Skip to main content Accessibility help
  • Print publication year: 2008
  • Online publication date: December 2009

9 - Infective disorders


The spectrum of infectious diseases causing cognitive impairment and dementia has changed over the past century. Whereas neurosyphilis was once common, now infection with human immunodeficiency virus and herpes viruses, and diseases caused by prions (see Section 2.5), are perhaps the most notable infectious causes of cognitive decline and dementia (Almeida & Lautenschlager, 2005).

Encephalitides and meningoencephalitides

Infection of the brain parenchyma with or without involvement of the surrounding meninges may be caused by a wide variety of organisms, most usually viral, but sometimes protozoan, rickettsial, or fungal (Anderson, 2001). Despite intensive investigation, a causative organism is not always found and treatment may of necessity be empirical, covering the most likely candidate organisms.

Encephalitis is often a medical emergency, requiring intensive supportive care and control of epileptic seizures. With the advent of antiviral agents such as aciclovir, mortality has declined considerably, leaving increased numbers of survivors who may have neuropsychological sequelae.

Encephalitides and meningoencephalitides covered elsewhere include Rasmussen's syndrome of chronic encephalitis and epilepsy (see Section 4.2.2), in which an infective aetiology remains a possibility, and chronic inflammatory meningoencephalitis, a term sometimes used for Sjögren's syndrome (Section 6.5).

