The aim of this study was to assess the clinical characteristics of hypertensive encephalopathy according to the underlying etiologies in children.
We retrospectively evaluated 33 pediatric patients who were diagnosed as having hypertensive encephalopathy in Chonbuk National University Children's Hospital. Among the patients, 18 were excluded because of incomplete data or because brain magnetic resonance imaging (MRI) was not performed. Finally, 17 patients were enrolled and divided into a renal-origin hypertension group and a non-renal-origin hypertension group according to the underlying cause. We compared the clinical features and brain MRI findings between the 2 groups.
The renal group included renal artery stenosis (4), acute poststreptococcal glomerulonephritis (2), lupus nephritis (2), and acute renal failure (1); the nonrenal group included essential hypertension (4), pheochromocytoma (2), thyrotoxicosis (1), and acute promyelocytic leukemia (1). The mean systolic blood pressure of the renal group (172.5±36.9 mmHg) was higher than that of the nonrenal group (137.1±11.1 mmHg,
We conclude that the patients with renal-origin hypertension had a more severe clinical course than those with non-renal-origin hypertension. Furthermore, the renal-origin group was highly associated with PRES on brain MRI.
In children, hypertension is a rare disease with a prevalence of less than 1%
Hypertension can cause various complications, with hypertensive encephalopathy a particularly unfavorable prognosis. Hypertensive encephalopathy is a common manifestation of malignant hypertension which is characterized by grade III/IV retinopathy and widespread endothelial damage with uncontrolled hypertension
Hypertensive encephalopathy is defined as acute brain dysfunction such as severe headache, changes in consciousness, seizure, and retinal hemorrhage induced by sustained severe hypertension
For this reason, we tried to assess the relationship between the underlying causes of hypertensive encephalopathy and clinical characteristics or brain MRI findings in pediatric patients.
The total number of pediatric patients (younger than 20 years of age) who were admitted to our Pediatric Department with hypertension as the main symptom between 2000 and 2015 was 197.
Hypertension was diagnosed when the systolic or diastolic blood pressure was over the 95% percentile for the relevant age categories. All initial blood pressure was measured from an upper extremity with an appropriate pediatric manual arm cuff. Blood pressure was measured continuously when neurologic symptoms were present at the time of admission.
Hypertensive encephalopathy was diagnosed when patient showed hypertension with more than one neurologic symptom including headache, seizure, dysarthria, motor weakness, or loss of consciousness
Patients underwent brain MRI and electroencephalography (EEG) within one day of hospitalization. Patients with PRES lesion on brain MRI and those with other findings including infarction or hemorrhage without PRES lesion on brain MRI were classified into ‘typical MRI’ group and ‘atypical MRI’ group, respectively.
We reviewed 33 patients who showed hypertensive encephalopathy. Among them, 16 patients were additionally excluded because of incomplete data (4 patients), or lack of brain imaging study (8 patients), or neurologic symptoms which already had occurred before hypertension onset (4 patients). Consequently, we enrolled 17 children with hypertensive encephalopathy.
Patients were divided into 2 groups according to their cause, and the clinical characteristics of each group were analyzed. The renal group included renal artery stenosis (4), acute poststreptococcal glomerulonephritis (2), lupus nephritis (2), and acute kidney injury (1). The nonrenal group included essential hypertension (4), pheochromocytoma (2), thyrotoxicosis (1), and acute promyelocytic leukemia (1). Blood pressure, clinical manifestations and prognosis, EEG, and brain MRI findings were compared between the groups.
This study was performed with approval from the Institutional Review Board of Chonbuk National University Research Council.
Statistical analysis was conducted with IBM SPSS ver. 18.0 (IBM Co., Armonk, NY, USA). A Pearson chi-square test was used to compare symptoms and radiologic findings between the groups. For comparing blood pressure and prevalence, a simple correlation analysis and Mann-Whitney
Nine out of 17 patients were included in the renal origin hypertension group and 8 patients were in the nonrenal origin hypertension group (
Eleven out of seventeen patients manifested seizure, which was the most common symptom in our study group (64.7%). Seizure was more common in the renal group, and there was a significant difference when compared to the occurrence of seizure in the nonrenal group (88.9% vs. 37.5%,
Brain MRI was performed in all 17 patients, of whom 7 patients had typical PRES lesion (41.2%), and 2 had multifocal infarction without PRES lesion (11.8%). In the renal group, with all patients manifesting seizures, every patient showed abnormal MRI findings (100%), and 6 patients had PRES lesion (66.6%). All patients with PRES lesions showed seizures, but PRES lesions were improved after treatment (
Clinical outcomes were not as detrimental as already known
Hypertension in children is usually related to secondary hypertension, unlike in adults in which primary hypertension is the major cause of hypertension
Hypertensive encephalopathy can manifest seizures, intracranial hemorrhage, posterior reversible encephalopathy syndrome, and papilledema. In a narrow spectrum, hypertensive encephalopathy has the same meaning as posterior reversible encephalopathy syndrome, but any symptoms related to hypertension with neurologic impairment have been described as hypertensive encephalopathy in other studies
Many of the young patients with secondary hypertension had renal disease; hence, evaluation of hypertension in children includes the use of renal ultrasonography, echocardiogram, and laboratory findings
The differences in the prevalence of typical findings between the groups were related to 2 major factors. First, higher blood pressure can make hypertensive encephalopathy more likely, and these can give rise to typical radiologic findings. Among our study groups, most of the patients with renal disease did not know they had hypertension before a hypertensive crisis attack. Hypertensive encephalopathy was the first symptom of their disease, so their peak and mean blood pressure could be higher than those in the other group because of untreated hypertension. As mentioned in previous studies, acute onset and high blood pressure were directly related with hypertensive encephalopathy onset; therefore, a difference between the 2 groups existed in this study. The other factor is related to a hypertensive encephalopathy mechanism. In the past, auto-regulatory vasoconstriction in the cerebral vasculature was thought to be the main cause of hypertensive encephalopathy
Brain MRI is the most effective diagnostic tool in patients with hypertensive encephalopathy
As the mean blood pressure was higher in the renal group, neurologic symptoms and typical MRI findings were also prominent in this group. However, all patients were included in the study based on peak blood pressure, and those who had no neurologic impairment despite high blood pressure were excluded. This finding could be meaningful in itself. This is a limited study because only 17 patients were suitable according to our criteria. Therefore, we cannot generalize the relationship between hypertensive encephalopathy and underlying diseases. For this, a wider range study with adult patients should be performed. Furthermore, other objective parameters, such as serologic biomarkers, could reveal the exact pathophysiology that could explain the corelation between underlying diseases and the initiation of hypertensive encephalopathy.
