Fungal pericarditis

Article written and reviewed by Dr Luca Moretti

Fungal pericarditis is inflammatory involvement of the pericardium associated with a mycosis. In true infectious disease, the fungus reaches the pericardial fluid or tissue and may cause exudation, suppuration, necrosis, and adhesions. There is, however, a fundamental distinction: some pericardial manifestations, particularly in histoplasmosis, depend mainly on the immune response to a thoracic infection without demonstration of invasion of the sac. The presence of a fungus somewhere in the body is therefore not sufficient to define the mechanism of pericarditis.

This is a rare condition, and its specific literature consists mainly of reports and selected series. A systematic review published in 2025 collected 101 cases with microbiologic or tissue documentation: this number describes the published case series, not population incidence. The importance of immunosuppression, procedures, and disseminated infections requires joint cardiologic, infectious disease, and, when necessary, cardiac surgical assessment. Identification of the organism and control of the collection are as important as treatment of hemodynamic compromise.

The phenotype may overlap with purulent pericarditis, but not all fungal infections produce pus and not all fibrinous collections are infected. This monograph considers invasion, inflammatory response, and residual damage separately because therapy appropriate for one of these processes may be insufficient or harmful in the others.

Etiologic agents, predisposing conditions, and routes of infection

Candida species are among the organisms most frequently represented in reports of pericardial infection. They may reach the sac during candidemia, after cardiothoracic surgery, or through pathologic communications with adjacent structures. Parenteral nutrition, vascular access, broad-spectrum antibiotics, and disruption of mucosal barriers contribute to the risk of invasive candidiasis without individually constituting etiologic proof. Colonization of the skin, mouth, or respiratory tract must be distinguished from isolation from a normally sterile site.

Invasive aspergillosis mainly affects patients with prolonged neutropenia, hematologic malignancies, transplantation, or substantial immunosuppression. A pulmonary or mediastinal focus may spread by contiguity; hematogenous dissemination may involve the myocardium, endocardium, and other organs at the same time. The absence of candidemia or positive blood cultures does not reduce the probability of all mycoses to the same extent: invasive molds are often poorly documented by routine blood cultures, and diagnosis may require tissue material.

Mucorales are another possibility, particularly in the presence of poorly controlled diabetes, ketoacidosis, neutropenia, or immunosuppressive treatment. Vascular invasion promotes ischemic injury and necrosis, making diagnostic speed and surgical assessment essential. These infections should not be equated therapeutically with aspergillosis: some drugs active against Aspergillus do not cover Mucorales. A generic designation of mold based on an initial histologic examination should therefore be further specified without delaying clinically appropriate coverage.

Cryptococcus may involve the pericardium as part of disseminated disease, especially in people with impaired cell-mediated immunity. Assessment cannot stop at the chest because possible neurologic involvement changes the regimen and duration of therapy. Endemic mycoses instead require a careful geographic history, including remote residence, travel, and environmental exposures. The interval between acquisition and manifestation may be long; absence of recent travel does not exclude a relevant previous exposure.

In histoplasmosis classic pericardial involvement is often an inflammatory complication of thoracic disease. Its relationship with mediastinal lymphadenopathy and local inflammation explains why pericarditis may occur without a positive pericardial culture. This form must be distinguished from fungal invasion during disseminated disease, in which the problem is control of an organ infection. Immune status, lesion distribution, and microbiologic evidence guide this distinction, avoiding automatic application of the same treatment to pathogenetically different conditions.

The portal of entry should be reconstructed together with fungal identification. An esophageal fistula, mediastinitis, surgical wound, or infected device may maintain contamination despite therapy that is active in vitro. In other patients, dissemination primarily reflects the host's inability to contain infection. The relative frequency of individual organisms therefore depends strongly on the population observed: findings from a transplant series cannot be transferred without qualification to community-acquired pericarditis.

Pathogenesis, tissue injury, and hemodynamic consequences

Pericardial invasion activates the inflammatory response and alters microvascular permeability. The accumulating fluid contains proteins, cells, and variable amounts of fibrin; in suppurative forms, debris and necrotic material are added. Histologic expression depends on both the pathogen and host defenses. A neutropenic patient may have extensive infection without a marked neutrophilic response: the absence of macroscopically obvious pus therefore does not equal absence of invasive disease.

