Arthritis, or joint inflammation, is a health issue commonly seen in general practitioners’ and rheumatologists’ offices. The severity of symptoms and prognosis vastly vary, and the potential causes are numerous: from injury and infections to metabolic and immunity disorders.
Viral arthritis is an acute inflammation of the joints caused by a viral infection. It usually develops at the same time, or immediately after a viral disease. The prevalence is difficult to estimate, as viral infections are rarely diagnosed microbiologically in clinical practice. Some reliable studies state that 1% of arthritis’ is of viral origin.
The immune system produces antibodies in response to a viral infection. Antibodies are made to recognize specific parts of the virus known as antigens, and they bind together to create deposits known as immune complexes. Immune complexes further activate and stimulate different parts of the immune system in an array of events which eventually leads to the elimination of the pathogen. However, sometimes the immune complexes are deposited in certain parts of the body (usually the kidneys, the blood vessels, and the joints), where they trigger inflammation and tissue damage.
Many viruses are known to cause arthritis. Parvo B19 and rubella viruses are common causes of viral arthritis, though the latter is nowadays rarely seen thanks to vaccination. Hepatitis B and C, and Ross River viruses also frequently come with joint inflammation. Others, such as adenoviruses, HIV, Epstein Barr virus, herpes viruses, and mumps are sometimes associated with arthritis too. Even a case of COVID-19 arthritis was described in a recent study by Parisi and associates!
Just like other inflammatory processes, viral arthritis is characterized by some or more of the following symptoms:
Typically more than one joint is involved – the disease symmetrically affects joints on both sides of the body. Small joints of the hands, wrists, and knees are the most common sites of inflammation.
Viral arthritis usually develops suddenly and temporally coincides with other symptoms of a certain viral infection. These habitually involve flu-like symptoms, fever, rash, and swelling of the lymph nodes.
In patients with existent joint diseases, viral infections often cause worsening of the symptoms.
Diagnosing viral arthritis is difficult, costly, and, above all, not a very necessary task. Here is why: like most viral infections, viral arthritis is usually a self-limiting disease, which resolves spontaneously in a short time. However, in cases of infections such as HBV, HCV, EBV, or HIV, specific tests are necessary to confirm the causative agent.
There are two common ways to detect a viral infection: to detect the virus itself, which usually means to detect its genetic material using PCR; or to detect the body’s response to the virus, i.e. to measure the levels of IgM and IgG antibodies. Some blood analyses, such as rheumatoid factor, antinuclear antibodies, CRP, or sedimentation rate, are also useful for establishing the diagnosis and/or excluding other diseases.
Overall clinical presentation must be taken into account too, as it may raise suspicion of a certain infection, especially in unclear cases. For example, parvo B19 usually causes flu-like symptoms, with mild rash and arthritis, none of which is specific. But 20% of the patients will have the so-called “slapped cheek” appearance, which is very specific, and will lead a careful doctor to the right diagnosis.
As mentioned, viral arthritis is normally a self-limiting disease, with sudden onset and spontaneous resolution within six weeks. No specific treatment is needed during that time. Over-the-counter analgesics and non-steroid anti-inflammatory drugs (NSAIDs) can be used to alleviate the pain and inflammation during that time, and applying ice or warming stiff joints may help relieve the symptoms too.
However, if the symptoms persist for over six weeks, or other joint diseases (for example rheumatoid arthritis) are suspected, the patient should seek help from a rheumatologist. It is also of crucial importance for the doctor who first sees the patient not to oversee the signs and symptoms of potentially dangerous and treatable infections, such as HIV or hepatitis. For the best possible outcomes, these infections require urgent referral to a specialist too.