Hypertensive Encephalopathy

Circadian and Diurnal Regulation of Cerebral Blood Flow

Circadian and diurnal variation in cerebral blood flow directly contributes to the diurnal variation in the risk of stroke, either through factors that trigger stroke or due to impaired compensatory mechanisms. Cerebral blood flow results from the integration of systemic hemodynamics, including heart rate, cardiac output, and blood pressure, with cerebrovascular regulatory mechanisms, including cerebrovascular reactivity, autoregulation, and neurovascular coupling. We review the evidence for the circadian and diurnal variation in each of these mechanisms and their integration, from the detailed evidence for mechanisms underlying the nocturnal nadir and morning surge in blood pressure to identifying limited available evidence for circadian and diurnal variation in cerebrovascular compensatory mechanisms. We, thus, identify key systemic hemodynamic factors related to the diurnal variation in the risk of stroke but particularly identify the need for further research focused on cerebrovascular regulatory mechanisms.

Unusual Presentation of Reversible Transient Vision Loss After Caesarean Section Under Subarachnoid Block: A Case Report

A transient vision loss is not commonly encountered during the postoperative period following a caesarean section. Although numerous causes have been suggested for transient vision loss, when loss of vision is associated with seizures and headaches, the differential diagnoses include hemolysis, elevated liver enzymes, low platelet syndrome, reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome (PRES), dural venous thrombosis, and central retinal arteriolar occlusion. We report a case of a 35-year-old patient who underwent an elective caesarean section under spinal anaesthesia and developed a headache followed by loss of vision and seizures during the postoperative period. An MRI scan of the brain on the same day revealed subtle hyperintensity in bilateral parieto-occipital lobes in the cortical and subcortical areas and bilateral cerebral hemispheres, which indicates PRES. Rapid and complete resolution of symptoms was observed with supportive treatment. Therefore, prompt suspicion and effective management of PRES are of paramount importance to prevent short- and long-term neurological deficits.

Efficacy of Magnesium Sulfate on Maternal Mortality in Eclampsia

Eclampsia is a common complication of preeclampsia patients and can be life-threatening for both the mother and the fetus. Hence, timely intervention and appropriate management of this detrimental condition are extremely crucial. Eclampsia is described as the occurrence of generalized convulsions in patients with preeclampsia. Magnesium sulfate (MgSO₄) is the drug of choice for treating and preventing eclampsia. This review aims to study and analyze the available literature on the pathogenesis of eclampsia, the pharmacology of MgSO₄, and its effectiveness in the management of eclampsia. Other proposed treatments and their comparative study with MgSO₄ are also discussed. Additionally, we examine the data regarding the impact of eclampsia, its public health burden, and the cost-effectiveness of MgSO₄. One of the major drawbacks associated with the use of MgSO₄ in low-income countries has been the cost of treatment and the lack of resources. We have analyzed the trials that have proposed alternate treatment regimens which could shape new guidelines to resolve these issues. For this review, we extensively studied abstract and full-text articles from multiple databases. This article discusses the pathophysiology of eclampsia, the pharmacology of MgSO₄, the issues surrounding eclampsia management, and how MgSO₄ benefits these patients.

Posterior reversible encephalopathy syndrome in the setting of trauma: A case report

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Posterior reversible encephalopathy syndrome (PRES) in the setting of trauma and acute care surgery.

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Posterior reversible encephalopathy syndrome (PRES) in trauma patients with a specific pattern of neuroimaging and clinical symptoms.

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T2 weighted diffusion hyperintensities were present on MRI of the brain in both cases.

Reports of posterior reversible encephalopathy syndrome (PRES) in the setting of trauma and acute care surgery are scarce. PRES presents rapidly with a variety of symptoms including headaches, visual disturbances, altered consciousness, and seizures. It is associated with acute hypertensive episodes. PRES is diagnosed with a specific neuroimaging pattern and a constellation of clinical symptoms. This case report presents two traumatically injured patients with one confirmed case of PRES and the other with a potential case of PRES. The diagnosis was made through neuroimaging showing patchy T2 and diffusion hyperintensity in the periphery of both occipital lobes and adjacent cerebellar hemispheres on MRI in one case. The other case highlights extensive stable white matter disease without evidence of acute infarct on MRI, as well as diminished attenuation within the cerebral white matter in the occipital lobes on CT scan. There was resolution of visual symptoms in one patient while the other patient's neurologic status did not allow for evaluation of symptom resolution. This report aims to emphasize the possibility of PRES in trauma patients with a specific pattern of neuroimaging and clinical symptoms, and to increase the index of suspicion in acute care providers.

