View source for Rapidly progressing dementia

== Background ==
* Subacute and accelerated decline, developing over 2 years
* Must rule out [[Creutzfeldt-Jakob disease]] (CJD)

== Differential Diagnosis ==

* [[Creutzfeldt-Jakob disease]] (CJD), especially when myoclonus is present
* Atypical course of a more common form of dementia
** [[Frontotemporal dementia]], [[progressive supranuclear palsy]], [[Lewy body dementia]], and [[Alzheimer dementia]]
* [[Limbic encephalitis]]: short-term memory loss, executive dysfuntion, personality changes, panic attacks, and delusions and hallucinations, as well as seizures
** Paraneoplastic syndromes
*** Anti-Hu: often found in small cell lung cancer
*** CV2: only found in small cell lung cancer or thymoma
*** Ma2: testicular germ-cell tumours, breast cancer, and NSCLC
*** VGKC
** Anti-voltage-gated potassium channel encephalopathy (VGKC-E): often has hyponatremia
** [[HSV encephalitis]]
* [[Hashimoto encephalitis]] (steroid-responsive encephalopathy): often in patients with other autoimmune disorders, diagnosed with anti-TPO and anti-TG antibodies

=== Extended Differential Diagnosis ===

* Vascular
** [[Stroke]], [[vascular dementia]]
** [[CADASIL]]
** [[Thrombotic thrombocytopenic purpura]] (TTP)
** Hyperviscosity
** Syndromes/paraproteinemias ([[polycythemia]], [[Monocloncal gammopathy|monocloncal gammopathies]])
** [[Hypoxic-ischemic encephalopathy]]
* Infectious
** [[Whipple disease]]
** [[Syphilis]]
** [[Lyme disease]]
** [[Subacute sclerosing panencephalitis]] (SSPE) (measles)
** [[HIV-associated dementia]]
** [[Progressive multifocal leukoencephalopathy]] (JC virus)
* Toxic/metabolic
** [[Vitamin B12 deficiency]]
** [[Thiamine deficiency]]
** [[Niacin deficiency]]
** [[Folate deficiency]]
** [[Uremic encephalopathy]]
** [[Wilson disease]]
** [[Hepatic encephalopathy]]
** [[Porphyria]]
* [[Heavy metal toxicity]]
** [[Bismuth toxicity]]
** [[Alcohol toxicity]]
** [[Lithium toxicity]]
** [[Mercury toxicity]]
** [[Arsenic toxicity]]
** [[Lead toxicity]]
* Electrolyte abnormalities
** [[Kuf disease]]
** [[Methylmalonic acidemia]]
** [[Mitochondrial encephalopathy|Mitochondrial encephalopathies]]
* Autoimmune
** [[Paraneoplastic limbic encephalitis]]
** Anti-VGKC-E
** [[Hashimoto encephalopathy]]
** [[Lupus cerebritis]]
** [[Neurosarcoidosis]]
** [[CNS vasculitis]]
** [[Celiac disease]]
* Metastases/neoplastic
** CNS metastases
** [[Primary CNS lymphoma]]
** Intravascular lymphoma
** [[Lymphomatoid granulomatosis]]
** [[Gliomatosis cerebri]]
* Iatrogenic/idiopathic
** [[Central pontine myelinolysis]]
** Insulin-induced [[hypoglycemia]]
** [[Normal pressure hydrocephalus]] (NPH)
* Neurodegenerative
** [[Alzheimer dementia]]
** [[Creutzfeldt-Jakob disease]]
* Frontotemporal syndrome
** Behavioural variant [[frontotemporal dementia]]
** Semantic dementia
** Progressive non-fluent aphasia
** Frontotemporal dementia-motor neuron disease
* [[Parkinson syndrome]]
** [[Dementia with Lewy bodies]]
** [[Corticobasal degeneration]]
** [[Progressive supranuclear palsy]]
** [[Parkinson disease dementia]]
** High definition
* Systemic
** [[Vasculitis]] ([[giant cell arteritis]])
** [[Sleep apnea]]

== Investigations ==
* MRI: CJD is the only degenerative condition that causes hyperintensities in DWI and FLAIR

[[Category:Neurology]]
[[Category:Geriatrics]]