In conclusion, there are many underlying diseases that induce neurologic impairment. Therefore, when physicians suspect hypertensive encephalopathy, a differential diagnosis is important for proper treatment. The basic treatment for hypertensive encephalopathy is an antihypertensive drug; however, additional treatment for underlying diseases should be administered. Hence, we studied the characteristics of hypertensive encephalopathy in children who had different causes for hypertension compared to adults. In this study, renal disease was found to be a common cause of typical hypertensive encephalopathy. Therefore, it is critical that physicians should be aware of hypertensive encephalopathy and hypertensive crisis in children with renal origin hypertension.
Characteristic | Renal-origin hypertension group (n=9) | Non–renal-origin hypertension group (n=8) |
---|---|---|
Sex, male:female | 5:4 | 4:4 |
Age (yr) | ||
Mean±SD | 11.7±4.3 | 13.0±4.5 |
Range | 8–20 | 4–16 |
Mean blood pressure (mmHg) | ||
Systolic | 172.5±36.9 | 137.1±11.1 |
Diastolic | 108.7±18.8 | 87.1±17.0 |
MRI findings | ||
Typical | 6 (66.7) | 1 (12.5) |
Atypical | 3 (33.4) | 2 (25.0) |
Normal | 0 (0) | 5 (62.5) |
Values are presented as mean±standard deviation (SD) or number (%) unless otherwise indicated.
MRI, magnetic resonance imaging.
Variable | Renal-origin hypertension group (n=9) | Non–renal-origin hypertension group (n=8) |
---|---|---|
Seizure | 8 (88.9) | 3 (37.5) |
Headache | 3 (33.3) | 5 (62.5) |
Blurred vision | 1 (11.1) | 1 (12.5) |
Palpitation | 0 (0) | 2 (25) |
Dysarthria | 0 (0) | 1 (12.5) |
Case | Age (yr)/sex | Diagnosis | Height (percentile) | BP (mmHg) | MRI | EEG |
---|---|---|---|---|---|---|
1 | 4/F | Thyrotoxicosis | 103 cm (50–75) | 130/70 | Normal | S; Rt. Po |
2 | 20/M | Renal artery stenosis | 180 cm (50–75) | 160/120 | Rt. P, O | |
3 | 13/F | Essentialhypertension | 160 cm (50–75) | 130/90 | Rt. T | S, Sp; Rt. T |
4 | 9/M | Essentialhypertension | 127 cm (10–25) | 120/60 | Rt. P | S; Lt. Po |
5 | 8/M | APSGN | 133 cm (75–90) | 130/90 | Both O | |
6 | 9/M | Renal artery stenosis | 130 cm (25–50) | 190/130 | Both O | |
7 | 8/M | Renal artery stenosis | 127 cm (25–50) | 170/100 | Both O | S; both Po |
8 | 12/M | Lupus nephritis | 141 cm (10–25) | 240/140 | F, P, T | S; both Po |
9 | 17/F | Renal artery stenosis | 168 cm (75–90) | 200/100 | Both B, P | S; F, P |
10 | 8/F | APSGN | 128 cm (50–75) | 130/90 | Rt. O | |
11 | 15/M | Pheochromocytoma | 178 cm (75–90) | 150/90 | Normal | N |
12 | 14/M | Essentialhypertension | 165 cm (50–75) | 140/90 | Normal | N |
13 | 11/M | ARF | 154 cm (90–95) | 160/100 | Both P, O | S; Rt. |
14 | 16/M | Pheochromocytoma | 182 cm (75–90) | 150/100 | Normal | S; Lt. |
15 | 18/F | Essentialhypertension | 161 cm (25–50) | 140/110 | Normal | |
16 | 12/F | Lupus nephritis | 154 cm (50–75) | 160/100 | Rt. P, T | |
17 | 15/F | APL | 159 cm (25–50) | 150/80 | Both B, O |
BP, blood pressure; MRI, magnetic resonance imaging; EEG, electroencephalography; Rt, right; Lt, left; N, normal; F, frontal; P, parietal lobe; O, occipital; T, temporal; B, basal ganglia; S, slow wave; Sp, spike wave; Po, posterior; APL, acute promyelocytic leukemia; ARF, acute renal failure.