UMEM Educational Pearls - By Amal Mattu

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).

 Myocardial infarctions involving the left circumflex artery are often associated with ECGs that lack any ST-segment changes (38% in one representative study). Oftentimes when there are ST-changes, there may simply be anterior lead ST-segment depression. In these patients, acquisition of a few posterior leads frequently demonstrates STEMI. Some data does exist that failure to diagnose these posterior STEMIs (e.g. simply diagnosing anterior "ischemia" rather than posterior "STEMI") results in increased mortality.

So what's the bottom line?
1. In patients with isolated anterior lead ST-segment depression, always check for posterior STEMI with a couple of posterior leads.
2. In patients with non-significant ECGs but concerning persistent symptoms, always check for posterior STEMI with a couple of posterior leads.

This is always a great time to use that 80-lead ECG if your ED has one.

Amal

During this season of the ever-present viral respiratory illness, we must be on the lookout for the potentially-deadly -entity of myocarditis. A recent study suggests some clues to when the diagnosis should more strongly be considered in patients presenting with viral respiratory symptoms.

1. Most cases of myocarditis were not initially recognized by primary care MDs or emergency health care providers. 84% of patients needed more than one visit within 2 weeks before the diagnosis was made. This highlights the difficulty in Dx and frequent misdiagnosis rate.
2. The most common presenting symptom was dyspnea (69%) and most common sign was tachypnea (60%).
3. Although resting tachycardia is often taught as a common finding, 66% of patients had a normal HR.
4. The most helpful findings in terms of helping distinguish myocarditis from benign common viral URIs was hepatomegaly (present in 50%) and cardiomegaly (present in 60%).
5. An abnormal ECG was present in 100% of cases. The most common abnormalities were tachycardia, ventricular hypertrophy, and ST or T wave changes.
6. 54% of patients had elevated troponin levels.

So what's the bottom line?
1. If your patient has tachypnea or dyspnea, strongly consider getting a CXR. In that case, look carefully for cardiomegaly.
2. Always assess for and document the presence or absence of hepatomegaly.
3. A completely normal ECG is strong evidence against myocarditis.

[Durani Y, Egan M, Baffa J, et al. Pediatric myocarditis: presenting clinical characteristics. Am J Emerg Med 2009;27:942-947.]

Increasing literature has demonstrated that patients post-cardiac arrest benefit from induced hypothermia (IH). In addition, increasing literature has demonstrated that patients with cardiac arrest associated with STEMI are best treated with rapid percutaneous intervention (PCI) after their resuscitation. But what about the combination of IH + PCI in resuscitated cardiac arrest patients with STEMI?

There's now growing support for this concept as well. Wolfrum et al. demonstrated an improved mortality at 6 mos. (35% vs. 25%) in patients that had the combination of IH + PCI vs. patients receiving PCI alone after cardiac arrest and they also had better neurological outcomes.

Next time you have a STEMI patient that has a cardiac arrest who you resuscitate, talk to your cardiologists about the literature demonstrating the improved outcomes with combination IH plus PCI.

[Wolfrum S, Pierau C, Radke PW, et al. Mild therapeutic hypothermia in patients after out-of-hospital cardiac arrest due to acute ST-segment elevation myocardial infarction undergoing immediate percutaneous coronary intervention. Crit Care Med 2008;36:1780-1786.]

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 recent Baltimore City Marathon served as a nice reminder in a few cases that long-distance running and other ultra-endurance events can produce elevations in troponin levels. To review the non-cardiac-disease causes of troponin elevations:

sepsis, PE, COPD, carbon monoxide, intracranial abnormalities (including SAH, stroke, IC hemorrhage, seizures), ESRD, rhabdomyolysis, eclampsia and preeclampsia, extreme endurance exercises, UGI bleeding, LVH, catecholamine toxicity 

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.

