Continuing Education Activity

Dressler syndrome, also known as postmyocardial infarction syndrome, is a form of secondary pericarditis with or without pericardial effusion that occurs as a result of injury to the heart or pericardium. Given its wide-ranging clinical presentation, Dressler syndrome can be difficult for health professionals to recognize. This activity reviews the clinical presentation, evaluation, and management of patients with Dressler syndrome and highlights the role of the interprofessional team in caring for patients with this condition.

Objectives:

• Describe the clinical presentation of a patient with Dressler syndrome.
• Identify risk factors for the development of Dressler syndrome.
• Review treatment considerations for patients with Dressler syndrome.
• Explain the need for a well-integrated, interprofessional team approach to improve care for patients with Dressler syndrome.

Introduction

Dressler syndrome (DS), also known as postmyocardial infarction syndrome, is a form of secondary pericarditis with or without pericardial effusion resulting from injury to the heart or pericardium.[1] Though not a common condition, Dressler syndrome should be considered in all patients presenting with persistent malaise or fatigue following a myocardial infarction (MI) or cardiac surgery, especially if symptoms present greater than two weeks following the event.[2]

Etiology

Pericarditis is a condition in which the pericardium (a fibroelastic sac surrounding the heart comprised of a parietal and visceral layer that is separated by a potential space) becomes inflamed. Under normal circumstances, the pericardial cavity holds 15 to 50 mL of pericardial fluid (an ultrafiltrate of plasma).

Dressler syndrome is part of a group of post-cardiac injury syndromes, which include:

1. postpericardiotomy syndrome
2. post-traumatic pericarditis from blunt or penetrating trauma
3. iatrogenic causes including
   1. percutaneous coronary or intracardiac interventions 
   2. pacemaker lead insertion,
   3. radiofrequency ablation[3][4][5]

Each represents a different clinical condition characterized by an initial cardiac injury involving the pericardium/myocardium and/or pleura and the subsequent inflammatory syndrome ranging from simple, uncomplicated pericarditis to more complicated cases with pleuropericarditis, cardiac tamponade, or massive pleural effusion.[6]

The exact cause of Dressler syndrome is unknown, though it is presumed that an initial injury to mesothelial pericardial cells combined with blood in the pericardial space triggers an immune response and results in an immune complex deposition in the pericardium, pleura, and lungs which causes an inflammatory response.[7]

This theory is supported by a number of observations regarding post-cardiac injury syndromes. There is often a distinct latency period observed at the time of cardiac injury and the development of post-cardiac injury syndromes, with symptoms typically starting anywhere from 3 or 4 days to 2 to 6 weeks post-injury(with occasional symptoms developing a few months post-injury). Both pleural effusion and/or pulmonary infiltrates sometimes present. Additionally, patients that have undergone cardiac surgery with subsequent post-cardiac injury syndrome often are found to have more elevated levels of anti-actin and actomyosin antibodies postoperatively. Finally, patients with Dressler syndrome or another post-cardiac injury syndrome tend to respond very well to anti-inflammatory treatments, and relapses are occasionally seen with withdrawal from steroids. 

Epidemiology

In the initial study examining Dressler syndrome in 1956, William Dressler suggested that the syndrome would occur in approximately 3% to 4% of patients with myocardial infarction (MI). However, with modern improvements in managing acute myocardial infarctions, the condition is seen in much fewer patients. This may be attributable to successful interventions resulting in a reduction in the size of the infarct and subsequently damaged myocardium, thereby preventing the immune-mediated response seen in Dressler syndrome.

The risk of developing Dressler syndrome tends to be greater in post-MI patients who have suffered a more extensive infarction. Also, relapses are more likely to occur if a patient has already had a previous Dressler syndrome episode. Additional predisposing factors for Dressler syndrome include:

1. viral infections
2. surgeries involving more significant myocardial damage
3. younger age
4. prior history of pericarditis
5. prior treatment with prednisone
6. B negative blood type
7. and use of halothane anesthesia 

In terms of viral infections, a seasonal variation in the incidence of the condition has been noted, where the condition is seen more commonly when the prevalence of a viral infection in the community is greatest too. Though elevated viral titers are found in patients experiencing associated Dressler syndrome, viral components have not been isolated from the pericardium itself or the pleural effusion of these patients.[8]

Surgeries that result in greater damage to the myocardium (e.g., aortic valve replacement) are more likely to result in Dressler syndrome than those that cause less myocardial injury (e.g., mitral valve replacement). It is, however, important to note that Dressler syndrome can occur in patients that have undergone surgeries resulting in minimal trauma to the myocardium (e.g., needle puncture of a ventricle, CABG). Therefore, it is difficult to determine whether the extent of myocardial damage predicts the incidence of Dressler syndrome.[9]

Finally, patients undergoing cardiac surgery that have a higher risk for developing Dressler syndrome are:

