Urinary catecholamines during stress and ambulatory blood pressure in children born full term but small for
Apinya Thanapinyo1, Pracha Nuntnarumit, Kwanchai Pirojsakul
1Department of Pediatrics, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
Insights
Masked hypertension is common in children born small for gestational age. Stress increases urinary norepinephrine in these children, indicating heightened sympathetic activity.
Area of Science:
- Pediatric Cardiology
- Neonatology
- Hypertension Research
Background:
- Children born small for gestational age (SGA) may have increased sympathetic activity, a potential mechanism for high blood pressure.
- Masked hypertension, normal office blood pressure with elevated out-of-office readings, is understudied in SGA children.
- Urinary catecholamines reflect sympathetic nervous system activity, particularly under stress.
Purpose of the Study:
- To investigate the prevalence of masked hypertension in children born SGA.
- To examine the association between ambulatory blood pressure and urinary catecholamines following stress in SGA children.
Main Methods:
- Nineteen SGA children and 17 controls (ages 6-14) underwent office BP measurement and ambulatory BP monitoring.
- Urinary catecholamines (norepinephrine, dopamine) were measured before and after a stressor (math test, venipuncture).
Main Results:
- Masked hypertension was diagnosed in 32% of SGA children versus 11.7% of controls.
- SGA children with masked hypertension showed a significant increase in urinary norepinephrine post-stress.
- Awake systolic blood pressure z-scores correlated positively with pre- and post-stress urinary dopamine in SGA children.
Conclusions:
- Masked hypertension is prevalent in children born SGA.
- Increased urinary norepinephrine after stress in SGA children with masked hypertension suggests sympathetic dysregulation.
Objectives:
Increased sympathetic activity is proposed to be a mechanism of high blood pressure in children born small for gestational age. Ambulatory blood pressure monitoring is a form of blood pressure measurement that can detect high blood pressure outside the hospital in patients with normal office blood pressure. This condition is called masked hypertension. There are limited data on association between ambulatory blood pressure and urinary catecholamines during exposure to stress in children born small for gestational age.
Methods:
Nineteen children born small for gestational age and 17 healthy controls ages 6-14 years old were included. Demographic data and office blood pressure were collected. Urinary catecholamines were collected before and after exposure to stress including mathematical test and venipuncture. Afterwards, ambulatory blood pressure monitoring was performed to obtain 24-hour blood pressure profiles.
Results:
All children had normal office blood pressure but ambulatory blood pressure monitoring revealed masked hypertension in six children born small for gestational age (32%) and two controls (11.7%). After stress, median percentage of increase in urine norepinephrine levels was greater in children born small for gestational age with masked hypertension than that of children born small for gestational age without masked hypertension (9.2 vs. -13.2 μg/g creatinine, P = 0.05). There was no increase in urine norepinephrine levels in controls with masked hypertension. Among children born small for gestational age, awake SBP z-scores had significant positive correlations with pre- and post-stress urinary dopamine levels (r = 0.530, P = 0.02 and r = 0.597, P = 0.007, respectively).
Conclusion:
Masked hypertension is not uncommon in children born small for gestational age. After stress, urinary norepinephrine levels were increased in children born small for gestational age with masked hypertension.
Related Concept Videos
02:44The Born-Haber Cycle
01:24Blood Pressure
01:30Blood Pressure
The average BP in an adult is typically around 120/80 mmHg (millimeters of mercury). In this measurement, the numerator (120) indicates the systolic pressure, which is the pressure in the arteries during the contraction of the heart's ventricles as blood is expelled. The denominator (80) represents the...
01:17Measurement of Blood Pressure
01:28Factors affecting Blood pressure
Physiological Factors:
01:30Alterations in Blood Pressure
Hypertension (High blood pressure)
Hypertension occurs when blood pressure readings consistently exceed the normal range. It is diagnosed when systolic blood pressure (the top number, indicating pressure while the heart...