1.2 Adult Development, Aging & Geriatric Assessment
Key Takeaways
- Normal physiological aging causes decreased arterial compliance (leading to isolated systolic hypertension), reduced GFR (~1 mL/min/year decline after age 40), decreased lung compliance with increased residual volume, and slowed processing speed with preserved crystallized intelligence.
- Activities of Daily Living (ADLs) assess basic self-care (bathing, dressing, eating), whereas Instrumental ADLs (IADLs) evaluate independent community living (finances, medication management, transportation).
- Comprehensive Geriatric Assessment (CGA) evaluates cognitive impairment (MMSE <24, MoCA <26), depression (GDS >=5/15), fall risk (Timed Up and Go >12 seconds), and frailty syndrome (>=3 of 5 Fried criteria: weight loss, exhaustion, weakness, slow gait, low activity).
- Polypharmacy (concurrent use of >=5 medications) increases adverse drug reaction risks; the AGS Beers Criteria identifies potentially inappropriate medications in older adults, such as first-generation antihistamines, benzodiazepines, anticholinergics, and tricyclic antidepressants.
- Delirium is an acute, fluctuating disturbance in attention and awareness diagnosed via the Confusion Assessment Method (CAM), requiring feature 1 (acute onset/fluctuating course) AND feature 2 (inattention), PLUS either feature 3 (disorganized thinking) OR feature 4 (altered level of consciousness).
Physiological Changes of Aging
Normal aging is characterized by progressive, predictable physiological changes across all major organ systems. On USMLE Step 2 CK, distinguishing normal physiological aging from pathological disease is critical. Aging decreases homeostatic reserve (homeostenosis), making older adults more vulnerable to decompensation during acute illness, surgery, or medication adjustments.
Normal Aging vs. Pathological Disease
| System | Normal Physiological Aging | Pathological Disease State |
|---|---|---|
| Cardiovascular | Decreased arterial compliance, myocardial stiffening, isolated systolic hypertension, decreased max heart rate (220 - age) | Heart failure with preserved ejection fraction, severe symptomatic hypertension, aortic stenosis |
| Renal & Urinary | Decreased GFR (~1 mL/min/yr after age 40), decreased renal blood flow, reduced tubular secretion, urinary frequency | Acute kidney injury, chronic kidney disease, urinary incontinence (urge, stress, overflow) |
| Respiratory | Decreased chest wall compliance, decreased elastic recoil, increased residual volume (RV), decreased FEV1 and FVC (FEV1/FVC ratio remains normal) | Chronic obstructive pulmonary disease (COPD), restrictive lung disease, pneumonia |
| Neurological | Decreased brain volume/weight, slower processing speed, mild memory retrieval delay; crystallized intelligence preserved | Major neurocognitive disorder (dementia), mild cognitive impairment, acute delirium |
| Gastrointestinal | Decreased colonic motility, delayed gastric emptying, decreased hepatic drug metabolism (Phase I cytochrome P450 decreases more than Phase II) | Severe constipation/fecal impaction, dysphagia, gastrointestinal bleeding |
| Musculoskeletal | Loss of muscle mass (sarcopenia), decreased bone mineral density, cartilage thinning | Osteoporosis (T-score <= -2.5), fragility fractures, severe osteoarthritis |
| Immunological | Immunosenescence (decreased T-cell diversity/function, blunted fever response) | Severe atypical infection presentations, reactivation of varicella-zoster virus |
Functional Assessment: ADLs vs. IADLs
Functional status is the single strongest predictor of morbidity and mortality in older adults. Function is classified into Activities of Daily Living (ADLs) and Instrumental Activities of Daily Living (IADLs).
Comparing Functional Domains
| Domain | Specific Activities | Clinical Significance |
|---|---|---|
| Basic ADLs | DEATH: Dressing, Eating (feeding self), Ambulating (transferring), Toileting, Hygienes (bathing) | Loss of basic ADLs indicates need for full-time caregiver support or long-term nursing care facility placement. |
| Instrumental IADLs | SHAFT: Shopping, Housekeeping, Accounting (finances), Food preparation, Telephone/Transportation & Medication management | Loss of IADLs occurs earlier in cognitive decline and indicates need for community support services. |
Comprehensive Geriatric Assessment & Frailty
The Comprehensive Geriatric Assessment (CGA) is a multidimensional diagnostic process used to evaluate functional capacity, physical health, cognition, mental health, and socio-environmental circumstances in older patients.
Key Assessment Metrics
- Cognitive Screening: Evaluated using the Mini-Mental State Exam (MMSE) (score <24/30 indicates impairment) or Montreal Cognitive Assessment (MoCA) (score <26/30 indicates impairment; MoCA is more sensitive for mild cognitive impairment and vascular dementia).
- Depression Screening: Evaluated using the Geriatric Depression Scale (GDS) (score >=5/15 suggests depression). Depressive symptoms in older adults often present atypically with somatic complaints, executive dysfunction, or pseudo-dementia.
