探讨烦渴-间歇性低钠血症-精神病综合征(PIP)的诊断学特征。

回顾性分析2021年2月1日临沂市精神卫生中心内科收治的1例PIP患者的临床资料，并复习相关文献，总结PIP的诊断学特征。

44岁男性，患精神分裂症29年，自2011年出现烦渴、大量饮水，近2年饮水量多时每天达30 000 ml。入院当日大量饮水后出现目光呆滞、呼之不应、小便失禁、言语紊乱。入院时血压158/102 mmHg(1 mmHg＝0.133 kPa),神志模糊；四肢肌张力偏高、肌力检查不合作；生理反射存在、病理反射未引出。入院时血钾3.13 mmol/L，血钠105.3 mmol/L，血氯70.9 mmol/L。心电图示心率101次/min，窦性心动过速。颅脑CT和鞍区MRI均未见异常。支持治疗后血钾水平渐恢复正常，但血钠、血氯水平一直未恢复，严重时达到危急值。应用丙戊酸钠缓释片、帕利哌酮缓释片、氯氮平等药物治疗，患者病情变化不明显，仍无法控制地饮水。试用盐酸氟西汀胶囊20 mg/d，逐渐增量至60 mg/d，应用1个月后患者饮水量渐减少，两个月后血钠、血氯水平恢复正常。出院7个月后随访患者规律服药，病情稳定，饮水量正常。

临床上发现精神疾病患者精神症状突然恶化，突发抽搐、意识障碍等，应考虑低钠及水中毒的可能性，及时抢救以降低病死率。

To investigate the diagnostic features of polydipsia, intermittent hyponatremia and psychosis syndrome(PIP).

The clinical data of a PIP patient admitted to the Department of Internal Medicine of Linyi Municipal Mental Health Center On February 1, 2021 was retrospectively evaluated and studied.

The 44-year-old man endured 29 years of schizophrenia. He started experiencing polydipsia in 2011 and began to drink a lot of water, up to 30 000 ml a day over the past two years. He had urine incontinence, glazed eyes, being unresponsive to calls, and slurred speech after drinking a large amount of water on the day of admission. At the time of admission, the patient′s consciousness was blurry and his blood pressure was 158/102 mmHg(1 mmHg=0.133 kPa). The muscles in the limbs were tense, making it difficult to coordinate the testing of muscle strength. The pathogenic reflex was not elicitable, but the physiological reflex was evident. Serum potassium was 3.13 mmol/L, sodium was 105.3 mmol/L, and chlorine was 70.9 mmol/L at the time of admission. The electrocardiogram showed sinus tachycardia, with a heart rate of 101 beats per minute. No anomalies were found in the head CT or the saddle region of MRI. After being admitted, the patient received nutritional support, potassium, and sodium supplements. The blood potassium level progressively returned to normal, but the blood sodium and chlorine level did not, occasionally reaching critical levels. During this hospital stay, the patient received clozapine, paliperidone, and sodium valproate sustained-release pills. The patient′s condition remained unaltered, and he continued to struggle with his inability to resist the urge to drink water. We tried to use fluoxetine hydrochloride tablets daily starting at 20 mg and progressively increasing to 60 mg. One month later, the patient′s water intake progressively dropped. Two months later, the blood′s levels of sodium and chlorine were back to normal.The patient was followed on seven months after being discharged, he was taking his medication as prescribed, and his condition was stable. His water intake also turned normal.

In clinical practice, the likelihood of low sodium and water poisoning should be considered when a mental patient exhibits sudden mental symptoms deterioration, convulsions, disturbance of consciousness, and other symptoms. Prompt rescue should be carried out to reduce mortality.