Normal pressure hydrocephalus

Serial Tap Test of patients with idiopathic normal pressure hydrocephalus: impact on cognitive function and its meaning

Background

Idiopathic normal pressure hydrocephalus (INPH) is characterized by gait disturbance, urinary incontinence and cognitive decline. Symptoms are potentially reversible and treatment is based on cerebrospinal fluid shunting. The tap test (TT) is used to identify patients that will benefit from surgery. This procedure consists of the withdrawal of 20 to 50 mL of cerebrospinal fluid (CSF) through a lumbar puncture (LP) after which the symptoms of the triad are tested. Improvement in the quality and speed of gait are already recognized but cognitive improvement depends on several factors such as tests used, the time elapsed after LP for re-testing, and the number of punctures. Serial punctures may trigger similar conditions as external lumbar drainage (ELD) to the organism.

Objective

This study aimed to identify how serial punctures affect cognition to increase the sensitivity of the test and consequently the accuracy of surgical indication.

Methods

Sixty-one patients with INPH underwent baseline memory and executive tests repeatedly following the 2-Step Tap Test protocol (2-STT – two procedures of 30 mL lumbar CSF drainage separated by a 24-h interval). The baseline scores of INPH patients were compared with those of 55 healthy controls, and with intragroup post-puncture scores of the 2-STT.

Results

The group with INPH had lower performance than the control group in all cognitive tests (RAVLT, Stroop, CFT, FAR-COWA, FAB, MMSE, orientation, mental control), except for the forward digit span test (p = 0.707). After conducting LP procedures, the Stroop test (words, colors and errors), RAVLT (stage A1, A6 and B1), and CFT (immediate and delayed R) scores were equal to those of the control group (p > 0.05). The INPH group presented significant improvement after the first puncture in MMSE (p = 0.031) and in the Stroop Test (points) (p < 0.001). After the second puncture, subjects improved in orientation, MMSE, RAVLT (B1), Stroop (points, words, errors) and CFT (IR).

Conclusion

Progressive cognitive improvement occurred over the 2-STT and changes were more significant after the second LP in all cognitive domains except for RAVLT (A7). Encephalic alert system ‘arousal’ seems to participate in early improvements observed during 2-STT. The second LP increased the sensitivity of the drainage test to detect changes in cognitive variables, and consequently improved the quality of the method.

Reversible dementia in idiopathic normal pressure hydrocephalus. A case report

OBJECTIVE

To present a woman with idiopathic normal pressure hydrocephalus (NPH) showing marked improvement in mental function after shunt operation.

DESIGN

Case report.

SETTING

Primary health care.

PATIENT

The clinical symptoms of gait disturbance, occasional urine incontinence and severely impaired mental function typical of NPH were all present. Although dementia predominated in the clinical picture, the diagnosis was confirmed by computer tomography (CT) and cerebrospinal fluid infusion test and cisternography.

MAIN OUTCOME MEASURES

A marked improvement of mental functions was observed after shunt operation.

RESULTS

Mini Mental State Examination score before shunt operation was 9 compared with 20 one year after operation. Also ventricle size was reduced as evaluated by CT scan.

CONCLUSION

This reported case contrasts previous reports concluding that shunt responsive patients have only slight mental disturbances without significant improvement of mental status after shunt operation.

Normal pressure hydrocephalus and deep white matter stroke: a case report

The symptoms of urinary incontinence, ataxia, and mental confusion are an integral part of the clinical presentation of normal pressure hydrocephalus (NPH). They are also common presentations in the rehabilitation setting of patients who have had a cerebral vascular accident. The concurrence of these entities challenges the physiatrist to carefully diagnose and properly manage the patient to maximize the rehabilitation outcome. In the older population the clinical picture may be clouded by several overlapping conditions such as dementia, deconditioning, and age-related decline in bladder control. A case is presented in which the diagnosis of NPH was made after the patient showed a lack of progress in ambulation despite dramatic improvement in strength of the lower extremities.

Do surgical brain lesions present as isolated dementia? A population-based study

OBJECTIVE

To determine the incidence of clinically important subdural hematoma (SDH), hydrocephalus not associated with a recent intracranial bleed, and intracranial tumor that is not obviously metastatic, and to test the sensitivity of a promising decision rule for computerized tomography (CT) in dementia.

DESIGN

Population-based, retrospective, sequential case series.

SETTING

Staff model health maintenance organization (HMO).

PATIENTS

Patients aged 65 years and older with one of the three lesions, diagnosed over a 4.5-year period, identified mainly through computerized databases of hospital discharge diagnoses and a registry of malignant tumors.

