What is the most common late manifestation of Lyme disease?

In the context of Lyme disease, the most common late manifestation is indeed joint pain, which is experienced as Lyme arthritis. This condition typically presents with recurrent episodes of inflammation in large joints, especially the knees.

The mechanism behind this manifestation involves the immune response to the spirochete Borrelia burgdorferi, which can persist in the body, leading to chronic inflammatory reactions in the joints. This can result in significant morbidity, and patients may experience pain, swelling, and reduced mobility in the affected joints.

While other manifestations such as neurological deficits and cardiac abnormalities can also occur, they are often less common in the late stages of the disease. Neurological complications, when they do occur, such as meningitis or cranial nerve palsies, tend to manifest earlier in the disease course. Similarly, cardiac abnormalities like Lyme carditis, characterized by heart block or myopericarditis, typically arise before joint pain in the course of the illness.

Rash, specifically erythema migrans, is one of the earliest signs of Lyme disease and does not appear as a late manifestation. After the initial stage, the rash resolves, and it is not commonly seen in the chronic or late phase of the disease.

Therefore, joint pain stands