1. younger age
2. have a B-negative blood type
3. prior history of pericarditis or treatment with prednisone

The above should raise clinical suspicion, and practitioners should be cautious to note early signs of the condition (e.g., chest pain, persistent de novo fever).[10]

Pathophysiology

The exact cause of Dressler syndrome is unknown, though it is thought to be immune-mediated. Antimyocardial antibodies have been shown to be elevated in the blood of patients with Dressler syndrome. Still, it is unclear whether these antibodies are the cause or occur as a result of the syndrome. These anti-myocardial antibodies are thought to target antigens that have become exposed through damage to the pericardium.[11]

Viruses that have been associated with Dressler syndrome include:

1. Coxsackie B
2. Adenovirus
3. Cytomegalovirus

 These patients present with elevated levels of viral components.[12]

History and Physical

Patients typically present with symptoms of Dressler syndrome 1 to 6 weeks following the initial damage to the pericardium. The most commonly encountered symptoms include

1. fever
2. malaise/generalized weakness,
3. pleuritic chest pain
4. irritability
5. decreased appetite
6. Palpitations/tachycardia
7. dyspnea (with or without hypoxia)
8. arthralgias

Though most patients tend to present with a temperature between 100.4 F and 102.2 F (measured orally), occasional reports of temperatures as high as 104 F have been noted. Not all patients will appear concomitantly ill, and the fever generally will subside within 2 to 3 weeks.

Children with Dressler syndrome may complain of chest pain that is worse with inspiration or while lying down. Emesis often occurs in children with Dressler syndrome who have a risk of impending cardiac tamponade.

On physical examination, patients with Dressler syndrome are often tachycardic with a pericardial friction rub heard on auscultation. This characteristic pericardial friction rub may disappear. This can be secondary to either improvement in or worsening of accumulation of pericardial fluid and, therefore, cannot be used predictively. Additionally, patients may present with pulsus paradoxus (greater than 10 mmHg decrease in blood pressure with inspiration and decreased pulse amplitude palpated on the radial artery).

Finally, some patients with Dressler syndrome may exhibit signs of pneumonitis (e.g., a cough, decreased oxygen saturation, fever). The pulmonary component to symptoms ranges from minimal with no pulmonary complaints to significant respiratory distress with large pulmonic effusions.   

Evaluation

The standard diagnostic procedure and most sensitive imaging study for evaluating a patient with suspected Dressler syndrome is an echocardiogram (echo). An echo will allow for evaluation of the pericardial fluid, if present, and help discern the exact cause of reduced cardiac output (i.e., determine whether truly DS or another condition such as congestive heart failure). An echo will further allow for the evaluation of ventricular contractility, in addition to the assessment of the potential risk of cardiac tamponade (i.e., if cardiac chambers appear compressed by pericardial fluid). The more pericardial fluid that accumulates, the easier it is to detect its presence by echocardiography.[13]

While definitive evaluation with an echocardiogram is the gold standard, bedside cardiac ultrasound by a skilled emergency physician may be necessary. These patients are at risk for cardiac tamponade, and care should NOT be delayed while awaiting formal echocardiography.  

If it is difficult to assess the posterior pericardium with an echo, cardiac magnetic resonance imaging (MRI) may be employed to determine whether there is any effusion. In some instances, fluid collections may also become loculated. This is also more readily visualized with cardiac MRI than with echo.[14]

Chest radiography (X-ray) may be employed if echocardiography is not available. A chest X-ray will reveal flattening of the costophrenic angles and enlargement of the cardiac silhouette as a result of both pleural and pericardial effusions.[15][16]

An electrocardiograph (ECG) in a patient with Dressler syndrome will initially demonstrate global ST-segment elevation and T-wave inversion, such as with pericarditis. Further inflammation of the myocardium will also result in ST-segment elevations. Both electrical alternans (variation in amplitude or directionality of QRS from beat to beat) and/or a low voltage QRS may also be observed if there is a large volume of pericardial effusion. 

Blood cultures should be obtained early in the workup of Dressler syndrome as this will help differentiate between inflammatory versus infectious causes of the patient’s condition. In the case of true Dressler syndrome, blood cultures should be negative.

Laboratory studies that may help point toward a diagnosis of Dressler syndrome include an elevated white blood cell count (with a leftward shift) and elevated acute phase reactants (e.g., erythrocyte sedimentation rate and C-reactive protein). Additionally, a high titer of anti-heart antibodies may present in serology.

