Tick paralysis

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Tick paralysis
ICD-10 T63.4
ICD-9 989.5
DiseasesDB 31779
MedlinePlus 001359
MeSH D013985

Tick paralysis is the only tick-borne disease that is not caused by an infectious organism. The illness is caused by a neurotoxin produced in the tick's salivary gland. After prolonged attachment, the engorged tick transmits the toxin to its host. The incidence of tick paralysis is unknown.

Signs and symptoms

Tick paralysis results from inoculation of a toxin from tick salivary glands during a blood meal. The toxin causes symptoms within 2-7 days, beginning with weakness in both legs that progresses to paralysis. The paralysis ascends upward to trunk, arms, and head within hours and may lead to respiratory failure and death. The disease can present as acute ataxia without muscle weakness.

Patients may report minor sensory symptoms but constitutional signs are usually absent. Deep tendon reflexes are usually hypoactive or absent and ophthalmoplegia and bulbar palsy can occur.

Electromyographic (EMG) studies usually show a variable reduction in the amplitude of compound muscle action potentials but no abnormalities of repetitive nerve stimulation studies. These appear to result from a failure of acetylcholine release at the motor nerve terminal level. There may be subtle abnormalities of motor nerve conduction velocity and sensory action potentials.

Pathogenesis

Tick paralysis is believed to be due to toxins found in the tick's saliva that enter the bloodstream while the tick is feeding. The two ticks most commonly associated with North American tick paralysis are the Rocky Mountain wood tick (Dermacentor andersoni) and the American dog tick (Dermacentor variabilis); however, 43 tick species have been implicated in human disease around the world.[1] Most North American cases of tick paralysis occur from April to June, when adult Dermacentor ticks emerge from hibernation and actively seek hosts.[2]. In Australia, tick paralysis is caused by the tick Ixodes holocyclus. Up to 1989 20 fatal cases have been reported in Australia.[3]

Tick paralysis has killed thousands of animals, mainly cows and sheep, in other parts of the world. Although tick paralysis is of concern in domestic animals and livestock in the United States as well, human cases are rare and usually occur in children under the age of 10.

Tick paralysis occurs when an engorged and gravid (egg-laden) female tick produces a neurotoxin in its salivary glands and transmits it to its host during feeding. Experiments have indicated that the greatest amount of toxin is produced between the fifth and seventh day of attachment (often initiating or increasing the severity of symptoms), although the timing may vary depending on the species of tick.

Unlike Lyme disease, ehrlichiosis, and babesiosis, which are caused by the systemic proliferation and expansion of parasites in their hosts long after the offending tick is gone, tick paralysis is chemically induced by the tick and can therefore usually only continues in its presence. Once the tick is removed, symptoms usually diminish rapidly. However, in some cases, profound paralysis can develop and even become fatal before anyone becomes aware of a tick's presence.

Diagnostic tests

Diagnosis is based on symptoms and upon finding an embedded tick, usually on the scalp.

In the absence of a tick, the differential diagnosis includes Guillain-Barre syndrome and botulism.

Differential Diagnosis

Tick paralysis should be differentiated from other causes of muscle weakness, hypotonia and flaccid paralysis. The differentials include the following:[4][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]

Diseases History and Physical Diagnostic tests Other Findings
Motor Deficit Sensory deficit Cranial nerve Involvement Autonomic dysfunction Proximal/Distal/Generalized Ascending/Descending/Systemic Unilateral (UL)

or Bilateral (BL)

or

No Lateralization (NL)

Onset Lab or Imaging Findings Specific test
Acute Flaccid Myelitis + + + - Proximal > Distal Ascending UL/BL Sudden MRI (Longitudinal hyperintense lesions) MRI and CSF PCR for viral etiology Drooping eyelids

Difficulty swallowing

Respiratory failure

Adult Botulism + - + + Generalized Descending BL Sudden Toxin test Blood, Wound, or Stool culture Diplopia, Hyporeflexia, Hypotonia, possible respiratory paralysis
Infant Botulism + - + + Generalized Descending BL Sudden Toxin test Blood, Wound, or Stool culture Flaccid paralysis (Floppy baby syndrome), possible respiratory paralysis
Guillian-Barre syndrome + - - - Generalized Ascending BL Insidious CSF: ↑Protein

