Ans. c. Polymorphonuclear lymphocytosis in CSF suggest meningeal involvement Meningitis (meningeal involvement) is the most common neurological event that occurs in the setting of early tyme dissemination. In this clinical setting CSF is always abnormal and shows pleocytosis with predominantly lymphocytosis (not pttlymorphonut lear leucocytosis).Lyme's Disease* Caused by Borrelia burgdorferi0, transmitted by bite of Ixodid ticks0* Borrelia burgdorferi is inoculated in the skin, where local replication takes place locally and outward migration in the dermis occurs.* Days to week after the tick bite, hematogenous dissemination to secondary sites (like joints, heart eye, nerv ous system) takes place.* If untreated, the bacteria may persist in the body for months or even years, despite the production of anti- Borrelia burgdorferi antibodies by the immune system.Clinical Features of Lyme's DiseaseStage 1(Localized infection)Stage II(Disseminated infection)Stage III(Persistent infection)* After incubation period of 3 to 32 days Erythema mi grans occurs at the site of bite,* Erythema migrans is not painful.* Disseminate hematogenously to produce secondary annular skin lesion, meningitis, carditis* MC cardiac finding is fluctuating degree of AV heart block0* Usually present as oligoarticular arthritis (MC knee), encephalopathy, polyneuropathy.* Acrodermatitis chronica atrophicans is late skin manifestation. Lyme Meningitis* Meningitis (meningeal involvement) is the most common neurological event that occurs in the setting of earlylyme dissemination.* In this clinical setting CSF is always abnormal and shows:- Pleocytosis with predominantly lymphocytosis0 (not polymorphonuclear leucocytosis).- Increased protein* Glucose content is usually normal, but it falls below the serum concentration in 20% of patients.* Immunoglobulin abnormalities are common in the CSF of patients with lyme meningitis.* Specific IgM, IgG or IgA antibody against B. burgdorferi appears in CSF and indicates intrathecal antibody synthesis. Lyme's DiseaseDiagnosis:* ELISA followed by western blot is best investigation.* Culture in BSK mediumy gives definitive diagnosis but not useful clinically.Treatment:* For nervous manifestation and 3deg heart block: Ceftriaxone is DOC.* For skin manifestation, arthritis. ldegand 2deg AV block: Doxycycline is DOC.