Amal Mattu, MD FAAEM
If you hear a friction rub, mark the date on your calendar because it may be a long time before you hear another.
Cardiology Corner: Pericarditis
- The diagnosis of acute pericarditis requires at least two of the following symptoms or signs: chest pain consistent with pericarditis, pericardial friction rub, typical ECG changes, or a pericardial effusion of more than a trivial size.
- Misinterpretation of the ECG is a potential pitfall; look for any ECG changes that rule-in STEMI.
- Treatment with nonsteroidal anti-inflammatory drugs and colchicine is well-studied and effective.
- Troponin elevation may indicate concurrent myocarditis; these patients are at higher risk for complications of CHF or arrhythmia.
LeWinter MM, et al. Clinical practice. Acute pericarditis. N Engl J Med. 2014 Dec 18;371(25):2410-6. PMID: 25517707.
What are the biggest pitfalls in the diagnosis and treatment of pericarditis? Misinterpretation of the ECG. Overdiagnosis of acute pericarditis rather than true STEMI based on age of the patient or characterizations of pain. STEMI may produce sharp and positional pain and may occur in younger patients.
How do you diagnose pericarditis?
- If you hear a pericardial friction rub, you are lucky. The rub is very specific but less sensitive for pericarditis. It occurs at some point during the disease process in most patients but is transient. The rub is usually a high-pitched, scratching sound that is heard best at the left sternal border. It may be heard in any or all of the phases of cardiac activity. You can listen to the heart sounds with the patient supine, sitting up, and leaning forward.
- The diagnosis of acute pericarditis requires at least two of the following symptoms or signs: chest pain consistent with pericarditis, pericardial friction rub, typical ECG changes, or a pericardial effusion of more than a trivial size. There aren’t any good studies that have determined clear diagnostic criteria; most of this appears to be based upon consensus and experience.
- What are the classic chest pain symptoms? Sharp chest pain that tends to be pleuritic. It tends to be positional. Classically, it radiates to the trapezius ridge as the left phrenic nerve lies across the pericardium.
- The ECG is not always a classic presentation. You may have pericarditis with non-specific ECG findings.
- There are probably many patients with pericardial inflammation that we send home with a diagnosis of musculoskeletal or non-specific chest pain, and the majority do fine. We should probably be concerned about the patients with pronounced symptoms and ECGs.
How common are the ECG changes? There isn’t good literature available, possibly due to the vague diagnostic criteria of pericarditis. The majority of patients with a final diagnosis of pericarditis have ECG changes, but there is diagnostic bias involved.
What are typical ECG changes?
- ST elevation in multiple leads. It does not have to involve all 12 leads. There will often be PR segment depression in the involved leads. There are some caveats: the ST elevation may be very subtle and sometimes only PR depression is apparent.
- PR depression is not pathognomonic for acute pericarditis; acute coronary syndromes may produce PR depression. Any atrial abnormality can produce PR segment changes. It is helpful, but it is not pathognomonic for pericarditis.
- Look for any ECG changes that rule-in STEMI: ST elevations which are horizontal or convex, ST segment or reciprocal depression. ST depression may be present in leads V1 or aVR in many conditions. However, if you see ST depression in any of the other ten leads, it virtually rules out pericarditis and you are looking at a STEMI.
- Spodick’s sign is downsloping of the TP segment. This is fairly predictive of pericarditis. A study examining this association is currently underway.
- The classic diffuse ST elevation and PR depression is often present only with viral pericarditis. There has to be inflammation in the pericardial region to produce the classic ECG changes, and conditions such as uremia may not manifest with classic ECG findings.
- Four stages of ECG findings in pericarditis are often taught, however it is very rare that we see this in the Emergency Department. This is more useful for board examination preparation. Stage 1 is the classic ST elevation with PR depression. Stage 2 has normalization of the ST and PR segments. Stage 3 has inversion of the T waves. Stage 4 has normalization of all segments. This process may take a week or more.
The review article recommends a work-up including a complete blood count with a differential, high-sensitivity C-reactive protein (CRP), measurements of troponin I or T, serum creatinine, and liver function tests. Is this really necessary? These are designed to identify unusual causes of pericarditis and complications. Troponin may be elevated in about 15-25% of patients with pericarditis. The pericardium does not release troponin. Elevation in troponin suggests that there may be concurrent myocarditis. These patients are at higher risk for complications such as congestive heart failure or arrhythmias. This might be an indication to admit or monitor the patient.
Not all patients with pericarditis need to be admitted. If the patient has reasonable follow-up, the patient might be discharged. Patients that are afebrile, not immunosuppressed, have no history of trauma, have no evidence of myopericarditis, have no large pericardial effusion, and are not on anticoagulants tend to do well when managed as outpatients. If they have any of the above conditions, they should probably be observed or admitted to rule out complications such as congestive heart failure or arrhythmias.
Patients may have a low grade fever with pericarditis, especially with suspected viral etiology. However, fevers greater than 38.5ºC (101.3ºF) might indicate another etiology such as a bacterial infection or tuberculosis.
It is a good idea to get an echocardiogram. This does not necessarily need to be done prior to discharge if the patient has good follow-up. This is to make sure they don’t have a large effusion, as this is a predictor of complications. However, if you have bedside ultrasound available, it is very simple to rapidly identify a large pericardial effusion.
- The nonsteroidal anti-inflammatory drug (NSAID) and colchicine combination has been well-studied and found to be effective.
- NSAIDs used are often ibuprofen (600-800mg every 6-8 hours) or indomethacin. However, indomethacin tends to have more side effects. In Europe, aspirin is frequently used (2-4 grams per day in divided doses). A proton pump inhibitor (PPI) is also recommended.
- Colchicine is recommended and recent literature has been supportive. The anti-inflammatory effect is thought to be due to blockage of microtubule assembly in white cells. Colchicine has been found to decrease the duration and intensity of symptoms, as well as decrease the likelihood of recurrence. It needs to be given for about 3 months. The most common side effects are gastrointestinal, but most patients tolerate it well. There are several different dosing regimens. The review article recommends a dose of 0.5 mg twice a day in patients with a body weight >70 kg and 0.5 mg daily with a body weight <70 kg.
- Most patients’ symptoms resolve within the first week. Some suggest following the CRP to determine duration of therapy.
- Steroids are not recommended. There is some evidence that they may increase the rate of recurrence and blunt the effect of colchicine. They may be an option in patients with renal insufficiency who are not candidates for treatment with NSAIDs or colchicine, but this has not been discussed much in the literature. Aspirin in combination with a PPI may be another option in patients with renal insufficiency.
Should recurrences be treated differently? No. Give NSAIDs and colchicine.