MEASUREMENTS

Clinical data were based on chart review. The decision rule, based on one that had been previously proposed and tested, stated that CT would be required if any one of 11 clinical criteria were met by a patient with cognitive impairment. Rule sensitivity was evaluated using clinical information recorded before CT.

MAIN RESULTS

One hundred forty-five clinically important lesions were identified among 137,100 person-years at risk. Average annual incidence per 100,000 was 46.7 (95% CI 36.0, 59.6) for SDH, 5.8 (95% CI 2.5, 11.5) for hydrocephalus not associated with a recent intracranial bleed, and 53.2 (95% CI 41.7, 66.9) for intracranial tumors that were not obviously metastatic. Using the 65 to 74- year age strata as a reference, the relative risk for SDH was 4.8 (95% CI 2.7, 8.5) in 75 to 84-year-olds and 13.1 (95% CI 7.7, 22.5) in the 85 and older strata. Among 59 patients who presented with cognitive impairment, without altered sensorium or physical evidence of trauma, decision rule sensitivity was 93.2% (95% CI 83.5%, 98.1%). Sensitivity was 90.7% (95% CI 77.9%, 97.4%) in the subgroup that presented to an ambulatory care clinic rather than to an emergency department.

CONCLUSIONS

These three lesions, which are the most common surgical lesions that may present as dementia, are rare. Most cases have presentations that easily distinguish them from typical Alzheimer's disease. This case series indicates that it may be feasible to develop a decision rule for the selective use of CT in dementia. Disease spectrum will influence measures of decision rule performance such as sensitivity and specificity.

Probabilistic diagnosis of normal pressure hydrocephalus and other treatable cerebral lesions in dementia

Clinical profiles of dementia patients, differing with respect to age, presence of gait abnormalities and urinary incontinence are discussed. Epidemiological data, subjective probabilities and clinical reasoning are used to predict a treatable cerebral lesion, i.e., an intracranial space occupying lesion or normal pressure hydrocephalus (NPH). Our calculations help in distinguishing clinically between demented patients who are, and who are not likely to benefit from computed tomography (CT) investigation for treatable lesions and, eventually, from cerebrospinal fluid shunting for NPH. Utility calculations show that shunting can be recommended only for a patient with the full triad of symptoms of NPH, and CT evidence of NPH, when no other prognostic information is available. Future clinical research should address the long-term prognosis of (treated) NPH patients, and the mortality of shunting, because these two factors are critical to the shunting decision.

NORMAL PRESSURE HYDROCEPHALUS A POTENTIALLY reversible FORM OF DEMENTIA

1. Normal pressure hydrocephalus (NPH) is a rare but potentially treatable form of dementia. Shunting will improve functioning in 40% to 50% of patients. 2. The classic symptoms of NPH are dementia characterized by mild memory impairment and apathy, ataxic gait, and urinary hesitancy or incontinence. 3. The patient with NPH may present with psychiatric symptoms of depression, paranoia, visual hallucinations, irrational hostility, and aggression or mania. 4. Patients with NPH are indifferent about activities of daily living and personal safety and require close supervision.

Alzheimer's disease

Alzheimer's disease is one of the most severe and most common chronic diseases of older persons. Because occurrence of the disease is strongly related to age, its public health impact is likely to continue to increase as the population ages. As with many other diseases, a diagnosis of Alzheimer's disease is made through a combination of clinical history, physical, and neurologic examination, and laboratory evaluation. Because the dominant feature of this disease is its effect on cognition, its diagnosis requires careful evaluation of cognitive function usually with formal neuropsychological performance testing. Clinical evaluation of persons for Alzheimer's disease has four objectives: (1) to determine as accurately as possible if the person has dementia; (2) if dementia is present, to determine whether its presentation and course are consistent with a diagnosis of Alzheimer's disease; (3) to assess evidence for any alternate diagnoses, especially if the presentation and course are atypical for Alzheimer's disease; and (4) to evaluate evidence of other, coexisting, diseases that may contribute to the dementia, with strong emphasis on conditions that might respond to treatment. There is no reliable antemortem diagnostic test for Alzheimer's disease; the main purpose of laboratory testing is to identify other conditions that might cause or exacerbate dementia. Pathologically, Alzheimer's disease is characterized by the presence of two lesions on microscopic examination of the brain: neuritic plaques and neurofibrillary tangles. Both lesions can be seen in the brains of older persons without dementia. However, they are found in greater numbers in the neocortex and hippocampus with Alzheimer's disease. Caring for patients with Alzheimer's disease is demanding and requires compassion and skills that go beyond the choices among sophisticated and effective therapies that characterize much of modern medical practice. The current lack of effective pharmacotherapy for cognitive dysfunction in Alzheimer's disease should not obscure that there are many areas in which intervention can improve quality of life for both the patient and the caregiver. Achieving success in these areas typically requires that the physician work effectively with providers of many other medical and nonmedical services. Community resources, advocacy, behavior management, and experimental therapies and procedures, should be discussed with the family of each patient. In addition, persons with mild disease should be promptly informed of their diagnosis in order to obtain their wishes regarding life prolonging measures and extended care options.

