The pericardium is a serous membrane that envelops the heart, providing mechanical protection, reducing friction during cardiac movement, and contributing to the maintenance of intrathoracic pressure. It consists of two layers:
The parietal pericardium, the outermost layer, which is closely connected to the pleura and diaphragm.
The visceral pericardium, also called epicardium, which adheres directly to the heart and great vessels.
Between these two layers there is a virtual space, known as the pericardial cavity, containing a small amount of serous fluid (about 10-50 mL) with lubricating function, produced by pericardial capillaries and reabsorbed by lymphatic vessels.
Pathophysiology of Pericarditis
Pericarditis is an inflammatory process of the pericardium accompanied by a series of structural and functional alterations of the pericardial membrane. Inflammation leads to:
Increased vascular permeability → with leakage of plasma proteins into the pericardial fluid.
Activation of the immune system → with recruitment of leukocytes and release of pro-inflammatory mediators (IL-1, IL-6, TNF-α).
Changes in pericardial fluid → which turns from a serous transudate into a pathological exudate.
Pericarditis and Pericardial Effusion
Pericarditis is not always associated with a significant effusion: small amounts of fluid may also be present in healthy individuals or in patients with systemic conditions (heart failure, nephrotic syndrome).
When present, the effusion may vary in quantity and composition, influencing the clinical presentation:
Moderate effusion → usually well tolerated, without hemodynamic compromise.
Large effusion → may cause cardiac compression with risk of cardiac tamponade.
Chronic effusion → may evolve into constrictive pericarditis, with fibrosis and calcification.
Classification of Pericarditis
Pericarditis is classified according to the characteristics of the exudate:
Caseous pericarditis: characterized by necrotic material, typical of tuberculosis.
Hemorrhagic pericarditis: exudate mixed with blood, frequent in neoplasms and advanced tuberculosis.
This classification has important clinical implications, as the different forms may have different etiologies, course, and prognosis.
Clinical Presentation and Symptoms
The clinical manifestations of pericarditis may vary according to the severity of inflammation and the amount of pericardial fluid accumulated. The most common symptoms include:
Chest pain: typically pleuritic, worsened by deep breathing and supine position, improved by sitting up.
Dyspnea: related to the presence of effusion and impaired cardiac dynamics.
Fever and malaise: mainly present in infectious or autoimmune forms.
Pericardial friction rub: a distinctive auscultatory sign, due to the presence of fibrin between the pericardial layers.
Diagnosis of Pericarditis
Diagnosis is based on a combination of clinical, laboratory, and instrumental data:
Echocardiography: useful for assessing the presence of effusion and cardiac function.
Cardiac MRI: indicated in doubtful cases to confirm pericardial inflammation.
Blood tests: increased CRP, ESR, and leukocytosis in inflammatory forms.
Pericardial fluid analysis: performed in cases of significant effusion to determine the etiology.
Treatment of Pericarditis
Treatment varies according to the cause and severity of pericarditis:
NSAIDs (ibuprofen, aspirin): first-line therapy in viral and idiopathic pericarditis.
Colchicine: used to reduce the risk of recurrence.
Corticosteroids: indicated only in cases of autoimmune etiology or refractory to NSAIDs.
Antibiotics: necessary in bacterial or suppurative pericarditis.
Pericardiocentesis: indicated in cases of large effusion or cardiac tamponade.
Prognosis and Evolution
The prognosis of pericarditis depends on the underlying cause:
Viral or idiopathic forms → generally benign, with spontaneous resolution.
Autoimmune forms → possible recurrences, requiring immunosuppressive therapy.
Bacterial or tuberculous forms → high risk of progression to constrictive pericarditis.
An adequate echocardiographic follow-up is essential to monitor the resolution of inflammation and prevent complications.
Serous Pericarditis
Serous pericarditis is the mildest and most frequently self-limiting form of pericardial inflammation. It is characterized by the presence of a clear exudate or slightly cloudy, rich in proteins, monocytes, and lymphocytes, but devoid of fibrin. This distinction is crucial, as it prevents the formation of adhesions between the pericardial layers.
The inflammatory process is mediated by the production of pro-inflammatory cytokines (IL-1, IL-6, TNF-α), which increase capillary permeability and promote the passage of fluid into the pericardial cavity. However, in the absence of fibrin, resolution is generally spontaneous and without fibrotic sequelae.
Treatment is generally symptomatic with NSAIDs and colchicine. In more complex cases, corticosteroids may be necessary.
Serofibrinous Pericarditis
Serofibrinous pericarditis represents an intermediate form between serous pericarditis and fibrinous pericarditis. It is distinguished by the presence of a cloudy exudate, rich in inflammatory proteins and fibrin strands, which may deposit on the pericardial surfaces.
This condition is associated with a more marked inflammatory process, with greater activation of mediators such as IL-1, IL-6, and TNF-α, which increase vascular permeability and promote the recruitment of inflammatory cells.
