What is Monoarticular Arthritis?

Monoarthritis is a condition where one joint in the body gets inflamed. This can cause that joint to swell up and become painful and warm to touch. Some people may even experience fever and reddening of the skin around the inflamed joint. Usually, arthritis which refers to inflammation of the joints, is associated with stiffness in the joint and a decrease or complete loss in the ability to move the joint as freely as before.

What Causes Monoarticular Arthritis?

Monoarticular arthritis, which affects only one joint, can result from acute or chronic factors. Acute factors consist of things like infections, injuries, crystal-related arthritis, loss of blood supply to a bone, and mechanical issues. Chronic conditions usually affect more than one joint – for instance, diseases affecting whole systems of the body, like seronegative spondyloarthritis, osteoarthritis, and rheumatoid arthritis – though in some cases these diseases might start by affecting only a single joint.

All types of bacteria can potentially cause septic arthritis, which is an infection in a joint caused by bacteria. Based on risk factors, this type of arthritis is generally divided into two types: gonococcal and non-gonococcal septic arthritis. The former is caused by the sexually transmitted bacteria Neisseria gonorrhea. When this bacteria spreads in the blood, the infection can become widespread in the whole body. It can cause a group of symptoms like skin rashes, inflammation of the tendon sheath and arthritis, but might also occur without skin rashes. Risk factors for this infection include young age, having multiple sexual partners, certain immune deficiencies, HIV, menstrual disorders, usage of intrauterine devices, pregnancy, and a history of pelvic disease or surgery. The diagnosis involves a detailed health history, examination, lab work of blood and synovial fluid (fluid within a joint), and swab cultures from sites like the throat, urethra, cervix, or rectum.

Staphylococcus aureus is the most common cause of non-gonococcal septic arthritis, followed by Streptococcus species and gram-negative bacteria. Septic arthritis mainly affects larger joints like the knee and hip, but the wrist and ankle can also be affected. Septic arthritis can develop either from bacteria in the blood, direct injury to the joint (such as a bite), or infection spreading from bone into the joint cavity. Risk factors include intravenous drug use, artificial joints, catheters, chronic kidney disease, diabetes, cancer, rheumatoid arthritis, and weakened immune systems. Septic arthritis is a medical emergency, and diagnosis is based on taking and analyzing a sample of joint fluid. Lab tests of the joint fluid and blood should be done before taking any antibiotics. Mycobacterium and fungi can rarely cause septic arthritis, usually among people with weakened immune systems or travel to endemic areas.

Later stages of Lyme disease can also present as arthritis affecting only one joint, most often the knee. A blood test for Lyme disease is necessary for diagnosis because a joint or tissue culture won’t show the bacteria. Certain viruses like hepatitis B, hepatitis C, parvovirus, Epstein Barr virus, HIV, alphavirus and Zika virus can cause monoarticular arthritis. Most viral illnesses are self-limiting, however, travel history, vaccination status, and specific blood tests may help rule out serious medical conditions like HIV and hepatitis.

Crystal-induced arthritis is characterized by deposits of chemical compounds in the joints. These include monosodium urate in gout, calcium pyrophosphate dehydrates in pseudo-gout, and calcium hydroxyapatite in calcific periarthritis. A classic gout attack affects a single lower limb joint, usually the big toe joint, or otherwise the midfoot, ankle, or knee. Gout involves severe pain, swelling, redness, and disability but seldom joint destruction. Risk factors include excessive alcohol use, being male, dehydration, trauma, surgery, metabolic disorders, hypertension, chronic kidney disease, and certain medications. Confirmation of diagnosis is by checking a joint fluid sample for the presence of monosodium urate crystals, which appear a certain way under a polarized light microscope. Pseudogout happens when calcium pyrophosphate crystals are deposited in a joint. These crystals appear differently under polarized light. This can often occur in the knee joint, though it may also occur in the ankle, shoulder and wrist joints, and may be associated with metabolic and endocrine disorders like hemochromatosis. Seronegative spondyloarthritis such as psoriatic arthritis and reactive arthritis can first present as monoarthritis and often affect joints of the lower extremity. Certain chronic conditions like osteoarthritis, rheumatoid arthritis, and bone tumors may initially present as monoarthritis and eventually affect other joints as well.

Risk Factors and Frequency for Monoarticular Arthritis

Every year, there are nearly 20,000 cases of septic arthritis – a serious infection in a joint – in the United States. This translates to around 7.8 cases for every 100,000 people per year. A condition called DGI is particularly common among sexually active young people, being responsible for 75% of cases of monoarticular arthritis (arthritis in just one joint). Every year, there are about 2.8 instances of DGI for every 100,000 people.

In the past, DGI was thought to be more common in women. However, the increasing rate of HIV among men who have sex with men has led to more cases in the male population in the United States. Another bacteria, S. aureus, is the main cause of septic arthritis in Europe, and of all septic arthritis cases in the U.S. that are not caused by gonococcus (“non-gonococcal”).

