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Powassan Encephalitis

Powassan encephalitis is a rare infection caused by Powassan virus in specific regions of North America, Canada, and Russia. The virus is transmitted by a tick bite, and constitutional symptoms followed by a range of neurological deficits, including altered consciousness, are typical features. The diagnosis rests on data obtained from patient history and specific microbiological studies.


Presentation

Powassan virus (POWV) belongs to the group of flaviviruses, and is a rare but possibly fatal cause of tick-borne encephalitis (TBE) in the Northeastern United States (New York, Minnesota, Wisconsin, Michigan, Maine, Vermont, Connecticut, Massachusetts, and Pennsylvania), Canada (Ontario, Quebec, and New Brunswick provinces), and certain parts of Russia [1] [2] [3] [4]. The virus possesses two distinct lineages, both being transmitted from a stable animal reservoir consisting of rodents (eg. white-footed mice) and medium-sized mammals (eg. woodchucks, red squirrels groundhogs, skunks) onto the Ixodes ticks, one of the most important tick species related to human diseases [3] [5] [6]. Reports have shown that only 15 minutes are sufficient for the tick to transmit the virus to the host once it attaches to the skin [1] [4]. Wide-scale epidemiologic studies have established that many patients (due to undisclosed reasons) have an asymptomatic form of POWV infection, but in some patients, infection of the central nervous system (CNS), known as Powassan encephalitis, can develop [2] [4]. The period between the tick bite and the appearance of symptoms (known as the incubation period) typically lasts between 1-5 weeks and a prodromal period of 1-2 days, comprised of nonspecific respiratory and constitutional complaints (fever, malaise, headaches), is common [1] [2] [4]. Soon after, severe deterioration characterized by ataxia, weakness, hemiplegia, ophthalmoplegia, confusion, somnolence and a severely altered level of consciousness, as well as seizures and other focal neurological deficits, are observed in the case of Powassan encephalitis [1] [4] [6]. In addition, gastrointestinal irritation and skin rash may be seen [4]. The mortality rates of Powassan encephalitis range from 10-15% and residual neurological impairment (hemiplegia, paresis of the lower extremities, and deficits in memory and other cognitive skills) is noted in up to 50% of patients who survive the infection [2] [4] [6].