Distinctive Features
Cloudy exudate with fibrin: the pericardial fluid is denser and richer in inflammatory proteins.
Thickened and opaque pericardial surfaces: loss of the mesothelial lining with possible subepicardial inflammatory infiltrate.
Presence of pericardial friction rubs: due to friction between the pericardial layers partially covered with fibrin.
Main Causes
The causes of serofibrinous pericarditis partially overlap those of the serous form, but with a more intense and prolonged inflammation. Among the main ones:
Treatment involves NSAIDs and colchicine, with possible use of corticosteroids in forms secondary to autoimmune diseases.
Fibrinous Pericarditis
Fibrinous pericarditis represents an advanced stage of serofibrinous pericarditis, characterized by a pericardial exudate almost exclusively fibrinous, with a scant liquid component. The reduced lubrication between the pericardial layers leads to the typical pericardial friction rub, a distinctive clinical sign of this condition.
Distinctive Features
Exudate rich in fibrin: reduced serous component with fibrin deposits on the pericardial surface.
Thickened and rough pericardium: “bread and butter” appearance due to the layering of fibrin.
Friction between the pericardial layers: causes pericardial friction rubs, audible on chest auscultation.
Main Causes
The causes of fibrinous pericarditis include:
Advanced uremia → the most common cause in renal failure.
Myocardial infarction → early phase or Dressler syndrome.
Treatment involves NSAIDs and colchicine, with possible drainage in the presence of associated effusion.
Purulent or Suppurative Pericarditis
Purulent, or suppurative, pericarditis is a severe form of pericardial inflammation caused by bacterial, fungal, or, more rarely, parasitic infections. It is distinguished by the presence of a dense, yellowish exudate rich in pus, with a high infiltration of neutrophils and a high risk of structural complications.
Distinctive Features
Purulent exudate: opaque, dense fluid loaded with cellular debris.
Severely inflamed pericardium: thickened, hyperemic, with possible necrosis.
Purulent pericarditis has an aggressive course and can lead to:
Cardiac tamponade → due to rapid accumulation of pus.
Constrictive pericarditis → due to massive post-infective fibrosis.
Septicemia → with high mortality if not treated early.
Treatment
Unlike other forms, purulent pericarditis requires:
Targeted antibiotic therapy → based on pericardial fluid culture.
Pericardial drainage → to prevent cardiac tamponade.
Pericardiectomy → in cases of advanced fibrosis.
Early treatment is crucial to prevent irreversible complications.
Caseous Pericarditis
Caseous pericarditis is a rare form of pericardial inflammation, typically associated with tuberculosis and, more rarely, chronic fungal infections such as histoplasmosis. It is characterized by the presence of a granulomatous, dense, white-yellowish exudate, with caseous necrosis and lymphomonocytic infiltrates.
Distinctive Features
Caseous necrosis: tissue destruction with deposits of yellowish, cheese-like material.
Granulomas with Langhans giant cells: a typical sign of tuberculosis.
High risk of constrictive pericarditis: due to a strong tendency toward fibrosis and calcification.
Main Causes
Caseous pericarditis is almost always secondary to:
Caseous pericarditis has a strong tendency to progress to constrictive pericarditis, due to progressive deposition of fibrotic tissue and calcifications.
Frequent complications include:
Fibrosis and pericardial thickening → reduced ventricular compliance.
Diffuse calcifications → a typical sign in advanced forms.
Risk of cardiac tamponade → in the case of massive effusion.
Treatment
Management of caseous pericarditis includes:
Antituberculous therapy → prolonged treatment with isoniazid, rifampicin, pyrazinamide, and ethambutol.
Pericardial drainage → in cases of significant effusion.
Early treatment is essential to avoid irreversible damage.
Hemorrhagic Pericarditis
Hemorrhagic pericarditis is a severe form of pericardial inflammation characterized by the presence of an exudate mixed with blood, fibrin, and, in some cases, pus. This condition is often a sign of advanced systemic diseases or neoplastic processes infiltrating the pericardium.
Distinctive Features
Bloody exudate: pericardium impregnated with blood, with fibrin and cellular debris.
Focal pericardial necrosis: possible in the most severe forms.
High risk of cardiac tamponade: due to rapid accumulation of fluid in the pericardial cavity.
Main Causes
The main causes of hemorrhagic pericarditis include:
Infiltrating neoplasms → lung tumors, breast tumors, mesotheliomas, and lymphomas.
Tuberculous pericarditis → frequently associated with hemorrhagic effusion.
Coagulopathies → use of anticoagulants, thrombocytopenia, DIC.
Cardiac trauma → iatrogenic perforations or post-surgical injuries.
Evolution and Prognosis
The main complications of hemorrhagic pericarditis are:
Cardiac tamponade → due to rapid accumulation of fluid.
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