Neurological Complications of Lyme Disease

A tick-bite associated rash with later neurological manifestations, including pa­ ralysis and meningitis, had been docu­ mented in Europe for several years before Lyme arthritis was recognized in the 1970s.-4 The illness was later understood to be part of a multisysrem disease caused by spirochetae and transmitted by Ixodes ticks. . " Borrelia burgdorferi, although initially thought to be a single species, has been found to have several sub-species. These subgroups may be responsible for the variation in clinical symptoms observed in different parts of the world. 7 The pathophysiology of neuro­ borreliosis is difficult to demonstrate, but mimics other spirochetal infections. In­ fection is local with subsequent dissemi­ nation. During this time spirochete num­ bers are high. B. burgdorferi components that induce cytokine production by T and B cells produce immune activation and indirect cell damage. Central ner­ vous system involvement is common and clinical syndromes tend to occur in stages. 7 Lyme disease has been implicated in a variety of peripheral and central ner­ vous system disorders. The neurological syndromes are often accompanied by more general complaints (arthralgias, fa­ tigue, myalgias). Earlier neurological symptoms, or those occurring during dis­ semination within weeks to months, tend to be more clinically obvious and develop in an estimated 15% to 20% of patients. Several late syndromes seem to follow a more insidious course. 8 For purposes of simplification, disorders of the peripheral and central nervous systems will be re­ viewed separately.


Neurological Complications of Lyme Disease
Syed Rizvi, MD, and Amanda Diamond, MD A tick-bite associated rash with later neurological manifestations, including pa ralysis and meningitis, had been docu mented in Europe for several years before Lyme arthritis was recognized in the 1970s. 1 -4 The illness was later understood to be part of a multisysrem disease caused by spirochetae and transmitted by Ixodes ticks.5 ." Borrelia burgdorferi, although initially thought to be a single species, has been found to have several sub-species.These subgroups may be responsible for the variation in clinical symptoms observed in different parts of the world. 7he pathophysiology of neuro borreliosis is difficult to demonstrate, but mimics other spirochetal infections.In fection is local with subsequent dissemi nation.During this time spirochete num bers are high.B. burgdorferi components that induce cytokine production by T and B cells produce immune activation and indirect cell damage.Central ner vous system involvement is common and clinical syndromes tend to occur in stages.

7
Lyme disease has been implicated in a variety of peripheral and central ner vous system disorders.The neurological syndromes are often accompanied by more general complaints (arthralgias, fa tigue, myalgias).Earlier neurological symptoms, or those occurring during dis semination within weeks to months, tend to be more clinically obvious and develop in an estimated 15% to 20% of patients. 4everal late syndromes seem to follow a more insidious course. 8For purposes of simplification, disorders of the peripheral and central nervous systems will be re viewed separately.

PERIPHERAL NERVOUS SYSTEM
The most common peripheral mani festations of Lyme disease are cranial neu ropathies, peripheral neuropathies and radicultis.However, many other syn dromes, including a "Guillian Barre-like" syndrome, motor neuron disease, axonopathies, brachial and lumbar plexopathies, mononeuropathy multiplex and even myositis have been described. 7

~
Radiculoneuropathy.Painful radicu litis is one of the most common early neu rologic symptoms of Lyme disease in Eu rope.Incidentally, it was also part of the symptom-complex described in the first patient reported with the syndrome. 1Usu ally occurring within the first weeks to months in the infection, the radiculoneutopathies of Lyme disease have included motor, sensory and mixed symp toms.They are usually self-limited and may be easily mistaken for nerve-impingement syndromes, with segmental symptoms of weakness, sensory or reflex changes. 9The symptoms may not occur in the region of the tick bit.Electrodiagnostic testing usu ally shows multifocal mild sensorimotor in volvement.lO.11  Cranial neuropathies.Involvement of cranial nerves, particularly the seventh nerve, may be present in up to 50%-75% of all patients experiencing neurologic syrnptoms. 4Multiple cranial nerves may be involved simultaneously.9Reports in clude symptoms of evety cranial nerve ex cept the olfactory nerve.The facial nerve involvement is reported to be bilateral in up to one third of cases.I I Facial nerve symptoms may not affect taste or hearing, indicating that involvement may be outside the subarachnoid space.Additionally, CSF analysis in isolated Lyme disease facial palsy may be normal.Complete recovery occurs in 80-90% of patients within weeks to months.
"Guillain Barre-like" syndrome.Although rare, an acute and severe syn drome of diffuse polyneuropathy, includ ing bifacial weakness, may mimic the symptoms of Guillan Barre.A CSF lym phocytic pleocytosis and/or neurophysi ologic testing may help differentiate be tween the syndromes.?
Peripheral neuropathy.Symptoms of peripheral neuropathies in patients with Lyme disease tend to be primarily sensory, occurring in a stocking-glove fash ion, although patchy paresthesias may also be noted.In some European pa tients, a dermatologic manifestation is often associated with the neuropathy.Labeled acrodermatitis atrophicans, the skin becomes tissue-thin and discolored.