- Fall Risk & Mobility: Assessed using the Timed Up and Go (TUG) test. The patient stands up from a chair, walks 3 meters (10 feet), turns, walks back, and sits down. A time of >12 seconds identifies high fall risk and warrants full fall evaluation (vision, gait, vitamin D, home safety, medication review).
- Frailty Syndrome: Diagnosed when a patient meets >=3 of the 5 Fried Frailty Criteria:
- Unintentional weight loss (>=10 lbs or >=5% of body weight in past year).
- Self-reported exhaustion.
- Weakness (reduced grip strength on dynamometry).
- Slow walking speed (>0.8 seconds to walk 1 meter, or >4.8 seconds for 4 meters).
- Low physical activity level.
Polypharmacy & The AGS Beers Criteria
Polypharmacy is defined as the routine concurrent use of 5 or more prescription medications. Pharmacokinetic changes in older adults include increased volume of distribution for lipophilic drugs (due to increased body fat) and decreased clearance of renal and hepatic drugs. The American Geriatrics Society (AGS) Beers Criteria identifies potentially inappropriate medications (PIMs) in older adults.
High-Yield Beers Criteria Medication Classes
| Medication Class | Examples | Adverse Clinical Effects in Older Adults |
|---|---|---|
| First-Gen Antihistamines | Diphenhydramine, chlorpheniramine, hydroxyzine | Highly anticholinergic: sedation, confusion, dry mouth, urinary retention, constipation, falls |
| Benzodiazepines & Z-drugs | Lorazepam, diazepam, alprazolam, zolpidem | Increased risk of cognitive impairment, delirium, falls, fractures, and motor vehicle accidents |
| Anticholinergics | Oxybutynin, benztropine, dicyclomine | Delirium, memory decline, urinary retention, narrow-angle glaucoma exacerbation |
| Tricyclic Antidepressants | Amitriptyline, imipramine, doxepin | Strong anticholinergic, orthostatic hypotension, cardiac conduction abnormalities |
| Antipsychotics | Haloperidol, risperidone, quetiapine | Increased mortality in dementia patients; extrapyramidal symptoms, metabolic dysfunction |
| Non-Selective NSAIDs | Indomethacin, ketorolac, naproxen, ibuprofen | Gastrointestinal bleeding, acute kidney injury, fluid retention, hypertension exacerbation |
| Long-Acting Sulfonylureas | Glyburide, glimepiride | Severe prolonged hypoglycemia (prefer short-acting agents like glipizide if required) |
| Central Alpha-Agonists | Clonidine, methyldopa | High risk of central nervous system adverse effects, bradycardia, orthostatic hypotension |
Delirium vs. Dementia Diagnostic Framework
Distinguishing delirium from dementia is a classic, high-yield USMLE Step 2 CK topic. Delirium is a medical emergency requiring rapid identification and reversal of underlying triggers.
[ Acute Change in Mental Status ]
|
[ Assess CAM Criteria for Delirium ]
|
+---------------------------+---------------------------+
| |
[ Meets CAM Criteria ] [ CAM Negative ]
(1: Acute/fluctuating AND (Insidious onset, stable course,
2: Inattention AND normal level of consciousness)
3: Disorganized thinking OR 4: Altered LOC) |
| |
[ Diagnosis: DELIRIUM ] [ Diagnosis: DEMENTIA ]
| |
Search for Triggers: Workup Cause:
- Infection (UTI, Pneumonia) - Alzheimer, Vascular, Lewy Body
- Medication (Beers drugs, narcotics) - Reversible: TSH, B12, RPR, NPH
- Metabolic (Hyponatremia, Hypoglycemia)
- Hypoxia / Hypercapnia / Restraints
Diagnostic Comparison: Delirium vs. Dementia
- Onset: Delirium has an acute onset (hours to days); dementia has an insidious, slow progression (months to years).
- Course: Delirium features a fluctuating course over 24 hours (symptom-free intervals alternated with severe agitation or lethargy); dementia demonstrates a gradual, progressive decline.
- Attention: Delirium features severely impaired attention and concentration; dementia attention remains relatively intact until end-stage disease.
- Consciousness: Delirium involves an altered level of consciousness (hyperactive, hypoactive, or mixed); dementia consciousness is unimpaired until late stages.
An 82-year-old female is brought to the emergency department by her daughter due to confusion and visual hallucinations that began 2 days ago. Her symptoms fluctuate, ranging from lethargy to severe agitation. Physical examination shows a temperature of 38.1°C (100.6°F) and suprapubic tenderness. Urinalysis reveals positive leukocyte esterase and nitrites. Which diagnosis and criteria best explain her clinical presentation?
A 78-year-old male with hypertension and mild osteoarthritis presents for a medication review. His current medications include lisinopril, acetaminophen, over-the-counter diphenhydramine for insomnia, and atorvastatin. Which medication class should be discontinued based on the AGS Beers Criteria due to strong anticholinergic side effects and fall risk?
An 80-year-old man undergoes a Comprehensive Geriatric Assessment. Functional evaluation reveals that he independently bathes, dresses, feeds himself, and transfers from chair to bed. However, his family reports that he can no longer manage his bank account, struggles to organize his prescription medications, and recently got lost while driving. How are these impaired tasks classified?