Almeida, OP, Lautenschlager, NT.Dementia associated with infectious diseases. Int Psychogeriatr 2005; 17 (Suppl 1): S65–77.
Caparros-Lefebvre, D, Girard-Buttoz, I, Reboul, S, et al. Cognitive and psychiatric impairment in herpes simplex virus encephalitis suggest involvement of the amygdalo-frontal pathways. J Neurol 1996; 243: 248–56.
Eslinger, PJ.Autobiographical memory after temporal and frontal lobe lesions. Neurocase 1998; 4: 481–95.
Gordon, B, Selnes, OA, Hart, J, Hanley, DF, Whitley, RJ.Long-term cognitive sequelae of acyclovir-treated herpes simplex encephalitis. Arch Neurol 1990; 47: 646–7.
Hokkanen, L, Launes, J.Cognitive recovery instead of decline after acute encephalitis: a prospective follow up study. J Neurol Neurosurg Psychiatry 1997a; 63: 222–7.
Hokkanen, L, Launes, J.Duration of transient amnesia correlates with cognitive outcome in acute encephalitis. Neuroreport 1997b; 8: 2721–5.
Hokkanen, L, Poutiainen, E, Valanne, L, et al. Cognitive impairment after acute encephalitis: comparison of herpes simplex and other aetiologies. J Neurol Neurosurg Psychiatry 1996a; 61: 478–84.
Hokkanen, L, Salonen, O, Launes, J.Amnesia in acute herpetic and nonherpetic encephalitis. Arch Neurol 1996b; 53: 972–8.
Kapur, N, Barker, S, Burrows, EH, et al. Herpes simplex encephalitis: long term magnetic resonance imaging and neuropsychological profile. J Neurol Neurosurg Psychiatry 1994; 57: 1334–42.
Kennedy, PGE, Chaudhuri, A.Herpes simplex encephalitis. J Neurol Neurosurg Psychiatry 2002; 73: 237–8.
Utley, TFM, Ogden, JA, Gibb, A, McGrath, N, Anderson, NE.The long-term neuropsychological outcome of herpes simplex encephalitis in a series of unselected survivors. Neuropsychiatry Neuropsychol Behav Neurol 1997; 10: 180–9.
Young, CA, Humphrey, PR, Ghadiali, EJ, Klapper, PE, Cleator, GM.Short-term memory impairment in an alert patient as a presentation of herpes simplex encephalitis. Neurology 1992; 42: 260–1.
Hokkanen, L, Launes, J, Poutiainen, E, et al. Subcortical type cognitive impairment in herpes zoster encephalitis. J Neurol 1997; 244: 239–45.
Wetzel, K, Asholt, I, Herrmann, E, et al. Good cognitive outcome of patients with herpes zoster encephalitis: a follow-up study. J Neurol 2002; 249: 1612–14.
Hokkanen, L, Poutiainen, E, Valanne, L, et al. Cognitive impairment after acute encephalitis: comparison of herpes simplex and other aetiologies. J Neurol Neurosurg Psychiatry 1996; 61: 478–84.
Peatfield, RC.Basal ganglia damage and subcortical dementia after possible insidious Coxsackie virus encephalitis. Acta Neurol Scand 1987; 76: 340–5.
Bollen, AE, Wartan, AN, Krikke, AP, Haaxma-Reiche, H.Amnestic syndrome after lung transplantation by human herpes virus-6 encephalitis. J Neurol 2001; 248: 619–20.
Dewhurst, S.Human herpesvirus type 6 and human herpesvirus type 7 infections of the central nervous system. Herpes 2004; 11: 105A–11A.
Kapur, N, Brooks, DJ.Temporally-specific retrograde amnesia in two cases of discrete bilateral hippocampal pathology. Hippocampus 1999; 9: 247–54.
Wainwright, MS, Martin, PL, Morse, RP, et al. Human herpesvirus 6 limbic encephalitis after stem cell transplantation. Ann Neurol 2001; 50: 612–19.
Hokkanen, L, Poutiainen, E, Valanne, L, et al. Cognitive impairment after acute encephalitis: comparison of herpes simplex and other aetiologies. J Neurol Neurosurg Psychiatry 1996; 61: 478–84.
Frings, M, Blaeser, I, Kastrup, O.Adult-onset subacute sclerosing panencephalitis presenting as a degenerative dementia syndrome. J Neurol 2002; 249: 942–3.
Singer, C, Lang, AE, Suchowersky, O.Adult-onset subacute sclerosing panencephalitis: case reports and review of the literature. Mov Disord 1997; 12: 342–53.
Günther, G, Haglund, M, Lindquist, L, Forsgren, M, Skoldenberg, B.Tick-borne encephalitis in Sweden in relation to aseptic meningo-encephalitis of other etiology: a prospective study of clinical course and outcome. J Neurol 1997; 244: 230–8.
