Prognostic analysis of orthostatic intolerance using survival model in children

Background Orthostatic intolerance （Ol） is a common disease at pediatric period which has a serious impact on physical and mental health of children.The purpose of this study was to investigate the effect of related factors on the prognosis of children with Ol.Methods The subjects were 170 children with Ol,including 71 males （41.8％） and 99 females （58.2％） with age from 6 to 17 （12.0±2.6） years.The effect of related factors on the prognosis of children was studied by using univariate analysis.Then,the impact of children＇s age,symptom score,duration,disease subtype,and treatment on patient＇s prognosis was studied via analysis of COX proportional conversion model.Results Among 170 cases,48 were diagnosed with vasovagal syncope,including 28 cases of vasoinhibitory type,16 cases of mixed type,and 4 cases of cardioinhibitory type; 115 cases were diagnosed with postural tachycardia syndrome and 7 cases with orthostatic hypotension.By using univariate analysis of Cox regression,the results showed that symptom score had a marked impact on the time of symptoms improvement of children after taking medication （P ＜0.05）,while other univariates had no impact （P ＞0.05）.Multivariate analysis using Cox proportional hazards regression model showed that the symptom score at diagnosis had a significant effect on holding time of symptoms improvement of children after taking medication （P ＜0.05）.Kaplan-Meier curve showed that symptom-free survival was higher in children with symptom score equal to 1 than children with symptom score equal to or greater than 2 during follow-up （P ＜0.05）.Conclusion Symptom score is an important factor affecting the time of symptom improvement after treatment for children with Ol.

Alcohol intolerance and myalgic encephalomyelitis/chronic fatigue

BACKGROUND The literature is mixed about the occurrence of alcohol intolerance among patients with myalgic encephalomyelitis/chronic fatigue syndrome(ME/CFS).Surveys that asked respondents with ME/CFS whether they experienced alcohol intolerance within a recent time frame might produce inaccurate results because respondents may indicate that the symptom was not present if they avoid alcohol due to alcohol intolerance.AIM To overcome this methodologic problem,participants in the current study were asked whether they have avoided alcohol in the past 6 mo,and if they had,how severe their alcohol intolerance would be if they were to drink alcohol.METHODS The instrument used was a validated scale called the DePaul symptom questionnaire.Independent t-tests were performed among the alcohol intolerant or not alcohol intolerant group.The alcohol intolerant group had 208 participants,and the not alcohol intolerant group had 96 participants.RESULTS Using specially designed questions to properly identify those with alcohol intolerance,those who experienced alcohol intolerance vs those who did not experience alcohol intolerance experienced more frequent/severe symptoms and domains.In addition,using a multiple regression analysis,the orthostatic intolerance symptom domain was related to alcohol intolerance.CONCLUSION The findings from the current study indicated that those with ME/CFS are more likely to experience alcohol intolerance.In addition,those with this symptom have more overall symptoms than those without alcohol intolerance.

Body Fluid Changes, Cardiovascular Deconditioning and Metabolic Impairment Are Reversed 24 Hours after a 5-Day Dry Immersion

Dry immersion is an effective and useful model for research in physiology and physiopathology. The focus of this study was to provide integrative insight into renal, endocrine, circulatory, autonomic and metabolic effects of dry immersion. We assessed if the principal changes were restored within 24 h of recovery, and determined which changes were mainly associated with immersion-induced orthostatic intolerance. Five-day dry immersion without countermeasures, and with ad libitum water intake, standardized diet and a permitted short daily rise was performed in a relatively large sample for this experiment type (14 healthy young men). Reduction of total body water derived mostly from extracellular compartment, and stabilized rapidly at the new operating point. Decrease in plasma volume was estimated at 20% - 25%. Five-day immersion was sufficient to impair metabolism with a decrease in glucose tolerance and hypercholesterolemia, but was not associated with pronounced autonomic changes. Five-day immersion induced marked cardiovascular impairment. Immediately after immersion, over half of the subjects were unable to accomplish the 20-min 70° tilt;during tilt, heart rate and total peripheral resistance were increased, and stroke volume was decreased. However, 24 hours of normal physical activity appeared sufficient to reverse orthostatic tolerance and all signs of cardiovascular impairment, and to restitute plasma volume and extracellular fluid volume. Similarly, metabolic impairment was restored. In our study, the major factor responsible for orthostatic intolerance appeared to be hypovolemia. The absence of pronounced autonomic dysfunction might be explained by relatively short duration of dry immersion and daily short-time orthostatic stimulation.

Clinical features and management of postural tachycardia syndrome in children： a single-center experience

Background The incidence of postural tachycardia syndrome （POTS） has been increasing in children and adolescents,while clinical characteristics of POTS in the pediatric population are not fully understood.Methods An observational study was performed in 150 pediatric patients aged between 5 and 18 years who underwent head-up tilt test （HUTT） with the diagnosis of POTS at Peking University First Hospital from March 2008 to August 2013.Demographic data,clinical presentation,autonomic parameters,laboratory findings,and treatments were recorded.Results POTS in children commonly occurred in the age of 7-14 years.Dizziness （84.00％） was the most common symptom,followed by weakness （72.00％） and orthostatic syncope （62.67％）.Positive family history of orthostatic intolerance （Ol） was found in 24.64％ of children with POTS.And 33.09％ of them had preceding infection history as precipitating events.Ten percent of them suffered from orthostatic hypertension.Hyperadrenergic status was documented in 51.28％ of 39 patients who were tested for the standing norepinephrine levels.More than half of POTS patients,with 24-hour urinary sodium level ＜124 mmol/24 hours,were suitable for treatment of salt supplementation.At least 25.74％ of POTS patients were of positive acetylcholine receptor （AChR） antibody.Low iron storage in children with POTS was relatively rare.Most patients responded well to treatments,43.51％ of patients recovered,while 7.63％ of them had relapse after symptoms disappeared.Conclusions POTS is a relatively common condition with complex pathophysiology and heterogeneous clinical manifestation.A comprehensive therapeutic regimen is recommended for the treatment.