Fever
  • Abstract This article discusses two tick-borne illnesses: Powassan encephalitis, a rare cause of central nervous system infection caused by the Powassan virus, and Colorado tick fever, an acute febrile illness caused by the Colorado tick fever virus common[ncbi.nlm.nih.gov]
  • […] nervous system infection caused by the Powassan virus, and Colorado tick fever, an acute febrile illness caused by the Colorado tick fever virus common to the Rocky Mountain region of North America[nebraska.pure.elsevier.com]
  • Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. There is currently no established treatment.Half of all cases results in permanent neurological damage and 10-15% result in death.[en.wikipedia.org]
  • Flaviviruses (Yellow Fever, Dengue, Dengue Hemorrhagic Fever, Japanese Encephalitis, West Nile Encephalitis, St. Louis Encephalitis, Tick-Borne Encephalitis). In: Mandell GL, Bennett JE, Dolin R, eds.[upmc-cbn.org]
  • MalaCards based summary : Powassan Encephalitis, also known as powassan encephalitis virus infection, is related to encephalitis and lyme disease, and has symptoms including seizures, fever and vomiting.[malacards.org]
High Fever
  • I didn't remember much of the treatment due to the infection and high fevers I experienced. I do remember ice baths and a spinal tap or two.[inspire.com]
  • It may start (up to 3 weeks) after onset of the measles rash and present with high fever, convulsions, and coma.[medicine.academic.ru]
  • Severe infections, however, occur with rapid onset and usually feature high fever, headache, and disorientation; they can include tremors, convulsions, paralysis, coma, and death.[mdedge.com]
  • The 73-year-old woman grew weak and developed a high fever and meningitis before lapsing into delirium, becoming paralyzed and requiring a ventilator to breathe. She died about a month later.[pressherald.com]
  • Clinical symptoms of Powassan virus begin with a high fever and progress to neurologic signs such as headache, vomiting, weakness, confusion, seizures and memory loss.[now.tufts.edu]
Chills
  • Other symptoms include chills, muscle aches and pains, headaches, and paralysis, Adalja says, noting that the disease can also cause encephalitis, which is an inflammation of the brain that can be deadly or lead to permanent disability, or meningitis,[yahoo.com]
  • He went home from his job working for a plumber and napped for two hours, only to feel worse when he work up, with tremors, nausea and chills. A medical center gave him antibiotics because of his tick-bite history, Lane said.[capecodtimes.com]
Rigor
  • A 60-Year-Old Man with Fever, Rigors, and Sweats . New England Journal of Medicine 349 : 1168 – 1175 .[cambridge.org]
Constitutional Symptom
  • The virus is transmitted by a tick bite, and constitutional symptoms followed by a range of neurological deficits, including altered consciousness, are typical features.[symptoma.com]
Vomiting
  • MalaCards based summary : Powassan Encephalitis, also known as powassan encephalitis virus infection, is related to encephalitis and lyme disease, and has symptoms including seizures, fever and vomiting.[malacards.org]
  • Symptoms, including fever, headache, vomiting and memory loss, can start anytime from a week to a month after the tick bite.[necn.com]
  • Symptoms include headache, fever, nausea, vomiting, stiff neck, and sleepiness, breathing distress, confusion, tremors, seizures, paralysis, and possible coma. Encephalitis and meningitis can occur – 10% of encephalitis cases result in death.[lymediseaseassociation.org]
  • Signs and symptoms can include fever, headache, vomiting, weakness, confusion, seizures, and memory loss. Long-term neurologic problems may occur. Symptoms can begin anytime from one week to one month after the tick bite.[extension.umaine.edu]
  • However, when they do, the symptoms are usually fever, headache, vomiting, weakness, confusion, loss of coordination, difficulty speaking, and sometimes seizures.[contagionlive.com]
Nausea
  • Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. There is currently no established treatment.Half of all cases results in permanent neurological damage and 10-15% result in death.[en.wikipedia.org]
  • The virus is antigenically related to the Far Eastern tick-borne encephalitis viruses . [4] Presentation Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma.[ipfs.io]
  • Symptoms include headache, fever, nausea, vomiting, stiff neck, and sleepiness, breathing distress, confusion, tremors, seizures, paralysis, and possible coma. Encephalitis and meningitis can occur – 10% of encephalitis cases result in death.[lymediseaseassociation.org]
  • Symptoms manifest within 7 10 days and include fever, headache, partial paralysis, confusion, nausea and even coma.[medicine.academic.ru]
  • Symptoms can last up to 8 days and include fever, headache, fatigue, muscle pain, nausea, and loss of appetite.[iamat.org]
Hypertension
  • Design/Methods: A case report of a 35-year-old woman who presented with worsening headaches, vomiting, hypertension, confusion, and fever.[neurology.org]
Headache
  • Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. There is currently no established treatment.Half of all cases results in permanent neurological damage and 10-15% result in death.[en.wikipedia.org]
  • Survivors of POW: 50% have permanent neurologic problems – Headaches, muscle wasting, memory problems Supportive treatment is the only available treatment.[lymediseaseassociation.org]
  • According to the Centers for Disease Control and Prevention, mild cases of arboviral encephalitis may present with only a slight fever and/or headache and body aches.[mdedge.com]
  • The infection has symptom headache, has symptom fever, has symptom vomiting, has symptom stiff neck, has symptom sleepiness, has symptom breathing distress, has symptom tremors, has symptom confusion, has symptom seizures, has symptom paralysis, and has[malacards.org]
  • Symptoms, including fever, headache, vomiting and memory loss, can start anytime from a week to a month after the tick bite.[necn.com]
Confusion
  • Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma. There is currently no established treatment.Half of all cases results in permanent neurological damage and 10-15% result in death.[en.wikipedia.org]
  • All but one patient developed encephalitis with acute onset of profound muscle weakness, confusion, and other severe neurologic signs.[doi.org]
  • The infection has symptom headache, has symptom fever, has symptom vomiting, has symptom stiff neck, has symptom sleepiness, has symptom breathing distress, has symptom tremors, has symptom confusion, has symptom seizures, has symptom paralysis, and has[malacards.org]
  • The virus is antigenically related to the Far Eastern tick-borne encephalitis viruses . [4] Presentation Symptoms manifest within 7–10 days and include fever, headache, partial paralysis, confusion, nausea and even coma.[ipfs.io]
Seizure
  • RESULTS: Case 1 was a 78 year old man who was presented with altered mental status and a 30 second generalized tonic-clonic seizure. He had no prior history of seizures.[neurology.org]
  • MalaCards based summary : Powassan Encephalitis, also known as powassan encephalitis virus infection, is related to encephalitis and lyme disease, and has symptoms including seizures, fever and vomiting.[malacards.org]
  • After the infant was treated for the seizures, he was released from the hospital, only to develop other complications 1 month later.[contagionlive.com]
  • Soon after, severe deterioration characterized by ataxia, weakness, hemiplegia, ophthalmoplegia, confusion, somnolence and a severely altered level of consciousness, as well as seizures and other focal neurological deficits, are observed in the case of[symptoma.com]
  • Symptoms include headache, fever, nausea, vomiting, stiff neck, and sleepiness, breathing distress, confusion, tremors, seizures, paralysis, and possible coma. Encephalitis and meningitis can occur – 10% of encephalitis cases result in death.[lymediseaseassociation.org]
Altered Mental Status
  • RESULTS: Case 1 was a 78 year old man who was presented with altered mental status and a 30 second generalized tonic-clonic seizure. He had no prior history of seizures.[neurology.org]
  • Symptomatic patients present 1 week to 1 month after infection with general symptoms of encephalitis, which include fever, headache, altered mental status, and seizures.[upmc-cbn.org]
  • Initial symptoms consist of fever and headache and, ominously, altered mental status. One-half have gastrointestinal symptoms and one-third have rash. Encephalitis, in some cases, may be delayed.[ahcmedia.com]
  • If not treated, symptoms could extend to meningoencephalitis, which may include: seizures, aphasia, cranial nerve palsies, paresis and altered mental status.[en.wikipedia.org]
  • This manifests itself as a painful or stiff neck, altered mental status, confusion, seizures, aphasia (inability to speak), tingling and numbness, movement disorders, or cranial nerve palsies (paralysis of the muscles of the face and eyes).[pestworld.org]
Dizziness
  • POWV infection can lead to encephalitis and varied neurologic presentations including headache, dizziness, hemiplegia, intraparenchymal hemorrhage and seizures. However, there are no known reports of status epilepticus secondary to POWV infection.[neurology.org]
  • Patients with symptoms of encephalitis accompanied by a fever, and dizziness who live in tick infested areas should be tested for POW. Are there any tick vaccines? Currently there are no available tick vaccines in the US.[prahs.com]
  • “But if there are neurological symptoms—weakness, dizziness, seizures—then it’s important to get to the doctor.”[time.com]
  • The journal of Clinical Infectious Diseases previously has reported that two Massachusetts men — one 82, the other 49 — died in 2015 and 2014 after contracting Powassan and demonstrating symptoms including dizziness, nausea, fever and headache.[capecodtimes.com]