t
.In the case of chronic infection, it has been estimated that one in four patients may have peripheral nerve involvement.These patients may present with mainly sensory symptoms.

NEUROBORRELIOSIS OF THE CENTRAL NERVOUS SYSTEM
Meningitis.Although many syn dromes involving the central nervous sys tem remain controversial, several have been well-defined.Certainly, the early appearance of lymphocytic meningitis is well recognized.Mildly increased CSF pressure with headache and papiledema may occur.The lympho cytic pleocytosis usually includes tens to hundreds of lymphocytic cells per mL.A mild elevation of protein may also be seen, with CSF glucose usually remain ing wirhin a normal range to minimally decreased. 12The 'typical' symptoms that usually occur with 'aseptic' menin gitis, such as photophobia, headache and neck stiffness, are extremely variable with Lyme meningitis.II,12 Intracranial hypertension syn drome.A rare complication of Lyme dis ease resulting in headache and potential papilledema, this syndrome seems to be associated more otten with children and adolescents.CSF abnormalities may oc cur.There does not appear to be a cor relation with female sex or obesity, as with pseudotumor cerebri.ll , 13 Encephalomyelitis.A chronic manifestation of Lyme disease, encepha litis is rare in North American (nearly all cases have been reported in Europe).On MRI there is evidence of parenchymal involvement.This can include hemi spheric or brainstem abnormalities and is usually nonspecific, although may mimic ischemic patterns.1l Myelopathy.Patients may present with symptoms of transverse myelitis so that Lyme disease should be considered in the diagnosis of these patients.11, 14 Rarely, a transverse myelopathy may ac company Lyme radiculoneuritis.This typically occurs at the same level as radicular involvement and may be preceeded by a leptomeningitis. 12yme encephalopathy.This may be the most common late neurologic mani festation ofLyme disease.Patients express difficulties with concentration, sleep dis turbance, emotional lability, memory and attention.I I , I;, Ii, Despite studies includ ing requirements for CSF abnormalities and SPECT imaging, the definitive di agnosis of Lyme encephalopathy remains elusive.Ii, In the consideration of acute encephalopathy, one should note that persons with Lyme-induced cognitive changes likely have a mild encephalitis; these patients should not be confused with mental status changes associated with systemic symptoms.I? Such patients are likely to have objective findings on neuropsychiatric testing and such a di agnosis should only be made in the pres ence of appropriate findings after test ing has been performed by a qualified professional.This is distinct from the more subjective symptoms patients often experience for weeks to months follow ing an episode of acute infection with B. burgdorferi (discussed below).
Post-Lyme disease.Several patients who have had Lyme disease have been noted to have other psychiatric and cog nitive symptoms, such as fatigue, cogni tive slowing and depression.These pa tients are sometimes diagnosed with post Lyme disease.It is unlikely that these symptoms indicate persistem neurologic infection, and studies have not shown that antimicrobial therapy is helpful in these patients.IS