The effect of presymptomatic hypertension in posterior reversible encephalopathy syndrome

OBJECTIVE

The effect of blood pressure (BP) on the lesion distribution of posterior reversible encephalopathy syndrome (PRES) is controversial. The aim of this study was to identify the relationship between brain lesion distribution patterns and BP.

METHODS

Sixty-five patients with PRES were selected from the database. Data regarding brain MRI findings, clinical symptoms, medical conditions, and BP at the presymptomatic period (24 hr before the symptom onset) and at the symptom onset were collected. The brain lesion distribution degree was numerically calculated (lesion scoring point [LSP]) and compared with BP and medical conditions.

RESULTS

Mean onset-MAP was higher than mean pre-MAP. Pre-MAP correlated with onset-MAP. The LSP was significantly correlated with pre-MAP (p = 0.009, correlation coefficient [cc] = 0.323), whereas no significant correlation was found between LSP and onset-MAP (p = 0.159, cc = 0.177). Similarly, when patients were grouped by mean MAP values, LSP was significantly higher in the patients with high MAP at the presymptomatic period (p = 0.004), whereas no difference was found in the LSP value between patients with low MAP and high MAP at the symptom onset (p = 0.272).

CONCLUSION

The patient with PRES who has relatively higher BP in the presymptomatic period would be more likely to have wider lesion distribution than the patient with lower BP. BP elevation during presymptomatic period may be a heralding sign of impending PRES and a factor affecting the severity of PRES although BP was not investigated at earlier time points.

Quantitative Magnetic Resonance Diffusion-Weighted Imaging Evaluation of the Supratentorial Brain Regions in Patients Diagnosed with Brainstem Variant of Posterior Reversible Encephalopathy Syndrome: A Preliminary Study

BACKGROUND AND PURPOSE

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity with several causes, characterized by rapid onset of symptoms and typical neuroimaging features, which usually resolve if promptly recognized and treated. Brainstem variant of PRES presents with vasogenic edema in brainstem regions on magnetic resonance (MR) images and there is sparing of the supratentorial regions. Because PRES is usually caused by a hypertensive crisis, which would likely have a systemic effect and global manifestations on the brain tissue, we thus proposed that some microscopic abnormalities of the supratentorial regions could be detected with diffusion-weighted imaging (DWI) using apparent diffusion coefficient (ADC) analysis in brainstem variant of PRES and hypothesized that "normal-looking" supratentorial regions will increase water diffusion.

METHODS

We retrospectively identified patients with PRES who underwent brain magnetic resonance imaging studies. We identified 11 brainstem variants of PRES patients, who formed the study cohort, and 11 typical PRES patients and 20 normal control subjects as the comparison cohorts for this study. Nineteen regions of interest were drawn and systematically placed. The mean ADC values were measured and compared among these 3 groups.

RESULTS

ADC values of the typical PRES group were consistently elevated compared with those in normal control subjects. ADC values of the brainstem variant group were consistently elevated compared with those in normal control subjects. ADC values of the typical PRES group and brainstem variant group did not differ significantly, except for the pons area.

CONCLUSIONS

Quantitative MR DWI may aid in the evaluation of supratentorial microscopic abnormalities in brainstem variant of PRES patients.

Isolated brainstem involvement in a patient with hypertensive encephalopathy

Hypertensive encephalopathy typically presents with headache, confusion, and bilateral parietooccipital vasogenic edema. Brainstem edema in hypertensive encephalopathy usually occurs in association with typical supratentorial parieto-occipital changes and is usually asymptomatic. We report here a patient with hypertensive encephalopathy, with isolated brain stem involvement on magnetic resonance imaging (MRI). Rapid treatment of hypertension resulted in clinical and radiological improvement. Prompt recognition of the condition and aggressive treatment of hypertension in such patients is crucial to relieve edema and prevent life-threatening progression.

