This Correspondence is accompanied by the following Invited Commentary:
Veyckemans F. Case reports: keep a critical eye! Eur J Anaesthesiol 2012; 29:559–560.
Huntington's disease is an autosomal dominant disorder that affects the basal ganglia with a prevalence of four to 10 per 100 000 people.1 Onset is typically between 30 and 50 years of age. There is also a juvenile onset of the disease wherein the symptoms begin before aged 20; this occurs in 10% of affected persons.2 This latter group is more prone to seizures, has impaired glucose metabolism and often inherits the disease in a sex-linked manner from the father. Genetic tests can confirm the diagnosis, even prenatally. Symptoms include choreic movements, personality disorders and impairment of swallowing and gag reflexes. The anaesthetic management of a patient with Huntington's disease provides particular challenges due to the risk of pulmonary aspiration3 and altered responses to anaesthetic drugs.1 Prolonged apnoea of between 1 and 2 h has been reported after the use of thiopentone and suxamethonium, and there is an increased sensitivity to anticholinergics.1 Whether these patients have low levels of atypical pseudocholinisterases remains unanswered. We know of no previous reports of the use of sugammadex in the anaesthetic management of patients with Huntington's disease. We have obtained the patient's written consent for publication of this case report.
A 60-year-old woman, weighing 61 kg, diagnosed with Huntington's chorea 6 years previously was admitted for a thyroid lobectomy. On preoperative assessment it was found that she suffered abnormal choreiform movements, acid reflux and snoring but with no signs or symptoms suggestive of obstructive sleep apnoea. She had an uneventful general anaesthetic 18 years previously for minor surgery. She was a nonsmoker and occasionally consumed alcohol. Full blood count, urea and electrolytes, liver function tests, thyroid function tests, chest radiograph and electrocardiogram performed preoperatively were all within normal limits. She had adequate mouth opening with a thyromental distance greater than 6.5 cm. There was no limitation of neck movement and the Mallampati Score was 2. Her regular medication included oxybutynin 20 mg and fexofenadine 100 mg for an unstable bladder and allergic rhinitis, respectively.
On arrival in the operating theatre, her blood pressure was 148/102 mmHg measured noninvasively, heart rate was 114 beats min−1 and oxygen saturation was 99% on air. A 20 and a 16 G peripheral intravenous cannula were placed, one to be used only for infusions of propofol and remifentanil. Bispectral index (BIS) monitor (Aspect Medical System, Inc., Norwood, MA, USA) and a Train of Four (TOF)-Watch (Organon Ltd., Durham, NC, USA) were also applied. The ulnar nerve was stimulated to observe the adductor pollicis response.
Due to the increased potential for oesophageal reflux, we planned a modified rapid sequence induction. She was preoxygenated and target controlled infusions (TCI) of propofol and remifentanil were set up. For induction of anaesthesia, TCI was commenced at 6 μg ml−1 for propofol and at 3 ng ml−1 for remifentanil. Once the patient started losing consciousness and the BIS value started to fall, cricoid pressure was applied and rocuronium 1 mg kg−1 was given. The lungs were gently ventilated and the trachea was intubated when there was no TOF count detectable. A 6.0 mm internal diameter cuffed Nerve Integrity Monitor Electromyography tracheal tube (Medtronic Inc., Minneapolis, MN, USA) was used for monitoring of the recurrent laryngeal nerve, intraoperatively. There was a grade 1 laryngoscopic view. Intubation was followed by a unilateral superficial cervical plexus nerve block with 10 ml of 0.25% levobupivacaine.
The patient was artificially ventilated with a 50 : 50 mixture of O2 and air. TCI plasma concentrations of propofol 3 to 5 μg ml−1 and remifentanil 1–3 ng ml−1 were maintained to provide a deep plane of anaesthesia (BIS ranged between 30 and 42) in order to facilitate surgery and to avoid the use of repeated doses of muscle relaxant, so that the recurrent laryngeal nerve could be monitored throughout the duration of surgery.4 Fluid warming and a Bair Hugger were used to maintain normothermia, perioperatively. Intraoperatively, she remained haemodynamically stable and received 1 g of paracetamol, intravenously.
