Management of Chest Pain in a 49-Year-Old Male with Recent Lithium Discontinuation
This patient requires immediate cardiac evaluation with a 12-lead ECG within 10 minutes and cardiac troponin measurement to rule out acute coronary syndrome (ACS), while simultaneously addressing the potential cardiac toxicity from lithium and the risks associated with abrupt lithium discontinuation. 1
Immediate Assessment (Within 10 Minutes)
Obtain a 12-lead ECG immediately to evaluate for ST-segment elevation, ST-segment depression, T-wave inversions, or new left bundle branch block that would indicate ACS. 1, 2 The patient's description of "squeezing" chest pain that radiates to the shoulder represents a concerning pattern that warrants urgent cardiac evaluation. 3, 4
Draw high-sensitivity cardiac troponin (preferably troponin T or I) immediately upon presentation, as this is essential for diagnosing myocardial injury. 1, 2 Repeat troponin measurement at 6-12 hours after symptom onset for complete risk stratification. 1, 2
Measure serum lithium level urgently given the recent medication change and potential for either lithium toxicity (if levels remain elevated) or withdrawal effects. 5 Lithium cardiotoxicity can cause ECG abnormalities, dysrhythmias, and even acute myocardial infarction, particularly in patients with underlying cardiac disease. 6, 5
Critical Differential Diagnosis Considerations
Cardiac Causes Requiring Immediate Attention
Acute Coronary Syndrome is the primary concern given the patient's age (49 years), male sex, and description of squeezing chest pain radiating to the shoulder. 3, 4 The ability to point to a specific location does not exclude ACS, as this characteristic alone is insufficient to rule out cardiac ischemia. 1, 3
Lithium-induced cardiotoxicity must be considered, as toxic lithium levels can cause myocardial infarction even with normal coronary arteries. 5 A 62-year-old woman with lithium level of 2.3 mmol/L presented with ST-elevation MI that resolved after lithium elimination, with normal coronary angiography. 5
Stress-induced cardiomyopathy (Takotsubo) should be considered given the temporal relationship with the disciplinary segregation stressor. 3
Non-Cardiac Causes to Evaluate
Musculoskeletal chest wall pain is possible given the punctual nature and ability to localize, but this diagnosis should only be made after cardiac causes are excluded. 3 The radiation pattern to the shoulder and squeezing quality are concerning for cardiac origin. 1, 3
Initial Medical Management
If ACS is suspected based on clinical presentation, immediately initiate:
- Aspirin 75-250 mg (or clopidogrel if aspirin contraindicated) 1, 2
- Low molecular weight heparin or unfractionated heparin 1, 2
- Beta-blocker (unless contraindicated by hemodynamic instability) 1, 2
- Nitrates (oral or intravenous) for persistent or recurrent chest pain 1, 2
Important caveat: Do not use nitroglycerin response as a diagnostic criterion, as esophageal spasm and other conditions also respond to nitroglycerin. 3
Risk Stratification and Disposition
High-Risk Features Requiring Urgent Coronary Angiography
Transfer immediately to a facility with cardiac catheterization capabilities if any of the following are present: 1
- Recurrent ischemia (recurrent chest pain or dynamic ST-segment changes, particularly ST-segment depression or transient ST-segment elevation) 1
- Elevated troponin levels 1, 4
- Hemodynamic instability (hypotension, pulmonary rales) 1, 4
- Major arrhythmias (repetitive ventricular tachycardia, ventricular fibrillation) 1
In high-risk patients, coronary angiography should be performed within 48 hours of presentation, or immediately if severe ongoing ischemia, major arrhythmias, or hemodynamic instability are present. 1
Additional Diagnostic Testing
Obtain chest X-ray to evaluate for alternative causes including pneumonia, pneumothorax, or heart failure. 1, 2
Measure hemoglobin to detect anemia as a potential contributor to cardiac ischemia. 1, 2
Perform transthoracic echocardiography if hemodynamic disturbances are present or to assess left ventricular function, particularly given the risk of lithium-induced cardiomyopathy. 1, 6
Lithium-Specific Considerations
The FDA label states that lithium should generally not be given to patients with significant cardiovascular disease, and toxic levels are close to therapeutic levels. 7 The abrupt discontinuation of lithium in this patient raises two concerns:
- Potential ongoing lithium toxicity if levels remain elevated, which can cause cardiac complications including myocardial infarction 5
- Risk of psychiatric decompensation from abrupt discontinuation, though this should not delay cardiac evaluation 7
If lithium toxicity is confirmed (level >1.5 mmol/L), treatment includes: 7
- Cessation of lithium (already done) 7
- Correction of fluid and electrolyte imbalance 7
- Hemodialysis for severe toxicity 7
- Serial lithium level monitoring 7
Common Pitfalls to Avoid
Do not dismiss this presentation as musculoskeletal pain simply because the patient can point to a specific location. The squeezing quality and radiation pattern are concerning for cardiac origin. 1, 3
Do not delay cardiac evaluation to address psychiatric concerns related to lithium discontinuation. Cardiac evaluation takes priority. 1
Do not assume a normal ECG excludes ACS. Serial ECGs and troponin measurements over 6-12 hours are required for complete evaluation. 1, 2
Do not discharge without observation if initial troponin is negative but clinical suspicion remains. A second troponin at 6-12 hours is mandatory. 1, 2
Observation Period Requirements
If initial ECG and troponin are normal but ACS cannot be excluded, observe for 6-12 hours with: 1
- Multi-lead continuous ECG ischemia monitoring 1
- Repeat 12-lead ECG if chest pain recurs 1
- Repeat troponin measurement at 6-12 hours after symptom onset 1, 2
- Monitoring for hemodynamic instability 1
Only after negative serial troponins, no recurrent symptoms, and no high-risk features can outpatient management be considered. 4