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Anatomy
Infectious arthritis may occur without any other infection present. However, it is usually the result of a previous infection. That is, a germ first causes an infection elsewhere in the body, then spreads to one or more joints to produce infectious arthritis.
A germ can enter through almost any place in a person's body. The most common places of entry are a person's skin, throat, ears, or nose. Once inside the body, the germs can get into the blood stream. From there they can travel to the person's joints (or any place that is suitable for them to live). Sometimes, a bacterium, virus, or fungus can enter a person's joint directly through a wound.
Most often, only one joint is affected. Sometimes, two or three joints become involved. The large joints are most often infected, especially the shoulders, hips, and knees, although other joints can also become involved.
Sometimes a condition called erythema nodosum can occur along with an infection. Although it is most often associated with tuberculosis and infections by certain fungi, it is not due directly to these infectious germs.
Symptoms
The most noticeable symptom of erythema nodosum is red, tender bumps about the size of a quarter--in the skin of the lower legs, and sometimes on other parts of the body. Other symptoms that may appear include inflammation of the ankle (and sometimes other joints) and fever.
Causes
Infectious arthritis may be caused by bacteria, viruses, or fungi.
Bacteria
Most types of infectious arthritis are caused by bacteria. There are many different kinds of bacteria that produce a variety of infections. Bacteria that can cause infectious arthritis include: gonococcus, certain Gram-positive bacteria, certain Gram-negative bacteria, spirochetes, and tuberculosis. Descriptions of these bacteria and the symptoms they produce are listed below.
Gonococcus
Gonococcus is the name of the bacterium that causes gonorrhea. Gonorrhea is a sexually transmitted disease. It primarily affects the genital area. However, the gonococcus bacterium can travel through the blood stream to other parts of the body. If it settles in one or more joints, infectious arthritis can develop in those joints and the area that surrounds the joints. Gonococcus generally affects the knee joints, and can also affect the tendons and bursae to cause tendonitis and bursitis.
This infectious arthritis can occur within days or weeks after the symptoms of gonorrhea appear. It occurs more often in women than in men. The symptoms of gonorrhea are not as obvious for women. Therefore, women generally seek treatment later than men. This delay in treatment gives the bacteria more time to travel through the bloodstream.
Symptoms of infectious arthritis caused by gonococcus may include:
- fever
- chills
- abdominal pain in women
- discharge from the penis or vagina
- rash, which appears as a few, red rimmed, dime-sized, pus filled spots that are raised in the center
- inflammation of the tendons (bands that connect bones to muscles)
- arthritis which develops in joints such as the knees or wrists
This type of arthritis should be treated immediately--as soon as you notice symptoms--to prevent serious damage to the joints.
Gonorrhea is spread from person to person by sexual contact. Therefore, care should be taken in sexual relationships where there may be a chance of getting the disease. The spread of gonorrhea can usually be prevented by the correct use of condoms. Anyone who thinks he or she may have gonorrhea should see a doctor as soon as possible. Appropriate treatment with antibiotics can prevent damage to joints and other parts of the body.
Gram-positive bacteria
There are several different kinds of Gram-positive bacteria. They are called Gram-positive because when mixed in the laboratory with a solution called "Gram's stain," they take on a bluish-purple stain or color. Some of the Gram-positive bacteria that can cause infectious arthritis are: staphylococcus, streptococcus, and pneumococcus.
These Gram-positive bacteria cause other illnesses such as meningitis, pneumonia, or an abscess. Often people with these illnesses develop infectious arthritis when the bacteria spread to a joint and produce inflammation. In other cases, Gram-positive bacteria cause infectious arthritis, but no other illness is detected.
Staphylococcus is the second most common cause of infectious arthritis. It is often called a "staph infection." A staph infection can occur as a result of a skin or sinus infection, or after surgery. People who have rheumatoid arthritis or who take steroids or immunosuppressive agents (such as imuran, cytoxan, and methotrexate) are more apt to get infectious arthritis from staphylococcus bacteria.
Symptoms of a "staph infection" in a joint may include:
- fever
- redness, swelling, extreme tenderness occurring in a single joint
- pus (yellowish-white substance) draining from a wound or abscess
Gram-Negative Bacteria
These bacteria are called Gram-negative because they do not take on a bluish-purple color when mixed with the Gram's stain. They are less likely to produce infectious arthritis than Gram-positive bacteria. Gram-negative bacteria commonly infect people whose bacteria-fighting defense system (immune system) is already weak.
Hemophilus is a Gram-negative bacterium that causes severe sore throat and meningitis. It is a major cause of infectious arthritis in infants, but rarely causes it in adults.
Spirochete- Lyme Disease
Spirochetes are bacteria that appear spiral shaped under a microscope. There are many different kinds of spirochetes. One kind (called Borrelia) causes a form of infectious arthritis called Lyme disease. This disease occurs in people as a result of a tick bite. Anyone can get Lyme disease, but it is more common in children.
