Pearls: Infectious Diseases Karen L. Roos, M.D.1 ABSTRACT Neurologists have a great deal of knowledge of the classic signs of central nervous system infectious diseases. After years of taking care of patients with infectious diseases, several symptoms, signs, and cerebrospinal fluid abnormalities have been identified that are helpful time and time again in determining the etiological agent. These lessons, learned at the bedside, are reviewed in this article. KEYWORDS: Herpes simplex virus, Lyme disease, meningitis, viral encephalitis CLINICAL MANIFESTATIONS does not have an altered level of consciousness, sei- zures, or focal neurologic deficits. Although the ‘‘classic triad’’ of bacterial meningitis is The rash of a viral exanthema typically involves the fever, headache, and nuchal rigidity, vomiting is a face and chest first then spreads to the arms and legs. common early symptom. Suspect bacterial meningitis This can be an important clue in the patient with in the patient with fever, headache, lethargy, and headache, fever, and stiff neck that the meningitis is vomiting (without diarrhea). Patients may also com- due to echovirus or coxsackievirus. plain of photophobia. An altered level of conscious- Suspect tuberculous meningitis in the patient with ness that begins with lethargy and progresses to stupor either several weeks of headache, fever, and night during the emergency evaluation of the patient is sweats or a fulminant presentation with fever, altered characteristic of bacterial meningitis. mental status, and focal neurologic deficits. Fever (temperature 388C[100.48F]) is present in An Ixodes tick must be attached to the skin for at least 84% of adults with bacterial meningitis and in 80 to 24 hours to transmit infection with the spirochete 1–3 94% of children with bacterial meningitis. Symp- Borrelia burgdorferi. An attached tick should be pulled toms of bacterial meningitis are often preceded by an out of the skin with a forceps, not smoked out with a upper respiratory tract infection, sinusitis, or otitis match or lighter. Patients frequently report bug bites media. and are often concerned that these are tick bites. The Downloaded by: World Health Organization ( WHO). Copyrighted material. The rash of meningococcemia begins with petechial classic lesion of Lyme disease, erythema migrans, is an lesions on the trunk and lower extremities, in the erythematous lesion that looks like a target because of mucous membranes and conjunctiva, and occasionally its characteristic pattern of concentric pale and red on the palms and soles. The meningococcal vaccine circles. The lesion enlarges day by day typically to does not contain serogroup B, which is responsible for more than 5 cm in diameter. The lesion is not painful one third of cases of meningococcal disease. Thus, a or pruritic.4 history of having been vaccinated does not rule out The classic clinical presentation of meningitis due to meningococcal disease. Lyme disease is fever, headache, meningismus, and Viral meningitis is a syndrome of fever, headache, photophobia. Patients may have either unilateral or nausea, photophobia, and meningismus. The patient bilateral facial nerve palsy or a painful radiculopathy. 1John and Nancy Nelson Professor of Neurology, Indiana University Neurologic Pearls; Guest Editor, Stephen G. Reich, M.D. School of Medicine, Indianapolis, Indiana. Semin Neurol 2010;30:71–73. Copyright # 2010 by Thieme Address for correspondence and reprint requests: Karen L. Roos, Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, M.D., Indiana University School of Medicine, 550 North University USA. Tel: +1(212) 584-4662. Blvd., Suite 1711, Indianapolis, IN 46202-5124 (e-mail: kroos@iupui. DOI: http://dx.doi.org/10.1055/s-0029-1244998. edu). ISSN 0271-8235. 71 72 SEMINARS IN NEUROLOGY/VOLUME 30, NUMBER 1 2010 Aradiculitismaybeduetoherpessimplexvirus Progressive multifocal leukoencephalopathy presents HSV-2 or Borrelia burgdorferi. The infectious etiol- with focal neurologic deficits (often visual field ab- ogies of a clinical syndrome of fever, headache, and normalities, typically homonymous hemianopia) and cranial nerve abnormalities are fungal meningitis behavioral or cognitive changes. (Cryptococcus neoformans, Histoplasma capsulatum, Coc- Myoclonus is not the first sign of sporadic Creutzfeldt- cidioides immitis), tuberculous meningitis, syphilitic Jacob disease. Cognitive decline alone or with ataxia is meningitis, Lyme disease, and HIV. usually the first sign. When myoclonus develops, the The onset of symptoms of arthropod-borne encepha- periodic complexes on electroencephalogram (EEG) litis may be preceded by an influenza-like prodrome of are often present as well. fever, malaise, myalgias, nausea, and vomiting. This When a patient