Healthy joints function like hinges in the human skeletal system, facilitating pain-free and efficient movement. Ensuring good joint health is of the utmost importance.
Wear and tear are among the biggest factors that hamper joint health. Infections are a major concern, too. The joints, especially the weight-bearing knee and hip joints, are susceptible to infection by certain pathogens, which could lead to septic arthritis.
Common causes of septic arthritis
Though most types of arthritis affect adults and elderly people, septic arthritis is seen in children as well.
“Septic arthritis is caused by [microbial] infection and inflammation of the joints,” says Dr Harish Puranik, senior consultant, orthopedics, Fortis Hospital, Bangalore. “In India, the common microorganisms that cause septic arthritis are staphylococcus, streptococcus and tuberculosis [mycobacterium tuberculosis].”
Apart from bacteria, septic arthritis is also caused when there is a fungal or viral infection of the joints.
“In adults, infection in the knee joint is common, whereas in children the infection is mostly seen in the hip joint,” says Dr R Raghavendra Reddy, consultant, orthopedics, Manipal Hospitals, Bangalore.
Who’s at risk of septic arthritis?
People who have had joint injuries are predisposed to developing septic arthritis.
“Children, especially when their bones are not completely developed, are at a slightly higher risk,” says Dr Puranik. “Those who have had some invasive procedures (like IV-line, central lines, urinary catheters) and people who have less immunity (either due to the consumption of steroids or having co-existing infections like HIV, etc.) are [also] predisposed to developing septic arthritis.”
Septic arthritis infection and invasion
Blood, which flows to most regions in the body, offers an avenue for infection of the joints. But there are also other means through which the joints can get infected.
“In children, the route of infection is mostly through blood,” says Dr Reddy. “If there is an infection in the blood, it can spread to the joints and lead to septic arthritis. However, for adults, there could be various other reasons. For instance, people who are immunocompromised or taking prolonged chronic medications are more prone to septic arthritis.”
An injury or injection at the joint can increase blood accumulation in that specific area and increase the chances of infection.
Once the joint is attacked by these microorganisms, they begin to break down the joint structure, which affects its function.
“On infection, the microorganisms begin to eat away the joint components, especially the cartilage — the smooth glistening layer which lubricates the joints and helps to maintain the joint in a healthy frictionless state,” says Dr Puranik.
As the body does not have the ability to regenerate the cartilage, the joint loses its lubricant, starts to undergo wear and tear, and gets destroyed within the next couple of years, adds Dr Puranik.
So, septic arthritis is considered an emergency and treated at the earliest to prevent further damage to the joint.
Diagnosis of septic arthritis
The initial diagnosis involves physical examination to check for signs of inflammation such as pain, localized warmth and redness along with loss of function and the inability to fully move the joint.
“Another major characteristic is feeling pain in the joint while at rest or sleeping,” says Dr Puranik. “And as the infection progresses, one might develop a fever as well.”
Blood reports can show the presence of the infective microorganism. “But the confirmatory test involves using a needle to aspirate the fluid from the joint and carrying out tests on it to confirm any microbial infection,” he adds.
Treatment for septic arthritis
As most joint infections are caused by bacteria, antibiotics are used for treatment.
“Predominantly, the treatment is surgical,” says Dr Puranik. “It can be done in a minimally invasive manner and then, based on what organism is causing the infection, that particular antibiotic is given. Very rarely is only an antibiotic used for treatment.”
Dr Reddy adds: “Almost 80% to 90% of it will be curable. But if the septic arthritis infection has been there for long time, [once the joint damage has occurred] it may not be completely curable, and some kind of residual damage will be there.”
Since the infection can have lasting effects, early diagnosis and surgical method of treatment (whenever required) are crucial to completely cure septic arthritis.
Takeaways
- Septic arthritis is caused by microbial (bacteria, fungi and viral) infection of the joints.
- The microorganism begins destroying the joint structure and breaking it down, resulting in joint damage and loss of function.
- The diagnosis involves physical examination combined with clinical diagnosis.
- Since it would be difficult to restore the joint completely after damage has occurred, it is necessary to diagnose and treat septic arthritis early.
- The treatment involves antibiotics. In severe cases, a surgical procedure is combined with medications.