First-attack pediatric hypertensive crisis presenting to the pediatric emergency department

Background

Hypertensive crisis in children is a relatively rare condition presenting with elevated blood pressure (BP) and related symptoms, and it is potentially life-threatening. The aim of this study was to survey children with first attacks of hypertensive crisis arriving at the emergency department (ED), and to determine the related parameters that predicted the severity of hypertensive crisis in children by age group.

Methods

This was a retrospective study conducted from 2000 to 2007 in pediatric patients aged 18 years and younger with a diagnosis of hypertensive crisis at the ED. All patients were divided into four age groups (infants, preschool age, elementary school age, and adolescents), and two severity groups (hypertensive urgency and hypertensive emergency). BP levels, etiology, severity, and clinical manifestations were analyzed by age group and compared between the hypertensive emergency and hypertensive urgency groups.

Results

The mean systolic/diastolic BP in the hypertensive crisis patients was 161/102 mmHg. The major causes of hypertensive crisis were essential hypertension, renal disorders and endocrine/metabolic disorders. Half of all patients had a single underlying cause, and 8 had a combination of underlying causes. Headache was the most common symptom (54.5%), followed by dizziness (45.5%), nausea/vomiting (36.4%) and chest pain (29.1%). A family history of hypertension was a significant predictive factor for the older patients with hypertensive crisis. Clinical manifestations and severity showed a positive correlation with age. In contrast to diastolic BP, systolic BP showed a significant trend in the older children.

Conclusions

Primary clinicians should pay attention to the pediatric patients who present with elevated blood pressure and related clinical hypertensive symptoms, especially headache, nausea/vomiting, and altered consciousness which may indicate that appropriate and immediate antihypertensive medications are necessary to prevent further damage.

Reversible posterior leukoencephalopathy syndrome induced by vinorelbine

Reversible posterior leukoencephalopathy syndrome (RPLS) was first described in 1996; clinical symptoms include the presence of headache, visual disturbance,seizure, hypertension, and encephalopathy. The syndrome is most commonly encountered in association with chemotherapeutic agents or targeted therapy. Many chemotherapeutic agents, such as cisplatin,gemcitabine, methotrexate, were reported to be associated with RPLS. Vinorelbine is commonly used for the treatment of metastatic breast cancer, but vinorelbine-induced RPLS has not been reported. We reported a 34-year-old woman, diagnosed with invasive ductal carcinoma of the left breast, who experienced acute hypertension after vinorelbine intravenous infusion. Accompanied symptoms included headache,seizure, and conscious disturbance. Magnetic resonance imaging of the brain showed symmetric signal hyperintensity with the cortical and subcortical white matter of bilateral frontal, parietal, and occipital (predominant) lobes. Vinorelbine is a semisynthetic vinca alkaloid and prevents cell division by inhibiting tubulin polymerization.Brain metastasis or leptomeningeal carcinomatosis is an important issue for patients with breast cancer who present with headache, seizure, or altered consciousness.However, now RPLS may be a new consideration,especially with the presentation of acute hypertension. Unlike brain or meningeal metastasis, RPLS is usually benign, and most patients recover within 2 weeks. Our case highlights an association between vinorelbine and RPLS, and the drug has not been described as a predisposing factor of RPLS in past reports. In the era of cancer treatment with chemotherapy or targeted therapy,clinicians should be aware of this syndrome.

Posterior reversible encephalopathy syndrome during posterior fossa tumor resection in a child

Posterior reversible encephalopathy syndrome (PRES) has been described in the setting of malignant hypertension, renal disease, eclampsia, and immunosuppression. In addition, a single case of intraoperative (posterior fossa craniotomy) PRES has been reported; however, this case occurred in an adult. The authors present a clinically and radiographically documented case of intraoperative PRES complicating the resection of a posterior fossa tumor in a 6-year-old child. During tumor resection, untoward force was used to circumferentially dissect the tumor, and excessive manipulation of the brainstem led to severe hypertension for a 10-minute period. An immediate postoperative MR image was obtained to rule out residual tumor, but instead the image showed findings consistent with PRES. Moreover, the patient's postoperative clinical findings were consistent with PRES. Aggressive postoperative management of blood pressure and the institution of anticonvulsant therapy were undertaken. The patient made a good recovery; however, he required a temporary tracheostomy and tube feedings for prolonged lower cranial nerve dysfunction. Posterior reversible encephalopathy syndrome can occur as a result of severe hypertension during surgery, even among young children. With prompt treatment, the patient in the featured case experienced significant clinical and radiographic recovery.