Solomon, T, Dung, NM, Kneen, R, et al. Japanese encephalitis. J Neurol Neurosurg Psychiatry 2000; 68: 405–15.
Dewar, BK, Wilson, BA.Cognitive recovery from encephalitis lethargica. Brain Inj 2005; 19: 1285–91.
Merkelbach, S, Sittinger, H, Schweizer, I, Müller, M.Cognitive outcome after bacterial meningitis. Acta Neurol Scand 2000; 102: 118–23.
Schmidt, H, Heimann, B, Djukic, M, et al. Neuropsychological sequelae of bacterial and viral meningitis. Brain 2006; 129: 333–45.
Beek, D, Schmand, B, Gans, J, et al. Cognitive impairment in adults with good recovery after bacterial meningitis. J Infect Dis 2002; 186: 1047–52.
Hotopf, M, Noah, N, Wessely, S.Chronic fatigue and minor psychiatric morbidity after viral meningitis: a controlled study. J Neurol Neurosurg Psychiatry 1996; 60: 504–9.
Schmidt, H, Heimann, B, Djukic, M, et al. Neuropsychological sequelae of bacterial and viral meningitis. Brain 2006; 129: 333–45.
Sittinger, H, Müller, M, Schweizer, I, Merkelbach, S.Mild cognitive impairment after viral meningitis in adults. J Neurol 2002; 249: 554–60.
Aharon-Peretz, J, Kilot, D, Finkelstein, R, et al. Cryptococcal meningitis mimicking vascular dementia. Neurology 2004; 62: 2135.
Gendelman, HE, Grant, I, Everall, IP, Lipton, SA, Swindells, S (eds.). The Neurology of AIDS (2nd edition). Oxford: Oxford University Press, 2005.
Harrison, MJG, McArthur, JC.AIDS and Neurology. Edinburgh: Churchill Livingstone, 1995.
American Academy of Neurology AIDS Task Force. Nomenclature and research case definitions for neurologic manifestations of human immunodeficiency virus-type 1 (HIV-1) infection: report of a Working Group of the American Academy of Neurology AIDS Task Force. Neurology 1991; 41: 778–85.
Catalan, J, Thornton, S.Whatever happened to HIV dementia? Int J STD AIDS 1993; 4: 1–4.
Grant, I, Atkinson, J. Psychiatric aspects of acquired immune deficiency syndrome. In: Sadock B (ed.), Comprehensive Textbook of Psychiatry. Baltimore: Williams & Wilkins, 1995: 1644–69.
Grant, I, Sacktor, N, McArthur, J. HIV and neurocognitive disorders. In: Gendelman HE, Grant I, Everall IP, Lipton SA, Swindells S (eds.), The Neurology of AIDS (2nd edition). Oxford: Oxford University Press, 2005: 357–73.
McArthur, JC, Hoover, DR, Bacellar, H, et al. Dementia in AIDS patients: incidence and risk factors. Neurology 1993; 43: 2245–52.
Navia, BA, Jordan, BD, Price, RW.The AIDS dementia complex: I. Clinical features. Ann Neurol 1986; 19: 517–24.
Oechsner, M, Möller, AA, Zaudig, M.Cognitive impairment, dementia and psychological functioning in human immunodeficiency virus infection: a prospective study based on DSM-III-R and ICD-10. Acta Psychiatr Scand 1993; 87: 13–17.
Power, C, Johnson, RT.HIV-1 associated dementia: clinical features and pathogenesis. Can J Neurol Sci 1995; 22: 92–100.
Price, RW, Brew, B, Sidtis, J, et al. The brain in AIDS: central nervous system HIV-1 infection and AIDS dementia complex. Science 1988; 239: 586–92.
Sacktor, N, McDermott, MP, Marder, K, et al. HIV-associated cognitive impairment before and after the advent of combination therapy. J Neurovirol 2002; 8: 136–42.
Stankoff, B, Tourbah, A, Suarez, S, et al. Clinical and spectroscopic improvement in HIV-associated cognitive impairment. Neurology 2001; 56: 112–15.
Berger, JR, Pall, L, Lanska, D, Whiteman, M.Progressive multifocal leukoencephalopathy in patients with HIV infection. J Neurovirol 1998; 4: 59–68.
Silva, MTT, Mattos, P, Alfano, A, Araújo, AQC.Neuropsychological assessment in HTLV-1 infection: a comparative study among TSP/HAM, asymptomatic carriers and healthy controls. J Neurol Neurosurg Psychiatry 2003; 74: 1085–9.
Carr, J.Neurosyphilis. Pract Neurol 2003; 3: 328–41.
Dewhurst, K.The neurosyphilis psychoses today: a survey of 91 cases. Br J Psychiatry 1969; 115: 31–8.
Fox, PA, Hawkins, DA, Dawson, S.Dementia following an acute presentation of meningovascular neurosyphilis in an HIV-1 positive patient. AIDS 2000; 14: 2062–3.