DISEASE
The crucial element for the consid eration of neurologic Lyme disease is the presence of an indicative neurologic symptom.Laboratory data should be complimentary and supportive of clini cal findings.In evaluating response to therapy, the clinician must remember thar many neurologic illnesses improve with time, regardless of treatent.l ?Un fortunately, sensitivity of culture in ner vous system infections is Jow (only about 10% in CSF in Lyme meningitis).The sensitivity of PCR testing appears to be low as well.Confirmation of the diagno sis, therefore, relies largely on serologic testing.Spinal fluid can, however, be tested for the presence of anti-B.

burgdorferi antibodies.] 9
The American Academy of Neurol ogy (AAN) guidelines for the diagnosis of neurologic Lyme disease include the consideration of exposure to ticks in an endemic region, clinical abnormalities other than those affecting the nervous system (including cardiac, rheumatologic and dermatologic symptoms), and ad equate laboratory support (proof of the presence of B. burgdorferi or immuno logic evidence of exposure) in addition to the causally-related neurologic disease or syndrome. 20

... prolonged courses of antibiotics do not improve outcomes
and are not recommended.
Additionally, the US Centers for Disease Control and Prevention (CDC) has recommended a two-tier system to test for anti-B.burgdorferi antibodies.Sero logic testing starts with enzyme-linked immunosorbent assay (ELISA), with usually high sensitivity depending on acuity of infection and organ systems in volved, and low specificity due to cross reacting antigens. 21Seropositivity may remain for years and can occur in up to 10% of the asymptomatic population in endemic areas.The antibody may not be detected within the first 2 to 6 weeks after exposure, so retesting (or treatment without testing in cases with Erythema migricans) may be important in cases of high clinical suspicion.Borderline or positive results are then confirmed by Western blot.IgM testing is recom mended only acutely in disease, when clinical history is limited to 1 to 2 months, and requires 2 of 3 possible bands (sensi tivity 32%).Confirmatory testing ofIgG presence requires 5 of 10 possible bands (sensitivity 83%).Given lower sensitivi ties, clinical judgment should in used in patients with positive ELISA whom do not meet Western blot criteria.Also, positive Western blot performed without ELISA may be deceptive and should not be used.J9, 20, 21 Given the high incidence of B. burgdorferi antibody in the CSF of pa tients who are seropostive but without neuroborreliosis, other tests for the di agnosis of central nervous system disease have been evaluated.A recent study by Blanc,et.al. 22 suggested the use of an anti-Borrelia antibody index (AI).The AI is the ratio of anti-Borrelia IgG in CSF to ami-Borrelia IgG in the serum and is considered positive if greater than or equal to two.The study noted 74 pa tients with diagnoses of other neurologic diseases all had positive CSF Lyme anti bodies; only two of those patients had a positive AI (specificiry of97%).The sen sitivity of positive AI was determined to be 75%.The authors suggested the fol lowing criteria for diagnosis of neuroborreliosis: presence of four of the following five items. 1)no past history of neuroborreliosis, 2) positive CSF anti Borrelia antibodies, 3) positive anti-Bor relia antibody index, 4) favorable out come after specific antibiotic treatment, 5) no other etiologic diagnosis. 22esearchers have also described a B-cell-tropic chemokine, CXCLl3, which appears abnormally elevated in CSF of patients with Lyme neuroborreliosis.If confirmed, this cytokine might serve as a marker to as sist in the confirmation of the diagnosis of neuroborreliosis. 21

TREATMENT OF NEUROBORRELIOSIS
Although the general recommen dation in the US is to use parenteral an tibiotics whenever the nervous system is involved, there is considerable evidence in the European literature suggesting oral doxycycline (200-400mg/day) may be equally effective in most patients.At the recommended doses it appears that the CSF concentrations of doxycycline exceed minimum inhibitory concentra tion for most strains.Although there are strain differences between United States and Europe, thete probably is not a sig nificant difference in antimicrobial sus ceptibiliry. 24Also, prolonged courses of antibiotics do not improve outcomes and are not recommended.The duration of parenteral treatmem suggested is 2 to 4 weeks, with no data showing any definite advantage of prolonged treatment.2j ,26 Oral regimens are generally given for 30 days.

Table 1 . Antimicrobial regimens for the treatment of nervous system Lyme disease
Treatmenr regimens are listed III TableI.