Congenital Insensitivity to Pain with Anhidrosis (HSAN Type IV), Extremely Rare Syndrome that Can Be Easily Missed by Bone and Joint Surgeons: A Case Report
A 5 year old girl of Indo-Aryan origin presented with one and a half month old neglected trauma left leg, managed by a local bone setter (quack). Examination revealed swelling from knee to ankle, 5cm×5cm ulceration over proximal part of shin, purulent discharging sinus and deformity. X-ray revealed non-union with exuberant callus at the fracture site.\nAt the age of 2 years patient developed ulcers of multiple fingers and toes followed by their self amputation (, ). Finger and toe tips showed multiple healed scars. Radiographs revealed osteoacrolysis (). In the same year, patient had trauma to left thumb which healed with a deformity (). There had been trauma to left forearm in childhood; X-ray revealed healed fracture of shaft of ulna. Parents mentioned all the above traumatic events were not associated with pain.\nAround the age of 2 and half years patient developed blisters over right lower extremity, which healed leaving scar marks ().\nThere is history of recurrent episodes of high grade fever since childhood. There was one such episode in the hospital lasting 4 days. There is history of lack of sweating since birth. Physical and laboratory tests revealed anhidrosis. Patient feels very uncomfortable during hot weather and comforts herself by taking a cold water bath which gives temporary relief.\nShe is born of non-consanguineous marriage. Family history was insignificant. Motor and mental milestones were delayed. Intelligence is low as compared to other siblings. There is history of repeated respiratory tract infections in childhood.\nNeurological examination was normal except inability to perceive painful stimuli. No pain was perceived even at the time of intravenous and intramuscular injections. Nerve conduction study revealed normal median nerve conduction velocity. There is history of several episodes of biting of tongue. The patient had normal eruption of teeth but had lost most of them; all the incisors and canines were absent.\nCRP was elevated. Culture of pus from discharging sinus cultured S. aureus. Serum calcium, serum phosphorus, renal function parameters, thyroid function tests, parathormone levels, serum uric acid were in normal range. Infected non-union was managed by curettage and debridement. Reduction was achieved and fixed using biplanar external fixator (). At 3 months follow up pus discharge had subsided with abundant granulation tissue at wound site. There was callus formation at fracture site and features of union on radiograph.