RESIDENT & FELLOW SECTION Child Neurology:

Section Editor Mitchell S.V. Elkind, MD, MS A diagnosis not to miss

Sarah L. Chagnon, MD A 4-year-old girl presented to our tertiary care hospital movements and normal pupillary response to light. Monica Naik, MD with a complaint of lower extremity weakness and Bulbar function was difficult to evaluate due to intu- Hoda Abdel-Hamid, MD unsteady gait for 2 days. She was able to pull herself bation. Repeat MRI of the brain and cervical spine to stand but could not stand unsupported. She had revealed continued resolution of syringomyelia and no sensory symptoms or pain. She did not complain no new abnormalities. A lumbar puncture showed Correspondence to of any weakness in her arms, trunk, face, or neck. mild albuminocytologic dissociation with of Dr. Chagnon: [email protected] She had no bowel or bladder incontinence or reten- 90, 2 leukocytes, and 1 erythrocyte. IV immunoglob- tion. On presentation to the emergency department, ulin (IVIg) therapy was instituted for presumed acute she had minimal antigravity strength of the lower inflammatory demyelinating polyneuropathy. extremities but normal strength elsewhere. In addition, On postoperative day 8, EMG and conduc- she was areflexic in both lower extremities and had a tion studies were completed. Nerve conduction stud- wide-based, unsteady gait but no appendicular dysmet- ies revealed low compound motor action potentials in ria or titubation. Sensory examination was normal. multiple with preserved sensory nerve action After consultation by the neurology service, MRI of potentials. There was no prolonged conduction veloc- the brain and total spine were completed and a plan ity seen and normal F-wave responses were noted. was made for subsequent lumbar puncture. Lyme dis- EMG/needle study revealed increased insertional ease antibodies were drawn because of exposure to a activity and positive sharp waves. The summation wooded area in West Virginia; these were negative. of these results suggested a possible diffuse motor axo- MRI of the spine showed syringomyelia extending nal neuropathy or a presynaptic neuromuscular junc- from T5 to T8 and an extramedullary, intradural cystic tion disturbance. Moreover, it did not fulfill criteria lesion dorsal to the spinal cord from T1 to T4, which for a primary demyelinating neuropathy. was believed to be consistent with an arachnoid cyst. Based on EMG results, we performed a thorough Due to this unexpected finding, the neurosurgical ser- evaluation of the patient’s skin and scalp. Along the vice was consulted, who believed that this cyst and the superior retroauricular scalp, a 3-cm engorged tick associated syrinx were the source of her paralysis. The was found and removed. This tick was identified following day, she was taken to the operating room for by an infectious disease specialist as a gravid female fenestration. Subsequent to the fenestration, repeat species tick. imaging showed resolution of syringomyelia. The following night, the patient developed DISCUSSION Tick paralysis (TP) is a rare and easily increasing respiratory distress, requiring mechanical reversible condition that if missed can lead to signifi- ventilation. Over the subsequent postoperative cant morbidity and mortality. In one series of chil- period, she failed multiple attempts at extubation. dren with TP between 1946 and 1906, 6% died.1 Extensive evaluation including infectious workup, However, in the modern era of respiratory support chest x-ray, ultrasonography of the diaphragm, and and intensive care, survival may be higher. TP in the upper airway endoscopy revealed no reason for her United States is more common in girls younger than ongoing breathing difficulties. In addition, it was 8 years with long hair, presumably due to the ability noted that the patient had not been able to move of the tick to go unnoticed on the scalp.2,3 her upper extremities at any point during the day of Most cases reported in the literature have been surgery or in the following days. identified in Australia, where the causative species is The neurology service was consulted again for fur- holyclus. In North America, most cases reported ther evaluation. Seven days after the initial surgery, the in the Rocky Mountain region, US Pacific North- patient’s neurologic examination revealed flaccid paral- west, and Southwestern Canada are transmitted by ysis of all 4 extremities, bifacial weakness, minimal gag species and in the Southeast reflex, and complete areflexia. She had full extraocular region are transmitted by .4

From the Children’s Hospital of Pittsburgh of UPMC, PA. Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.

