Have you ever noticed any swelling of any part of your body? If it was caused by trauma like accidental falls, you would not end up overthinking as it is obvious the swelling is caused by such injury. However, what if you notice swelling but do not understand why because it was not caused by an obvious physical injury? Pretty sure you will be worried about this sudden phenomenon. In this DoctorOnCall article, we will be focusing on what can cause the knee to swell without injury.
It is commonly known that the knee is a joint that is prone to injury from trauma, inflammation, infection and the ageing process causing it to become worn out. This is due to the fact that the knee itself acts as part of the limb that plays a big role in supporting the body weight and yet is quite unstable. A swollen knee is often described as knee effusion. A knee effusion is defined as accumulation of excess fluid in and around the knee joint.
It is easy to spot a swelling knee after a traumatic event but it is the exact opposite when the swelling is not predisposed by any injury. Here is example of causes that lead to a swollen knees that is not caused by injury:
1- Overuse knees. Physical activity and exercise that is done repeatedly can cause microtrauma that is not visible with the naked eye.
2- Osteoarthritis. A common disease affecting old people affecting the cartilage cushioning the joint to become wear down and cause abnormal growth of new bone around the joints.
3- Crystal-induced arthritis. Inflammation of the joint caused by crystals from the gout disease. History of usage of diuretic, diet high in purine such as in seafood and formation of renal stones is associated with gout arthritis. When the crystals presented in joints are not urate crystals such as in gout, it is called a pseudogout crystal such as the calcium crystals.
4- Rheumatoid arthritis. A form of autoimmune disease causing both sides of the joints of the limb to be painful and stiff and may involve multiple joints of the body.
5- Septic arthritis. An infection in the joint fluid and joint tissues caused by bacteria, viruses or fungi. In contrast with rheumatoid arthritis, septic arthritis usually affects one side of the joint and one joint at a time.
6- Tumour. Knee effusion can happen in both benign and malignant tumours. This includes unspecific symptoms of fever, unintentional weight loss, night sweats and pain intensified at night time.
Since a swollen knee can be caused by both trauma and non-traumatic causes, it is essential for healthcare professionals to identify exact causes of the phenomenon as the right treatment can only be given and be effective when in accordance with the causes. A thorough medical history will be taken to get a better understanding of the knee effusion. Physical examination will be done to help doctors narrow down possible sites affected by the swollen knee. Further tests such as x-ray and ultrasound may be required to get a better picture of the severity of the swollen knee. Arthrocentesis, a procedure involving usage of needle or syringe to drain the fluid from the swollen joint, is done to help provide relief and to obtain the fluid for analysis. This procedure is usually done when in cases of unexplained knee effusion, unclear causes or when infection is suspected.
All in all, a swollen knee can indeed be caused without injury. It is necessary for a person to get urgent medical advice if the knee swelling does not improve within two days as delaying treatment may jeopardise joint viability.