Joints and Gout
by Robert Tallitsch, PhD | March 25, 2024
Video explaining Joints and Gout with a patient example!
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(A note on sex and gender: Sex and gender exist on a spectrum. This Brain Builder article will use the terms “female” and “male,” or both, to refer to the sex assigned to the individual at birth.)
If you wake up in the middle of the night or early in the morning with sudden, painful joint swelling that is sensitive to pressure, red in color, and feels overheated, you might have gout — a form of inflammatory arthritis resulting from an excess of uric acid in the blood.
In this Brain Builder we will discuss the different types of joints of the skeletal system. Then we will discuss what is gout, what are the symptoms, causes, risk factors, diagnosis, and treatment of this inflammatory disease of the joints.
Joints of the Skeletal System
A joint is defined as a junction of two or more bones. Joints are classified according to their range of movement, or according to their structure. In this Brain Builder we will discuss the classification of joints according to their structure.
Fibrous joints: Fibrous joints have fibrous connective between the connecting bones. These bones have little or no range of motion between the articulating bones. Examples of fibrous joints include suture, syndesmoses and gomphosis joints.
- A suture joint has minimal connective tissue in the space between the connecting bones. An example would be the junction between two or more bones of the skull.
- A syndesmosis is a joint where there is considerable connective tissue between the connecting bones. An example would be the junction between the tibia and fibula of the lower limb
- A gomphosis is a unique joint found between a tooth and the one in its alveolus (tooth socket), where the peridontal ligament firmly anchors the tooth.
Cartilaginous joints: In cartilaginous joints there is some form of cartilage between the connecting bones. A cartilaginous joint would have minimal range of motion between the articulating bones. Examples would include
- Synchondrosis (also termed a primary cartilaginous joint): In this joint there is hyaline cartilage between the connecting bones, such as the joint between a rib and the sternum.
- Symphysis (also termed a secondary cartilage joint): Here fibrous cartilage (fibrocartilage) is found between the connecting bones, such as the pubic symphysis.
The type of joint with the greatest range of motion is the synovial joints. Synovial joints have three distinguishing characteristics:
- A joint cavity (termed the synovial cavity) filled with synovial fluid.
- Presence of articulating cartilage, which is typically hyaline cartilage
- Presence of an articular (joint) capsule. The capsule is composed of thick, regularly arranged connective tissue. The capsule is lined by a synovial membrane. This membrane secretes synovial fluid, which nourishes and lubricates the articulating cartilage.
A synovial joint may also have a variety of accessory structures. Examples of these accessory structures include bursae, tendons, ligaments, cartilages, menisci, and fat pads.
Bursae are fluid-filled pockets or sacs that function to reduce friction and act as shock absorbers. The walls of bursae are lined by a synovial membrane, and the bursae contain synovial fluid. Bursae are found around most synovial joints, and are also located where tendons or ligaments come in contact with other tissue.
Tendons are structures that connect skeletal muscle to bone or cartilage, while ligaments connect bone to bone, bone to cartilage, or cartilage to cartilage.
Cartilage is typically found between the articulating surfaces within synovial joints, and serves to modify the articulating surfaces of the bones. The menisci of the knee are examples of this type of cartilage.
Fat pads are typically found at the periphery of the joint capsule. These structures may or may not be covered by the synovial membrane of the joint. Fat pads serve to protect the articulating cartilages of a synovial joint. Fat pads also change location as the synovial joint moves, filling in spaces formed as the synovial cavity changes shape.
As one compares the various forms of joints it becomes evident that the greater the range of motion of the joint, the less stable the joint is. The shoulder joint of the upper limb has the greatest range of motion of any joint of the body, and is the least stable joint of the human skeleton. In contrast, the sagittal suture between the two parietal bones of a fully formed adult skull allows no motion, and is one of the most stable joints of the body.
Gout
Gout is the most common inflammatory joint disease in highly industrialized countries, with approximately 1 to 2% of the population being affected. Males have a five times higher probability of developing gout then females. Males also develop the disease at an earlier age than females, typically at or after the age of forty. Women, if they develop gout, rarely develop it prior to menopause.
Symptoms
The general symptoms of gout include sudden, painful joint swelling that is sensitive to pressure, is red in color, and feels overheated. The swelling and pain are at their greatest typically six to twelve hours after the initial onset of symptoms. The sensitivity to pressure can be so bad that many patients are unable to lie in bed with a sheet touching the affected joints, or are unable to wear socks or shoes during the greatest period of joint sensitivity.
