Intracranial Hypotension and Intracranial Hypertension

Authors: Esther L. Yuh a  and William P. Dillon

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.

Headache caused by raised intracranial pressure and intracranial hypotension

Author: N M Ramadan.

Extremes of intracranial pressure commonly cause headache. Benign intracranial hypertension is a rare syndrome of increased intracranial pressure manifesting as headache, intracranial noises, transient visual obscuration, and palsy of the sixth cranial nerve. Endocrine disorders such as obesity and hypoparathyroidism, hypervitaminosis A, tetracycline use and thyroid replacement are probable causes of benign intracranial hypertension. In the majority of cases, however, it is idiopathic. Benign intracranial hypertension is though to be caused by cerebral edema, high cerebrospinal fluid outflow resistance and high cerebral venous pressure, or a combination of the three. The management of benign intracranial hypertension includes, symptomatic headache relief, removal of offending risk factor(s), and medical or surgical reduction of intracranial pressure. Spontaneous intracranial hypotension is more rare than benign intracranial hypertension. Postural headache (worse in the upright position) is the hallmark of spontaneous intracranial hypotension. Typically, the cerebrospinal fluid pressure is less than 60 mm H2O. Diminished cerebrospinal fluid production, hyperabsorption, and leak are postulated mechanisms of spontaneous intracranial hypotension. Empirical treatment includes bed rest, administration of caffeine, corticosteroids or mineralocorticoids, epidural blood patch, and epidural saline infusion.

Increased intracranial pressure in a case of pediatric multiple sclerosis

Authors: Brice J Williams, Holly J Skinner, Bernard L Maria.

A 15-year-old girl presented to our emergency department with dizziness, anorexia, nausea, and malaise. Clinical examination and magnetic resonance imaging studies showed characteristic features of multiple sclerosis. Surprisingly, a diagnostic lumbar puncture showed significant intracranial hypertension in addition to numerous oligoclonal bands, elevated immunoglobulin G index and immunoglobulin G/albumin ratio in the cerebrospinal fluid. It is proposed that a large burden of active demyelinating disease may cause increased intracranial pressure, thus providing an additional sound rationale for prompt therapeutic administration of intravenous high-dose steroids.

Behavioral disorders in children with idiopathic intracranial hypertension

Authors: Reut Parness-Yossifon, Dov Margalit, Ayala Pollack, Hana Leiba.

The purpose of this research was to evaluate the association between idiopathic intracranial hypertension and behavior, attention, and learning abilities in children. Parents of school-age children with idiopathic intracranial hypertension were asked to fill out a questionnaire and to rank the child's behavioral patterns before and after the diagnosis and treatment of the disease. The questionnaire was based on Conners' test. Ten children were included in the study. Mean age at diagnosis was 11.5 years. Mean follow-up time was 25 months. Six patients (60%) met the definition of attention- and concentration-deficit disorders before diagnosis of idiopathic intracranial hypertension; 1 patient was treated with methylphenidate (Ritalin) before referral to eye examination. After the diagnosis was made and treatment was established, 5 patients (83%) reported an improvement in their attention and behavior. Of these 6 patients, 2 (33%) reported marked improvement. We conclude that attention- and concentration-deficit disorder might be an early sign for pediatric idiopathic intracranial hypertension. Diagnosis and treatment of idiopathic intracranial hypertension in these children may improve the child's behavior, attention, and achievements in school, without the need to resort to other modes of therapy.

Presentation, investigation and management of idiopathic intracranial hypertension in children

Authors: Lalania K. Schexnayder a and Kevin Chapman a

Idiopathic intracranial hypertension is characterised by increased intracranial pressure in the presence of normal cerebrospinal fluid, normal neuroimaging and no localising signs on neurologic exam except cranial nerve VI palsy. It is common in adults, particularly obese young women, but also occurs in children and adolescents. We discuss the clinical presentation of idiopathic intracranial hypertension in the pediatric population and how the presenting signs and symptoms may be different from those seen in adult patients. We discuss the differential diagnosis for idiopathic intracranial hypertension, as well as underlying conditions that may be associated with it. As in adults, therapy most often involves the use of carbonic anhydrase inhibitors, diuretics, and steroids. Children with vision loss due to idiopathic intracranial hypertension who not respond to aggressive medical therapy should be promptly referred for surgical intervention, including optic nerve fenestration and cerebrospinal (CSF) shunting procedures such as ventriculoperitoneal or lumboperitoneal shunting.

Raised intracranial pressure in acute viral encephalitis

Authors: Gyanendra Kumar a, Jayantee Kalita b and Usha Kant Misra b

There is paucity of data evaluating intracranial pressure (ICP) rise and its management in acute viral encephalitis (AVE). Noteworthy is the current prevalence of unselective and broad utilization of ICP lowering therapies in clinical practice. Trends in current management of ICP in AVE emanate from data extrapolated from results of studies done on cerebral malaria, bacterial meningitis, stroke, and brain trauma patients. In this article we review (1) clinical correlates of raised ICP, (2) pathology, (3) imaging data, (4) monitoring, and, (5) treatment, of raised ICP in AVE. ICP monitoring is a useful adjunct to management of raised ICP in adults, becoming especially important in Herpes encephalitis and encephalitis with status epilepticus. In children it substantially influences clinical management and continuous monitoring of mean blood pressure (MBP) and ICP can aid in early diagnosis and treatment when cerebral perfusion pressure (CPP) falls below critical levels. Current evidence suggests that the pathomechanisms that contribute to the development of raised intracranial pressure vary in viral encephalitides of different etiology, and different forms of cerebral edema result at different times in the course of the illness, thus creating a need for studies to investigate the usefulness of various edema-specific ICP lowering modalities in AVE.

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