presents with stroke and fever, the prodrome is followed by headache, an altered level of differential diagnosis is infective endocarditis, bacter- consciousness, seizures, and focal neurologic deficits. ial meningitis, varicella zoster virus encephalitis, sy- The flaviviruses, which include St. Louis encephalitis philis, tuberculous meningitis, and fungal meningitis. virus, West Nile virus, and Japanese encephalitis virus, Whipple’s disease is a clinical syndrome of weight loss, can cause an encephalitis associated with signs of diarrhea, migratory arthralgias, oculomasticatory or parkinsonism. The patient that presents with a polio- oculofacial skeletal myorrhythmia, vertical gaze palsy, myelitis-like syndrome with acute asymmetric flaccid and cognitive changes. weakness may have either an enteroviral infection or In the United States, most cases of rabies are due to infection due to West Nile virus. the bite or saliva of a bat, and patients often are not Herpes simplex virus 1 encephalitis is a febrile illness aware of having been bitten. Ask the patient’s family with hemicranial headache, confusion, disorientation, and friends about the possibility of exposure to a bat, language abnormalities, memory impairment, and including sleeping in a room with an open window seizures. Infection with Listeria monocytogenes, that did not have a screen. The incubation period can enterovirus-71, or HSV-1 may present as rhomben- be as long as 3 months. Rabies due to a bat bite cephalitis. presents with focal neurologic deficits, choreiform The classic symptoms of varicella zoster virus ence- movements, myoclonus, seizures, and hallucinations. phalitis are headache, fever, confusion, new-onset Phobic spasms are not a cardinal feature of bat rabies. seizures, and/or focal neurologic signs or symptoms. For many infectious diseases, an ophthalmological Ask patients about a history of shingles in the past evaluation can be helpful in diagnosis. For example, several months, but don’t exclude the possibility of the ophthalmologist can be very helpful in the evalua- varicella zoster virus encephalitis in the absence of tion of an immunosuppressed patient with encepha- such a history. Typically, varicella zoster virus ence- litis with associated cytomegalovirus retinitis or phalitis is due to ischemic and hemorrhagic infarc- toxoplasmic chorioretinitis. tions in both cortical and subcortical gray and white matter; therefore, patients present with an altered level of consciousness, new-onset seizures, or focal neurologic deficits. Zoster reactivation may also cause CEREBROSPINAL FLUID ventriculitis and periventriculitis with hydrocephalus, and when it does, the patient presents with altered The cerebrospinal fluid (CSF) should be examined Downloaded by: World Health Organization ( WHO). Copyrighted material. mental status and trouble with gait. promptly after it is obtained because white blood cells Rocky Mountain spotted fever due to infection with in the CSF begin to lyse after 90 minutes. A normal Rickettsia rickettsii presents with fever, headache, CSF-to-serum glucose ratio is 0.6. A CSF-to-serum altered mental status (stupor, confusion, delirium, glucose ratio of less than 0.31 is seen in 70% of coma), seizures, and focal neurologic deficits. A patients with bacterial meningitis. petechial rash is characteristic of Rocky Mountain Never send tube #1 for Gram’s stain as there is a risk spotted fever. The rash of Rocky Mountain spotted of the fluid being contaminated with the common skin fever consists initially of 1-to-5-mm pink macules contaminate Staphylococcus epidermidis (coagulase- that first appear on the wrists and ankles then spread negative staphylococci). This organism appears as centrally to the chest, face, and abdomen. Petechial gram-positive cocci on Gram’s stain. The temptation lesions in the axilla and around the ankles accompa- is strong to send any tube other than #1 for cell count nied by lesions on the palms and soles of the feet are because more red blood cells will appear in tube #1 characteristic of Rocky Mountain spotted fever. After than in subsequent tubes when the lumbar puncture afewdays,themaculeswillturnfrompinktodarkred has been traumatic. Tube #1 can be sent for glucose to purple. The other infectious diseases during which and protein concentrations. there may be a rash on the palms and soles are syphilis There may initially be a predominance of polymor- and meningococcemia. phonuclear leukocytes in the CSF in enteroviral PEARLS: INFECTIOUS DISEASES/ROOS 73 meningitis and in arthropod-borne viral central nerv- clinical picture. Cerebrospinal fluid 14-3-3 false- ous system (CNS) infections. In enteroviral meningi- positive results have been reported in HSV encepha- tis, there is a transition