Potentially reversible dementia: a review

Potentially reversible dementia is reviewed with reference to diagnosis, causes and outcome. Many disorders which cause cognitive impairment, such as drug toxicity and depression, fail to meet diagnostic criteria for dementia. These tend to have the best prognosis. Studies of the neuropsychiatric syndromes associated with disorders causing potentially reversible dementias suggest that dementia is an infrequent outcome and when it does occur, few cases recover. Factors predictive of improvement are short duration of symptoms and mild degree of cognitive impairment, usually subcortical in type. It is suggested that potentially reversible cognitive impairment would be a more accurate term as many cases are due to delirium and depression. While cases of well established dementia do not require extensive investigation, all cases should have a thorough clinical assessment as in many instances dual pathology exists and all require psychosocial management.

Reappraisal of the intracranial pressure and cerebrospinal fluid dynamics in patients with the so-called "normal pressure hydrocephalus" syndrome

Fifty-four shunt-responsive patients were selected from a prospective protocol directed to study patients with suspected normal pressure hydrocephalus (NPH). Patients with gait disturbances, dementia, non-responsive L-Dopa Parkinsonism, urinary or faecal incontinence and an Evans ratio greater or equal to 0.30 on the CT scan were included in the study. As a part of their work-up all patients underwent intracranial pressure monitoring and hydrodynamic studies using Marmarou's bolus test. According to mean intracranial pressure (ICP) and the percentage of high amplitude B-waves, patients were subdivided in the following categories: 1) Active hydrocephalus (mean ICP above 15 mmHg), which is in fact no tone normal pressure hydrocephalus; 2) Compensated unstable hydrocephalus, when mean ICP was below 15 mmHg and B-waves were present in more than 25% of the total recording time and 3) Compensated stable hydrocephalus when ICP was lower or equal to 15 mmHg and beta waves were present in less than 25% of the total recording time. The majority of the patients in this study (70%) presented continuous high or intermittently raised ICP (active or unstable compensated hydrocephalus group). Mean resistance to outflow of CSF (Rout) was 38.8 mm Hg/ml/min in active hydrocephalus and 23.5 mm Hg/ml/min in the compensated group (Students t-test, p less than 0.05). Higher resistance to outflow was found in patients with obliterated cortical sulci and obliterated Sylvian cisterns in the CT scan. No statistically significant correlation was found when plotting the percentage of beta waves against pressure volume index (PVI), compliance or Rout. An exponential correlation was found when plotting beta waves against the sum of conductance to outflow and compliance calculated by PVI method (r = 0.79). Patients with the so-called normal pressure hydrocephalus syndrome have different ICP and CSF dynamic profiles. Additional studies taking into consideration these differences are necessary before defining the sensitivity, specificity and predictive value of ICP monitoring and CSF studies in selecting appropriate candidates for shunting.

Delayed intracerebral hemorrhage after CSF shunt for communicating "normal-pressure" hydrocephalus. Case report

A patient with arterial hypertension and a history of cerebrovascular accidents presented with communicating normal-pressure hydrocephalus. Two weeks after ventriculo-peritoneal CSF shunt he had a fatal intracerebral hemorrhage. Delayed intracerebral hemorrhage is an extremely rare complication of ventricular CSF shunting, the possible mechanisms of which are briefly discussed.

Natural course of intracranial pressure and drainage of CSF after recovery from subarachnoid hemorrhage

Twenty-eight patients were followed 12 months or longer after recovery from subarachnoid hemorrhage (SAH). The examination included spinal infusion test (SIT), clinical evaluation and cerebral computertomography (CT). The results indicate that when resting pressure and drainage of CSF are within normal limits 3 months after the hemorrhage there is little if any risk of developing late communicating hydrocephalus. In this study, most patients with a moderate impaired CSF drainage and/or slightly increased resting pressure 3 months after SAH did not show any increase in the ventricular size or clinical deterioration during the follow-up period. None of the 28 patients developed late communicating hydrocephalus or the clinical picture of normal pressure hydrocephalus.