Biological mechanisms of bevacizumab-associated adverse events

The perception that inhibition of cancer-associated angiogenesis would be an effective treatment strategy was based on the fundamental difference in cell cycle activity between neoplastic and normal endothelial cells. Selective targeting of tumor vessels could have additional benefits, such as circumventing development of acquired resistance to these types of agents, overcoming intrinsic tumor resistance, exhibiting broad anti-tumor activity and decreasing normal tissue toxicity. Successful translation of anti-angiogenic therapy into the clinical setting was achieved only 5 years ago with the approval of bevacizumab for metastatic colorectal cancer. Although the benefits demonstrated in clinical trials led to the approval of bevacizumab for treatment of colorectal, lung and breast cancers, and most recently glioblastoma, a number of serious soft-tissue and vascular toxicities have also been observed in patients receiving this anti-angiogenic agent. This review assesses the relationship between inhibition of VEGF and toxicity, and proposes the pathogenic mechanisms that lead to the adverse events.

Reversible brainstem hypertensive encephalopathy (RBHE): Clinicoradiologic dissociation

We report two cases of reversible brainstem hypertensive encephalopathy (RBHE) with unusual magnetic resonance (MR) findings. Patient 1, an 85-year-old man without a history of hypertension, developed acute severe hypertension and mild consciousness disturbance as the only symptoms. Patient 2, a 46-year-old man with an untreated hypertension, presented with extremely high blood pressure and general fatigue, vertigo, and mild dysarthria as the initial manifestations. In these patients, fluid-attenuated inversion recovery (FLAIR) and T2-weighted MR images revealed diffuse hyperintensities in the brainstem. Diffusion-weighted imaging (DWI) findings were normal, and apparent diffusion coefficient (ADC) values were increased in the brainstem. The supratentorial regions were largely spared, and mildly diffuse hyperintensities were noted in the white matter. There were no accompanying changes in the occipital lobe and cerebellum. The lesions completely resolved after stabilization of blood pressure. The normal DWI findings and high ADC values were consistent with vasogenic edema due to severe hypertension. The characteristics of RBHE are a very high blood pressure, mild clinical and neurologic symptoms, rapidly improved MR findings after initial treatment with the control of hypertension, and a marked clinicoradiologic dissociation.

Posterior reversible encephalopathy syndrome, part 1: fundamental imaging and clinical features

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state coupled with a unique CT or MR imaging appearance. Recognized in the setting of a number of complex conditions (preeclampsia/eclampsia, allogeneic bone marrow transplantation, organ transplantation, autoimmune disease and high dose chemotherapy) the imaging, clinical and laboratory features of this toxic state are becoming better elucidated. This review summarizes the basic and advanced imaging features of PRES, along with pertinent features of the clinical and laboratory presentation and available histopathology. Many common imaging/clinical/laboratory observations are present among these patients, despite the perception of widely different associated clinical conditions.

Posterior reversible encephalopathy syndrome, part 2: controversies surrounding pathophysiology of vasogenic edema

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state accompanied by a unique brain imaging pattern typically associated with a number of complex clinical conditions including: preeclampsia/eclampsia, allogeneic bone marrow transplantation, solid organ transplantation, autoimmune diseases and high dose cancer chemotherapy. The mechanism behind the developing vasogenic edema and CT or MR imaging appearance of PRES is not known. Two theories have historically been proposed: 1) Severe hypertension leads to failed auto-regulation, subsequent hyperperfusion, with endothelial injury/vasogenic edema and; 2) vasoconstriction and hypoperfusion leads to brain ischemia and subsequent vasogenic edema. The strengths/weaknesses of these hypotheses are reviewed in a translational fashion including supporting evidence and current available imaging/clinical data related to the conditions that develop PRES. While the hypertension/hyperperfusion theory has been most popular, the conditions associated with PRES have a similar immune challenge present and develop a similar state of T-cell/endothelial cell activation that may be the basis of leukocyte trafficking and systemic/cerebral vasoconstriction. These systemic features along with current vascular and perfusion imaging features in PRES appear to render strong support for the older theory of vasoconstriction coupled with hypoperfusion as the mechanism.

