Further rare and unusual dementias

Abstract

SummARyIn the second of two articles on rare causes of dementia, the authors describe toxic, iatrogenic, nutritional, traumatic, metabolic, neoplastic and autoimmune causes of dementia. Disorders are graded according to their prevalence, to give an idea of the likelihood of their presentation. Guidance is given on the investigation of uncommon cognitive impairment and dementia, especially in early-onset illness. DECLARATIOn OF InTERESTNone. Susham Gupta

Rare and Unusual Dementias

“…High plasma homocystiene is associated with atrophic changes in the brain in Alzheimer's disease and other forms of dementias [5]. Inborn errors of folate transport and metabolism produce developmental delay, cognitive deterioration, motor and gait abnormality, seizures, vascular and demyelinating changes [6]. Patients may present with mild to moderate cognitive impairment or dementia associated with apathy, depression, and peripheral neuropathy.…”

“…Vitamin B12 deficiency can be caused by poor dietary intake, malabsorption from defective production of intrinsic factor (pernicious anemia, total gastrectomy), or release of intrinsic factor (gastric achorhydria, gastrectomy), disorders of terminal ileum (tropical and nontropical spruce, intestinal resection), Crohn's disease, competition for cobalamin (fish tapeworm, "blind loop" syndrome), and iatrogenic factors (colchicines, neomycin) [6]. Neurological damage and cerebral demyelination may be mediated through S-adenosylmethionine deficiency, leading to dementia associated with sensory neuropathy (more upper limbs), myelopathy, optic nerve dysfunction, and spinal degeneration.…”

“…Frontal meningomas, temporal gliomas, and multiple metastases are most likely to present as dementia, and this is often dependant on site and extent of malignancy. Other causes include neoplastic angioendotheliosis, which causes subacute dementia and lymphomatosis cerebri, leading to rapidly progressive dementia [6]. Paraneoplastic disorder is an immune-mediated secondary effect of systemic malignancies (lung, gastrointestinal, breast, testis, etc.)…”

“…Other metabolic disorders that can cause dementia include metachromatic leukodystrophy, a demyelinating storage disease due to lysosomal enzyme arylsulfatase A (ARSA) deficiency, cerebral adrenoleukodystrophy (ADL), and adult adrenomyeloneuropathy (AMN), neurodegeneration with brain iron accumulation Type-1 (NBIA1), or Hallervorden-Spatz syndrome, neuroacanthocytosis, and adult variant cerebral lipidoses [6].…”