Don't forget about pheochromocytoma as a possible cause of severe hypertension...especially in those patients that are recalcitrant to "normal" medications. A few important points:
1. Incidence may be as high as 0.2% of patients with hypertension...sounds very rare, but statistically we'll all see some during our career.
2. Mortality may be as high as 10% if unrecognized; but if recognized and treated, excellent prognosis.
3. Suspect this in patients with intermittent episodes of flushing, palpitations, diaphoresis, headaches, and hypertension.
4. Treatment with beta blockers alone (including labetalol) may induce unopposed alpha-activity and worsen BP.
5. Treat with nitroprusside or phentolamine (an alpha blocker). Phentolamine is 5 mg IV, can be repeated every 5-10min as needed.
6. After phentolamine is given, there may be reflex tachycardia. NOW you can add beta blockers.

The most important thing is to keep the diagnosis in mind. It's out there! But you'll miss 100% of the diagnoses you don't consider.

Systemic lupus erythematosus produces a significant predisposition towards premature atherosclerosis. Although the exact mechanism for what causes this is uncertain, premature CAD is at least partially (or largely) caused by systemic inflammation, which can produce endothelial damage and initiates the process of atherogenesis.

The literature indicates that there is a 9X increased risk of CAD in patients with lupus, and the risk increases to 50X higher in women 35-44 years of age! In general, patients with lupus develop their first MI 20 years earlier than age-matched non-lupus counterparts. 

[Mattu A, Petrini J, Swencki S, et al. Premature atherosclerosis and acute coronary syndrome in systemic lupus erythematosus. Am J Emerg Med 2005;23:696-703.]

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.

Acute aortic regurgitation pearls:
1. Most common cause is infective endocarditis
2. Also consider thoracic aortic dissection (chest pain plus new diastolic murmur)
3. Is the most common post-traumatic valvulopathy (chest trauma plus new diastolic murmur)
4. Presentation: diastolic decrescendo murmur at upper sternal border, may radiate to neck, hypotension, pulmonary edema
5. Treatment: get them to the OR! in the meantime, use vasopressors to support BP and afterload reduction to improve the pulmonary edema

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.

A recent study from Mayo evaluated 238 patients with acute pericarditis and found that the "classic" features of acute pericarditis that we learned about are actually not as common as we think:

1. Only 50% of patients reported that their pain was positional and 70% reported that their pain was pleuritic. On the other hand, 12% reported pain that was typical anginal in nature.

2. Only 35-45% of patients reported a recent history of a viral illness.

3. Only 15-25% of patients had a friction rub.

4. Further complicating matters was the presence of positive troponin levels in 13% of the patients.

In this study, 17% of patients were sent for PCI because the treating physicians diagnosed the patients as having an acute MI. This study highlights the importance of maintaining pericarditis in the DDx of any patients with chest pain, even when it "sounds like an MI," and also maintaining vigilance for atypical features of pericarditis.

Pericarditis is one of the conditions that is often misdiagnosed as STEMI, resulting in "inappropriate" cath lab interventions. In addition to producing STE, pericarditis also may produce dyspnea, diaphoresis, and elevations in TN levels, all of which will mimic true ACS.

On the other hand, pericarditis does NOT produce STE in up to one-third of cases, so the diagnosis may be missed. Non-STE cases of pericarditis occur more often in women, in patients with pericardial effusions, and in patients without preceding viral syndromes.

[Salisbury AC, et al. Frequency and predictors of urgent coronary angiography in patients with acute pericarditis. Mayo Clin Proc 2009;84:11-15.] 

Elderly are more likely to have non-diagnostic ECGs. The proportion of patients > 85 years of age with NSTEACS who had non-diagnostic ECGs was 43% vs. 23% for patients < 65 years of age. [Elderly are also more likely to have LBBB as well as prior evidence of MI, either one of which can cause some problems with interpretation of acute cardiac ischemia.] The lack of CP combined with non-diagnostic ECGs probably leads to delays and under-treatment of many of these patients.

[Alexander KP, et al. Acute coronary care in the elderly, part I: Non-ST-segment elevation acute coronary syndromes. Circulation 2007;115:2549-2569.]