A cumulative dose of propofol 1.2 g and remifentanil 1.07 mg was used and the total anaesthetic time was 130 min. Intraoperatively, we did not administer any further doses of muscle relaxant, and all four twitches of the TOF were present on the completion of surgery. Neuromuscular blockade was reversed with sugammadex 100 mg at this point to prevent residual curarisation.5 With the return of her airway reflexes, she was extubated uneventfully.
The patient was alert, orientated and pain free before she left the operating room. She had two further doses of paracetamol at 6 h intervals on the ward and made an unremarkable recovery. She was ready for discharge the same day but remained in hospital overnight as she had a surgical drain in situ as a precautionary measure. She had no complaints of postoperative nausea and vomiting and was comfortable throughout her overnight stay in the ward.
This case presents, to our knowledge, the first known use of sugammadex for reversal of neuromuscular blockade in a patient with Huntington's disease. A low dose of sugammadex was used as all four twitches of the TOF response were detectable.
Sugammadex (Org 25969), a modified γ-cyclodextrin, in appropriate doses allows rapid and complete reversal from any depth of rocuronium induced block.6 It also provides effective and rapid reversal of profound neuromuscular block induced by vecuronium.7 It encapsulates and inactivates rocuronium and selectively binds to free rocuronium molecules with an affinity in a molar ratio of 1 : 1. The resulting inactive complex is eliminated from the body in the urine with an elimination half-life of 1.8 h. It appears to have an acceptable safety profile. Although various nondepolarising muscle relaxants have been used successfully in patients with Huntington's chorea,3 we chose to use rocuronium not only to avoid the adverse effects of suxamethonium but also because it could be reversed rapidly with sugammadex.6
We avoided the neostigmine to prevent exacerbation of choreiform movements which may occur with the use of anticholinergics in combination with neostigmine.2 Moreover, sugammadex appears to reverse neuromuscular blockade more rapidly than neostigmine.8 After 100 mg sugammadex (corresponding to about 1.6 mg kg−1 in this patient) there was complete return of the airway reflexes, a desired effect in this group.
A Nerve Integrity Monitor Electromyography endotracheal tube was used to monitor the function of the recurrent laryngeal nerve, thereby avoiding inadvertent surgical injury of the nerve supply to the vocal cords, intraoperatively.9 We maintained an adequate depth of anaesthesia using TCI propofol and remifentanil with a BIS of 30 to 42, which allowed the presence of three to four twitches on the TOF count and successful intraoperative monitoring of the recurrent laryngeal nerve.4 The recommended dose for reversal of moderate block with sugammadex is 2 mg kg−1.8
TCI allow precise titration of anaesthesia, ease of induction, and a rapid, controlled recovery that has previously been successful in patients with Huntington's chorea.10 TCI avoid the theoretical risk of generalised muscle spasm and prolonged shivering associated with inhalational agents,10 which may trigger life-threatening tonic spasms. There are conflicting reports on the incidence of postoperative shivering with high doses of remifentanil which our patient did not experience.10 The superficial cervical plexus block decreased the need for analgesics, postoperatively.11
We recommend the use of rocuronium as the ideal neuromuscular blocking agent in rapid sequence induction procedures in these groups of patients as sugammadex can be used for rapid reversal of neuromuscular blockade if necessary. We also recommend neuromuscular monitoring in Huntington's patients. The anaesthetic technique used in our patient appeared to be effective and well tolerated providing good analgesia and a rapid recovery. A thorough knowledge of the disease process and anaesthetic implications is essential for the successful anaesthetic management of a patient with Huntington's disease.
Assistance with the study: none declared.
Financial support and sponsorship: none declared.
Conflicts of interest: none declared.
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