Workup

Powassan encephalitis is a very rare cause of this type of infection and the clinical presentation is indistinguishable from other causes of viral encephalitis. However, its distinct geographical and epidemiological features are quite useful in including POWV in the differential diagnosis of encephalitis. For this reason, a detailed patient history is perhaps the essential part of the diagnostic workup. Firstly, Powassan encephalitis has a seasonal appearance, meaning that most cases are diagnosed from May through September [4] [6]. Secondly, a positive travel history to the endemic areas of the United States, Canada, or Russia (or if patients are residents of those areas) could significantly aid in suspecting Powassan virus as the causative agent. And thirdly, reports of a recent tick bite must direct the attention toward tick-borne encephalitis viruses (TEBV). Thus, a thorough physical examination is also a vital component of the workup, as it might reveal the site of the tick bite. Lumbar puncture examination is a must in the evaluation of the central nervous system (CNS) infections. Elevated protein levels are infrequently observed, but either lymphocytic or polymorphonuclear pleocytosis (between 200-700 WBCs/µL) is always seen in Powassan encephalitis [4] [6]. A definite diagnosis, however, can be made through the enzyme-linked immunoassay (ELISA) testing that detects specific immunoglobulin-M (IgM) antibodies to the Powassan virus in the cerebrospinal fluid (CSF), but these tests are only available in specialized laboratories and tertiary care centers [1] [2] [4] [6]. Imaging studies might also be of use in Powassan encephalitis, as magnetic resonance imaging (MRI) reveals can ischemic or demyelinating lesions in the basal ganglia, thalamus and the brainstem on T2/FLAIR images [4] [6].

