Septic (Infectious) Arthritis

Original Editors - Amy Bramble & Kayla Klope from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Amy Bramble, Kelli House, Kim Jackson, Lucinda hampton, Admin, Elaine Lonnemann, WikiSysop, 127.0.0.1, Jill Thompson, Khloud Shreif, Nupur Smit Shah, Wendy Walker and Lauren Lopez  

Definition/Description

Septic arthritis is also commonly referred as bacterial or infectious arthritis. Septic arthritis is an intensely painful infection in a joint.  Bacteria, viruses and fungi may invade the joint through various routes which cause inflammation of the synovial membrane.  With the onset of inflammation, cytokines and proteases are released, thus resulting in potential joint destruction.  The infection is located in the synovial or periarticular tissues and is most commonly bacterial.  Bacteria or other foreign pathogens can infect either one joint or, if left untreated, can spread and cause further systemic damage. Septic arthritis may occur at any age but is more likely in children and older adults. The most commonly targeted joins in the body are the knee, hip, shoulder, ankle and wrists. 

Prevalence

In the United States, there are approximately 20,000 cases of septic arthritis reported each year. The most common strain is the staphyloccoccus aureus which is found in 60% of positive cultured joint aspirations. In non gonococcal strains, which includes staphylococcus, this incidence can increase to 28-38 cases per 100,000 in individuals also diagnosed with Rheumatoid Arthritis. 

Characteristics/Clinical Presentation

Typical presentation of septic arthritis in children and adults includes:

• Acute, rapid onset of pain
• Unable to move the joint through active and passive range of motion
• Typically only one joint (can be bilateral or more than one joint depending on the type of infection)
• Unable to bear any weight on the joint
• Effusion 

• Joint warmth
• Skin rash
• Low grade fever
• Lymphadenopathy 
• The joints of the arms and legs are the most commonly affected in adults (especially the knees)
• The hip joint is most commonly affected in children

Symptoms in Newborns/Infants

• Cries when infected joint is moved
• Fever
• Unable to move the limb
• Irritability

Note: A patient may be taking medications for other types of arthritis that may mask the original signs and symptoms of septic arthritis. Early diagnosis for proper treatment is critical. 

Prognosis:

Several factors influence how well the joint can fight the infection including other systemic issues occurring throughout the body. For example, patients with liver or kidney disease, or diseases that make the joint more susceptible to damage such as RA can all cause poorer outcomes. . The best outcome for individuals with septic arthritis is immediate treatment. Fifty percent of adults with septic arthritis have significant decreased range of motion or chronic pain after the infection.[8] Poor outcome predictors in prognosis of septic arthritis include the following: Age older than 60, infection of the hip or shoulder joints, underlying rheumatoid arthritis, positive findings on synovial fluid cultures after 7 days of therapy, delay of 7 days or longer in beginning treatment. Depending on associated risk factors, infection type, and response to treatment, mortality rate from septic arthritis has varied between published studies. One systematic review stated that mortality rate was around 11% between the studies assessed.

Associated Co-morbidities

• Systemic corticosteroid use
• Radiation therapy
• Preexisting arthritis
• Arthrocentesis: joint aspiration
• Human Immunodeficiency virus
• Diabetes Mellitus
• Alcohol or drug use
• Trauma
• Other infectious diseases
 

Medical Management 

The course of treatment for septic arthritis is case dependent. There is no conclusive evidence on the most effective way to begin. However, it is a combination of antibiotics, joint fluid removal, infection drainage, and/or total joint surgery. The course of treatment also depends on the type of joint invasion (bacterial, STD bacterial, viral etc..). The first round antibiotics can be directed at the most likely pathogen,  then the joint can be tested to see what further treatment may be necessary such as needle joint aspiration or drainage to release the fluid. Another option is to perform  joint aspiration before a round of antibiotics is chosen. If the infection is severe enough following a round of antibiotics and aspiration for fluid removal, surgery or even replacement of the entire joint may be necessary.

