Dementia diagnosis
Delirium vs.dementia (critical distinction). Delirium AKA acute confusional state. Distinct from dementia, however, patients with dementia are at increased risk of developing delirium 1) 2).
A primary disorder of attention that subsequently affects all other aspects of cognition 3). Often represents life-threatening illness, e.g. hypoxia, sepsis, uremic encephalopathy, electrolyte abnormality, drug intoxication, MI. 50% of patients die within 2 yrs of this diagnosis.
Unlike dementia, delirium has an acute onset, motor signs (tremor, myoclonus, asterixis), slurred speech, altered consciousness (hyperalert/agitated or lethargic, or fluctuations), hallucinations may be florid. EEG shows pronounced diffuse slowing.
Cerebrospinal fluid biomarker for dementia
Brain biopsy for dementia
Clinical criteria are usually sufficient for the diagnosis of most dementias. Biopsy should be reserved for cases of a chronic progressive cerebral disorder with an unusual clinical course where all other possible diagnostic methods have been exhausted and have failed to provide adequate diagnostic certainty 4).
A biopsy may disclose CJD, low-grade astrocytoma, and AD among others. The high incidence of CJD among patients selected for biopsy under these criteria necessitates appropriate precautions; see Creutzfeldt-Jakob disease.
In a report of 50 brain biopsies performed to assess the progressive neurodegenerative disease of unclear etiology, 5) the diagnostic yield was only 20% (6%were only suggestive of a diagnosis, 66% were abnormal but nonspecific, 8% were normal). The yield was highest in those with focal MRI abnormalities. Among the 10 patients with diagnostic biopsies, the biopsy result led to a meaningful therapeutic intervention in only 4.