Typically, only one joint is affected during the initial attack of gout. For unknown reasons this joint is almost always the base of the big toe (great toe). With subsequent attacks elbows, knuckles, foot, ankle, and knee joints may be affected. Hips and shoulders are rarely, if ever affected. Gout also affects the accessory structures of the joints, causing inflammation of the bursae and articular capsule of the affected synovial joints.
Symptoms are not constant. A patient with gout will experience symptomatic periods termed flares, which may last as long as one or two weeks. Flares are separated by periods without any symptoms when the patient is in remission. Experiencing gout repeatedly often results in gouty arthritis — a form of arthritis that becomes progressively worse after each flare of gout.
Because of the high blood levels of uric acid that are associated with gout, kidneys may form kidney stones during a flare and, although rare, kidney damage may also occur during a flare.
Although there are no known causes for the onset of flares, fatigue, regular or increased consumption of alcohol, periods of higher-than-normal consumption of protein-rich food, and emotional stress have a high correlation with the onset of gout flares.
Causes
Gout occurs when urate, which is formed from the oxidative breakdown of purines. Purines are commonly found within the body’s tissues and within may foods. Uric acid is formed during the last step of purine oxidation, and is typically removed from the blood by the filtering action of the kidneys. However, some individuals do not filter enough of the uric acid from the bloodstream, and blood levels rise to an abnormally high level. This results (in some individuals) in the formation of needle-shaped crystals within the kidneys and within the synovial fluid of synovial joints. The presence of uric acid within the synovial fluid of joints causes the flares of gout.
Risk Factors
Not everyone with higher-than-normal blood levels of uric acid develops gout. Scientifically proven risk factors for gout include
- Consumption of certain foods, such as
- Seafood, such as anchovies, herring, scallops, and sardines
- Consumption of large quantities of drinks with high levels of fructose
- Utilization of pharmaceuticals that promote the formation of uric acid, such as diuretics, low-dose aspirin, and cyclosporine, and immunosuppressant taken following an organ transplant.
Diagnosis
Diagnosis of gout can be frustrating, in that an accurate diagnosis can only be accomplished during a flare. Your physician will take blood samples to determine the uric acid concentration. This is often accompanied by a thorough physical examination, including x-rays.
Treatment
Treatment of gout is aimed at the prevention of flares, managing the pain during a flare, and prevention of the formation of kidney stones. Physicians will also recommend life-style changes to decrease the frequency of flares, as well as reducing symptoms associated with gout flares. These life-style changes include, but are not limited to, the following:
- Limit alcohol consumption
- Maintain a healthy diet and reduce the consumption of foods that are associated with gout flares.
- Increase your level of exercise, but only participate in exercises that minimize joint stress.
Life-style changes often eliminate gout flares, or significantly reduce the pain and discomfort experienced during flares.
Key Terms
Bursae - Bursae are fluid-filled pockets or sacs that function to reduce friction and act as shock absorbers. The walls of bursae are lined by a synovial membrane, and the bursae contain synovial fluid. Bursae are found around most synovial joints, and are also located where tendons or ligaments come in contact with other tissue.
Fibrous joints - A type of joint that has fibrous connective between the connecting bones. These bones have little or no range of motion between the articulating bones. Examples of fibrous joints include suture, syndesmoses and gomphosis joints.
Flare - A time period, which may last as long as one or two weeks, when a patient with gout will experience symptoms.
Cyclosporine - An immunosuppressant taken following an organ transplant.
Synovial joint - A type of joint that has the greatest range of motion of all of the joint types. This type of joint is characterized by the presence of a joint capsule, a joint cavity (that is typically filled with synovial fluid), and the presence of cartilage on the articulating surfaces.
Gout - The most common inflammatory form of arthritis. This form of arthritis is characterized by high levels of uric acid within the individual’s blood.
Synchondrosis - This type of joint, which is also termed a primary cartilaginous joint, has hyaline cartilage between the connecting bones, such as the joint between a rib and the sternum.
Fat pads - An accessory structure of a synovial joint. Fat pads are typically found at the periphery of the joint capsule. Fat pads serve to protect the articulating cartilages of a synovial joint. Fat pads also change location as the synovial joint moves, filling in spaces formed as the synovial cavity changes shape.
Tendons - Structures that connect skeletal muscle to bone or cartilage.
Ligaments - Structures connect bone to bone, bone to cartilage, or cartilage to cartilage.
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