↓Cells

Clinical & Lumbar Puncture Progressive ascending paralysis following infection, possible respiratory paralysis
Eaton Lambert syndrome + - + + Generalized Systemic BL Intermittent EMG, repetitive nerve stimulation test (RNS) Voltage gated calcium channel (VGCC) antibody Diplopia, ptosis, improves with movement (as the day progresses)
Myasthenia gravis + - + + Generalized Systemic BL Intermittent EMG, Edrophonium test Ach receptor antibody Diplopia, ptosis, worsening with movement (as the day progresses)
Electrolyte disturbance + + - - Generalized Systemic BL Insidious Electrolyte panel ↓Ca++, ↓Mg++, ↓K+ Possible arrhythmia
Organophosphate toxicity + + - + Generalized Ascending BL Sudden Clinical diagnosis: physical exam & history Clinical suspicion confirmed with RBC AchE activity History of exposure to insecticide or living in farming environment. with : Diarrhea, Urination, Miosis, Bradycardia, Lacrimation, Emesis, Salivation, Sweating
Tick paralysis (Dermacentor tick) + - - - Generalized Ascending BL Insidious Clinical diagnosis: physical exam & history - History of outdoor activity in Northeastern United States. The tick is often still latched to the patient at presentation (often in head and neck area)
Tetrodotoxin poisoning + - + + Generalized Systemic BL Sudden Clinical diagnosis: physical exam & dietary history - History of consumption of puffer fish species.
Stroke +/- +/- +/- +/- Generalized Systemic UL Sudden MRI +ve for ischemia or hemorrhage MRI Sudden unilateral motor and sensory deficit in a patient with a history of atherosclerotic risk factors (diabetes, hypertension, smoking) or atrial fibrillation.
Poliomyelitis + + + +/- Proximal > Distal Systemic BL or UL Sudden PCR of CSF Asymmetric paralysis following a flu-like syndrome.
Transverse myelitis + + + + Proximal > Distal Systemic BL or UL Sudden MRI & Lumbar puncture MRI History of chronic viral or autoimmune disease (e.g. HIV)
Neurosyphilis + + - +/- Generalized Systemic BL Insidious MRI & Lumbar puncture CSF VDRL-specifc

CSF FTA-Ab -sensitive

History of unprotected sex or multiple sexual partners.

History of genital ulcer (chancre), diffuse maculopapular rash.

Muscular dystrophy + - - - Proximal > Distal Systemic BL Insidious Genetic testing Muscle biopsy Progressive proximal lower limb weakness with calf pseudohypertrophy in early childhood. Gower sign positive.
Multiple sclerosis exacerbation + + + + Generalized Systemic NL Sudden CSF IgG levels

(monoclonal)

Clinical assessment and MRI Blurry vision, urinary incontinence, fatigue
Amyotrophic lateral sclerosis + - - - Generalized Systemic BL Insidious Normal LP (to rule out DDx) MRI & LP Patient initially presents with upper motor neuron deficit (spasticity) followed by lower motor neuron deficit (flaccidity).
Inflammatory myopathy + - - - Proximal > Distal Systemic UL or BL Insidious Elevated CK & Aldolase Muscle biopsy Progressive proximal muscle weakness in 3rd to 5th decade of life. With or without skin manifestations.

Treatment

Removal of the embedded tick usually results in resolution of symptoms within several hours to days. If the tick is not removed, the toxin can be fatal, with reported mortality rates of 10–12 percent,[20] usually due to respiratory paralysis. The tick is best removed by grasping the tick as close to the skin as possible and applying firm steady pressure.[21]

Prevention

No vaccine is currently available for any tick-borne disease, except for TBE. Individuals should therefore take precautions when entering tick-infested areas, particularly in the spring and summer months. Preventive measures include avoiding trails that are overgrown with bushy vegetation, wearing light-colored clothes that allow one to see the ticks more easily, and wearing long pants and closed-toe shoes. Tick repellents containing DEET (N,N, diethyl-m-toluamide) are only marginally effective and can be applied to skin or clothing. Rarely, severe reactions can occur in some people who use DEET-containing products. Young children may be especially vulnerable to these adverse effects. Permethrin, which can only be applied to clothing, is much more effective in preventing tick bites. Permethrin is not a repellent but rather an insecticide; it causes ticks to curl up and fall off of the protected clothing.

Toxin

Although several attempts have been made to isolate and identify the neurotoxin since the first isolation in 1966 the exact structure of the toxin is still unknown.[22] The 40-80 kDa protein fraction contains the toxine.[23]