Fibrin may organize into septa and compartments that prevent free movement of fluid. This anatomy makes the effectiveness of a single catheter less predictable and may cause regional compression. The drained volume describes only the compartment reached; it does not necessarily measure the total infectious burden. Concordance among clinical course, imaging, and drain function is more informative than the amount collected alone, especially after surgery, when pre-existing adhesions further alter distribution.

Tamponade occurs when external pressure limits cardiac filling. The rate of accumulation and pericardial distensibility matter more than an isolated measurement of effusion thickness. A rapidly progressive collection may cause shock, whereas a slowly developing effusion may reach a larger size before compromising output. Tachycardia and vasoconstriction are early compensatory responses; preserved blood pressure does not exclude an evolving situation or justify delaying urgent assessment.

Compression may coexist with septic shock, with vasodilation, microcirculatory abnormalities, and organ dysfunction. Decompression removes the obstructive component but does not automatically correct the distributive component. If myocardial invasion or sepsis-related cardiac depression also occurs, a pump-failure component may persist. Hemodynamics must therefore be reassessed after drainage, distinguishing residual collection, vasoplegia, and ventricular injury; incomplete improvement alone does not prove procedural failure.

Angioinvasion by molds may cause small-vessel thrombosis, necrosis, and poor perfusion of infected tissue. This mechanism contributes to difficulty in eradication and the possible need to remove devitalized material. Involvement is not always limited to the pericardium: myocardial, valvular, or vascular lesions require a different strategy from that for an isolated effusion. Imaging and surgical assessment must therefore define anatomic relationships, not merely confirm the presence of fluid.

During healing, collagen deposition may replace the exudate and produce persistent adhesions. This may result in constrictive pericarditis, or a constrictive component may already be evident after evacuation of the effusion. Part of the stiffness may depend on still-reversible inflammation, whereas an established fibrous shell responds differently. In immune-mediated forms associated with histoplasmosis, injury instead arises mainly from the host response: recognizing this difference prevents interpreting any persistent inflammation as active fungal replication.

Clinical presentation, history, and physical examination

The clinical presentation is often less typical than uncomplicated acute pericarditis. Fever, dyspnea, asthenia, and general deterioration may predominate over pleuritic or positional pain. In patients already hospitalized, the first sign may be unexplained persistent fever, hemodynamic worsening, or a new effusion during treatment of a mycosis at another site. The rarity of this localization should not lead to overlooking it when exposure, host conditions, and clinical course create a coherent suspicion.

The infectious disease history includes previous cultures, antifungals received, any prophylaxis, procedures, vascular access, and thoracic infections. A mycosis arising during prophylaxis may reflect insufficient drug exposure, resistance, or an organism not covered; simply increasing the same drug empirically without reassessing these possibilities is insufficient. Corticosteroids, chemotherapy, antirejection drugs, and other immunomodulators must also be recorded because they modify risk, inflammatory response, and interactions with the proposed treatment.

The environmental history may point toward endemic mycoses when it includes residence in risk areas, activities involving exposure to soil or organic material, and contact with environments contaminated by bird or bat droppings. The value of these elements depends on geographic and temporal plausibility. They are not independent diagnostic criteria and do not justify indiscriminate panels in every patient; they become useful when linked to pulmonary findings, lymphadenopathy, or signs of dissemination.

On physical examination, a pericardial friction rub and pain modified by posture support inflammation but may be absent. Jugular venous distention, tachycardia, pulsus paradoxus, hypotension, and reduced perfusion suggest impaired filling. The classic combination of hypotension, muffled heart sounds, and venous congestion is not always complete, particularly in loculated cases or mixed shock. Edema and ascites may instead indicate more prolonged congestion and require distinction among residual compression, constriction, and myocardial disease.

The search for associated sites of infection includes respiratory signs, infected wounds, skin manifestations, neurologic deficits, and ocular symptoms when relevant. Not all findings are specific: a rash may be infectious or drug-related, whereas confusion and renal failure may result from sepsis. Suspected central nervous system involvement, particularly in cryptococcosis, requires a dedicated pathway. Severity assessment must include mental status, oxygenation, urine output, and perfusion rather than being limited to cardiac findings.

In the immunocompromised patient, fever and inflammatory markers may be attenuated, and concomitant neoplasia, renal failure, or drug toxicity multiplies the possible explanations for effusion. Clinical reasoning must keep these alternatives open until adequate documentation is obtained. Conversely, a septic presentation with a pericardial collection and risk factors requires prompt hospital assessment: the pathway cannot be equated with outpatient management of low-risk idiopathic pericarditis.

