Monday, April 8, 2024

Posterior reversible encephalopathy syndrome in a child with renovascular hypertension

What suddenly caused a state of altered consciousness in a 6-year-old child who had been having seizures and daily headaches for the past month? That's what physicians in India had to determine, as Vimal Kumar Paliwal, DM, of Sanjay Gandhi Postgraduate Institute of Medical Sciences in Lucknow, and co-authors recounted in JAMA Neurology.

At presentation, the child's caregivers explained that the child had started having a mild to moderate occipital headache every day starting about 1 month ago, which they described as pulsating in nature. Sometimes, when the headache became severe, it was accompanied by vomiting and sensitivity to light and sound.

The previous day, the boy had passed out for several hours after having four to five episodes of generalized tonic-clonic seizures. He had come to on his own over the course of the day, they said.

He had not had a fever, lost weight, or had limb weakness, changes in vision, or any signs of stroke. His birth and childhood development had been unremarkable.

On physical examination, clinicians noted that the patient's heart rate was regular at 80 beats per minute, and all peripheral pulses were palpable without any radio-femoral delay. Blood pressure was 170/110 mm Hg, with "less than 10 mm Hg difference of systolic and diastolic blood pressure in other limbs," the authors noted.

Clinicians performed an abdominal examination and noted abdominal bruit. An abdominal ultrasound showed that the patient had a small asymmetrical right kidney and an enlarged left kidney; likewise, renal Doppler findings suggested stenosis of the right renal artery.

Fundus examination revealed papilledema with changes suggestive of hypertensive retinopathy. The child was not oriented to place and time, they said.

Examination of the patient's cranial nerves, and motor, sensory, and autonomic system revealed nothing unusual. Meningeal signs were absent, and there was no evidence of neurocutaneous markers. An MRI of the patient's brain showed bilateral white matter hyperintensity that was especially pronounced on both sides of the parieto-occipital region.

Findings of a CT angiogram of the patient's abdomen included short segment and short circumferential thickening of the descending aorta with right renal artery narrowing, the team noted. A follow-up MRI of the brain showed that the white matter hyperintensities were significantly reduced.

Clinicians considered several conditions that might have caused the patient's symptoms, including atherosclerosis, Moyamoya disease with renovascular hypertension, and fibromuscular dysplasia, before settling on Takayasu arteritis.

They explained why they ruled out the differential diagnoses. Renovascular hypertension is often caused by atherosclerosis in adults, and by fibromuscular dysplasia in children, Paliwal and colleagues noted. This patient did not have any evidence of the characteristic atheroma at the bifurcation of the renal artery and abdominal aorta. The team ruled out possible atherosclerosis based on CT findings of atheroma at origin of the renal artery, and narrowing of the whole length of the right renal artery.

They determined that the patient did not have fibromuscular dysplasia, which "is a nonatherosclerotic, noninflammatory vascular disease that mainly affects coronary and renal arteries." Fibromuscular dysplasia generally involves the middle and distal two-thirds of the main renal artery, spares ostia, and rarely involves the aorta, they added; thus, the diagnosis was ruled out in this case.

Regarding the third diagnosis considered, "Moyamoya disease is a nonatherosclerotic cerebrovascular disease that presents with supraclinoid stenosis of internal carotid arteries and produces extensive collaterals," Paliwal and co-authors wrote.

The disease tends to present quite differently in children than it does in adults, they noted. For instance, pediatric presentation of Moyamoya disease tends to involve cerebral ischemic events, as opposed to cerebral ischemia or intracerebral hemorrhage generally seen in adults. Children are also much less likely to present with renovascular hypertension, which has been observed in 5% to 8% of affected children versus 28.8% of adults, the authors said. In addition, Moyamoya disease affects only a third of the main renal artery, the ostia is spared, and the aorta only rarely involved.

In this patient, stenosis of the entire renal artery from its origin including the ostia, and thickening of the aorta wall, all suggested Takayasu arteritis as the correct diagnosis. This chronic granulomatous vasculitis "affects the tunica media of medium/large arteries and produces narrowing, stenosis, and aneurysmal dilatation of aorta and its branches," they wrote.

Takayasu arteritis "presents with an early systemic phase characterized by malaise, myalgia, weight loss, and fever, and the late vaso-occlusive phase that manifests with stroke, syncope, limb claudication, pulselessness, hypertension, and vascular bruit," Paliwal and team wrote.

Early systemic signs and symptoms tend to be missed in children, who are significantly more likely to have headache, cardiomyopathy, kidney failure, and elevated systolic blood pressure compared with adults.

The condition is also associated with elevations in biomarkers of inflammation, including C-reactive protein, erythrocyte sedimentation rate, fibrinogen, β-2-microglobulin, haptoglobin, and orosomucoid, although these are not diagnostic of Takayasu arteritis.

Evidence of hypertension, pulse deficit, or claudication; discrepancies in blood pressure in limbs and bruits; and abnormal findings on angiograms all support a Takayasu arteritis diagnosis.

Updated diagnostic criteria require "angiographic abnormality ... of the aorta or its main branches, coronaries, or pulmonary arteries not because of fibromuscular dysplasia or similar causes," the authors noted.

Similar conditions to rule out in diagnosing Takayasu arteritis include giant-cell arteritis with large vessel involvement in adults; medium-sized vasculitis with cross-symptomatology, such as Kawasaki disease with coronary involvement; polyarteritis nodosa that involves the mesentery and kidney; and lupus.

Takayasu arteritis can be managed by reduction of high blood pressure, treatment with oral corticosteroids, use of immunosuppressant medications to control disease activity, aspirin, and specific treatment for vaso-occlusive disease.

In this case, treatment with amlodipine and an ACE inhibitor relieved the child's headache and controlled his hypertension. The team prescribed oral corticosteroids but did not recommend kidney angioplasty, since a diethylenetriamine pentaacetic acid scan had revealed evidence of impaired right kidney function.

Posterior reversible encephalopathy syndrome rarely affects children, Paliwal and colleagues noted. It is most likely to occur in patients with acute lymphocytic leukemia who are starting chemotherapy, or less often, during hematopoietic stem cell transplantation.

However, "Takayasu arteritis frequently presents with hypertension in children, which makes it an ideal setting for the development of posterior reversible encephalopathy syndrome," they concluded.

Chavan A, Paliwal VK, Singh V. Posterior Reversible Encephalopathy Syndrome in a Child With Renovascular Hypertension. JAMA Neurol. 2023;80(7):760–761. doi:10.1001/jamaneurol.2023.1501

A 6-year child presented with headache for 1 month and seizures followed by altered consciousness for 1 day. He had new-onset daily occipital headache for 1 month of mild to moderate severity and pulsating character. Occasionally, the headache became severe accompanied by vomiting, photophobia, and phonophobia. The child had 4 to 5 episodes of generalized tonic-clonic seizures 1 day prior to admission. He remained unconscious for several hours and spontaneously regained consciousness over 24 hours. There was no history of fever, weight loss, limb weakness, vision impairment, or any strokelike illness. His birth and developmental history were unremarkable

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