Septic Arthritis
Also known as: Infectious arthritis or Pyogenic
arthritis
What is it?
Septic arthritis, also known as infectious arthritis or
pyogenic arthritis, is a serious infection of the joints
characterized by pain, fever, chills, inflammation and
swelling in one or more joints, and loss of function in
those joints.
Septic arthritis is considered a medical emergency because
of the damage it causes to bone as well as cartilage, and
its potential for creating septic shock, which is a
potentially fatal condition.
Who gets it?
Septic arthritis can strike any age group, including
infants and children. In adults, it most commonly affects
weight-bearing joints such as the knee, while in children
it is more common in the shoulders, hips, and knees. Risk
factors include patients diagnosed with chronic rheumatoid
arthritis, certain systemic infections, certain types of
cancer, diabetes, sickle cell anemia, or systemic lupus
erythematosus (SLE), IV drug abusers and alcoholics, and
patients with artificial (prosthetic) joints. Patients
with recent joint injuries or surgery, or patients
receiving medications injected directly into a joint are
also at a greater risk for developing septic arthritis.
Typically, women and male homosexuals are at greater risk
for septic arthritis than are male heterosexuals.
What causes it?
Septic arthritis occurs when some type of infecting
organism, most often bacteria, reaches a joint. Bacteria
can get into a joint through the bloodstream, or through
surgery, an injection, or injury that directly
contaminates the joint. The cause of septic arthritis in
babies and young children is usually staphylococci,
hemophilus influenzae, and gram-negative bacilli. In
adults and older children, septic arthritis is more
commonly caused by gonococci, staphylococci, and
streptococci. Mycobacteria, which causes tuberculosis, and
the bacteria that causes Lyme disease can also cause
septic arthritis. Intravenous drug users and people with
diseases that weaken the immune system, such as HIV, are
more likely to have septic arthritis caused by
gram-negative bacteria. The staphylococcus organism can
also be introduced to a joint during arthroscopic surgery
and prosthetic joint surgery.
What are the symptoms?
Symptoms of septic arthritis occur
suddenly and are characterized by severe pain, swelling in
the affected joint along with acute pain. Chills and fever
are also common symptoms. Septic arthritis in the hip may
be experienced as pain in the groin area that becomes much
worse if the patient tries to walk. In the majority of
cases, there is some leakage of tissue fluid into the
affected joint. The joint is sore to the touch, and may or
may not be warm to the touch, depending on how deep the
infection lies within the joint. Children sometimes
develop nausea and vomiting.
How is it diagnosed?
Your doctor will diagnose septic arthritis based upon
your symptoms, your medical history, a complete physical
exam, and synovial fluid and blood tests. After numbing
the area, he or she will withdraw a sample of synovial
fluid from the affected joint. This fluid will be tested
for white blood cells, which are usually high, and for
bacteria and other organisms. Some of the joint fluid will
be placed in a special container in which many types of
bacteria can grow and be identified.
The doctor may perform an
arthrocentesis, which is a procedure that involves
withdrawing a sample of synovial fluid from the joint with
a needle and syringe for testing. The doctor may also
perform a culture of blood and urine to rule out other
causes such as gout, acute rheumatic fever, rheumatoid
arthritis, Lyme disease and other disorders that can cause
a combination of joint pain and fever. In some cases, the
doctor may consult a specialist in orthopedics or
rheumatology to avoid misdiagnosis. Because septic arthritis can quickly destroy a
joint unless treated, your doctor may also order x-rays to
assess any joint damage.
What is the treatment?
Septic arthritis must be diagnosed quickly and treated
with antibiotics. Your doctor may first give these
antibiotics intravenously (through a vein) to make sure
the infected joint receives medication to kill the
bacteria as quickly as possible. Then, the remaining
course of antibiotics is taken orally.
The doctor may also need to drain the fluid from the
infected joints if it rapidly reaccumulates and causes
symptoms. Immediate surgical drainage is reserved for
septic arthritis of the hip, because that site is
inaccessible for repeated fluid removal. For most other
joints, surgical drainage is used only if medical therapy
fails over two to four days to alleviate symptoms.
Hot compresses and splinting the joint to provide it with
rest and support can help relieve pain. After a period of
rest, your doctor will recommend gentle exercise to
prevent stiffness. If septic arthritis occurs in an
artificial joint, antibiotic treatment may need to be
followed by surgery to replace the joint. Most patients
with no other serious underlying disease recover fully
from septic arthritis with antibiotic therapy.
Recovery from septic arthritis is usually good with most
patients undergoing treatment, although many patients will
develop osteoarthritis or deformed joints. Children with
infected hip joints sometimes suffer damage to the growth
plate. Patients with severe damage to bone or cartilage
may need reconstructive surgery, but it cannot be
performed until the infection is completely gone.
Self-care tips
While septic arthritis cannot be prevented in many
cases, you can reduce your risk by not indulging in high
risk activities such as intravenous drug use.
Patients receiving
corticosteroid injections into the joints for
osteoarthritis may want to weigh this treatment method
against the increased risk of septic arthritis. If you have
any symptoms similar to those listed here, see your doctor
immediately. Immediate treatment is necessary to prevent
any long-term damage to the joint.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
|
