Differential Diagnosis Differential Diagnosis of Dementiaof Dementia

Eric I. Rosenberg, MD, MSPH, FACP

Department of Medicine

University of Florida

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.

American Psychiatric Association. DSM IV. 1998.

• “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

Psychiatr Clin North Am 1998;21(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

Harrison's OnLine Internal Med 16th ed. 2005.

Dementia is Common

• > 4 million cases in the U.S.• > $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

Am Fam Physician 2001;63:703-13,717-8.

Signs and Symptoms

• Cognitive

• Psychiatric

• Personality

• Problem Behaviors

• Problems with Activities Daily of Living (ADL’s)

Ann Intern Med 2003;138:411-419.

Common Causes of Mild Memory Loss

• (Early) Alzheimer’s Disease

• Depression

• Hearing/Visual Impairment

• Polypharmacy & Polyprescribers

• Metabolic Conditions

• Substance Abuse

“Reversible” Causes of Dementia

1. CNS Conditions

2. Toxins

3. “Medical” Conditions

1.) CNS Conditions

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

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

Brain Tumors

• Usually seizures, focal deficits

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

Chronic Infection

• HIV risk factors– Cryptococcal meningitis, neurosyphilis– 20-30% of AIDS patients develop

dementia

• Headache, cranial neuropathies, radiculopathies, meningismus

Trauma

• Recent head trauma/fall– Chronic Subdural Hematoma

• Recurrent head trauma– Dementia Pugilistica

2.) Toxins

• Alcoholism• Other drugs of abuse• Heavy metals

– Fatigue– Tremors– Neuropathy– Anemia– Abdominal pain

3.) “Medical” Causes

Nutritional Deficiencies

• B-12

• Niacin (Pellagra)

• Thiamine (Wernicke-Korsakoff)

• Protein, calorie malnutrition

Chronic Organ Dysfunction

• Patients “lost” to medical care• Unusual weakness, malaise,

physical findings– Hypothyroidism

– Cushing’s/Addison’s Disease

– Hypo/Hyperparathyroidism

– Renal or Liver failure

– Pulmonary failure

Key Historical Cues

• Focus on health behaviors & ADL’s– 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?”

History Clinical Correlation

Slow memory loss Alzheimer’s

Stroke irregular progression Multi-infarct dementia

Rapid progression, myoclonus Prion disease

Seizures Stroke or neoplasm

Gait problems Multi-infarct, Parkinson’s, 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

Physical Exam

• General appearance

• Visual, auditory acuity

• Localizing deficits

• Gait abnormalities

• Fasiculations

• Gaze palsy

• Cogwheeling

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

Parkinson’s Disease and/or

Lewy Body Dementia

Selective Testing

• (Old Records)• Urinalysis• CBC• Comprehensive

Metabolic Panel• TSH• B-12, (Folate)• RPR (FTA)

• LP• Toxicology• HIV• EEG• Genetic

biomarkers/CSF markers

Neurology 2001;56(9).

Neuroimaging

• Non-contrasted CT or MRI

• Others (not routine… yet)– Quantitative CT/MR– PET– SPECT

When to Refer

• Unusually young patient (age<55)

• Abnormal/focal neurological findings

• Diagnosis in doubt

• Rapid progression

• Not responding to therapy

• Severe behavior problems

Rx Cause

Suggestive Signs or Symptoms

Selective Testing

“Reversible”

PalliateCounselControl risks

Doubt Dx?AgitationAtypical

NeuropsychReferral

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.

Bibliography• Armon C. Western pacific ALS/PDC and flying foxes. What’s

next? Neurology 2003;61:291-292. • Bair BD. Diagnostic Dilemmas, Part II: frequently missed

diagnosis in geriatric psychiatry. Psychiatr Clin North Am 1998;21(4):941-971.

• Bird TD, Miller BL. Alzheimer’s disease and other dementias. In: Kasper DL, et al (Eds.) Harrison’s Principles of Internal Medicine, 16th edition [Online]. Chapter 350. February 2005.

• Cummings JL. Alzheimer’s disease. N Engl J Med 2004;351(1):56-67.

• Karlawish JHT, Clark CM. Diagnostic evaluation of elderly patients with mild memory problems. Ann Intern Med 2003;138:411-419.

• Knopman DS, et al. Practice parameter: diagnosis of dementia (an evidence-based review). Neurology 2001;56(9).

• Santacruz KS, Swagerty D. Early diagnosis of dementia. Am Fam Physician 2001;63:703-13,717-8.