Antibiotic treatment:

Typically, the sexually transmitted related bacteria (gonococcal) is treated with antibiotics that other sexually transmitted infections are treated with. For example, doxycycline, ciproflaxin, and azythromyocin, amongst many others. The non-sexually transmitted bacterial infections can be treated with common antibiotics such as penecillin, vancomyocin, (etc), depending on the severity and resistance tendencies of the bacterial strain.

Below is non-exhaustive list of antibiotics commonly used in the treatment of septic arthritis: 

• Ceftriaxone (Rocephin)- Effective against gram-negative enteric rods
• Ciprofloxacin (Cipro) - Treat N gonorrhoeae and gram-negative enteric rods.
• Cefixime (Suprax) –Broad activity against gram-negative bacteria, by binding to one or more of the penicillin-binding proteins. Arrests bacterial cell wall synthesis and inhibits bacterial growth.
• Oxacillin - Oxacillin is useful against methicillin-sensitive S aureus (MSSA).
• Vancomycin (Vancocin) - An anti-infective agent used against methicillin-sensitive S aureus (MSSA), methicillin-resistant coagulase-negative S aureus (CONS), and ampicillin-resistant enterococci in patients allergic to penicillin.
• Linezolid (Zyvox) - An alternative antibiotic that is used in patients allergic to vancomycin and for the treatment of vancomycin-resistant enterococci.
  
  

Management regarding antibiotic choice, dosage, route of administration, and duration of treatment is unknown in the treatment of septic arthritis. In addition, no evidence has shown if closed aspiration or open arthroscopy is better at removing materials from a joint that’s infected. 

Joint Drainage and Surgical options (often used in combination with antibiotic treatment)

Much like antibiotics, the choice whether to use joint aspiration, arthroscopy, or total joint replacement is case dependent. There is no current definitive evidence on whether one treatment is more effective than the other. However, the most positive outcomes in general come from using one of these options. The main goal with this treatment is to continuously remove the accumulation of pus within the joint until it no longer forms. This is most commonly used in combination with the antibiotics to remove the pus both from the joint itself and via bloodstream.

[1]

www.cmaj.ca/content/176/11/1605.full.pdf+html

---> Insert joint arthroscopy video and site 

Diagnostic Tests/Lab Tests/Lab Values 

Joint aspiration:
Needle joint aspiration can be used as both a diagnostic tool and a treatment. A portion of the fluid can be taken out by aspiration needle to determine the type of bacteria causing the infection thus determining further course of treatment. 

Other diagnostic lab values: 

• Arthrocentesis with synovial fluid examination and culture
• Increased White blood cell count
• Increased Erythrocyte sedimentation rate (ESR)
• Increased Temperature
• Increased C-Reactive Protein (CRP)
• Imaging studies are used to rule out other conditions

 

 

www.vumc.nl/afdelingen-themas/41463/27797/2089686/2090082/1608664/8.pdf

Etiology/Causes

Septic arthritis is also known as infectious or bacterial arthritis and involves a local response causing inflammation of the synovial membrane of the joint affected. This is due to the invasion of bacteria, viruses, or fungi directly into the synovial membrane of the joint. The most common cause is bacterial, more specifically staphylococcus aureus, streptococci, or gonococci, a bacteria transferred via sexual activity. It can also be caused by viral infections such as Hepatitis B or Rubella.  

The bacterial or viral infection enters the joint via the bloodstream by three different ways:

1. Direct inoculation via surgery, arthroscopy, injection, central lines, or total joint replacements.
2. A wound that that breaks the skin such as a bite, cut, or open fracture.
3. Another systemic infection such as osteomyelitis, cellulitis, diverticulitis, or an abscess reaches the joint causing another infection.
   