© 2014 American Academy of Neurology e91 These distinctions are relevant due to the differences The diagnosis of TP is made by finding the in clinical presentation produced by the 2 species. engorged tick on a patient with symptoms that corre- Pupillary changes and focal weakness are more com- late clinically. The importance of a complete skin mon in Australian cases (i.e., Ixodes cases). In addi- evaluation including the scalp, external ear canals, tion, symptoms tend to remit immediately upon groin, and axillae is irrefutable. Neuroimaging studies removal of a Dermacentor tick, whereas they persist including CT and MRI are normal, although on for a day or two after removal of an Ixodes tick. Dura- closer inspection they may show the embedded tick tion of recovery is more prolonged in Australian cases, if located on the scalp. CSF should also be normal.9 often lasting days to weeks.1 The albuminocytologic dissociation in our patient TP is thought to be caused by a pro- was believed to be postsurgical. If performed, electro- duced in the insect’s salivary glands. The is physiologic tests show a diffuse reduction in the com- thought to decrease presynaptic release pound muscle action potentials (CMAPs) with at the neuromuscular junction, similar to botulinum preserved sensory nerve action potentials. The low toxin. It is possible that variations in the toxin of CMAPs are not usually accompanied by any abnor- Dermacentor compared to Ixodes ticks may mality of neuromuscular transmission with repetitive account for the variation in clinical features.1 nerve stimulation testing. Published cases have The classic clinical presentation of TP is an acute proved that the function is reversible after removal symmetric, ascending flaccid paralysis occurring over of the tick.10 hours to days. There can be a prodrome of restless- Despite attention to other tickborne diseases such ness, irritability, fatigue, and myalgias, but fever is as and Rocky Mountain spotted fever, noticeably absent. Weakness usually begins in the TP remains a frequently misdiagnosed entity. A recent lower extremity, and as the tick continues to feed, meta-analysis reviewed 50 cases of TP in the United the weakness ascends from the legs to the arms and States between 1946 and 2006 and revealed that 11 then to the muscles supplied by the cranial nerves, (22%) of these cases were initially misdiagnosed, with causing dysphagia, dysphonia, and facial weakness. mean time to correct diagnosis of 2.16 days. Of these Deep tendon reflexes are diminished or absent.1,5 A 11 cases, 9 were initially diagnosed as Guillain-Barré case series reported from Australia noted frequent syndrome (GBS), 1 as chronic polyneuropathy, and pupillary involvement and external ophthalmoplegia 1 as postinfectious polyneuritis. In this analysis, prep- in 2 of their patients, although this has not been the arations for invasive IV therapy for GBS were initiated case in the United States.6 Respiratory involvement in 4 patients before tick attachment was discovered and and requirement for mechanical ventilation occur 3 patients received IVIg, while 1 case was discovered invariably if the tick remains in place, though in some during the process of placing a central catheter to pre- patients the tick may have fallen off, accounting for pare for plasmapheresis.4 those patients who recover without assisted ventila- The definitive treatment of TP is removal of tion.1 Atypical presentations have been reported, the offending tick, after which symptoms rapidly including lower motor neuron facial nerve palsy, in resolve. Careful inspection of the rest of the body which ticks were identified in the external auditory foradditionalticksismandatory.Thetickshould canal,7 and left-sided arm weakness in a brachial be carefully removed by grasping it as closely as pos- plexus distribution, which resolved after an engorged sible to the attachment site and using steady traction tick was removed from the subclavian fossa.8 to avoid leaving the head or mouthparts engaged.5 TP presents as an acute-onset flaccid paralysis of the During paralysis, standard supportive therapy lower extremities with hyporeflexia or areflexia. There- should be utilized, including mechanical ventilation fore, the differential diagnosis typically includes pathol- when necessary for respiratory support.9 Antitoxin, a ogies of the lower motor neuron or neuromuscular hyperimmune dog serum used in veterinary medi- junction. See the table for full differential diagnosis. cine, has been used in severe cases but carries a high risk of adverse reaction.6