Diagnosis and management of labile blood pressure during acute cerebrovascular accidents and other hypertensive crises

It is estimated that with more than 40 million adults in the United States having uncontrolled hypertension, the risk of developing ischemic or hemorrhagic stroke in this population is significant. In addition, roughly 1 of 100 patients with essential hypertension will experience a hypertensive crisis during their lifetime, and these accelerated hypertensive emergencies and urgencies complicate more than 27% of all acute medical problems in patients presenting to emergency departments (EDs) in the United States. Arterial hypertension, a prominent feature of acute stroke syndrome, usually declines spontaneously within a few days, but its presence at hospital admission or its acute development during hospitalization is often associated with worsening stroke outcome and early mortality. Control of hypertension in patients with subarachnoid and intracerebral hemorrhage, both forms of acute stroke, is directed at maintaining adequate cerebral blood flow to minimize ischemic damage and control intracerebral pressure while reducing the risk of rebleeding and developing cerebrovasospasm. Inappropriate lowering of the blood pressure in acute stroke may increase neurologic damage. However, adequate blood flow around the central area of the acute ischemic stroke or penumbra may result in ischemic cells being salvaged. Clinicians must be mindful that accelerated hypertension is associated with other types of patients seen in the ED, such as perioperative patients and patients with traumatic head injuries.

Posterior leukoencephalopathy following cisplatin, bleomycin and vinblastine therapy for germ cell tumor of the ovary

A 31-year-old female developed multiple episodes of grand mal seizures after combination chemotherapy with cisplatin, vinblastine and bleomycin for germ cell ovarian cancer stage Ic. The clinicoradiologic features in this patient were consistent with posterior leukoencephalopathy, which is a rare complication of chemotherapy. Seizures were controlled by the anticonvulsive agent Dilantin (Pfizer, Khet Klongtoey, Bangkok) and she returned home without any permanent neurologic deficits. Follow-up magnetic resonance imaging 2 weeks later showed complete resolution of the abnormalities. This syndrome has been previously reported following cisplatin-based chemotherapy. Physicians should remain alert to the potential hazards of chemotherapy to the central nervous system. Risks and benefits should be seriously considered before starting treatment.

Hypertensive encephalopathy: complication in children treated for myeloproliferative disorders--report of three cases

We routinely perform echo-planar diffusion-weighted sequences in all brain magnetic resonance (MR) imaging studies. When three children undergoing chemotherapy for acute leukemia presented with seizures, conventional MR images demonstrated what appeared to be acute, posterior, parasagittal infarcts. However, diffusion-weighted images were normal. These MR imaging findings were consistent with those of hypertensive encephalopathy. Early recognition and treatment of minimal hypertension in these patients allows reversal of encephalopathy.

Occipital lobe seizures as the major clinical manifestation of reversible posterior leukoencephalopathy syndrome: magnetic resonance imaging findings

PURPOSE

Reversible posterior leukoencephalopathy syndrome (RPLS) is an increasingly recognized brain disorder most commonly associated with malignant hypertension, toxemia of pregnancy, or the use of immunosuppressive agents. When associated with acute hypertension, RPLS typically occurs concurrently with the fulminant clinical syndrome of hypertensive encephalopathy. We describe occipital lobe seizures, in the setting of only moderate elevations of blood pressure, as the major clinical manifestation of RPLS.

METHODS

Two patients from the Dent Neurologic Institute are presented with clinical and magnetic resonance imaging (MRI) correlation.

RESULTS

New onset secondarily generalized occipital seizures were noted, with MRI findings consistent with RPLS. Both of the patients had chronic renal failure and a moderate acute exacerbation of chronic hypertension. Other features of hypertensive encephalopathy were lacking, such as headache, nausea, papilledema, and an altered sensorium. Magnetic resonance imaging (MRI) showed edematous lesions primarily involving the posterior supratentorial white matter and corticomedullary junction, consistent with RPLS. With lowered blood pressure, the MRI lesions resolved and the patients became seizure-free without requiring chronic anticonvulsant therapy.

CONCLUSIONS

Occipital seizures may represent the only major neurologic manifestation of RPLS due to acute hypertension, especially in patients with renal failure. Other evidence of hypertensive encephalopathy, such as cerebral signs and symptoms, need not be present. Blood pressure elevations may be only moderate. Early recognition of this readily treatable cause of occipital seizures may obviate the need for extensive, invasive investigations. Despite the impressive lesions on MRI, prompt treatment of this disorder carries a favorable prognosis.