Moreover, the number of people with gout – a type of arthritis caused by too much uric acid in the blood – has been increasing. This condition is responsible for more than 7 million emergency visits in the United States every year. Gout is more common in men than in women, and affects 3% of people worldwide.

Signs and Symptoms of Monoarticular Arthritis

When a doctor is trying to figure out if a patient might have monoarticular arthritis (arthritis in just one joint), they will examine their medical history and do a physical exam. The doctor will collect information about the patient such as their age, gender, if they’ve had any recent injuries, if joint diseases run in their family, any other symptoms they might be experiencing, what medications they are taking, any illnesses they’ve had, places they’ve traveled, if they’ve been bitten by a tick, their diet, alcohol use, job, and if they use intravenous drugs.

Doctors also look for visible changes around the joint during a physical examination. These can include swelling or inflammation, which are signs of synovitis (inflammation of the joint lining). These clues can help doctors determine whether it’s inflammatory arthritis or a systemic rheumatic disease. The joint might also feel warm to the touch.

  • Age
  • Gender
  • Recent trauma
  • Family history of joint diseases
  • Review of systems
  • Medication use
  • Illnesses
  • Travel history
  • Tick bites
  • Diet
  • Alcohol use
  • Occupational assessment
  • Intravenous drug use
  • Presence or absence of effusion or synovitis

Testing for Monoarticular Arthritis

To confirm a doctor’s initial thoughts and to decide on the next steps to treat a patient’s condition, certain laboratory tests and imaging methods might be used. Based on the guidelines from the American Academy of Family Physicians (AAFP), different tests might be done to diagnose different types of joint diseases, called arthritis.

For example, a complete blood count (which measures the number of different types of cells in your blood), erythrocyte sedimentation rate (or ESR, which can show if there’s inflammation in your body), and arthrocentesis (a procedure where fluid is removed from a joint for testing) should be done when septic arthritis (an infection in a joint) is suspected.

Tests like looking at crystals under the microscope and measuring uric acid levels in the blood may be helpful in diagnosing crystal-induced arthritis (when crystals form in the joints causing inflammation).

In cases of gonococcal arthritis (a rare complication of a sexually transmitted disease caused by the bacteria Neisseria gonorrhoeae), some tests including a specific urine test, analyzing a fluid sample from the joint for the bacteria causing the infection, and blood cultures should be done.

To diagnose ankylosing spondylitis (a type of arthritis affecting the spine), tests looking for a specific gene marker called HLA-B27 and radiological imaging may be used.

If a person has experienced injury or has localized bone pain suggesting possible fracture or necrosis (death of bone tissue), X-rays should be used. X-rays can also reveal other changes in the joint like the presence of excess fluids, hardening of soft tissues, erosions caused by gout, and damage to joint cartilage and space.

Ultrasound, another imaging method, can also detect presence of fluid in the joints and can guide doctors during arthrocentesis, especially for joints that are difficult to access.

Computerized Tomography (CT) scans and Magnetic Resonance Imaging (MRI) are used mainly for joints that are deep inside the body like the hip and shoulder joints. It’s important to note that if cellulitis, a common skin infection, is present, it’s considered unsafe to do a synovial fluid aspiration procedure as this can spread the infection.

Treatment Options for Monoarticular Arthritis

Treatment for arthritis that affects only one joint will depend on the cause and severity of the condition. The main aim is usually to ease pain and to prevent further harm to the joint. If the arthritis is caused by infection (a condition called septic arthritis), medication that targets and kills the infection-causing bacteria may be used to prevent the infection from spreading to other tissues. If the arthritis is due to crystals forming inside the joint (crystal-induced arthritis), injections into the joint or medications taken by mouth that help to calm down the body’s immune system might be used. Similarly, medications that can lower the level of a chemical called urate in the body, or that help the body to get rid of urate, may be used to stop the disease from flaring up again in the future.

Diagnosing single-joint arthritis includes differentiating joint pain from conditions like bursitis or tendinitis, which can present similar symptoms. The timing of the pain is important to note. Quick onset of pain within moments could indicate injury, such as a fracture or dislocation, or the presence of a loose body within the joint.

On the other hand, pain that develops over several hours or days typically points towards an infection or arthritis caused by crystals. And if the pain has been progressing over several days to weeks, this might signal the early stages of chronic conditions like osteoarthritis or rheumatoid arthritis.

Certain things can increase the likelihood of septic arthritis. These include intravenous drug use or being on medication that suppresses the immune system. There’s a recognizable trio of symptoms – urethritis, conjunctivitis, and arthritis developing after an infection – that generally indicate reactive arthritis.

What to expect with Monoarticular Arthritis

The outlook of having arthritis in just one joint relies on several aspects such as how quickly the condition is diagnosed and the timing of starting treatment.