Cerebrospinal Fluid Abnormality
  • Moderate pleocytosis and increased albumin can be found in the cerebrospinal fluid; abnormalities in the thalamus, cerebellum, and brainstem in MRI may be shown as well.[columbia-lyme.org]

Treatment

  • Survivors of POW: 50% have permanent neurologic problems – Headaches, muscle wasting, memory problems Supportive treatment is the only available treatment.[lymediseaseassociation.org]
  • Status Epileptics was aborted after treatment with leviteractam, lacosamide, topamax and midazolam anesthesia. Investigation results and outcomes were similar to case 1.[neurology.org]
  • As only 1 type of viral encephalitis has a specific treatment—acyclovir for herpes encephalitis—pathogen-specific diagnosis may seem superfluous.[upmc-cbn.org]
  • Prognosis There is currently no established treatment. [5] Half of all cases results in permanent neurological damage and 10-15% result in death. References[ipfs.io]
  • I didn't remember much of the treatment due to the infection and high fevers I experienced. I do remember ice baths and a spinal tap or two.[inspire.com]

Prognosis

  • Prognosis There is currently no established treatment. [5] Half of all cases results in permanent neurological damage and 10-15% result in death. References[ipfs.io]
  • What is the prognosis for Powassan virus disease? Those individuals who develop Powassan viral disease with little or no symptoms have a good to excellent prognosis.[medicinenet.com]
  • In addition, even experienced physicians often are uncertain about the cause, appropriate therapy, and prognosis.[pedsinreview.aappublications.org]

Etiology

  • CSF proteins were 57 mg/dL.CSF testing for autoimmune and other viral etiologies were normal.[neurology.org]
  • ., in the differentiation of encephalitis cases not associated etiologically with the virus of the spring-summer tickborne encephalitis.[link.springer.com]
  • The majority of presumed infectious encephalitis cases do not have an identified etiology, 3 reinforcing the fact that our diagnostic ability in this arena is not optimal.[upmc-cbn.org]
  • SYNOPSIS: Powassan virus is transmitted by the same tick that carries the etiologic agent of Lyme disease and several other pathogens. The number of cases of encephalitis caused by this virus may be increasing in the endemic areas.[ahcmedia.com]

Epidemiology

  • However, its distinct geographical and epidemiological features are quite useful in including POWV in the differential diagnosis of encephalitis. For this reason, a detailed patient history is perhaps the essential part of the diagnostic workup.[symptoma.com]
  • .” – Professor Emeritus of Epidemiology at the Yale School of Public Health, Durland Fish, PhD. Powassan Virus photo: Canad. Med Assn. J. 5-2-64 LDA. 2018. 2014. 2015.[lymediseaseassociation.org]
  • Louis encephalitis and yellow fever, an epidemiologic history of the patient should help distinguish among them. The major drawback is that the detection of seroconversion may require a week or more, delaying diagnosis.[cmaj.ca]
  • Isachkova, in: Etiology, Epidemiology, and Preventive Measures against Tickborne Encephalitis in the Far East [in Russian], Khabarovsk (1978), pp. 105–107. Google Scholar 30. L. M.[link.springer.com]
Sex distribution
Age distribution

Prevention

  • The findings underscore the need for personal protective measures to prevent tick bites and continued encephalitis surveillance.[ncbi.nlm.nih.gov]
  • Centers for Disease Control and Prevention. Preventing tick bites. Available at: . Accessed May 7, 2017.[ahcmedia.com]
  • الصفحة 1607 - Centers for Disease Control and Prevention: 1994 Revised Classification System for Human Immunodeficiency Virus Infection in Children Less Than 13 Years of Age, MMWR, 43, 1-19, No. ‏[books.google.com]
  • Because no vaccine or specific therapy is available, the basis of prevention is personal protection from ticks (or “tick hygiene”) and reduced exposure to peridomestic wild mammals.[doi.org]
  • Because no vaccine or specific therapy is available, the basis of prevention is personal protection from ticks (or "tick hygiene") and reduced exposure to peridomestic wild mammals.[ncbi.nlm.nih.gov]

References

Article

  1. Birge J, Sonnesyn S. Powassan Virus Encephalitis, Minnesota, USA. Emerg Infect Dis. 2012;18(10):1669-1671.
  2. Raval M, Singhal M, Guerrero D, Alonto A. Powassan virus infection: case series and literature review from a single institution. BMC Res Notes. 2012;5:594.
  3. Anderson JF, Armstrong PM. Prevalence and Genetic Characterization of Powassan Virus Strains Infecting Ixodes scapularis in Connecticut. Am J Trop Med Hyg. 2012;87(4):754-759.
  4. Piantadosi A, Rubin DB, McQuillen DP, et al. Emerging Cases of Powassan Virus Encephalitis in New England: Clinical Presentation, Imaging, and Review of the Literature. Clin Infect Dis. 2016;62(6):707-713.
  5. Tavakoli NP, Wang H, Dupuis M, et al. Fatal Case of Deer Tick Virus Encephalitis. N Engl J Med. 2009;360(20):2099-2107.
  6. Mandell GL, Bennett JE, Dolin R. Mandel, Douglas and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, Pennsylvania: Churchill Livingstone; 2015.

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Last updated: 2019-07-11 21:00