If possible, pericardial fluid (e.g., through a pericardial drain) should be examined for cell count, differential, cultures, Gram stain, cytology, total protein, and triglyceride levels.[17]

Treatment / Management

Most patients with suspected Dressler syndrome are treated in an outpatient setting with close follow-up unless the patient is hemodynamically unstable. The approach typically involves NSAIDs (e.g., aspirin, ibuprofen, naproxen) tapered over 4 to 6 weeks as the accumulated pericardial fluid diminishes. Patients who do not respond to NSAID therapy may be given a course of corticosteroids (e.g., prednisone) tapered over a 4-week period.[18]  Another potential treatment option is colchicine. Some studies suggest that taking this drug before cardiac procedures may reduce the risk of Dressler syndrome; its effectiveness, once Dressler syndrome has developed, is unclear

More severe cases of Dressler syndrome (i.e., symptoms that may indicate imminent cardiac tamponade or constrictive pericarditis) may require inpatient care involving pericardial drainage. Pericardiocentesis with subsequent catheter drainage (generally 24 to 48 hours) and concomitant initiation of anti-inflammatory treatment is considered the standard of care for patients with a significant pericardial effusion. If the effusion is global (surrounding the entire heart) and visible anteriorly (in front of the right ventricle), the subxiphoid approach for pericardiocentesis is recommended in addition to echocardiographic guidance. 

Recurrence of post-pericardiotomy syndrome, including Dressler syndrome, is common, and relapses have been reported up to 1 year following the initial event. Some suggest that intravenous immunoglobulin therapy has some benefits in refractory cases, especially in children.[19] Clinicians should remember that the number one risk factor for developing Dressler syndrome is having had it before.

Differential Diagnosis

With presenting symptomology being so wide and varied, the differential diagnosis could also be very broad. However, with the more classic symptoms of chest pain, dyspnea, fever, malaise, and tachycardia, there are certainly a few very important differentials. As often most of these patients have been recently hospitalized and undergone some sort of procedure, they are at risk for several other potentially serious problems. This list would include the following:

1. Pulmonary embolus
2. Sepsis
3. Pneumonia
4. Congestive heart failure
5. Influenza
6. Recurrent cardiac injury (such as acute MI/in-stent re-stenosis or valve failure)
7. Acute anemia with or without GI bleed
8. Endocarditis
9. Uremia

Secondary to this broad and potentially life-threatening subset of other disease processes, the evaluation for Dressler syndrome will often include evaluation for these other processes.

Treatment Planning

As mentioned above, the treatment options range from the simple use of NSAIDs, with close out-patient cardiology follow-up, to the need for emergent pericardiocentesis for those patients with hemodynamic compromise. The majority of patients with Dressler syndrome are those patients who are non-toxic, without hemodynamic compromise, and often able to be safely discharged once other potentially serious diagnoses have also safely been ruled out.

Prognosis

The prognosis for patients with Dressler syndrome is typically quite good. Even those patients requiring pericardial drainage usually have a favorable prognosis. Still, they have an increased risk for reaccumulation of fluid and subsequent need for repeat pericardiocentesis and adjustments to medication regimens. If constrictive pericarditis develops, the need for pericardial stripping may become evident.

Complications

The most serious potential complication from Dressler syndrome is by far pericardial tamponade leading to a risk of complete cardiovascular collapse. There is often a pericardial effusion with Dressler syndrome, and this fluid build-up around the heart can lead to ineffective relaxation and filling of the atrioventricular system by causing direct pressure and therefore affecting both diastolic filling and systolic squeeze. Classic findings of tamponade include Beck's triad:

1. Low blood pressure
2. Distended neck veins (jugular venous distension)
3. Muffled/distant heart tones

This is a true emergency and requires rapid action. Delay in providing removal can lead to cardiac collapse and death. As little as 200 cc can cause tamponade depending upon how rapidly the collection developed. The potential space can hold up to 2 liters of fluid; however, this is quite rare.

Consultations

Early cardiology consultation in suspected Dressler syndrome is recommended.

Deterrence and Patient Education

In those patients being discharged, all should be made aware of the need to return for an evaluation immediately if signs of Dressler syndrome develop, including signs of progression of effusion and signs of developing infection (i.e., increased shortness of breath, increased pain, palpitations, dizziness/lightheadedness, fevers, altered mentation, and syncope). Cardiology follow-up should be arranged by the referring physician.

Enhancing Healthcare Team Outcomes

The diagnosis of Dressler syndrome is not easy and can be confused with many other cardiac disorders. Hence, it is best managed with an interprofessional team that includes a cardiac nurse, emergency department physician, cardiologist, radiologist, and intensivist.

Most patients with suspected Dressler syndrome are treated in an outpatient setting with close follow-up unless the patient is hemodynamically unstable. The approach typically involves NSAIDs (e.g., aspirin, ibuprofen, naproxen) tapered over 4 to 6 weeks as the accumulated pericardial fluid diminishes.  Patients who do not respond to NSAID therapy may be given a 1-week course of corticosteroids (e.g., prednisone) tapered over a 4-week period.[18]

More severe cases of Dressler syndrome may require pericardial drainage by the cardiac surgeon or cardiologist.

The outlook for most patients with Dressler syndrome is excellent.  However, the recovery may take 2 to 4 weeks.[20]