Intraoperative exacerbation of Parkinson's disease typically begins with subtle, fine skeletal muscle tremors that are not easily detectable. These tremors may initially be grossly unrecognizable, but under regional anesthesia, an acute exacerbation may occur while the patient remains awake and alert. The patient often reports feelings of discomfort during the procedure. Upon examination, fine tremors can be observed in the chest and upper extremities, which may progress to more pronounced tremors and muscle rigidity within 5 to 15 minutes. As the skeletal muscle activity worsens, it can lead to full-blown rigors, which not only affect the quality of the surgical procedure but also prolong the operating time.
A noteworthy complication during these episodes is the appearance of a coarse fibrillatory pattern on the electrocardiogram (ECG), which may be caused by fine skeletal muscle tremors. This can be mistakenly interpreted as ventricular fibrillation, leading to an unnecessary and potentially harmful decision to perform electrical defibrillation, which should be avoided.
Despite the progression of tremors and muscle rigidity, the patient's arterial blood pressure, heart rate, respiratory rate, and oxygen saturation typically remain stable. Treatment involves administering levodopa and carbidopa orally, which can be done with a sip of water while surgery continues. Symptoms of discomfort and motor activity usually subside within approximately 20 minutes after initiating therapy.
Patients with advanced Parkinson’s disease are at heightened risk for perioperative exacerbations. Even when these patients adhere to their perioperative levodopa therapy, the unpredictable timing of surgery may result in the emergence of Parkinsonian symptoms intraoperatively. In such cases, levodopa should be administered 20 minutes before anesthesia induction to prevent exacerbation, and this can be repeated every two hours during and after surgery through a nasogastric tube positioned in the proximal small bowel.
Postoperative ileus is a serious concern for patients with severe Parkinson's disease, as it can interfere with the absorption of oral levodopa, rendering the medication ineffective when given as a suppository. Levodopa is typically absorbed in the proximal small bowel and may still be used in many post-laparotomy patients. However, for patients who cannot absorb the medication through the intestine, alternative treatments such as diphenhydramine and benztropine are available.
