCP and PIP joints. A characteristic feature of RA is symmetry, meaning that the same joint in both hands is affected at the same time.
In RA, in addition to pain and stiffness, the patient can also feel swelling, heat, and redness in the joints (a sign of active inflammation). If left untreated, RA can cause severe joint deformities, loss of cartilage, and loss of mobility.
Symptoms of RA:
- Constant joint pain, especially in the morning
- Joints that are red, swollen, and warm
- Joints that last more than 30 minutes after waking up
- Fatigue, low-grade fever, loss of appetite
- Can affect the eyes, heart, and lungs if severe
Other forms of arthritis that can affect the fingers and thumbs
1. Psoriatic Arthritis
Often accompanied by psoriasis. This form of arthritis can affect the joints that connect the fingers and big toes, causing swelling and pain. It is also characterized by small pits in the nails, making the nails appear rough or thin.
2. Systemic Lupus Erythematosus (SLE)
Another autoimmune disease that can cause painful inflammation of many joints throughout the body, including the small joints in the fingers. The pain may be accompanied by a butterfly-shaped rash on the face, fatigue, and affect many internal organs.
3. Gout
Usually associated with the big toe, but the fingers and thumbs can also be affected. The disease occurs due to the accumulation of uric acid in the blood, forming sharp crystals in the joints causing acute inflammation. The joints become extremely painful, red, hot, and swollen, often with a sudden onset and recurring many times if the diet and medication are not controlled properly.
