Frontotemporal dementia

On this page

Pathophysiology - The Brain's Bad Build-up

FTD results from progressive neuronal loss and focal atrophy in the frontal and temporal lobes. The underlying cause is the accumulation of one of two main abnormal proteins:

  • Tauopathy (~40% of cases)

    • Aggregates of hyperphosphorylated tau protein form neurofibrillary tangles.
    • The classic finding is the Pick body: a spherical, silver-staining intraneuronal inclusion.
    • Associated with mutations in the MAPT gene.
  • TDP-43 Proteinopathy (~50% of cases)

    • Cytoplasmic inclusions of TDP-43 protein are the hallmark.

Pick bodies and filaments in frontotemporal dementia

⭐ The C9orf72 gene expansion is the most common genetic cause of both FTD and Amyotrophic Lateral Sclerosis (ALS), creating an FTD-ALS clinical spectrum.

Clinical Presentation - Personality & Language Gone

Presents in two main forms, often before age 65.

  • Behavioral Variant (bvFTD): Most common form.

    • Personality/Behavioral Changes: Early, prominent signs.
      • Disinhibition: Socially inappropriate behavior, impulsivity.
      • Apathy: Loss of motivation and interest.
      • Loss of Empathy/Sympathy: Emotional blunting.
    • Stereotyped/Compulsive Behaviors: Repetitive actions, hoarding.
    • Dietary changes: Hyperorality, preference for sweets.
  • Primary Progressive Aphasia (PPA): Language function declines first.

    • Semantic Variant (svPPA): "What is a 'fork'?"
      • Loss of word/object meaning (anomia).
      • Fluent, grammatically correct but empty speech.
    • Non-fluent/Agrammatic Variant (nfvPPA): "Fork... eat... food."
      • Effortful, halting speech with grammatical errors (agrammatism).
      • Apraxia of speech often present.

⭐ In early FTD, memory and visuospatial functions are often strikingly preserved, distinguishing it from Alzheimer's disease where memory loss is the initial, dominant feature.

MRI scans of brain atrophy in FTD variants

Diagnosis - Finding the Frontal Faults

  • Clinical Criteria: Diagnosis relies on international consensus criteria for behavioral variant FTD (bvFTD) or primary progressive aphasia (PPA).
  • Neuropsychological Testing: Confirms executive dysfunction (e.g., poor planning, disinhibition) or specific language deficits.
  • Neuroimaging: Crucial for diagnosis.
    • MRI: Shows characteristic, often asymmetric, atrophy in the frontal and/or temporal lobes.
    • PET/SPECT: Reveals ↓ frontotemporal hypometabolism or hypoperfusion, helping differentiate from other dementias.

Frontotemporal Dementia (FTD) Variants and Symptoms

Exam Favorite: In contrast to Alzheimer's disease, memory and visuospatial skills are typically well-preserved in the early stages of FTD.

Management - Support, Not Cure

  • Core Goal: Primarily symptomatic and supportive, as no disease-modifying therapies currently exist. Focus on safety and quality of life.
  • Non-Pharmacologic (First-Line):
    • Behavioral redirection, environmental modification.
    • Speech, physical, and occupational therapy.
  • Pharmacologic (Symptom-Targeted):
    • Behavioral: SSRIs (e.g., sertraline) for disinhibition, anxiety, and compulsive behaviors.
    • Sleep: Trazodone for insomnia and agitation.

High-Yield: Unlike Alzheimer's, cholinesterase inhibitors (e.g., donepezil) and memantine are not effective and may worsen agitation in FTD.

High-Yield Points - ⚡ Biggest Takeaways

  • Presents at a younger age (<65) than Alzheimer's disease.
  • Characterized by early personality and behavior changes (apathy, disinhibition, compulsivity) or language dysfunction.
  • Memory and visuospatial skills are relatively preserved in the early stages.
  • Two primary variants: behavioral variant (bvFTD) and primary progressive aphasia (PPA).
  • Pathology is linked to tau protein (Pick bodies) or TDP-43 proteinopathy.
  • Neuroimaging reveals focal atrophy of the frontal and/or temporal lobes.

Practice Questions: Frontotemporal dementia

Test your understanding with these related questions

A 73-year-old man is brought in by his wife with a history of progressive personality changes. The patient’s wife says that, over the past 3 years, he has become increasingly aggressive and easily agitated, which is extremely out of character for him. His wife also says that he has had several episodes of urinary incontinence in the past month. He has no significant past medical history. The patient denies any history of smoking, alcohol use, or recreational drug use. The patient is afebrile, and his vital signs are within normal limits. A physical examination is unremarkable. The patient takes the mini-mental status examination (MMSE) and scores 28/30. A T2 magnetic resonance image (MRI) of the head is performed and the results are shown in the exhibit (see image). Which of the following is the next best diagnostic step in the management of this patient?

Image for question 1
1 of 5

Flashcards: Frontotemporal dementia

1/10

What are the first-line pharmacologic treatments (2) for panic disorder? _____

TAP TO REVEAL ANSWER

What are the first-line pharmacologic treatments (2) for panic disorder? _____

SSRIs or venlafaxine

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start For Free