Possible Complications When Diagnosed with Monoarticular Arthritis

If septic arthritis is not treated, it might quickly result in serious problems, including osteomyelitis, necrosis (cell death), bone erosion, fibrous ankylosis (abnormal stiffness), sepsis (a serious infection that spreads throughout the body), and even death. Gout, another form of arthritis, can cause damage or deformities in the joints, tophi (hard, uric acid deposits under the skin), kidney stones, and kidney failure.

List of Possible Complications:

  • Osteomyelitis
  • Necrosis
  • Bone erosion
  • Fibrous ankylosis
  • Sepsis
  • Death
  • Joint damage or deformity
  • Tophi
  • Kidney stones
  • Kidney failure

Preventing Monoarticular Arthritis

Arthritis is simply an inflammation or swelling in the joint. The reason behind this inflammation can be numerous. It could be due to an injury, aging-related changes, also known as osteoarthritis, or bacterial infection known as septic arthritis. It could also result from autoimmune conditions like rheumatoid arthritis, among others. Early signs to look out for include pain in the joint, red or warm skin over the joint, stiffness, and reduced movement.

If you notice these symptoms, visit your primary care doctor, who can then decide if you need to see a specialist like a rheumatologist (arthritis doctor) or an orthopedist (bone and joint doctor). To figure out what is causing the arthritis, your doctor will likely ask about your symptoms and medical history, physically examine the problematic joint, order lab tests, and take pictures of the joint, like with an X-ray.

Most times, arthritis can be managed with medications. But in some cases, like when something is lodged in the joint or the joint is internally damaged, surgery may be necessary.

Frequently asked questions

Monoarticular arthritis is a condition where one joint in the body becomes inflamed, causing swelling, pain, and warmth. It may also be accompanied by fever and reddening of the skin around the affected joint.

Monoarticular arthritis is responsible for about 75% of cases of DGI, and there are about 2.8 instances of DGI for every 100,000 people per year.

Signs and symptoms of monoarticular arthritis can include the following: - Swelling or inflammation around the affected joint, which is a sign of synovitis (inflammation of the joint lining). - Warmth in the joint area. - Pain or tenderness in the joint. - Limited range of motion in the joint. - Redness or discoloration of the skin around the joint. - Stiffness in the joint, especially after periods of inactivity. - Difficulty bearing weight or using the joint for daily activities. - Fatigue or general malaise, which can be associated with systemic rheumatic diseases. It's important to note that these signs and symptoms can vary depending on the underlying cause of the monoarticular arthritis. Therefore, a thorough medical history and physical examination by a doctor are necessary to make an accurate diagnosis.

Monoarticular arthritis can result from acute factors such as infections, injuries, crystal-related arthritis, loss of blood supply to a bone, and mechanical issues. It can also be caused by chronic conditions like seronegative spondyloarthritis, osteoarthritis, and rheumatoid arthritis.

The doctor needs to rule out the following conditions when diagnosing Monoarticular Arthritis: - Bursitis or tendinitis - Injury such as a fracture or dislocation - Presence of a loose body within the joint - Infection or arthritis caused by crystals - Chronic conditions like osteoarthritis or rheumatoid arthritis - Septic arthritis (especially if the patient has a history of intravenous drug use or is on medication that suppresses the immune system) - Reactive arthritis (if the patient has urethritis, conjunctivitis, and arthritis developing after an infection)

For Monoarticular Arthritis, the following tests may be needed for diagnosis: - Complete blood count (CBC) - Erythrocyte sedimentation rate (ESR) - Arthrocentesis (fluid removal from the joint for testing) - X-rays to assess for fractures or necrosis - Ultrasound to detect fluid in the joints and guide arthrocentesis - CT scans or MRI for deep joints like the hip and shoulder These tests can help determine the cause and severity of the condition and guide appropriate treatment.

Treatment for Monoarticular Arthritis will depend on the cause and severity of the condition. The main goal is usually to alleviate pain and prevent further damage to the joint. If the arthritis is caused by infection, medication that targets and kills the infection-causing bacteria may be used. If the arthritis is due to crystals forming inside the joint, injections into the joint or medications that help to calm down the immune system might be used. Additionally, medications that can lower the level of urate in the body or help the body to eliminate urate may be used to prevent future flare-ups of the disease.

The possible complications when treating Monoarticular Arthritis include: - Osteomyelitis - Necrosis (cell death) - Bone erosion - Fibrous ankylosis (abnormal stiffness) - Sepsis (a serious infection that spreads throughout the body) - Death - Joint damage or deformity - Tophi (hard, uric acid deposits under the skin) - Kidney stones - Kidney failure

The prognosis for monoarticular arthritis depends on several factors, including the speed of diagnosis and the timing of treatment.

You should see a specialist like a rheumatologist (arthritis doctor) or an orthopedist (bone and joint doctor).

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