Underlying Factors Behind Dementia

Creutzfeldt - Jakob Disease

• Rapid progression
• Death: <1 year

Symptoms

• Dementia
• Cortical sign
• Rigidity
• Myoclonic jerks (Startle)- caused by accumulation of misfolded proteins called PrPSc in the cytoplasm of neurons

Diagnosis

• EEG: Periodic complexes
• MRI
  • Cortical ribboning
  • Basal ganglia hyperintensities

Differential Diagnosis

• Hashimoto's encephalopathy
• CNS vasculitis
• Paraneoplastic syndromes (limbic encephalitis)

Also read: NEET PG Eligibility Criteria—All You Need to Know

Huntington's Disease  

• Autosomal dominant
• Accumulation of Huntingtin protein in cytoplasm of the neurons—present on chromosome 4
• Age: 4^th-5^th decade

Symptoms

• Chorea
• Behavioral changes
• Executive skills: Lost
• Memory affected: Late
• Delusions, depression

Treatment

• Increased Dopamine & Decreased GABA
• Tetrabenazine is used to reduce dopamine levels

Normal Pressure Hydrocephalus  

Hakim's triad: AID

• Ataxia (cerebellar): Gait abnormality
• Apraxia: Magnetic gait abnormality
• Short walking steps, low foot clearance
  • Incontinence of urine
  • Dementia - Loss of executive skills

Also read: Radiology Image-based Questions for NEET PG

Neuroimaging 

• Enlarged lateral ventricles with no or minimal cortical atrophy
• Normal Hippocampus

Reason for normal pressure in NPH

It is a communicating hydrocephalus caused due to obstruction of reabsorption of CSF on cerebral convexities

Lumbar Puncture

• Opening pressure may be normal or high normal
• Cells: Normal
• Protein in CSF: Normal
• Used as both diagnostic and partially therapeutic
• Therapeutic test - Fisher test
• Serial lumbar puncture is done
  • 30 to 50 ml of CSF is removed
  • Improvement in cognition and gait - transient gait

Radionuclide Cisternography

• Demonstrates the delay in reabsorption of CSF

Treatment

• Definitive: Ventricular shunting
• Fisher test

Also read: Orthostatic Hypotension: Causes and Treatment

Intracranial Hypotension  

• Low CSF pressure
• Downward pressure on subcortical areas

Symptoms

• Headache: Increases during Coughing/Valsalva maneuver/Lying and then standing
• BvFTD: Behavioral variant of frontotemporal dementia
  • Characterized by antisocial behavior
• Vomiting

Reasons for Low CSF pressure

• CSF leak - post lumbar puncture (use of wide bore needle)
• Post head injury
• Spinal cord arachnoid cysts

Marchiafava Bignami Disease  

• Mostly seen in alcoholics
• Dementia in red wine drinkers in Italy
• Seizures
• MRI shows: Degeneration of corpus callosum

Wernicke's Encephalopathy

• Occurs in alcoholics and malnourished patients

Areas damaged- Inflammed/necrosed

• Dorsomedial Thalamus (correlates best with memory loss)
• Mammillary bodies
• Midline cerebellum
• Trochlear, Abducens nucleus

Also read: High-Yield Image-Based Questions for INI-CET Medicine​

Clinical Features (Mnemonic: GOA)

• Global confusion
• Ophthaloplegia (6^th nerve palsy)
• Ataxia

Treatment

• IV thiamine for 3 days, then orally
• Subsequently Glucose is given

Korsakoff Psychosis 

• Irreversible profound amnestic syndrome
• Mammillary body atrophy is seen

Affected areas

• Thalamus
• Mammillary bodies

Clinical Features

Confabulation: Patient creates new memory without intention of deceit. Normal attention span. Easily confused and cannot store information for more than few minutes

Also read: Essential Medicine Image-based Questions for NEET PG

Vitamin B12 Deficiency  

Neurological features develop in the absence of hematological features (macrocytic anemia). Serum vitamin B12 is a best way to determine the deficiency than CBC

Neurological Features

• Myelopathy—Pathways affected:
  • Post column affected
    • Loss of vibration or position sense
  • Corticospinal pathway
    • Extensor planters are present
    • Brisk DTR reflexes with Babinski sign (upper motor symptom)
  • Peripheral neuritis
    • Areflexia (lower motor symptom)
    • Sensory loss

Risk Factors

• Use of Metformin
• Use of histamine blockers
• Vegetarians
• Autoimmunity (Pernicious anemia)
• Malabsorption syndromes

Reason for Dementia

• Vitamin B12 deficiency decreases S-adenosylmethionine which is responsible for myelin formation leading to Dementia

Treatment

• Parenteral vitamin B12 for a week- First IV for 7days and then IM for weekly
• Then Oral treatment is initiated - lifelong treatment

Expected timeline of improvement with vitamin B12

• Biochemical recovery: <1 week
• Homocysteine and methyl melodic acid levels become normal
• Clinical recovery: 6 to 12 weeks
  • Neurological symptoms improvement
    • Partial reversal
    • Stopping Disease progression

• Hematological recovery: 8 weeks
• Anemia, Leukopenia and platelets are improved

Also read: Important Topics in Dermatology for NEET-PG

Other B complex vitamin deficiency leading to dementia

• Nicotinic acid - mainly accounted in prisoners of war

• Rash on sun exposed areas (photodermatitis)
• Glossitis
• Angular stomatitis
• Dementia (no complete recovery)

Miscellaneous Causes   

• Brain tumor
• Should have originated from the Temporal lobe - Focal neurological deficits + Seizures
• Limbic Encephalitis
  • Seen with - Oat cell lung cancer (most aggressive) 
• Paraneoplastic Encephalitis
• Seen with Ovarian teratoma
• Presents with NMDA receptor antibodies
• Hypothyroidism
• CLD/CKD
• Neurosyphilis
• CSF VDRL test is used

CNS Granulomatous Vasculitis

• Diagnosis can be made postmortem.
• Brain or meningeal biopsy is used.
• Angiography shows multifocal stenosis.
• Not specific.

Chronic Metal Exposure

• Lead: Fire glaze pottery workers affected more
• Symptoms
  • Recurrent abdominal pain
  • Gray line on gums
  • Peripheral neuropathy
  • Elevated urinary aminolevulinic acid levels
• Mercury: Dementia, Ataxia and tremulousness
• Arsenic
• Mee lines in the nails
• Hyperpigmentation
• Scaling of skin
• Aluminum: Dialysis dementia 
• Eradicated because deionized water is being used these days

Also read: Medicine Important Questions for NEET PG/FMGE

Punch drunk syndrome 

• Also called chronic traumatic encephalopathy
• Can be seen in boxers after retirement
• Frontal lobe is affected
• Personality changes - explosive rage
• Parkinsonism features
• Ataxia
• Autopsy shows tau positive inclusions (neurofibrillary tangles)

Download the PrepLadder app now and unlock a 24-hour FREE trial of premium high-yield content. Access Video Lectures also in हिंglish, digital notes, QBank, and Mock Tests for FREE to ace your NEET PG preparation. Elevate your study experience and gear up for success. Start your journey with PrepLadder today!