Syphilis, caused by the bacterium *Treponema pallidum*, is primarily known as a sexually transmitted infection that progresses through several stages, each with distinct symptoms and effects on the body. While it mainly affects the skin, mucous membranes, and internal organs, its impact on joint health is less direct but still significant, especially in certain forms and stages of the disease.
In general, syphilis does not commonly infect joints directly during the early or middle stages of infection. However, in the most advanced stage, known as tertiary syphilis, and in cases of congenital syphilis (where the infection is passed from mother to baby during pregnancy), the joints can be affected more seriously. Congenital syphilis often leads to destructive inflammation in the growing cartilage at the ends of bones in newborns. This inflammation can cause deformities and restrict the growth of the affected bones, leading to long-term joint problems if untreated. Early treatment with antibiotics like penicillin can prevent or even reverse these joint complications.
One specific joint condition linked to congenital syphilis is called Clutton’s joint. This condition typically occurs in children between the ages of 6 and 16 and involves true inflammation of the synovial membrane—the lining of the joint. Clutton’s joint usually causes swelling, particularly in the knees, but it tends to be relatively benign and does not cause severe joint destruction. This contrasts with other forms of arthritis that can cause permanent joint damage.
In adults with tertiary syphilis, joint involvement is rare but can occur. The disease may cause lesions in the joints, but these are not common and usually appear only after many years of untreated infection. These late-stage syphilitic joint lesions are part of a broader pattern of tissue damage caused by the bacteria’s slow, chronic infection and the body’s immune response to it.
Syphilis can also cause systemic symptoms that indirectly affect joint health. For example, during treatment, some patients experience a reaction called the Jarisch-Herxheimer reaction, which can include joint pain along with fever, headache, and malaise. This reaction occurs shortly after starting antibiotic therapy and is a temporary inflammatory response to the dying bacteria, not a direct infection of the joints.
It is important to distinguish syphilitic joint involvement from other sexually transmitted infections that more commonly cause joint problems, such as gonorrhea, which can lead to infectious arthritis. Syphilis-related joint issues are less frequent and usually appear only in advanced or congenital cases, whereas gonorrhea can cause more acute and direct joint infections.
In summary, while syphilis does not typically infect joints directly during its early stages, it can cause joint inflammation and damage in congenital cases and in the late tertiary stage. Early diagnosis and treatment are crucial to prevent these complications. Joint symptoms related to syphilis are generally part of a broader systemic infection or immune response rather than isolated joint disease.