Anesthetic experience using total intravenous anesthesia in a patient with Isaacs' syndrome -A case report-
A 74 year-old female patient, 158 cm tall and weighing 62 kg, was diagnosed with a full thickness RC tear of her right shoulder. She was scheduled to undergo open RC repair. Her physical status was American Society of Anesthesiologists physical status II. Her prior medical history included hypertension, stable angina, and diabetes mellitus, which were well controlled with medication. Four years previously, the patient had experienced painless cramps in both hands and feet and excessive sweating without any palpitations, even during the winter season. Then, two years later she was diagnosed with Isaacs' syndrome through EMG. The nerve conduction study was unremarkable. Studies for serum anti-VGKC antibodies were not performed and antiacetylcholine-receptor antibodies produced negative results. The patient complained of gradual progressive painless flexion of her left ring and little fingers, which led to contractures (). The fingers could only be extended passively. No other neurologic abnormalities and sensory deficits were noted. A course of intravenous immunoglobulin was ineffective, and the patient was placed on a regimen of oral carbamazepine 200 mg and gabapentin 300 mg per day. She showed some improvement in symptoms without complete resolution.\nSerum electrolytes including calcium, magnesium, sodium, and potassium ions were within the normal limits. Thyroid hormone levels, creatine kinase, and aldonase were also normal. Computerized tomographic scan of the thorax did not reveal thymoma. Pulmonary function tests showed a normal pattern. There was no family history of neuromuscular disease. The patient had undergone general anesthesia for spinal stenosis before her Isaacs' syndrome diagnosis in another hospital. Unfortunately, the details of the anesthetic agents used were unavailable.\nUpon arrival in the operating room, the patient's blood pressure was 155/82 mmHg, heart rate was 51 beats/min, and oxygen saturation was 97%. She was premedicated with intravenous glycopyrrolate 0.2 mg before the surgery. Preoperative monitoring including ECG, pulse oximeter, capnogram, and direct arterial pressure monitoring via the left radial arterial cannula was performed. Bispectral index (BIS) and train-of-four (TOF) monitors were attached to the patient. Three minutes after preoxygenation, lidocaine 40 mg was administered prior to target controlled infusion (TCI) of propofol (target blood concentration 2.5 µg/ml) and remifentanil (target blood concentration 2.0 ng/ml). The patient rapidly fell into sleep with loss of eyelid reflex but abnormal muscle activity still persisted. When the numerical value of the BIS was 48, atracurium 30 mg (0.5 mg/kg) was administered. Ninety seconds later, the involuntary cramps were arrested and no response to TOF stimuli (2 Hz for 2 sec at 10-sec intervals) was observed. The patient was grade IIb on the modified Cormack and Lehane scoring system on laryngoscopy. Only the patient's glottis and vocal cords were visible. Nevertheless, endotracheal intubation was performed without complications. The patient was ventilated with a mixture of oxygen and air (FiO2 0.5). Warm forced air devices were used to maintain body temperature.\nDuring anesthesia, the patient showed no specific abnormalities of her vital signs, and an open RC repair was smoothly performed in 90 minutes. At the end of the surgery, the propofol and remifentanil infusion was stopped and the patient resumed spontaneous breathing. On the nerve stimulator, the TOF ratio was kept above 0.90. After the patient had recovered spontaneous respiration to a sufficient extent, glycopyrrolate 0.4 mg and pyridostigmine 15 mg were intravenously injected to reverse the muscle relaxation. Extubation was performed at a final TOF ratio of 1. The time from the end of surgery to extubation was about 10 minutes. We then moved the patient to the intensive care unit for continuous hemodynamic monitoring. One day after the operation, the patient was transferred to the general ward, but she complained of difficult urination. Urologic evaluation revealed a flaccid-type neurogenic bladder, and a suprapubic catheter was placed for urination. There were no further complications, and on the 22nd day after the operation, the patient was discharged from the hospital.