Associated risk factors:

Two of the most important factors that put a patient at risk are a pre-existing joint pathology, especially Rheumatoid Arthritis, or a recent prosthetic joint surgery. Other risk factors to be considered are: 

Other risk factors: 

• Increasing age
• History of infection of any kind
• Autoimmune conditions such as Systemic Lupus Erythematosus
• Scleroderma or mixed connective tissue disease
• Diabetes
• Sarcoidosis
• Human bite or tick bite
• Fracture
• Central line placement
• Indwelling catheter
• Immunocompromised condition
• Chronic joint damage (RA, OA)
• Sexually transmitted infection
• Injection drug user
• Alcoholism
• Recent immunization
• Malnutrition
• Skin breakdown
• Rarely seen is a case of Infectious Arthritis as a complication from ACL reconstruction due to contaminated bone-tendon-bone allografts.
  

Systemic Involvement

Septic arthritis presents with a multitude of signs and symptoms affecting visceral systems. Joint symptoms may present in conjunction with a skin rash, low-grade fever, chills, and lymphadenopathy.  Bilateral joint involvement is common in the fingers, knees, shoulders, and ankles. The classic signs of infection may be present including increased temperature, swelling, redness, and loss of function.   Acute symptoms of an arthritic joint in the presence of fever should alert the health care provider of potential septic arthritis and should be treated as a medical emergency.

Medical Management (current best evidence)

Antibiotic Treatment- Septic arthritis is best treated immediately with antibiotics. There is no one antibiotic better than another; rather it is based on the organism involved. Antibiotics will need to be chosen based on the culture. 

Joint Drainage and Surgical options- Removal of infected joint material is imperative in improving a patient’s status. One systematic review found “the results suggested that needle aspiration appeared, in general, to be preferable to surgical treatment as an initial mode of treatment of joint sepsis, although the results did not reach statistical significance (and there was a trend towards higher mortality in the needle aspiration group)".

Management regarding antibiotic choice, dosage, route of administration, and duration of treatment is unknown in the treatment of septic arthritis. In addition, no evidence has shown if closed aspiration or open arthroscopy is better at removing materials from a joint that’s infected.

Physical Therapy Management (current best evidence)

It is important to first immobilize the joint. This will control the patient’s pain because it is often too painful to bear weight. Gentle mobilization of the infected joint can begin if the patient is responding well following 5 days of gentle treatment. Patients will usually respond better to aggressive PT to allow maximum post infection functioning. PT needs to consists of allowing the joint to be in its functional position and positioning the joint to allow passive range of motion activities.

Differential Diagnosis

Septic arthritis presents as many associated arthropathies, these must be ruled out in order for a definitive diagnosis to be made. With the immediacy of joint destruction with septic arthritis, the differential diagnosis must be performed with urgency to initiate proper treatment immediately. Conditions that must be considered include: rheumatoid arthritis, osteoarthritis, HIV infection, Lyme disease, and gout. Patients with these diagnoses often have a poor prognosis secondary to delays in the proper diagnosis of septic arthritis. Clinicians often attribute the signs and symptoms to the preexisting conditions. Other conditions that must be ruled out include: infective endocarditis, reactive arthritis, and viral arthritis. 

Case Reports/ Case Studies

• Septic arthritis of the hip:

www.ncbi.nlm.nih.gov/pmc/articles/PMC2485040/

• Pneumococcal polyarticular septic arthritis after a single infusion of infliximab in a rheumatoid arthritis patient:

www.jmedicalcasereports.com/content/6/1/81

• Cervical facet joint septic arthritis:  

ukpmc.ac.uk/articles/PMC2958294/

Resources

Mayo Clinic  www.mayoclinic.com/health/bone-and-joint-infections/DS00545

Medscape emedicine.medscape.com/article/236299-overview

Merck Manual

 www.merckmanuals.com/professional/musculoskeletal_and_connective_tissue_disorders/infections_of_joints_and_bones/acute_infectious_arthritis.html

PubMed www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001466/

Recent Related Research (from Pubmed)

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References

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