Radiology 20 SA JOURNAL OF RADIOLOGY • February 2005 Abstract Hypertensive encephalopathy (HE) is a clinical syndrome that occurs infre- quently in children and is often underdiagnosed. We review four patients with HE and describe their clinical presentation and radiological findings on computed tomography (CT). Our cases demonstrate typical features on CT and correlate clinically with the syndrome of HE. Prompt recognition of the syndrome aids in earlier diagnosis and treatment, and hence proves beneficial to the patient. Introduction Hypertensive encephalopathy (HE) is a clinical syndrome consisting of rapidly progressive symptoms and signs. It occurs in the setting of acute and/or prolonged systemic hyperten- sion that disrupts cerebral auto- regulation. Recent studies involving the pathophysiologic mechanisms of HE have postulated that cerebral vas- cular vasodilatation from high-pres- sure autoregulatory failure results in increased vascular permeability and cerebral oedema.1,2 The clinical fea- tures include headache, seizures, visu- al disturbances, altered mental state and focal neurological signs. Delayed diagnosis can prove fatal for the patient, but with treatment there is usually full recovery. HE is rare in paediatric patients and frequently presents in conjunc- tion with a systemic disorder. The clinical presentation and CT findings of 4 recently identified paediatric cases with HE as a complication of renal disease are reviewed. Case 1 A 10-year-old boy presented with headaches, facial swelling, visual impairment, vomiting and a right- sided focal seizure which became gen- eralised. His legs were covered with old impetiginous skin lesions, his AntiDNAse B levels were raised at 480 (titre) (normal < 200) and he was diagnosed with acute post-streptococ- cal glomerulonephritis. Renal func- tion on presentation was fairly well preserved (urea 7.4 mmol/l and crea- tinine 61 umol/l), but the blood pres- sure (BP) at admission was raised at 140/91 mmHg (the 95th percentile for his height is 116/78 mmHg). CT demonstrated low density areas in the subcortical white matter of the cere- bellar hemispheres and in the posteri- or parietal parafalcine regions bilater- ally (Fig. 1). Case 2 A 10-year-old girl presented with acute renal failure and hypertension with a BP of 149/86 mmHg (95th per- centile for her height – 118/78 CASE REPORT Hypertensive encephalopathy with CT confirma- tion in four chil- dren with acute renal disease S Andronikou MB BCh, FCRad (Diag) (SA), FRCR (Lond) M Patel MB ChB, FCRad (Diag) (SA) Department of Paediatric Radiology Red Cross Children’s Hospital and University of Cape Town P Sinclair MB ChB, DCH (SA), FCP Paeds (SA) M McCulloch MB ChB, DCH (SA), DTM&H (Lond), MRCPCH (Lond), FCP Paeds (SA) Department of Paediatric Nephrology Red Cross Children’s Hospital and University of Cape Town Fig. 1. Axial post-contrast CT scan of the brain shows bilateral parafalcine posterior parietal white matter low densities (arrows) without associated enhancement. Radiology 2/24/05 4:50 PM Page 20 mmHg). She subsequently developed seizures and became progressively obtunded. A history of recurrent pharyngitis was elicited. Renal func- tion on presentation was extremely deranged (urea 65 mmol/l and creati- nine 1 095 umol/l). ASOT (anti- streptolysin O titre) was > 2 560 IU (normal < 200) and antiDNAse B 1 960 (titre). Renal biopsy showed rapidly progressive post-infective nephritis with crescents. Peritoneal dialysis was required for 7 days and she responded well to steroids and cyclophosphamide. Creatinine at dis- charge from hospital was 56 umol/l. In view of her seizures, a CT scan was performed. CT showed low-density changes within the white matter of the high occipital and posterior parietal regions on either side of the midline, with focal areas of peripheral enhancement (Fig. 2). Case 3 A 10-year-old boy presented with a 2-day history of generalised body swelling, dark urine, vomiting and headaches and also a past history of skin infections. Clinically, there were widespread impetiginous lesions together with a scabies infestation. At presentation he had a generalised tonic-clonic seizure and was poorly responsive with a BP of 164/107 mmHg (95th percentile for his height – 113/74 mmHg). His renal function deteriorated rapidly and peaked at a urea of 14.5 mmol/l and a creatinine of 114 umol/l, but settled to a urea of 6.2 mmol/l and creatinine of 55 umol/l on discharge 5 days later. AntiDNAseB was greater than 2 560 (titre) and ASOT was 320 IU, and therefore a diagnosis of post-strepto- coccal glomerulonephritis was made. At CT there were symmetrical white matter hypodensities in the high pari- etal parasagittal regions (Fig. 3). Case 4 An 8-year-old boy with acute renal failure as the result of tumour lysis after chemotherapy for Burkitt's lym- phoma, presented with a seizure. The BP at the time was 133/102 mmHg (95th percentile for his height - 113/76 mmHg). He also had pul- monary oedema and was clinically fluid overloaded. Urea was 21 mmol/l, creatinine 205 umol/l, uric acid 0.61 mmol/l and lactate dehydroge- nase (LDH) 1 300 U/l. He was placed on haemodialysis for a week and recovered his renal function (urea 2.4 mmol/l and creatinine 35 umol/l). CT scan showed bilateral, assymetrical cortical and subcortical hypodensities in the cerebellar hemispheres, as well as in the posterior parietal regions. No associated enhancement was