How a Painless Patient Fooled Every Monitor

Medscape

30-06-2025

A man in his 30s with congenital indifference to pain with anosmia (CIP) presented to a tertiary centre for elective biopsy and video-assisted thoracoscopic surgery (VATS). Post-operatively, the patient developed intermittent tachycardia, hypertension, and pyrexia.
A case report by Thomas French, MD, research fellow in the Department of Cardiothoracic Surgery, Royal Infirmary of Edinburgh, Edinburgh, England, documented a rare case of congenital pain insensitivity.
The Patient and His History
The patient presented for an elective endoscopic ultrasound-guided biopsy (EBUS) of a lesion in his right middle bronchus and video-assisted thoracoscopic lung resection for two nodules in his right lung.
He had undergone excision and adjuvant radical radiotherapy of a pT3 N0 M0 sarcoma on the right side of his neck 4 years earlier. Forty-six months later, a chest x-ray revealed a 9 mm nodule in the apical segment of his right lung.
His past medical history was notable for CIP with anosmia and a host of related hospital presentations, including poorly healing ulcers, scoliosis, Staphylococcus discitis , and infected soft tissue injuries.
On one occasion, he presented to the emergency department after feeling a painless 'popping' sensation in his left arm and was diagnosed with a biceps tendon rupture. Imaging revealed widespread skeletal degeneration.
His condition had first come to his attention after scalding himself while working as a plumber. He had not noticed the injury until later. Subsequent genetic sequencing led to the diagnosis of CIP.
He had not required analgesia following his previous surgeries but had experienced autonomic responses to pain, characterised by tachycardia, hypertension, and pyrexia.
Findings and Diagnosis
During EBUS, a lesion was observed at the bifurcation of the right middle and lower lobes. A VATS wedge resection of the right upper and lower lobes was performed, and three tissue samples — from the lesion, the upper lobe, and the lower lobe — were sent for histopathology. Intraoperatively, the patient's blood pressure, pulse, and respiratory rate remained stable, with no autonomic responses to surgical stimuli.
He underwent EBUS of the lesion located at the bifurcation of his right middle and right lower lobes and VATS wedge resections of the right upper lobe and right lower lobe. Three samples were sent for histopathologic analysis: biopsied lesion, upper lobe wedge, and lower lobe wedge.
The patient displayed no autonomic response to the primary incision while under general anaesthesia: his blood pressure, pulse rate, and respiratory rate remained constant throughout the entire operation, from the induction of anaesthesia onward.
Post-operatively, the patient was started on an oxycodone patient-controlled analgesia (PCA) regime. He exhibited intermittent tachycardia, hypertension, and low-grade pyrexia in the immediate post-operative period, which resolved following administration of an opioid bolus. The PCA was stopped at 8 hours post-operatively, as he was feeling nauseous after each bolus without any analgesic benefit.
As with the intravenous opioid, oral opioids and oral paracetamol in the immediate post-operative period successfully resolved the patient's tachycardia, blood pressure elevation, and pyrexia. His chest drain was removed one day after surgery, and he was discharged on the second post-operative day.
Four days after the surgery, the patient was readmitted because of fever, cough, and some small-volume purulent discharge from his drain site. A repeat chest x-ray was unremarkable, and a wound swab was negative. He was empirically treated with 24 hours of intravenous antibiotics and given a short, 4-day oral course to complete at home. The team felt that a lower threshold for treating infection would be appropriate, given his diagnosis of CIP. He was discharged one day after readmission and made a good recovery.
Histopathology of the lesion biopsy at the bifurcation of the right middle and lower lobe bronchus was consistent with metastatic synovial carcinoma. The same finding was reported for a nodule contained within the right upper lobe wedge. The histopathology of the lower lobe wedge was unremarkable.
He was referred back to the sarcoma multidisciplinary team and underwent radiotherapy for the lower lobe nodule.
Discussion
'CIP encompasses a wide range of overlapping and poorly understood phenotypes. Patient analgesic requirements are likely to vary significantly from patient to patient, but opioids can be useful in controlling the autonomic response to painful stimuli,' the authors wrote.