Investigations and demonstration of a fungal cause

Echocardiography is the initial examination for effusion size and distribution, signs of compression, ventricular function, and Doppler assessment. Echogenic material or septa suggest complex contents but do not prove a fungal origin. CT complements the study when posterior loculations, relationships with lung and mediastinum, or possible fistulas need to be defined. Magnetic resonance can characterize pericardial inflammation and myocardial involvement in a stable patient without replacing decompression when hemodynamics are compromised.

Blood tests include complete blood count, inflammatory markers, renal and liver function, and electrolytes; lactate and coagulation assessment are particularly relevant in sepsis. ECG and troponin help recognize cardiac involvement but do not identify the fungus. Blood cultures should be obtained when indicated before treatment, provided this does not delay urgent care. A positive Candida blood culture is clinically significant, whereas negative blood cultures do not exclude localized pericardial infection or an invasive mold.

Pericardiocentesis, when indicated for tamponade or suspected infection, can combine treatment and diagnosis. Material should be sent for direct examination, fungal and bacterial cultures, cytology, and selected additional investigations. The laboratory should know the clinical suspicion, previous therapies, and plausible organisms. A sample obtained under sterile conditions directly from the collection has a different value from material sampled later from a drainage circuit, in which contamination and colonization may complicate interpretation.

Pericardial biopsy is useful in selected cases, especially if drainage does not clarify the diagnosis or if a surgical procedure is already necessary. Histology and dedicated stains may demonstrate yeasts, hyphae, and tissue invasion. Morphology is informative but does not always distinguish species with different drug susceptibilities; culture and molecular techniques may complete identification. Material intended for microbiology must be separated from that fixed for histology because inappropriate preservation may preclude decisive tests.

Fungal biomarkers are supportive tools. Galactomannan and beta-D-glucan have context-dependent performance and do not localize infection to the pericardium; the latter is not specific for Aspergillus and is not a universal test for all fungi. Previously started therapy, fungal burden, and pre-analytical conditions influence results. Cryptococcal antigen, antigens, or serology for endemic mycoses should be selected according to suspicion. Thresholds validated only for blood or other samples should not be transferred to pericardial fluid.

Etiologic diagnosis requires synthesis: demonstration in a sterile site or tissue, clinical-anatomic compatibility, and assessment of alternatives. A serologic test showing exposure does not prove invasion, just as a fungus isolated from respiratory secretions may represent colonization. Tuberculosis, bacterial infections, neoplasms, and immune-mediated causes must be considered; multiple processes may coexist in vulnerable patients. Response to an antifungal may support a probable diagnosis but does not replace documentation when it can be obtained safely.

Definition of extent and treatment planning

After initial recognition, it is necessary to determine whether there is disseminated disease or predominantly pericardial localization. The extent of investigation depends on the fungus, symptoms, and host defenses. A pulmonary finding may be the source or another manifestation of the same dissemination; a neurologic lesion may affect drug selection because central nervous system penetration is required. The goal is not to perform every test indiscriminately but to identify sites that modify prognosis, duration, and mode of therapy.

Possible concomitant endocarditis should be assessed in the presence of persistent fungemia, prosthetic material, emboli, or suspicious findings. In this setting, transesophageal echocardiography may add information beyond transthoracic imaging. Valvular infection changes surgical indications and may require much more prolonged therapy. Recommendations developed for fungal endocarditis should not automatically be transferred to isolated pericarditis, nor should an infected valve be overlooked by attributing all instability to the effusion.

Assessment of the anatomic source includes any wounds, mediastinal collections, devices, and communications with the esophagus or other structures. Drug treatment does not close a fistula or remove an infected foreign body. The decision must integrate imaging, microbiology, and surgical feasibility, recognizing that pericardial drainage may be only one component of treatment. If multiple collections are present, the source-control plan should specify which compartments are accessible and which remain to be treated.

Species identification and susceptibility testing are particularly important when there has been previous exposure to azoles or echinocandins, or when response is inadequate. An in vitro result must be interpreted together with the site, drug exposure, and amount of necrotic tissue. Failure may result from resistance but also from inadequate absorption, interactions, incomplete drainage, or persistent immunosuppression. Changing drugs without distinguishing these possibilities risks leaving the principal determinant of poor response unchanged.

