Dengue: a new challenge for neurology

Abstract

Dengue infection is a leading cause of illness and death in tropical and subtropical regions of the world. Forty percent of the world's population currently lives in these areas. The clinical picture resulting from dengue infection can range from relatively minor to catastrophic hemorrhagic fever. Recently, reports have increased of neurological manifestations. Neuropathogenesis seems to be related to direct nervous system viral invasion, autoimmune reaction, metabolic and hemorrhagic disturbance. Neurological manifestations include encephalitis, encephalopathy, meningitis, Guillain-Barré syndrome, myelitis, acute disseminated encephalomyelitis, polyneuropathy, mononeuropathy, and cerebromeningeal hemorrhage. The development of neurological symptoms in patients with positive Immunoglobulin M (IgM) dengue serology suggests a means of diagnosing the neurological complications associated with dengue. Viral antigens, specific IgM antibodies, and the intrathecal synthesis of dengue antibodies have been successfully detected in cerebrospinal fluid. However, despite diagnostic advancements, the treatment of neurological dengue is problematic. The launch of a dengue vaccine is expected to be beneficial.

Neurological complications in dengue infection: a review for clinical practice

“…Viral and host factors may play an important role in the neurological disorders associated with Dengue. In this context, direct viral infection of central nervous system (CNS), autoimmune reaction, metabolic and hemorrhagic disturbances can be involved in the pathogenesis 9 .…”

“…Routine hematologic, biochemical, and liver function, tests for rheumatic diseases, B/C hepatitis, and human immunodeficiency virus-1 (HIV-1) should be carried out in all suspected patients. Routine CSF analysis include total and specific cell count, determination of protein and glucose/lactate concentration, a smear and culture for bacteria and fungi, an assessment of blood-CSF barrier function by albumin quotient (CSF/serum), detection of intrathecal synthesis of total IgG, and measurement of specific antibodies against syphilis, cytomegalovirus, EpsteinBarr, and herpes simplex viruses 9 .…”

“…The absence of specific IgM detection in CSF, however, does not exclude dengue as the causative agent of neurological disorder 6,7,28 . It is important to note that the detection of specific IgG in CSF is not a useful diagnostic tool, since they may be due to a prior infection and they can cross the blood-CSF barrier 9 . In relation of intrathecal synthesized dengue specific antibodies, previous study demonstrated that this is a potential marker of myelitis associated with dengue infection 29 …”

“…Notwithstanding, in those cases, the CSF analysis still is of utmost importance 9 . In this respect, the CSF findings and possible neurological manifestation are resumed in Table 1.…”

“…Cranial palsy may also occur, mostly with oculomotor and facial nerves involvement 9 . Benign acute myositis in dengue infection could be consequent of direct viral invasion and/or immune-mediated damage of muscle fibers 18 .…”