In the USA, Lyme disease is contracted from Ixodesticks harbouring the spirochete Borreliaburgdorferi.Borreliagariniiand Borreliaafzeliiaccount for the overwhelming majority of organisms isolated in Europe in cases of neuroborreliosis. Lyme neuroborreliosis is felt to occur in Asia and has been documented in Russia. Currently, there is no evidence of the disease in South America or Africa⁸.The majority of cases in the USA occur in northeastern, mid-Atlantic and north-central states. The number of cases reported to the Centers for Disease Control (CDC) in Atlanta, Georgia has climbed steadily since it became a reportable disease in 1991⁹. In 1992 approximately 10 000 cases were reported, while 2007 produced more than 27 000 cases with an incidence of 9.1/100 000. In the 10 states reporting the most cases, the incidence was significantly higher at 34.7/100 000¹⁰. Mandatory reporting does not exist in Europe, so obtaining accurate epidemiological data is more difficult. The eastern central region of Europe probably has the highest incidence of neuroborreliosis⁸.

Early manifestations of Borreliaburgdorferiinfection include an expanding ‘bullseye’ rash, also known as erythema migrans, as well as headache, fever, myalgia or arthralgia, and fatigue¹¹.CDC review of cases from 2003 to 2005 demonstrated that erythema migrans was present historically in about 70% of cases⁹, while other sources cite 90% of cases with rash, about 40% of which have central clearing¹². The rash typically appears within 30 days of Ixodestick exposure. In the European form, rash is much less common. Other early presentations include facial palsy, radiculopathy, meningitis/encephalitis and heart block. European Lyme neuroborreliosis most commonly presents with a painful radiculitis (86%), which is called Bannwarth’s syndrome⁸. Onset of symptoms in the USA is typically during the months of June, July or August, and less than 8% of cases occurred from December to March⁹. Rickettsial infections, including Rocky Mountain spotted fever, can also present with acute encephalitis and patients may have cranial neuropathies, focal neurological signs and seizures.

Patients with untreated Borreliaburgdorferiinfections often develop a subacute to chronic disease with musculoskeletal, cardiovascular or neurological symptoms. Arthritis is typically oligoarticular and most commonly involves the knee joint (60%). Cardiovascular involvement occurs in about 8% of patients and is typically a pericarditis or myocarditis producing conduction abnormalities⁵. Chronic skin manifestations are more common in European Lyme neuroborreliosis and take the form of acrodermatitis chronica atrophicans and lymphocytoma. Neurologic symptoms and signs develop in about 15% of patients and include cranial neuropathy, painful radiculopathy, peripheral neuropathy and meningoencephalitis. The most common cranial nerve affected in Lyme neuroborreliosis is the facial nerve, causing a ‘Bell’s palsy’. Between 25% and 50% of patients developing meningitis will have multiple radiculopathies or peripheral nerve lesions. The peripheral neuropathy is typically axonal and not severe⁸. Myelitis, cerebellar ataxia, seizures and chorea are rare⁵.

Manifestations of chronic infection may overlap with its subacute features and include fatigue, dermatitis, arthritis and neuropsychiatric symptoms such as depression and cognitive dysfunction. Patients with chronic Lyme disease may report poor concentration and attention, irritability and memory complaints. Other considerations in the differential diagnosis typically include fibromyalgia and chronic fatigue syndrome. Importantly, symptoms and signs suggestive of early disseminated disease should have been present at an earlier point¹³. Other reported psychiatric symptoms include mania, delirium, dementia, psychosis, panic attacks, personality change, obsessions/compulsions and catatonia^14,15. There is no clear evidence that Lyme disease causes the majority of these reported symptoms.

Cerebrospinal fluid examination in patients with Lyme disease typically shows a mild lymphocytic pleocytosis with a mildly elevated protein and normal glucose. In patients with a history of tick exposure, erythema migrans and suggestive symptoms and signs, the enzyme linked immunosorbent assay (ELISA) is a helpful screening test. A positive test with a rise in IgM occurs in about 90% of patients who have acute and chronic serum samples tested⁵.The presence of elevated IgG without IgM suggests a chronic exposure. A positive ELISA test must be confirmed with Western blot due to the possibility of false positive screening tests. In Europe where multiple strains cause neuroborreliosis, an antibody index comparing CSF and serum antibody levels is typically used for diagnosis⁸. CSF culture has a yield of about 5% and is not useful, while CSF PCR is positive in about 30–40% of cases, usually early in the disease. CT and MRI are usually most helpful in ruling out other neurological diseases, but may rarely demonstrate multifocal periventricular white matter lesions in advanced cases⁵. These lesions are not specific for Lyme disease and are seen in several other neurological diseases, including demyelinating disease, migraine and cerebrovascular disease.

Treatment of acute disease is typically with oral doxycycline (100–200mg bid) or amoxicillin (500mg tid) for 2–4 weeks. Options for neuroborreliosis include intravenous ceftriaxone (2 g daily) for 2–4 weeks, high-dose penicillin (20 million units daily) for 2–4 weeks or tetracycline (500mg qid) for 30 days¹⁶. A recent European trial demonstrated similar efficacy when comparing two weeks of therapy with intravenous ceftriaxone 2 g daily versus oral doxycycline 200 mg daily¹⁷. Following treatment, patients may report continued fatigue, difficulty concentrating and memory difficulty. This is the so-called ‘post-Lyme syndrome.’ These patients have often been given extended courses of treatment with oral or intravenous antibiotics in an attempt to clear their ‘chronic infection’. Typically, there are alternative explanations for their symptoms, and there is a little data to support prolonged antimicrobial treatment in individuals who have received adequate treatment^8,16,18.

Close to 37 000 cases of syphilis were reported in the continental United States in 2006 and the majority occurred in the southeastern region. Late and latent syphilis accounted for over 17 000 of the total cases¹⁹