Differential Diagnosis of Dementia

1
Differential Diagnosis of Dementia

• Eric I. Rosenberg, MD, MSPH, FACP
• Department of
  Medicine
• 
  University of Florida

2
Objectives

• Describe signs and symptoms concerning for early
  dementia.
• Describe common causes of memory loss in the
  elderly.
• Help integrate history, physical, and laboratory
  findings to diagnose reversible causes of
  dementia.
• Discuss when referral to a neurologist or
  psychiatrist may be helpful.

3

• An acquired deterioration in cognitive abilities
  that impairs the successful performance of
  activities of daily living
• Cognitive Losses in two or more
• Memory
• Language
• Visuospatial (recognize objects)
• Executive function (tasks)
• Progressive

4
A Syndrome

• Made up of multiple causes, multiple disorders
• Cluster of abnormal results from history,
  physical, and selected testing
• Early detection requires continuity of care
  attention to cognitive deficits

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Dementia is Common

• gt 4 million cases in the U.S.
• gt 100 billion/year
• 10-15 from reversible causes
• Clinicians fail to detect in 20-70 patients
  until severe
• Early detection important
• diagnose cause
• prolong function/comfort
• patient family can plan future preferences

6
Signs and Symptoms

• Cognitive
• Psychiatric
• Personality
• Problem Behaviors
• Problems with Activities Daily of Living (ADLs)

7
Common Causes of Mild Memory Loss

• (Early) Alzheimers Disease
• Depression
• Hearing/Visual Impairment
• Polypharmacy Polyprescribers
• Metabolic Conditions
• Substance Abuse

8
Reversible Causes of Dementia

• CNS Conditions
• Toxins
• Medical Conditions

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1.) CNS Conditions

• Normal-Pressure Hydrocephalus
• Primary/Metastatic Brain Tumor
• Chronic infection
• Trauma

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Normal Pressure Hydrocephalus

• Abnormal gait, dementia, urinary incontinence
• Likely have other concomittant dementias
• 30-50 show improvement with ventricular shunting
• Balance risk of subdural hematoma/infection

11
Brain Tumors

• Usually seizures, focal deficits
• But if in frontal or temporal lobes, can present
  with personality changes and memory problems

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Chronic Infection

• HIV risk factors
• Cryptococcal meningitis, neurosyphilis
• 20-30 of AIDS patients develop dementia
• Headache, cranial neuropathies, radiculopathies,
  meningismus

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Trauma

• Recent head trauma/fall
• Chronic Subdural Hematoma
• Recurrent head trauma
• Dementia Pugilistica

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2.) Toxins

• Alcoholism
• Other drugs of abuse
• Heavy metals
• Fatigue
• Tremors
• Neuropathy
• Anemia
• Abdominal pain

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3.) Medical Causes
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Nutritional Deficiencies

• B-12
• Niacin (Pellagra)
• Thiamine (Wernicke-Korsakoff)
• Protein, calorie malnutrition

17
Chronic Organ Dysfunction

• Patients lost to medical care
• Unusual weakness, malaise, physical findings
• Hypothyroidism
• Cushings/Addisons Disease
• Hypo/Hyperparathyroidism
• Renal or Liver failure
• Pulmonary failure

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Key Historical Cues

• Focus on health behaviors ADLs
• Prescription management
• Missed appointments
• Non-adherence
• Health maintenance
• Neglected appearance
• Family concerns
• Polite, detailed probing
• How is he managing the bills? What about the
  checkbook? Are there any changes in how that is
  being organized/balanced?

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History Clinical Correlation
Slow memory loss Alzheimers
Stroke ? irregular progression Multi-infarct dementia
Rapid progression, myoclonus Prion disease
Seizures Stroke or neoplasm
Gait problems Multi-infarct, Parkinsons, NPH
HIV risk factors CNS infection (AIDS)
Recurrent head trauma Chronic subdural hematoma
Remote gastric bypass, alcoholism, malnutrition B-12 deficiency, thiamine
Depressive symptoms Pseudodementia
Factory (battery/chemicals) Heavy metal toxins
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Physical Exam

• General appearance
• Visual, auditory acuity
• Localizing deficits
• Gait abnormalities
• Fasiculations
• Gaze palsy
• Cogwheeling

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Physical Finding Clinical Correlation
Hemiparesis, focal neuro deficit Multi-infarct dementia, neoplasm
Peripheral neuropathy and myelopathy B-12 deficiency, heavy metal intoxication
Bradycardia, hair loss, dry skin Hypothyroidism
Confusion and repetitive movements Seizure disorder
Hearing impairment, vision loss Pseudodementia due to disorientation
Axial rigidity Gaze palsy Cogwheel rigidity, brady kinesia Dystonia Frontotemporal Dementia and/or Parkinsons Disease and/or Lewy Body Dementia
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Selective Testing

• (Old Records)
• Urinalysis
• CBC
• Comprehensive Metabolic Panel
• TSH
• B-12, (Folate)
• RPR (FTA)

• LP
• Toxicology
• HIV
• EEG
• Genetic biomarkers/CSF markers

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Neuroimaging

• Non-contrasted CT or MRI
• Others (not routine yet)
• Quantitative CT/MR
• PET
• SPECT

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When to Refer

• Unusually young patient (agelt55)
• Abnormal/focal neurological findings
• Diagnosis in doubt
• Rapid progression
• Not responding to therapy
• Severe behavior problems

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Suggestive Signs or Symptoms
Selective Testing
Doubt Dx? Agitation Atypical
Reversible
Palliate Counsel Control risks
Rx Cause
Neuropsych Referral
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Objectives

• Describe signs and symptoms concerning for early
  dementia.
• Describe common causes of memory loss in the
  elderly.
• Help integrate history, physical, and laboratory
  findings to diagnose reversible causes of
  dementia.
• Recognize when referral to a neurologist or
  psychiatrist may be helpful.

27
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