Table Differential diagnosis of tick paralysis1,9 CASE SUMMARY Within 24 hours after removal of

Guillain-Barré syndrome (acute Spinal cord compression Transverse myelitis the tick, our patient started to regain some movement inflammatory demyelinating polyneuropathy or acute motor in her upper and lower extremities. Within 48 hours, axonal neuropathy) reflexes were elicited in the patella, ankles, biceps, and Cerebellar Poliomyelitis Myasthenia gravis brachioradialis bilaterally. By 3 days after removal, she

Botulism Organophosphate ingestion Lambert-Eaton syndrome was extubated. She had normal facial strength but

Encephalomyelitis Periodic paralysis Diphtheria continued to have some weakness, primarily in the upper extremities, likely due in part to decondition- Porphyria Electrolyte imbalance Heavy ing. The patient was able to sit independently, feed e92 Neurology 82 March 18, 2014 herself, and walk with minimal assistance 6 days after 2. Li Z, Turner RP. Pediatric tick paralysis: discussion of tick removal and was discharged home. two cases and literature review. Pediatr Neurol 2004;31: 304–307. AUTHOR CONTRIBUTIONS 3. Felz MW, Smith CD, Swift TR. A six-year-old girl with – Sarah L. Chagnon: corresponding author responsible for case report, tick paralysis. N Engl J Med 2000;342:90 94. literature review, and primary content of the manuscript. Monica Naik: 4. Diaz JH. A 60-year meta-analysis of tick paralysis in the coauthor responsible for revision of the manuscript. Hoda Abdel-Hamid: United States: a predictable, preventable, and often mis- coauthor responsible for revision of the manuscript and execution and diagnosed poisoning. J Med Toxicol 2010;6:15–21. interpretation of EMG and nerve conduction studies. 5. Pecina CA. Tick paralysis. Semin Neurol 2012;32:531–532. 6. Grattan-Smith PJ, Morris JG, Johnston HM, et al. Clin- STUDY FUNDING ical and neurophysiological features of tick paralysis. Brain No targeted funding reported. 1997;120:1975–1987. 7. Indudharan R, Dharap AS, Ho TM. Intra-aural tick caus- DISCLOSURE ing facial palsy. Lancet 1996;348:613. The authors report no disclosures relevant to the manuscript. Go to 8. Engin A, Elaldi N, Bolayir E, Dokmetas I, Bakir M. Tick Neurology.org for full disclosures. paralysis with atypical presentation: isolated, reversible involvement of the upper trunk of brachial plexus. Emerg Received July 22, 2013. Accepted in final form November 13, 2013. Med J 2006;23:e42. 9. Edlow JA, McGillicuddy DC. Tick paralysis. Infect Dis REFERENCES Clin N Am 2008;22:397–413. 1. Edlow JA. Tick paralysis. Curr Treat Options Neurol 10. Vedanarayanan V, Sorey WH, Subramony SH. Tick paral- 2010;12:167–177. ysis. Semin Neurol 2004;24:181–184.

Neurology 82 March 18, 2014 e93 Child Neurology: Tick paralysis: A diagnosis not to miss Sarah L. Chagnon, Monica Naik and Hoda Abdel-Hamid Neurology 2014;82;e91-e93 DOI 10.1212/WNL.0000000000000216

This information is current as of March 17, 2014

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References This article cites 10 articles, 1 of which you can access for free at: http://n.neurology.org/content/82/11/e91.full#ref-list-1 Subspecialty Collections This article, along with others on similar topics, appears in the following collection(s): All Pediatric http://n.neurology.org/cgi/collection/all_pediatric Peripheral neuropathy http://n.neurology.org/cgi/collection/peripheral_neuropathy Permissions & Licensing Information about reproducing this article in parts (figures,tables) or in its entirety can be found online at: http://www.neurology.org/about/about_the_journal#permissions Reprints Information about ordering reprints can be found online: http://n.neurology.org/subscribers/advertise

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