UMEM Educational Pearls - Geriatrics

[from Hals G. Common diagnoses become difficult diagnoses when geriatric patients visit the emergency department, part I. Emergency Medicine Reports 2010;31(9):101-110.]

Elderly patients have slightly lower body temperatures than younger adults, and as a result it has been suggested that "fever" be defined as anything > 99 degrees F. One study found that by lowering the definition to this number improved the sensitivity and specificity to 83% and 89%, respectively.

from Hals G. Common diagnoses become difficult diagnoses when geriatric patients visit the emergency department, part I. Emergency Medicine Reports 2010;31(9):101-110.

study referred to: Castle SC, et al. Fever response in elderly nursing home residents: are the older truly colder? J Am Geriatric Soc 1991;39:853-857.

Elderly patients should be considered immunocompromised for several reasons:
1. T cell function and reduced cellular immunity occur as we get older.
2. B cell antibody production decreases.
3. Host defenses against infection are reduced with aging, such as reduced circulation and thinning skin.
4. Miscellaneous factors, such as malnutrition and co-existing illnesses contribute to increased risk of infection as well.

[Good reference and suggested reading: Hals G. Common diagnoses become difficult diagnoses when geriatric patients visit the emergency department: Part I. Emergency Medicine Reports 2010;31(9):103-111.]

When prescribing quinolones to elderly (e.g. for UTI) patients that are taking iron supplements, advise them to take the antibiotic several hours before taking the iron. Iron will bind the antibiotic in the GI tract and reduce its bioavailability.

[Anderson RS, Liang SY. Infections in elderly patients. Critical Decisions in Emergency Medicine, 2010;24(8):13-18.]

Up to 10% of elderly patients in the ED meet criteria for acute delirium, though misdiagnosis rates are very common.
The most common cause of delirium in the elderly, overall, is medication effects. Other common causes are infections (UTIs most common), CNS abnormalities, cardiovascular abnormalities, electrolyte/metabolic abnormalities, and temperature abnormalities (fever or hypothermia).

A handful of lab abnormalities occur as a normal part of aging. Elderly patients will often demonstrate the following lab abnormalities without these indicating pathology:
1. ESR increases...use the following correction factor: top normal ESR < (age + 10)/2
2. creatinine falls
3. alkaline phosphatase may be elevated 2-3 fold
4. urinalysis may show asymptomatic pyuria or bacteriuria
5. ABGs demonstrate lower PaO2s and elevated A-a gradients
6. the top normal D-dimer level elevates slightly
7. the top normal BNP level elevates slightly
8. the ECG may show a first degree AV block, poor R-wave progression, leftward axis, and PVCs

It's no secret that the elderly are at high risk for adverse drug effects. The average elderly patient takes 5 prescribed medications plus two over-the-counter medications. As many as 5% of admissions in the elderly are attributable to adverse drug effects. 

Anytime you prescribe a new medication to an elderly patient, ALWAYS check for the possibility of drug interactions.

The top-normal value for ESR (sed rate) increases with age, such that the top-normal ESR value = (age +10)/2. For example, if you were checking the ESR for evaluation of temporal iritis in an 80yo patient, the top normal value of his ESR is 45.

Elderly patients are at higher risk of barotrauma with positive pressure ventilation (e.g. CPAP, BiPAP, and especially after intubation) because of decreased vital capacity and lung compliance. Watch those plateau pressures closely!

If an elderly patient develops hypotension within minutes of endotracheal intubation, always consider tension PTX (and don't forget about hypovolemia, as we've discussed before).

The most common cause of delirium in the elderly is infection, and the most common type of infection is just a simple UTI. The second most common cause of delirium is medication effects. ALWAYS look carefully for signs of infection and look carefully at medication lists whenever evaluating an elderly patient with a change in mental status.

When caring for elderly patients that are having dysrhythmias, especially ventricular dysrhythmias, or in cardiac arrest, give strong consideration to empiric use of magnesium. Elderly patients are more likely to be hypomagnesemic because of diuretic use, poor GI absorption, poor daily intake, and diabetes.

[Narang AT, Sikka R. Resuscitation of the elderly. Emerg Med Clin N Am 2006;24:261-272.]

Be wary of the limitations of correlating a temperature with infection in the elderly:
1. The elderly are 3-4x more likely to develop hypothermia in response to serious infections. Never rule out a serious infection simply based on a low or normal body temperature.
2. The elderly take longer to mount a fever than younger patients.
3. The elderly have a slightly lower body temperature at baseline, possibly 1 degree lower. As a result, "fever" in the elderly is sometimes defined as 99.5 degrees rather than the traditional 100 or 100.4 used in younger patients.

Hypovolemia is very common in the ederly for two reasons:

1. The elderly have a decreased thirst response...in other words, it takes longer for them to develop thirst in the setting of dehydration.

2. The elderly have a decreased renal vasopressin response to hypovolemia.

From a treatment standpoint, one should always assume an elderly patient is hypovolemic. Hydration is incredibly important during resuscitation of the elderly patient.

The elderly are at tremendous risk of death after MI, in no small part because we tend to undertreat them. The 30-day mortality rate after MI in patients < 65 is 3%.

In patients 65-74, the 30-day mortality is 10%.

In patients 75-84, the 30-day mortality is 20%.

In patients > 85, the 30-day mortality is 30%.

Be vigilant and be aggressive with elderly patients. Their early management has a tremendous bearing on their later outcomes.

Whereas only 6% of young patients with PE present with syncope, 15-20% of elderly patients with PE present with syncope. The simple takeaway point is that whenever an elderly patient presents with syncope, always strongly consider the possibility of PE, even though they may lack classic pleuritic chest pain.
Count that respiratory rate for an inexpensive clue!