See also

References

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  2. Dworkin MS, Shoemaker PC, Anderson D (1999). "Tick paralysis: 33 human cases in Washington state, 1946–1996". Clin Infect Dis. 29: 1435&ndash, 9.
  3. Masina S, Broady K. W. (1999). "Tick paralysis: development of a vaccine". International Journal for Parasitology. 29 (4): 535–541. doi:10.1016/S0020-7519(99)00006-5.
  4. 4.0 4.1 Kira R (February 2018). "[Acute Flaccid Myelitis]". Brain Nerve (in Japanese). 70 (2): 99–112. doi:10.11477/mf.1416200962. PMID 29433111.
  5. Hopkins SE (November 2017). "Acute Flaccid Myelitis: Etiologic Challenges, Diagnostic and Management Considerations". Curr Treat Options Neurol. 19 (12): 48. doi:10.1007/s11940-017-0480-3. PMID 29181601.
  6. Messacar K, Schreiner TL, Van Haren K, Yang M, Glaser CA, Tyler KL, Dominguez SR (September 2016). "Acute flaccid myelitis: A clinical review of US cases 2012-2015". Ann. Neurol. 80 (3): 326–38. doi:10.1002/ana.24730. PMC 5098271. PMID 27422805.
  7. Chong PF, Kira R, Mori H, Okumura A, Torisu H, Yasumoto S, Shimizu H, Fujimoto T, Hanaoka N, Kusunoki S, Takahashi T, Oishi K, Tanaka-Taya K (February 2018). "Clinical Features of Acute Flaccid Myelitis Temporally Associated With an Enterovirus D68 Outbreak: Results of a Nationwide Survey of Acute Flaccid Paralysis in Japan, August-December 2015". Clin. Infect. Dis. 66 (5): 653–664. doi:10.1093/cid/cix860. PMC 5850449. PMID 29028962.
  8. Messacar K, Asturias EJ, Hixon AM, Van Leer-Buter C, Niesters H, Tyler KL, Abzug MJ, Dominguez SR (August 2018). "Enterovirus D68 and acute flaccid myelitis-evaluating the evidence for causality". Lancet Infect Dis. 18 (8): e239–e247. doi:10.1016/S1473-3099(18)30094-X. PMID 29482893. Vancouver style error: initials (help)
  9. Chen IJ, Hu SC, Hung KL, Lo CW (September 2018). "Acute flaccid myelitis associated with enterovirus D68 infection: A case report". Medicine (Baltimore). 97 (36): e11831. doi:10.1097/MD.0000000000011831. PMC 6133480. PMID 30200066.
  10. "Botulism | Botulism | CDC".
  11. McCroskey LM, Hatheway CL (May 1988). "Laboratory findings in four cases of adult botulism suggest colonization of the intestinal tract". J. Clin. Microbiol. 26 (5): 1052–4. PMC 266519. PMID 3290234.
  12. Lindström M, Korkeala H (April 2006). "Laboratory diagnostics of botulism". Clin. Microbiol. Rev. 19 (2): 298–314. doi:10.1128/CMR.19.2.298-314.2006. PMC 1471988. PMID 16614251.
  13. Brook I (2006). "Botulism: the challenge of diagnosis and treatment". Rev Neurol Dis. 3 (4): 182–9. PMID 17224901.
  14. Dimachkie MM, Barohn RJ (May 2013). "Guillain-Barré syndrome and variants". Neurol Clin. 31 (2): 491–510. doi:10.1016/j.ncl.2013.01.005. PMC 3939842. PMID 23642721.
  15. Walling AD, Dickson G (February 2013). "Guillain-Barré syndrome". Am Fam Physician. 87 (3): 191–7. PMID 23418763.
  16. Gilhus NE (2011). "Lambert-eaton myasthenic syndrome; pathogenesis, diagnosis, and therapy". Autoimmune Dis. 2011: 973808. doi:10.4061/2011/973808. PMC 3182560. PMID 21969911.
  17. Krishnan C, Kaplin AI, Deshpande DM, Pardo CA, Kerr DA (May 2004). "Transverse Myelitis: pathogenesis, diagnosis and treatment". Front. Biosci. 9: 1483–99. PMID 14977560.
  18. Amato AA, Greenberg SA (December 2013). "Inflammatory myopathies". Continuum (Minneap Minn). 19 (6 Muscle Disease): 1615–33. doi:10.1212/01.CON.0000440662.26427.bd. PMID 24305450.
  19. Berger JR, Dean D (2014). "Neurosyphilis". Handb Clin Neurol. 121: 1461–72. doi:10.1016/B978-0-7020-4088-7.00098-5. PMID 24365430.
  20. Schmitt N, Bowmer EJ, Gregson JD (1969). "Tick paralysis in British Columbia". Can Med Assoc J. 100: 417&ndash, 21.
  21. Needham GR (1985). "Evaluation of five popular methods for tick removal". Pediatrics. 75: 997&ndash, 1002.
  22. Doube B. M. (1975). "Cattle and Paralysis Tick Ixodes-Holocyclus". Australian Veterinary Journal. 51 (11): 511–515.
  23. B. F. Stone, K. C. Binnington, M. Gauci, J. H. Aylward (1989). "Tick/host interactions forIxodes holocyclus: Role, effects, biosynthesis and nature of its toxic and allergenic oral secretions". Experimental and Applied Acarology. 7 (1): 59–69. doi:10.1007/BF01200453.

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