Piloerection: A Rare Ictal Phenomenon – Case Report and Review of Literature

Sir,

We report the case of a 28-year-old man who presented with spells of unusual nature for 8 months. These events were characterized by frequent brief episodes of fearfulness and sensation of panic associated with goose bumps or piloerection over the left upper limb with unusual cold sensation going down his spine, palpitations, brief breathing difficulty and brief change in voice. He was completely aware and communicative during the episodes which lacked other autonomic or motor symptoms, lasted for 30 s-1 min and occurred 10–20 times a day. Although mainly spontaneous, there was increased frequency during periods of mental stress. An additional history of loss of consciousness with probable tonic-clonic limb movements was elicited at the very onset of this illness. However, no specific antiepileptic drug had been given. There was no febrile seizure, head trauma, encephalitis, meningitis, or cerebrovascular disease in the past. Family history was not contributory. The patient had attributed these symptoms to certain significant recent stressful life events and his inability to deal them. He initially consulted a psychiatrist and was treated as a case of panic disorder with anxiolytics and beta-blockers with marginal improvement. After 8 months, one of the authors considered the possibility of partial seizures with autonomic features though psychogenic nonepileptic events could not be ruled out completely. Long-term video-electroencephalography (EEG) monitoring showed intermittent theta (5–6 Hz) activity and frequent spike wave discharges over the left frontotemporal region. Ten habitual events characterized by piloerection over his left forearm with the sensation of cold running down his spine were recorded while conscious and responsive. No orofacial or limb automatism, speech arrest or behavioral arrest was noted. Ictal EEG showed ictal onset over left frontotemporal region preceding the clinical event by 10–15 s [Figure 1a and b]. Magnetic resonance imaging brain showed features suggesting left mesial temporal sclerosis. The patient was initiated on antiepileptic drugs (lamotrigine and clobazam with gradual dose escalation) and behavioral counseling with 80% seizure reduction at 6 months follow-up. The patient's family refused surgery due to personal reasons.

Figure 1.

(a and b) Ictal electroencephalography shows rhythmic spike wave discharges followed by 5–6 Hz theta activity over left temporal region

The interaction between seizures and autonomic nervous system is very complex. Abnormal neuronal electrical activity arising from autonomic centers can result in autonomic symptoms anytime in the peri-ictal period. Episodic autonomic dysfunction is sometimes difficult to diagnose as seizures. Piloerection which may be accompanied by cold shiver is a very uncommon ictal sign of visceral epilepsies and may be isolated or occur in combination with other autonomic signs or complex partial seizures.[1,2] About 106 cases of pilomotor seizures have been reported in literature.[1,2,3,4,5,6,7,8,9,10,11,12,13] Out of these, 31 had isolated pilomotor phenomenon without any other aura or dialeptic features. The majority of patients reported in literature were noted to have ictal onset over the temporal region.[1,2,6,7,10] Piloerection is mostly unilateral or initially unilateral with later contralateral spread, and at times it can be bilateral at onset. Although majority had left temporal localization, one-third (35 cases) had right temporal localization.[1,2,3,4,5,6,7,8,9,10,11,12,13] On the other hand, bilateral piloerection had no definite lateralizing value.[1] Varied etiology of pilomotor seizures includes tumors, encephalitis, stroke, neurodegenerative disease, hippocampal sclerosis, or autoimmune process. Although hippocampal sclerosis is a more frequent cause,[1,2,7] a few recent reports have recorded pilomotor seizures in autoimmune nonparaneoplastic limbic encephalitis especially in relation to voltage-gated potassium channel antibodies.[6,10]

In temporal lobe epilepsy, piloerection, and other autonomic phenomena are proposed to reflect seizure spread to the insula.[1] An interesting observation is the high frequency of ictal pilomotor events with multiple daily to weekly events up to 20–30/h.[1,3,5,6,7,8,9,10,11,12,13] The exact pathophysiology of this high frequency of neuronal hypersynchronization is unclear. The presence of dysplastic cells, inflammation or involvement of limbic circuit including amygdala, mesial temporal and probably orbitofrontal structures may trigger increased seizure frequency due to high epileptogenicity index. We postulate that a reverberating circuit between limbic regions and centers of autonomic control may lead to a vicious cycle wherein pilomotor seizures and panic/anxiety or behavioral changes may be perpetuating each other. Further research using stereoelectroencephalography looking at the epileptogenic network involved in pilomotor seizures may answer this question. The peculiar features of ictal piloerection may masquerade as other psychiatric or cardiac disorders [Table 1]. The conglomerate of symptoms of gooseflesh, tachycardia, palpitations and sweating in themselves can easily be confused as neurovegetative dysfunction due to possible nonepileptic events.[5,6,7,8,10,11] As a consequence of the ictal phenomena and high frequency of recurrent events, personality and behavioral traits may develop simultaneously, further confusing the diagnosis. Eleven patients have been reported in literature to have initial misdiagnosis, 5 as due to psychiatric cause,[5,6] one as cardiac and one as migraine. This leads to a significant delay in diagnosis with patients undergoing elaborate investigative tests and treatment for other disorders. The label of a psychiatric disorder may negatively impact the quality of life of the patient.

Table 1.

Literature review of 11 patients with ictal piloerection and delay in diagnosis

Therefore, it is of paramount importance to suspect an epileptic etiology when encountering stereotyped, short-lasting, episodic events, howsoever bizarre, and uncommon in symptomatology.

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Conflicts of interest

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