Brain MRI findings in two cases with eclampsia

Neurological complications in patients with eclampsia are varied and include headache, visual disturbances, focal neurological deficits, altered mental status and coma. Occasionally, a focal neurological deficit includes a variety of visual disturbances. The pathophysiology of CNS abnormalities in patients with eclampsia is uncertain. Our cases, combined with a review of the literature, demonstrate that there is no correlation among severity of hypertension, parity, and location of lesions at initial magnetic resonance (MR) imaging findings or between the severity of hypertension and neurological symptoms. Two typical patterns are seen on MR images of patients with eclampsia. Lesions in the region of the posterior cerebral circulation are most common and are frequently associated with visual disturbances. Although there are lesions in the deep white matter or basal ganglia, a focal neurological deficit or alterations in mental status may not develop. This demonstrates the sensitivity of MR imaging in the detection of abnormalities in patients with eclampsia, even those without neurological deficits.

Brain edema after carotid surgery

The postoperative hyperperfusion syndrome describes an abrupt increase in blood flow with loss of autoregulation in surgically reperfused brain. Reports described a spectrum of findings, including severe headache, transient ischemia, seizures, and intracerebral hemorrhage. Hypertension is common after carotid artery surgery and often plays a role in the pathophysiology. We now report five patients with severe white matter edema after carotid surgery, a finding not previously included in the hyperperfusion syndrome. Five to 8 days after carotid surgery and after hospital discharge, each patient developed hypertension, headache, hemiparesis, seizures, and aphasia or neglect due to severe white matter edema ipsilateral to the carotid surgery. One patient had a small hemorrhage within the edematous area. Hypertension was severe in four patients and moderate in one. The carotid artery was patent by ultrasound or angiography in each patient after surgery. Transcranial Doppler showed increased velocities ipsilateral to surgery in two patients and bilaterally in one. Computed tomographic abnormalities and neurologic signs resolved within 3 weeks in four of the five patients treated with antihypertensives and anticonvulsants. The fifth patient died from herniation secondary to massive edema. Brain edema with focal neurologic signs should be included as a serious but potentially reversible component of the postoperative hyperperfusion syndrome.

The role of neuroeffector mechanisms in cerebral hyperperfusion syndromes

Cerebral hyperperfusion, a state in which blood flow exceeds the metabolic needs of brain, may complicate a number of neurological and neurosurgical conditions. It may account for the propensity with which hemorrhage, cerebral edema, or seizures follow embolic stroke, carotid endarterectomy, or the excision of large arteriovenous malformations, and for some of the morbidity that accompanies acute severe head injury, prolonged seizures, and acute severe hypertension. Hyperperfusion syndromes have in common acute increases in blood pressure, vasodilatation, breakdown of the blood-brain barrier, and the development of cerebral edema. These common features suggest the possibility that they share the same pathogenic mechanisms. It was believed until recently that reactive hyperemia was caused primarily by the generation of vasoactive metabolites, which induced vasodilatation through relaxation of vascular smooth muscle. However, the authors have recently established that the release of vasoactive neuropeptides from perivascular sensory nerves via axon reflex-like mechanisms has a significant bearing upon a number of hyperperfusion syndromes. In this article, the authors summarize their data and discuss possible therapeutic implications for blockade of these nerves or their constituent neuropeptides.

Repeated cranial computed tomographic and magnetic resonance imaging scans in two cases of eclampsia

In two cases of eclampsia with consumptive thrombocytopenia, the maximum increase in blood pressure and the lowest platelet count coincided with the maximum degree of neurologic and neuroradiologic abnormality. Computed tomograms showed decreased attenuation, and T2-weighted magnetic resonance images showed increased signal intensity focally in the cerebral cortex and the deep gray and white matter. Blood pressure, platelet count, clinical status, and roentgenograms normalized completely in both cases. Severe arterial hypertension and disseminated transitory microvascular occlusions presumably caused multiple small foci of brain edema that resolved without remaining detectable ischemic brain damage.

Hypertensive crisis

Although rare, hypertensive crises may rapidly lead to irreversible organ damage or death. Their prompt recognition, based primarily on physical signs and symptoms, is essential. Appropriately aggressive therapy, and evaluation of precipitating and exacerbating conditions, will often result in a satisfactory outcome.