Dissimulation in patients with myotonic dystrophy
2010-03-18

Editor, Performing general anaesthesia in patients with myotonic dystrophy is still a challenge. Some reviews have been published that deal with anaesthetic problems and complications1,2 and that discuss anaesthetic priorities and procedures.3–5 Although there remain several open questions, for example the proper choice of a general anaesthetic, most authors agree with the statement made by Hannon et al.6 that recognition of the disorder during the preoperative assessment is the key to avoiding perioperative complications. However, preoperative screening requires the cooperation of the patient. In the following, we report a patient with myotonic dystrophy, which complicated perioperative care because the patient had disregarded her disease. A 60-year-old woman presented in our anaesthesiology outpatient clinic for preoperative assessment for laparoscopic cholecystectomy. She reported a medical history of thyroidectomy, cataract surgery and hysterectomy without any complications. She mentioned that, after cataract surgery, she was thought to have myotonic dystrophy, although the diagnosis had never been confirmed. On explicit questioning by the anaesthesiologist, the patient stated that she had an unimpaired exercise tolerance. Thyronajodid was her sole long-term medication and she was classified as having American Society of Anesthesiologists II (ASA II) status. On the day of surgery, she was questioned by the anaesthesiologist and, again, she denied having myotonic dystrophy. Subsequently, anaesthesia was induced with sufentanil (25 μg), propofol (150 mg) and rocuronium (30 mg). During laryngoscopy, unusual jaw stiffness was observed. General anaesthesia was continued by total intravenous anaesthesia with propofol (4 mg−1 kg−1 h−1) and repeated boluses of sufentanil (35 μg). Twenty minutes before the end of the 90 min surgery period, the patient received 7.5 mg piritramide. Recovery from anaesthesia was prolonged, though relaxometry demonstrated a complete recovery from muscle relaxation. After 40 min, the trachea was extubated and the patient was taken to the recovery unit. There she appeared to be disorientated and agitated, making monitoring of her vital parameters and preventing her from falling out of bed almost impossible. Pulse oximetry revealed a desaturation of 80% and the ECG showed a new atrial fibrillation of approximately 130 beats min−1. The analysis of heart enzymes, 12-channel ECG and chest radiograph demonstrated no pathological results. As desaturation persisted and the patient required noninvasive ventilatory support, she was transferred to the ICU for one night, where she recovered and from where she was discharged to the surgery ward the following day. Contacting her general practitioner and her husband, it emerged that the diagnosis of myotonic dystrophy had been confirmed by genetic analysis in 1998, with her father and uncle also being affected. The patient's first symptoms of muscle weakness occurred at the same time. In 2004, her exercise tolerance was limited to 500 m of walking and she had developed a severe mental depression, which had required neuropsychiatric rehabilitation. The patient was, in fact, mostly wheelchair-dependent, but she had completely disregarded her symptoms. Medical reports concerning her poor physical condition and history were not available. On being confronted with this information, the patient still denied any physical restrictions. Hence, after consultation with neurologists, the patient was recommended for further neuropsychiatric rehabilitation. Myotonic dystrophies are dominantly inherited disorders characterized by muscle weakness and atrophy, myotonia and endocrine effects such as cataract, or hypogonadism, together with involvement of different organs, including the brain.7 Anaesthetic problems in patients with myotonic dystrophy are frequent. The complication rate ranges between 52%2 and 8%.1 However, typical complications have been reported to be pulmonary, including acute ventilatory failure, atelectasis and pneumonia, as well as cardiological, such as first-degree heart block and other rhythm disturbances.2 So far, the problems described in this case report seem to be typical in patients with myotonic dystrophy. Owing to the increased risk of perioperative pulmonary complications, careful monitoring during the postoperative period, chest physiotherapy and protection of the upper airways are recommended in patients with severe muscular disability or those who have undergone upper abdominal surgery.1 The problem complicating perioperative care in our patient was that she had ignored the diagnosis and the progress of the disease. As there have been some reports describing perioperative complications unmasking the diagnosis of myotonic dystrophy,1,2,6 we would like to raise the question of whether anaesthesiologists should anticipate that patients with myotonic dystrophy tend to conceal their disease deliberately. Recently published literature in neurology focused on the cerebral involvement in myotonic dystrophies. Meola and Sansone7 reported that patients minimize their symptoms, do not keep outpatient appointments and seem unconcerned about their health. The authors characterized the clinical impression of patients with myotonic dystrophy to be one of apathy, decreased emotional participation and psychomotor delay. Neuropsychiatric interviews demonstrated an avoidant trait personality disorder.8 Investigating psychopathological and emotional deficits in these patients, Bungener et al.9 measured low scores for expressiveness and high scores for anhedonia. They hypothesized that this emotional deficit may be either an adaptive reaction to the disease or the effect of CNS lesions, which occur with myotonic dystrophy, or both.9 In summary, we want to point out that patients with myotonic dystrophy are not only compromised by perioperative pulmonary and cardiac complications, but also tend to disregard their physical impairment, thereby impeding adequate anaesthesia and postoperative care. Thus, anaesthesiologists should be very alert if there is any uncertainty in respect of the diagnosis or the progress of the disease, and should contact the patient's general practitioner or relatives rather than relying on the patient's statement.