Intracranial hypotension and intracranial hypertension.
ABSTRACT Intracranial pressure (ICP) is the pressure within the intracranial space. Intracranial hypotension is a clinical syndrome in which low cerebrospinal fluid volume (CSF) results in orthostatic headache. Severe cases can result in nausea, vomiting, photophobia, and, rarely, decreased level of consciousness and coma. CSF opening pressure can be within the normal range in spontaneous intracranial hypotension. Imaging tests therefore play a key and decisive role in the diagnosis, as well as treatment, of intracranial hypotension. Intracranial hypertension occurs in a chronic form known as idiopathic intracranial hypertension, as well as in a large variety of neurologic and systemic disorders. Symptoms include headache, nausea and vomiting, blurred vision, and in severe cases, altered level of consciousness that can progress to coma and death. Direct measurements of CSF pressure through lumbar puncture (in idiopathic intracranial hypotension) or invasive ICP monitoring (in acute intracranial hypertension) are the key diagnostic tests. Imaging is used primarily to determine treatable causes of increased ICP, to assess for impending brain herniation, and to evaluate ventricular size.
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ABSTRACT: Most Plasmodium falciparum-infected children with cerebral malaria (CM) die from respiratory arrest, but the underlying pathology is unclear. Here we present a model in which the ultimate cause of death from CM is severe intracranial hypertension. Dynamic imaging of mice infected with P. berghei ANKA, an accepted model for experimental CM, revealed that leukocyte adhesion impairs the venous blood flow by reducing the functional lumen of postcapillary venules (PCV). The resulting increase in intracranial pressure (ICP) exacerbates cerebral edema formation, a hallmark of both murine and pediatric CM. We propose that two entirely different pathogenetic mechanisms—cytoadherence of P. falciparum-infected erythrocytes in pediatric CM and leukocyte arrest in murine CM—result in the same pathological outcome: a severe increase in ICP leading to brainstem herniation and death from respiratory arrest. The intracranial hypertension (IH) model unifies previous hypotheses, applies to human and experimental CM alike, eliminates the need to explain any selective recognition mechanism Plasmodium might use to target multiple sensitive sites in the brain, and explains how an intravascular parasite can cause so much neuronal dysfunction. PERSPECTIVE Most pediatric cerebral malaria (CM) patients die from respi-ratory arrest (Waller et al., 1991; Newton et al., 1997), but the underlying pathology is unclear. One suggestion has been that P. falciparum causes injury to a sensitive location such as the brainstem, where a small lesion could have fatal consequences (Haldar et al., 2007). Alternatively, death may require a combi-nation of predisposing factors, thus explaining the relatively low mortality rate (WHO, 2011). Here, we discuss insights gained from P. berghei ANKA (PbA) infected mice, an accepted model for experimental cerebral malaria (ECM), in the context of recent advances in the understanding of the pathogenesis of human cere-bral malaria (HCM). For the purpose of this Perspective, we focus on pediatric HCM, because African children with HCM tend to exhibit more BBB dysfunction, monocyte and platelet accumula-tion in the brain, and intracranial hypertension (IH) compared to adult HCM patients in Southeast Asia (Hawkes et al., 2013). Pediatric HCM therefore resembles more closely the murine ECM model in terms of clinical features, autopsy findings, and cerebral edema formation.Frontiers in Cellular and Infection Microbiology 11/2014; 4(Article 155):1`. · 2.62 Impact Factor
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ABSTRACT: Objective: Intracranial hypotension (ICH) can be a challenging diagnosis as CSF leak may be difficult to confirm, patients may have other causes for clinical symptoms, and imaging findings can be nonspecific, particularly in the setting of comorbidities. We investigate the use of brain diffusion measurements (ADC values) in the assessment of intracranial hypotension. Methods: 13 cases of ICH identified retrospectively based on imaging findings and clinical history were compared with 13 control subjects. Regional ADC values and Dav from brain slice ADC histograms were measured. Results: ADC values trended higher in all brain regions in ICH when compared with control subjects, with statistically significant differences in frontal white matter, midbrain and deep gray structures. Dav determined by a single-slice ADC histogram was significantly higher in ICH than in the control group (p=.008). In two cases followed longitudinally, Dav correlated with the patient's symptoms, and decreased towards normal value with blood patch. In one case, decreased Dav correlated with the formation of subdural collections. Conclusions: Cerebral edema as assessed by increased ADC is strongly correlated with ICH (10 of 13 cases). Histographic analysis of ADC values may offer increased accuracy of ADC measurement. ADC value assessment in the determination of ICH may be particularly useful in complex clinical cases, cases where treatment is followed over time, or cases where gadolinium is not used and meningeal enhancement cannot be assessed. Advances in knowledge: This article investigates the use of brain diffusion measurements in the assessment of intracranial hypotension in the clinical setting.The British journal of radiology. 06/2014;
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ABSTRACT: Increased incidence world-wide of cancer and increased survival has also resulted in physicians seeing more complications in patients with cancer. In many cases, complications are the first manifestations of the disease. They may be insidious and develop over a period of months, or acute and manifest within minutes to days. Imaging examinations play an essential role in evaluating cancer and its complications. Plain radiography and ultrasonography (US) are generally performed initially in an urgent situation due to their wide availability, low cost, and minimal or no radiation exposure. However, depending on a patient’s symptoms, evaluation with cross-sectional imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI) is often necessary. In this review article, we discuss some of the most important acute noninfectious oncological complications for which imaging methods play an essential role in diagnosis.Cancer Imaging 04/2014; 14(8):xx. · 1.29 Impact Factor