Paroxysmal extreme pain disorder

Abstract

Editor—We report the successful anaesthesia of a 15-yr-old girl (Miss A) with paroxysmal extreme pain disorder (PEPD) for laparoscopic ovarian cystectomy. PEPD is a rare condition caused by inherited sodium channel abnormalities. There are a variety of clinical manifestations (Table 1). Sudden attacks of severe pain lasting seconds to hours occur, usually in characteristic distributions, namely rectal, ocular, and submaxillary. Flushing accompanies the pain, with harlequin skin changes in some patients (suddenly developing areas of sharply demarcated erythema). These attacks can escalate to seizures, hypertonia, respiratory arrest, and even asystolic cardiac arrest.1Fertleman CR Ferrie CD Aicardi J et al.Paroxysmal extreme pain disorder (previously familial rectal pain syndrome).Neurology. 2007; 69: 586-595doi:10.1212/01.wnl.0000268065.16865.5fCrossref PubMed Scopus (129) Google ScholarTable 1PEPD signs and symptoms1Fertleman CR Ferrie CD Aicardi J et al.Paroxysmal extreme pain disorder (previously familial rectal pain syndrome).Neurology. 2007; 69: 586-595doi:10.1212/01.wnl.0000268065.16865.5fCrossref PubMed Scopus (129) Google ScholarRectal, ocular, and jaw painFlushingLimb swellingTonic non-epileptic seizuresPupillary changesSalivationApnoeaAsystole Open table in a new tab Explanation of the constellation of symptoms is found in the identified sodium channel abnormalities. The majority of affected patients have mutations in the SCN9A gene. There is an autosomal-dominant abnormality in a voltage-gated sodium channel, Nav1.7.2Fertleman CR Baker MD Parker KA et al.SCN9A mutations in paroxysmal extreme pain disorder: allelic variants underlie distinct channel defects and phenotypes.Neuron. 2006; 52: 767-774doi:10.1016/j.neuron.2006.10.006Abstract Full Text Full Text PDF PubMed Scopus (576) Google Scholar This leads to hyperexcitability in the affected neurones. Nav1.7 is found in the dorsal root and sympathetic ganglia. It is particularly highly expressed in nociceptors.3Dib-Hajj S Estacion M Jarecki BW et al.Paroxysmal extreme pain disorder M1627K mutation in human Nav1.7 renders DRG neurons hyperexcitable.Mol Pain. 2008; 4: 37doi:10.1186/1744-8069-4-37Crossref PubMed Scopus (100) Google Scholar The effects of hyperexcitability in these areas correlate to the clinical picture. Miss A is unusual among PEPD patients in that she had had multiple episodes of cardiorespiratory arrest requiring resuscitation. The longest documented asystolic episode has been 45 s. Owing to these episodes, she has, from infancy, received 24 h care from an advanced life support provider. Bag-mask ventilation has occasionally been described as very difficult because of severe laryngospasm and hypertonia. The anaesthetic plan was for conventional i.v. induction undertaken with particular attention to avoidance of provoking undue anxiety in Miss A. Emergency drugs were drawn up and all resuscitation equipment was checked and kept nearby but out of sight of the patient. Routine monitoring was established before anaesthesia. A 22 G cannula was in situ and functioning. Preoxygenation was followed by induction of anaesthesia with fentanyl 100 mg, propofol 150 mg, rocuronium 40 mg, and glycopyrrolate 200 mg. Intubation was achieved easily with a Cormack and Lehane Grade 1 view. Anaesthesia was maintained with desflurane in an oxygen/air mix. An 18 G cannula was sited under anaesthesia. The siting of a larger cannula before induction of anaesthesia had been considered a significant risk of triggering an attack of PEPD. Analgesia and antiemesis was provided by paracetamol 1 g, paracoxib 40 mg, dexamethasone 8 mg, and morphine 5 mg. Oxygen saturations were kept at 97% and above with an FIO2 of 0.5. Haemodynamic stability was maintained without support and 1 litre of Hartmann's solution was administered over the course of the surgery. The procedure lasted ∼45 min. A 6 cm haemorrhagic cyst was removed from the right ovary. At the end of surgery, neostigmine 2.5 mg/glycopyrrolate 0.5 mg was given after confirmation of the presence of four twitches on train-of-four monitoring. Extubation was uneventful. We feel cutaneous evidence of an attack at the end of a procedure and general anaesthetic should prompt consideration of continuing anaesthesia until the attack has resolved. The patient should be made as pain free as possible before emergence from anaesthesia is considered. The patient remained stable and comfortable in the recovery room. Although considered before operation, a patient-controlled analgesia with morphine was not required for postoperative pain relief. The remainder of Miss A's hospital stay was also uneventful; she has been seen in clinic after discharge and was fully recovered. Although uneventful, we felt that this case was of interest due to the rarity of the condition and the potentially serious adverse outcomes including sudden cardiac arrest. There is no established guidance for anaesthesia in these patients reported in the anaesthetic literature. Conventional but meticulous anaesthesia with particular attention to minimizing distress and anxiety proved successful. Published with the written consent of the patient and her parents. No external funding or competing interests declared.