Nieman, EA.Neurosyphilis yesterday and today. J R Coll Physicians Lond 1991; 25: 321–4.
Schied, R, Voltz, R, Vetter, T, et al. Neurosyphilis and paraneoplastic limbic encephalitis: important differential diagnoses. J Neurol 2005; 252: 1129–32.
Timmermans, M, Carr, J.Neurosyphilis in the modern era. J Neurol Neurosurg Psychiatry 2004; 75: 1727–30.
Akritidis, N, Galiatsou, E, Kakadellis, J, Dimas, K, Paparounas, K.Brain tuberculomas due to miliary tuberculosis. South Med J 2005; 98: 111–13.
Ceccaldi, M, Belleville, S, Royere, ML, Poncet, M.A pure reversible amnesic syndrome following tuberculous meningoencephalitis. Eur Neurol 1995; 35: 363–7.
Jha, S, Patel, R.Some observations on the spectrum of dementia. Neurol India 2004; 52: 213–14.
Meador, KJ, Loring, DW, Sethi, KD, et al. Dementia associated with dorsal midbrain lesion. J Int Neuropsychol Soc 1996; 2: 359–67.
Adams, WV, Rose, CD, Eppes, SC, Klein, JD.Long-term cognitive effects of Lyme disease in children. Appl Neuropsychol 1999; 6: 39–45.
American Academy of Neurology Quality Standards Subcommittee. Practice parameter: diagnosis of patients with nervous system Lyme borreliosis (Lyme disease). Summary statement. Neurology 1996; 46: 881–2.
Benke, T, Gasse, T, Hittmair Delazer, M, Schmutzhard, E.Lyme encephalopathy: long-term neuropsychological deficits years after acute neuroborreliosis. Acta Neurol Scand 1995; 91: 353–7.
Danek, A, Uttner, I, Yousry, T, Pfister, HW.Lyme neuroborreliosis disguised as normal pressure hydrocephalus. Neurology 1996; 46: 1743–5.
Etienne, M, Carvalho, P, Fauchais, AL, et al. Lyme neuroborreliosis revealed as a normal pressure hydrocephalus: a cause of reversible dementia. J Am Geriatr Soc 2003; 51: 579–80.
Halperin, JJ, Volkman, DJ, Wu, P.Central nervous system abnormalities in Lyme neuroborreliosis. Neurology 1991; 41: 1571–82.
Kaplan, RF, Woodward, Jones L, Workman, K, et al. Neuropsychological deficits in Lyme disease patients with and without other evidence of central nervous system pathology. Appl Neuropsychol 1999; 6: 3–11.
Kobayashi, K, Mizukoshi, C, Aoki, T, et al. Borrelia burgdorferi-seropositive chronic encephalomyelopathy: Lyme neuroborreliosis? An autopsied report. Dement Geriatr Cogn Disord 1997; 8: 384–90.
Pollina, DA, Sliwinski, M, Squires, NK, Krupp, LB.Cognitive processing speed in Lyme disease. Neuropsychiatry Neuropsychol Behav Neurol 1999; 12: 72–8.
Steere, AC.Lyme disease. N Engl J Med 1989; 321: 586–96.
Waniek, C, Prohovnik, I, Kaufman, MA, Dwork, AJ.Rapidly progressive frontal-type dementia associated with Lyme disease. J Neuropsychiatry Clin Neurosci 1995; 7: 345–7.
Westervelt, HJ, McCaffrey, RJ.Neuropsychological functioning in chronic Lyme disease. Neuropsychol Rev 2002; 12: 153–77.
Garcia, HH, Del Brutto, OH.Neurocysticercosis: updated concepts about an old disease. Lancet Neurol 2005; 4: 653–61.
Garcia, HH, Gonzalez, AE, Tsang, VCW, Gilman, RH, for the Cysticercosis Working Group in Peru. Neurocysticercosis: some of the essentials. Pract Neurol 2006; 6: 288–97.
Ramirez Bermudez, J, Higuera, J, Sosa, AL, et al. Is dementia reversible in patients with neurocysticercosis?J Neurol Neurosurg Psychiatry 2005; 76: 1164–6.
Terra Bustamente, VC, Coimbra, ER, Rezek, KO, et al. Cognitive performance of patients with mesial temporal lobe epilepsy and incidental calcified neurocysticercosis. J Neurol Neurosurg Psychiatry 2005; 76: 1080–3.
Anderson, M.Neurology of Whipple's disease. J Neurol Neurosurg Psychiatry 2000; 68: 2–5.
Louis, ED, Lynch, T, Kaufmann, P, Fahn, S, Odel, J.Diagnostic guidelines in central nervous system Whipple's disease. Ann Neurol 1996; 40: 561–8.
Manzel, K, Tranel, D, Cooper, G.Cognitive and behavioral abnormalities in a case of central nervous system Whipple disease. Arch Neurol 2000; 57: 399–403.
Panegyres, PK, Edis, R, Beaman, M, Fallon, M.Primary Whipple's disease of the brain: characterization of the syndrome and molecular diagnosis. Q J Med 2006; 99: 609–23.