The Borrelia spirochete is carried by a small tick (called Ixodes) that lives on deer and mice. It is found in wooded areas during the spring and early summer. Many areas of the country have reported cases of Lyme disease. However, most cases occur in seven states: New York, New Jersey, Rhode Island, Connecticut, Massachusetts, Wisconsin, and Minnesota.
People infected may not have seen the tick because it is very tiny. It is oval, has eight legs, and is often no larger than a pinhead or match head.
When the tick bites someone, it injects the spirochete into the person's blood stream. Symptoms of the infection usually do not appear until 1-3 weeks after the bite.
You may want to protect yourself and others from Lyme disease when you visit wooded or lake areas, as suggested below.
The following measures may help prevent tick bites:
- wear long sleeves and pants
- pull socks over pant legs
- wear closed shoes
- wear a hat
- use tick repellent on clothes
- shower afterwards and inspect for ticks, particularly checking arms, legs, and hairline
Symptoms of early Lyme disease include:
- Skin rash which is 5-20 inches in diameter. It is white in the center and bright red on the outside. The center is hard and hot to touch. It may occur around the bite and on different parts of the body. It may last up to a month.
- Flu-like symptoms of fever and chills, fatigue, headache, vomiting, and soreness all over.
- Joint pain and swelling usually in the knees, and sometimes also in the hips, shoulders, and ankles.
- Sore throat, dry cough, stiff neck, swollen glands.
- Dizziness and sensitivity to sunlight.
If untreated, the spirochete may spread to the person's brain, heart, and nervous system. This could lead to symptoms such as:
- temporary paralysis of the face
- numbness and tingling in the hands or feet
- severe headaches, depression, memory lapses
- poor muscle coordination
- heart problems.
With proper medication, Lyme disease usually goes away in a short time. However, if not diagnosed and treated properly, symptoms can become more severe and recur several times over a year or more.
Tuberculosis Bacteria
The bacterium that causes tuberculosis can also cause infectious arthritis. It is much less common today than it was years ago. When it does occur, it is often very slow to develop, and usually spreads from the lung to involve only one joint.
Viruses
Infectious arthritis can also be caused by viruses. It is usually produced by a viral infection that is already present in a person's body. Infectious hepatitis, mumps, and infectious mononucleosis are viral infections that can lead to a short bout of infectious arthritis. Generally, the joint inflammation lasts no more than one to two weeks. German measles can also produce an infectious arthritis which may occasionally last as long as one year after the measles rash is gone.
Fungi
Fungi are the least common cause of infectious arthritis. Arthritis produced by a fungus usually develops very slowly. Types of fungi that can produce arthritis are usually found in soil, bird droppings and certain plants (especially roses). Chicken farmers and gardeners are especially likely to be exposed to this type of arthritis.
Differences
Differences
Bacterial, viral, and fungal infections are different from each other in the following ways:
Bacterial infection:
- Generally located in one place or area
- Usually accompanied by fever and shaking chills
- Usually begins quite suddenly
- Usually cured by taking antibiotics
Viral infection:
- Ache all over
- Usually mild or no fever
- Not cured by antibiotics
- Usually goes away on its own
Fungal infection:
- May be in one area or throughout the body
- May have low-grade fever or none at all
- Usually begins quite slowly, over weeks or months
- Usually treated with anti-fungal medication
Can periodontal surgery cause infectious arthritis?
Any significant manipulation of the gums can cause bacteria to enter the blood stream--even brushing the teeth in the presence of gum disease. Periodontal health is important. In rare cases, periodontal disease may cause an infectious arthritis especially when extensive dental work is being done. We worry about it in particular for those with artificial joints in place as they can not combat the bacterial that might get into the blood stream. Infectious arthritis occurs more frequently in people with abnormal joints especially rheumatoid arthritis, people with artificial joints or those with diabetes. For those with arthritis or artificial joints in place, consult your rheumatogist or orthopedist before having dental work done. An antibiotic 1 hour before and 8 hours after may be in order.
Diagnosis
To determine if a person has infectious arthritis, the doctor will first ask about the person's symptoms and any other medical conditions.
The doctor will want to know about any recent travel, illness, or contact with people who have had infections. Work or home conditions might also give the doctor clues about the illness.
After the medical history the doctor will do a physical exam and order special tests. X-rays may be taken to determine if there is joint damage. Various laboratory tests can be done to find out if an infection is present.
It is most important to identify the specific germ causing the infection. Bacteria and fungi can usually be identified from joint fluid, blood, urine, or the infected area. The doctor will almost always want to remove and examine fluid from the infected joint. If tuberculosis or fungi are suspected, it will be necessary to remove a tiny piece of tissue from the joint. This is called a biopsy. In the laboratory, the fluid or tissue will be examined under the microscope to determine what kind of bacteria or fungi are present.
A viral infection is usually diagnosed by a person's symptoms and medical history. After the infection has been present for weeks or longer, blood tests may show the presence and amount of a person's own virus-fighting proteins (antibodies) in response to a viral infection.
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