Twenty-one Years with Congenital Insensitivity to Pain: A Case Report.

Abstract

Congenital insensitivity to pain with anhidrosis (CIPA) is caused by a defect in the neurotrophin signal transduction system and is classified under hereditary sensory and autonomic neuropathy (HSAN)1. The defect lies in the NTRK1 gene coding for neurotrophic tyrosine kinase on chromosome 1q21-q222. Its incidence within the global population has been estimated to be 1 in 25,0003. First described in 1846 by Leplat4, the diagnosis of CIPA or HSAN IV is based on the clinical presentation, skin and nerve biopsies, and molecular DNA analysis1,5. Dyck has classified HSAN into five types1. Type I is relatively mild, mainly affects the lower limbs, and manifests in the second to fourth decade. Type II is more severe and presents in infancy. Type III is familial dysautonomia or Riley-Day syndrome, a multisystem disease predominantly affecting Ashkenazi Jews. Type IV features insensitivity to pain, heat intolerance, and mental deficiency. Type V selectively affects nociception. “Painless whitlows,” “mal perforant du pied,” and “Morvan syndrome” are some of the many names used to describe a wide range of conditions that have been grouped under the HSAN classifications. Common to these conditions is insensitivity to pain, but in addition, proprioception, temperature sensitivity, and sense of vibration may also be affected, along with wider systemic problems2. Charcot arthropathy may complicate fractures and osteomyelitis6. The classical clinical presentation of CIPA in childhood is apathy, refusal to feed, absence of sweating, and unexplained hyperpyrexia. There may be a mild degree of mental retardation and delayed motor activities7. The tongue may appear bifid as a result of biting. There may be autoextraction of teeth and scarring of the lips as well as rounded fingertips with dystrophic nails. We present the case of …