noted (Fig. 4). A repeat CT scan after 2 months demonstrated complete reso- lution. Discussion Although clinical hypertension occurs less frequently in children than in adults, it still has significant conse- quences. New data for normal BP ranges are available for children and adolescents, and depend on height CASE REPORT 21 SA JOURNAL OF RADIOLOGY • February 2005 Fig. 2. Post-contrast CT scan of the brain demon- strates bilateral parafalcine areas of low density in the posterior parietal and occipital white matter (straight arrows). There is focal enhancement at the periphery (curved arrow). Fig. 3. Axial post-contrast CT scan of the brain shows subtle parasagittal white matter low densi- ties in the high parietal regions (arrows). Fig. 4. Axial post-contrast CT scan of the brain demonstrates bilateral assymetrical hypodensities in the cortical and subcortical regions of the cere- bellar hemispheres with no associated enhance- ment (arrows). Radiology 2/24/05 4:50 PM Page 21 22 SA JOURNAL OF RADIOLOGY • February 2005 percentiles, age and gender.3 Each of the children in our cases was plotted on these charts and had elevated BPs on presentation. Clinically, they all had features of hypertensive encephalopathy, presenting with seizures. Typically in HE, cerebral imaging indicates oedema in the posterior temporal, parietal and occipital regions, predominantly in the para- median subcortical white matter.4 The oedema appears hypodense on CT and may enhance post contrast. On T2-weighted magnetic resonance imaging (MRI), these areas show increased signal intensity and on dif- fusion-weighted imaging, there are no features of ischaemia or infarction.1,2 Abnormalities have also been report- ed in the parieto-occipital areas, frontal lobes, basal ganglia, brainstem and cerebellum, but occur less often.2 Further confirmation of the diag- nosis is obtained with resolution of the imaging abnormalities after nor- malisation of the blood pressure. If the BP is not normalised, irreversible cerebral ischaemia and infarction or haemorrhage may result. It is reason- able to assume that the precise range of cerebral blood flow autoregulation is lower in children than adults. Children may develop HE at a lower absolute BP than adults. Although several paediatric cases of HE have been reported, a limited num- ber have been documented or illustrat- ed with CT or MRI findings.1,5-10 The 4 cases reviewed showed characteristic imaging abnormalities of HE on CT. At follow-up all 4 patients were found to have neither neurological symp- toms nor any clinical sequelae. However, confirmation was not obtained with a repeat radiological investigation in each case. In conclusion, HE is often under- diagnosed in children and early recog- nition of characteristic radiographical findings on CT or MRI allows for the implementation of appropriate anti- hypertensive therapy with the poten- tial for complete neurological recov- ery. References 1. Cooney MJ, Bradley WG, Symko SC, et al. Hypertensive encephalopathy: Complications in children treated for myeloproliferative disor- ders — Report of three cases. Radiology 2000; 214: 711-716. 2. Schwartz RB, Mulkern RV, Gudbjartsson H, Jolesz F. Diffusion-weighted MR imaging in hypertensive encephalopathy: Clues to patho- genesis. Am J Neuroradiol 1998; 19: 859-862. 3. National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents. Update on the 1987 Task Force Report on High Blood Pressure in Children and Adolescents: A Working Group Report from the National High Blood Pressure Education Program. Pediatrics 1996; 98: 649-658. 4. Schwartz RB, Jones KM, Kalina P, et al. Hypertensive encephalopathy: Findings on CT, MR imaging, and SPECT imaging in 14 cases. Am J Roentgenol 1992; 159: 379 -383. 5. Jones BV, Egelhoff JC, Patterson RJ. Hypertensive encephalopathy in children. Am J Neuroradiol 1997; 18: 101-106. 6. Pavlakis SG, Frank Y, Chusid R. Hypertensive encephalopathy, reversible occipitoparietal encephalopathy, or reversible posterior leuko- encephalopathy: Three names for an old syn- drome. J Child Neurol 1999; 14: 277-281. 7. Kandt RS, Caoili AQ, Lorentz WB, Elster AD. Hypertensive encephalopathy in children: Neuroimaging and treatment. J Child Neurol 1995; 10: 236-239. 8. Assadi FK, Lansky LL, John EG, Helgason CM, Tan WS. Acute hypertensive encephalopathy in minimal change nephrotic syndrome. Child Nephrol Urol 1990; 10: 96-99. 9. Shanley DJ, Sisler CL. MR demonstration of reversible cerebral lesions in a child with hyper- tensive encephalopathy caused by Wilms' tumor. Am J Roentgenol 1992; 158: 1161-1162. 10. Weingarten K, Barbut D, Filippi C, Zim- merman RD. Acute hypertensive encephalo- pathy: Findings on spin-echo and gradient- echo MR imaging. Am J Roentgenol 1994; 162: 665-670. CASE REPORT Australia RADIOLOGISTS Attractive terms and conditions in sunny and secure Melbourne An opportunity to work in a private, patient focussed environment, employing state of the art equipment including Stereotaxis & Mammatome in Victoria. A complete spectrum of breast disease presents in this Unit, which operates in close association with the multi-disciplinary Breast Unit @ Mercy, affording a unique relationship with the breast surgeons. Our migration agent will assist with visa and registration applications Please forward your detailed C.V. via email: grace@austmigrate.com.au Fax: 61 3 98527889 • Tel: 61 3 98527095 Radiology 2/24/05 4:50 PM Page 22