Lumbar puncture and the risk of herniation: when should we first perform CT?

Death following lumbar puncture (LP) is feared by physicians. Many opinions are found in literature on the question whether computed cranial tomography (CT) should be performed before LP, to prevent herniation. These opinions are mainly based on retrospective studies and pathophysiological reasoning. In this review the difficulties in the decision whether we should perform CT before LP are discussed. It is explained that the concept of "raised intracranial pressure" is confusing, and that the less ambiguous terms "brain shift" and "raised CSF pressure" should be used instead. Brain shift is a contraindication to LP, whether CSF pressure is raised or not, and whether papilloedema is present or not. Subsequently, recommendations are offered for indications to perform CT before LP, grouped according to the safety and clinical utility of LP.

Early diagnosis of dementia: which tests are indicated? What are their costs?

Dementia is reversible in a minority of patients, and these should be diagnosed but without subjecting the majority with irreversible disease to an excessive set of investigations. Should a battery of ancillary investigations be performed routinely in dementia? Or can these tests be carried out as clinically indicated? Three arguments are important to answer this question. (a) Reversible dementia is rare: about 1% of cases. (b) If the clinical criteria for diagnosing primary degenerative disease are used consistently, the results of investigations can be predicted with sufficient accuracy, except those of blood tests. (c) Treatment of reversible dementia has the best results in its most frequent causes: depression and drug intoxication; however, treatment of medical and surgical causes of dementia may also be effective. Based on these three considerations, we propose the following guideline in the setting of a memory clinic: to perform blood tests in every patient with dementia, but also to perform other tests, such as electroencephalography (EEG) and computed tomography (CT), as clinically indicated.

[Revised consensus 'Diagnosis of the dementia syndrome']. / Herziening consensus 'Diagnostiek bij het dementiesyndroom'.

Dementia is a clinical syndrome and is diagnosed on clinical grounds. Various types can be distinguished: the Alzheimer-type, frontal lobe dementia and subcortical dementia syndromes. Neuropsychological examination can contribute to the clinical diagnosis. Differentiation from delirium and depression, which may co-exist with dementia, is necessary. Once a dementia syndrome has been diagnosed its cause has to be ascertained. Alzheimer's disease is the most common cause and can often be diagnosed clinically. The clinical suspicion of vascular dementia has to be confirmed by imaging methods. Drug intoxication may cause or contribute to dementia. Blood tests should be performed routinely, but EEG, CT or MRI, SPECT and genetic tests can be carried out on clinical indication. Subsequently the need for care of the patient has to be established, as well as the ability of the carers to meet it. Regular follow-up is necessary. A definite diagnosis can only be made post-mortem when neuropathological examination has been performed. The organisation of diagnosis in the dementia syndrome should preferably take place in specialised multidisciplinary teams.

Reversible dementia in elderly patients referred to a memory clinic.

Dementia has a reversible cause in some cases, and these should be diagnosed without over-investigating the many patients with irreversible disease. We prospectively studied the prevalence of reversible dementia in a memory clinic, determined the added value of investigations compared with clinical examination and assessed the outcome of treatment of potentially reversible causes by measuring (1) cognition, (2) disability in daily functioning, (3) behavioural changes and (4) caregiver burden. Two hundred patients aged 65 years and over were examined, using the CAMDEX-N. If they were demented, the probable cause was diagnosed clinically and confirmed or excluded by a standard set of investigations, which were done in all patients. Of the patients, 170 (mean age 79.2 years) were demented; 31 were treated for potentially reversible causes. At follow-up after 6 months, no patients showed complete reversal of dementia. Five patients improved on clinical impression, but only one on clinical measurement. Thirty patients were cognitively impaired, but not demented; seven were treated. Judged clinically, three patients improved, but on assessment only one did so; she recovered completely. Blood tests often produced diagnostic results that were not expected clinically, but electroencephalography and computed tomography of the brain did not. None of the investigations had an effect on outcome of dementia after treatment. We conclude that in elderly patients referred to a memory clinic, the prevalence of reversible dementia is of the order of 1%, if outcome after treatment is assessed by a standardized measurement. We recommend blood tests in all patients, to detect not only metabolic causes of dementia but also co-morbidity possibly worsening the dementia. Other investigations can be performed on clinical indication. Clinical evaluation remains the mainstay of diagnosis in dementia.

Symptomatic treatment of elderly patients with early Alzheimer's disease at a memory clinic.

It is widely accepted that excess disability (treatable coexisting physical disorders and psychiatric phenomena) is common in demented patients, and should be looked for carefully and treated properly, as it may result in improvement. This idea, however, does not state what investigations should be performed and what kind of improvement can be expected. Therefore, we studied prospectively in elderly outpatients with early Alzheimer's disease the prevalence of excess disability, the results of medication treatment, and the added value of investigations for diagnosis, treatment, and outcome after clinical examination. Outcome was assessed clinically and clinimetrically (using instruments with regard to cognition, disability in daily functioning, behavior, and caregiver burden). Excess disability was present in 66% of patients. Medication treatment was effective with regard to target symptoms, but (partial) reversal of dementia did not occur. Only blood tests produced unexpected results with consequences for treatment and outcome. Positive treatment effects often resulted from clinical examination only. We recommend blood tests in all patients; other investigations can be performed on clinical indication.