The recommended treatment in the first stage of the disease, mainly referring to the initial rash and the subsequent presence of facial or other cranial nerve palsies alone, is oral doxycycline (100 mg bid) for 14 days. Alternate therapies include amoxicillin 500 mg tid, used sometimes in children, or cefuroxime axetil 500 mg bid. CNS cardiac and arthritic disease can thereby be prevented in almost all cases. It follows that one is justified in being suspect of cases of “late Lyme” in patients who have undergone adequate early treatment. Once the meninges and central or peripheral nervous system are implicated, treatment in the U.S has been ceftriaxone, 2 g daily, usually given intravenously for 4 weeks. In other regions, oral treatment has been used.
Tetracycline, 500 mg qid for 30 days, is recommended for patients who are allergic to these intravenous drugs. Other alternative drugs are cefotaxime 2 g IV q8h and penicillin G 18 to 20 million units per day in divided doses q4h. For late or persistent clinical features ostensibly attributed to Lyme, antibiotics have not been shown to be effective. However, most of the symptoms tend to regress regardless of the type of treatment given.
According to Kaiser, more than 90 percent of subacute neuropathies and facial palsies resolve by 1 year after treatment, but a smaller proportion of spastic and ataxic myelopathy cases are improved. In other studies, up to a fifth of children with facial palsies have residual weakness.
This systemic spirochetal infection, caused by Leptospira interrogans, is characterized primarily by hepatitis but may include aseptic meningitis during the second part of a biphasic illness. Initially there is high fever, tender muscles, chest and abdominal pain, and cough. An extreme form (Weil disease) comprises hepatic and renal failure. Prominent conjunctival suffusion and photophobia are typical of leptospirosis and should draw attention to the diagnosis but viral infections that cause meningitis are capable of producing the same eye signs. The CSF during the meningitic stage contains approximately 100 lymphocytes/ mm3, but cell counts in excess of 10,000 have been reported and the protein concentration may reach high levels. Subarachnoid and intracerebral bleeding, probably from inflamed blood vessels, is known to occur. The diagnosis is made by serologic methods (ELISA, indirect hemoglutination assay, followed by specific agglutination tests and culture).
Treatment Antibiotic treatment seems to be effective only if implemented during the initial febrile phase. Penicillin, doxycycline, or ceftriaxone have been used. The meningitis is usually self-limited.
Described in the following pages are a number of infectious diseases, much less common than bacterial ones, in which a systemic fungal infection secondarily involves the CNS. For the neurologist, the diagnosis rests on two lines of clinical information: evidence of infection in the lungs, skin, or other organs and the appearance of a subacute meningeal or multifocal encephalitic disorder. Although a large number of fungal diseases may involve the nervous system, only a few do so with regularity. Of 57 cases assembled by Walsh and coworkers, there were 27 of candidiasis, 16 of aspergillosis, and 14 of cryptococcosis. Among the opportunistic mycoses (see in the following text), the majority is accounted for by species of Aspergillus and Candida. Mucormycosis and coccidioidomycosis are less frequent, and blastomycosis and actinomycosis (Nocardia) occur in isolated instances. However, of all of these infections, cryptococcal meningitis, which can occur in immunocompetent patients, is being seen more frequently as a result of its association with HIV and in patients on immunosuppression medications.