stylistic:tone, structural:summarization, linguistic:voice_change
Early disseminated infection

Within days to weeks after the onset of local infection, the Borrelia bacteria may spread through the lymphatic system or bloodstream. In 10–20% of untreated cases, EM rashes develop at sites across the body that bear no relation to the original tick bite. Transient muscle pains and joint pains are also common.

In about 10–15% of untreated people, Lyme causes neurological problems known as neuroborreliosis. Early neuroborreliosis typically appears 4–6 weeks (range 1–12 weeks) after the tick bite and involves some combination of lymphocytic meningitis, cranial neuritis, radiculopathy, and/or mononeuritis multiplex. Lymphocytic meningitis causes characteristic changes in the cerebrospinal fluid (CSF) and may be accompanied for several weeks by variable headache and, less commonly, usually mild meningitis signs such as inability to flex the neck fully and intolerance to bright lights but typically no or only very low fever. After several months neuroborreliosis can also present otolaryngological symptoms. Up to 76.5% of them present as tinnitus, the most common symptom. Vertigo and dizziness (53.7%) and hearing loss (16.7%) were the next most common symptoms. In children, partial loss of vision may also occur. Cranial neuritis is an inflammation of cranial nerves. When due to Lyme, it most typically causes facial palsy, impairing blinking, smiling, and chewing on one or both sides of the face. It may also cause intermittent double vision. Lyme radiculopathy is an inflammation of spinal nerve roots that often causes pain and less often weakness, numbness, or altered sensation in the areas of the body served by nerves connected to the affected roots, e.g. limb(s) or part(s) of trunk. The pain is often described as unlike any other previously felt, excruciating, migrating, worse at night, rarely symmetrical, and often accompanied by extreme sleep disturbance. Mononeuritis multiplex is an inflammation causing similar symptoms in one or more unrelated peripheral nerves. Rarely, early neuroborreliosis may involve inflammation of the brain or spinal cord, with symptoms such as confusion, abnormal gait, ocular movements, or speech, impaired movement, impaired motor planning, or shaking.

In North America, facial palsy is the typical early neuroborreliosis presentation, occurring in 5–10% of untreated people, in about 75% of cases accompanied by lymphocytic meningitis. Lyme radiculopathy is reported half as frequently, but many cases may be unrecognized. In European adults, the most common presentation is a combination of lymphocytic meningitis and radiculopathy known as Bannwarth syndrome, accompanied in 36-89% of cases by facial palsy. In this syndrome, radicular pain tends to start in the same body region as the initial erythema migrans rash, if there was one, and precedes possible facial palsy and other impaired movement. In extreme cases, permanent impairment of motor or sensory function of the lower limbs may occur. In European children, the most common manifestations are facial palsy (in 55%), other cranial neuritis, and lymphocytic meningitis (in 27%).

In about 4–10% of untreated cases in the United States and 0.3–4% of untreated cases in Europe, typically between June and December, about one month (range 4 days to 7 months) after the tick bite, the infection may cause heart complications known as Lyme carditis. Symptoms may include heart palpitations (in 69% of people), dizziness, fainting, shortness of breath, and chest pain. Other symptoms of Lyme disease may also be present, such as EM rash, joint aches, facial palsy, headaches, or radicular pain. In some people, however, carditis may be the first manifestation of Lyme disease. Lyme carditis in 19–87% of people adversely impacts the heart's electrical conduction system, causing atrioventricular block that often manifests as heart rhythms that alternate within minutes between abnormally slow and abnormally fast. In 10–15% of people, Lyme causes myocardial complications such as cardiomegaly, left ventricular dysfunction, or congestive heart failure.

Another skin condition, found in Europe but not in North America, is borrelial lymphocytoma, a purplish lump that develops on the ear lobe, nipple, or scrotum.