Q: What is the differential diagnosis for this patient's complaints and physical findings? Do either the subjective or objective findings provide a clear indication of the diagnosis?

A: The differential for the patient's subacute onset of dyspnea includes primarily cardiac and pulmonary disorders. Coronary ischemia should be considered highly as a possible cause of dyspnea in this patient, even in the absence of chest pain. Other nonspecific presentations of acute coronary ischemia and myocardial infarction in older people include confusion, syncope, weakness, abdominal pain, nausea/vomiting and stroke, but aside from weakness, these symptoms are not present in this case. Left ventricular failure commonly presents with breathlessness and tachypnea, either with or without overt congestive signs or symptoms. In elderly people, both systolic dysfunction and diastolic dysfunction (with diminished left ventricular compliance and decreased diastolic filling) are common causes of symptomatic heart failure. Among the possible pulmonary causes, pneumonia and pulmonary embolism are potential causes in the absence of a history of an underlying chronic pulmonary condition.

This presentation is notable for a lack of specific physical findings to confirm or rule out any of these causes of dyspnea. Such nonspecific presentations of serious illness are common in frail elderly people, and the presence of diabetes may further blunt subjective and objective signs of disease.

In this case, onset of dyspnea occurred after an exertional episode. Aerobic capacity is diminished in congestive heart failure (CHF), and symptoms are provoked when tissue demands exceed that capacity. The patient's insomnia could be due to orthopnea or paroxysmal nocturnal dyspnea from CHF, even in the absence of signs of either right heart failure (peripheral edema) or left heart failure (rales, S3, S4, neck vein distention). The quick look EKG evaluation shows sinus rhythm, but little else can be ascertained from this quick-look. A 12-lead EKG evaluation is indicated to assess for coronary ischemia, although it is not helpful in diagnosing heart failure per se. However, even if EKG indicators of cardiac ischemia and infarction such as ST segment depression or elevation are absent, significant ischemia cannot be ruled out on this basis alone. Both elderly patients and diabetics more frequently present with non Q wave infarcts and are more likely to have either no changes appreciated on EKG evaluation, or to have baseline EKG abnormalities such as bundle branch block that limit the utility of diagnostic EKG for determining ischemia. As a result, "silent" myocardial infarction in older diabetic patients may be appreciated only in retrospect, based on the presence of new Q waves on a routine EKG.)

Lack of fever or cough make pulmonary infection less likely, but elderly and diabetic patients may present with atypical, subtle or delayed symptoms. Findings of systemic illness such as fever and elevated white count may not be present. This patient has adequate O2 saturation, arguing against a severe V/Q mismatch, but this alone is not sufficient to rule out a pneumonia or a pulmonary embolism. At this point, there is no history to suggest that this patient has risk factors for lower extremity deep venous thrombosis (DVT), but DVT cannot be ruled out based on a lack of physical findings such as unilateral edema, presence of Homan's sign or palpable venous cords. Based on the nonspecificity of this presentation, together with a high index of suspicion for cardiac disease, further evaluation should be undertaken to elucidate the cause of his symptoms.

Further evaluation includes a 12-lead EKG that shows 2mm ST segment elevation in the anterior precordial leads, and a portable chest x-ray reveals a normal heart size and an absence of infiltrates or pulmonary edema.

IMPRESSION: Probable acute anterior myocardial infarction. As an elderly male diabetic with symptoms suggestive of acute coronary ischemia, his pre-test probability of an acute coronary event is high. The 12-lead EKG provides additional confirmation of this suspicion. The earliest onset of his symptoms was about 8 hours previously, although it appears his symptoms of dyspnea increased markedly less than 3 hours ago. At this point, a decision must be made either to proceed with immediate treatment for myocardial infarction with a thrombolytic agent or other aggressive intervention, to opt for a less aggressive treatment approach (e.g., a symptom management approach), or to proceed with further diagnostic testing to rule out other causes of his symptoms.

Q: What would be your next step in this situation?

A: Based on the information available, the most urgent (and likely) diagnostic possibility is that this patient is having a myocardial infarction. The age of this patient does not preclude providing standard therapy for treatment of an acute infarction. Based on the time of onset of his marked dyspnea less than 3 hours ago, together with EKG evidence of acute anterior infarction, it is appropriate to consider him for emergent thrombolytic therapy. In the absence of chest pain, his dyspnea may be considered a "chest pain equivalent", and he should be given therapy as indicated for ischemic chest pain, including oxygen 4L/minute, nitroglycerin sublingually, 325mg aspirin (bite and swallow) and IV morphine as needed to relieve the discomfort. As for younger patients, he may also benefit from adjunctive therapies such as IV nitroglycerin, additional ACE inhibitor therapy, and IV beta-adrenergic blocking agents, although in patients with systolic blood pressure of <100, these agents may be contraindicated. Current studies indicate that thrombolytic therapy is beneficial for elderly people with acute infarction who are otherwise appropriate for this therapy. IV thrombolytic therapy reduces mortality from acute myocardial infarction in older patients, and the benefit of treatment is similar or greater than in younger patients.

Elderly people should also be considered for more invasive therapy if indicated, including coronary angioplasty and bypass surgery, although they have increased peri-procedural morbidity and mortality rates compared with younger individuals. Little is known about the efficacy of standard therapy in the "oldest old" age group (>85years).

A less aggressive, symptomatic management approach (potentially including the other therapies such as morphine, nitroglycerin, oxygen and aspirin mentioned above) would be indicated if the patient refuses thrombolytic agents or an invasive procedure after being fully informed of their benefits and risks, or contraindications are present.

After administration of thrombolytic therapy or a coronary revascularization procedure, close observation is warranted for complications such as congestive heart failure and arrhythmias, as in younger individuals. Moreover, there is still a possibility that one of the other diagnoses in the original differential may also be present, and further management for one of these conditions may be necessary.

Copyright 1999, 2000 David A. Gruenewald, M.D. and Kayla I. Brodkin, M.D. All rights reserved.