Assessment of immune defenses includes neutropenia, HIV infection when relevant, and the intensity of immunosuppressive treatments. Reducing immunosuppression may facilitate control of the mycosis but must be coordinated with the team managing transplantation or the underlying disease. Indiscriminate withdrawal may cause rejection or reactivation of the original disease. Likewise, immune recovery may modify the inflammatory expression: worsening imaging should not automatically be interpreted as fungal growth without reassessing clinical and microbiologic data.

Before and during therapy, a drug-monitoring plan is defined. Renal function, potassium, and magnesium are important with amphotericin B; liver function, ECG, and interactions are relevant with several azoles. For drugs and conditions that require it, measurement of plasma concentrations helps identify underexposure and toxicity. The medication list must include immunosuppressants and cardiovascular drugs: effective antifungal treatment may become dangerous if it significantly alters exposure to concomitant therapies.

Antifungal therapy, drainage, and control of inflammation

Etiologic therapy must be timely in severe invasive forms and adapted as soon as identification and susceptibility are available. There is no single regimen validated for all fungal pericarditis: many choices derive from recommendations for invasive mycoses integrated with pericardial case series. In an unstable patient, sampling, antifungal therapy, drainage assessment, and organ support proceed simultaneously. The benefit of drug treatment does not justify waiting when the collection causes tamponade or remains an uncontrolled infected source.

In invasive candidiasis, an echinocandin is frequently used as initial therapy, whereas lipid formulations of amphotericin B or azoles are indicated according to susceptibility, severity, and associated sites. Step-down to fluconazole requires stability and a susceptible isolate in addition to source control. Pericarditis is a deep-seated infection: the two-week rule after clearance used for candidemia without metastatic complications does not define the duration of this infection. Treatment should be continued according to clinical, anatomic, and microbiologic response.

For Aspergillus, voriconazole or a lipid formulation of amphotericin B are relevant options, with specialist selection and consideration of susceptibility. Echinocandins are not standard initial monotherapy for invasive aspergillosis. In mucormycosis, liposomal amphotericin B is central, combined when possible with removal of necrotic tissue; isavuconazole or posaconazole may have selected roles. Voriconazole does not cover Mucorales. These differences make it dangerous to treat all antifungals as interchangeable when the species has not yet been defined.

In cryptococcosis that is disseminated or involves deep sites, induction and subsequent consolidation should follow the overall disease picture, including investigation for neurologic disease. Amphotericin B and flucytosine, when indicated and available, are part of this pathway, followed by appropriate azoles. For severe or disseminated histoplasmosis, the IDSA consensus updated in 2026 favors initial amphotericin B, preferably liposomal. Reactive pericarditis associated with thoracic histoplasmosis is different: inflammation may require primarily anti-inflammatory treatment and individualized assessment of the need for antifungal therapy.

Drainage should be selected according to hemodynamics, viscosity, loculations, and the need for tissue. A catheter can decompress and provide diagnostic material; a window or more extensive procedure may be necessary when the collection is not controlled, septations are present, or devitalized tissue exists. Pericardiectomy is not automatic for every fungal isolate. Intrapericardial instillation of antifungals is not a routine strategy supported by comparative evidence and does not replace adequate systemic therapy.

Corticosteroids are not the usual treatment for invasive fungal infection because they may further impair host defenses. Their use for a well-defined immune-mediated response, such as some pericarditis associated with histoplasmosis, requires reasoned exclusion of invasion and infectious disease management of dissemination risk. NSAIDs and colchicine may relieve a selected inflammatory component but do not sterilize the collection. Azoles may also increase colchicine toxicity through metabolic interactions: the prescription must be reviewed, particularly in renal or hepatic impairment.

Prognosis, follow-up, and complications

Prognosis depends on the pathogen, immunity, extent of disease, timeliness of therapy, and ability to control the source. Percentages derived from published cases are influenced by selection of severe presentations, delayed diagnoses, and complex patients and should not become automatic individual estimates. Even an observed association between surgery and survival may be affected by candidate selection. Decisions should be based on anatomic and clinical indications while keeping transparent the limitations of evidence specific to such a rare disease.

Early follow-up assesses fever, perfusion, urine output, organ function, and symptoms together with echocardiography and microbiology when relevant. Cessation of drain output may indicate resolution but also fibrin obstruction or isolation of a residual pocket. An enlarging collection or persistent sepsis requires reassessment of the source, drug, and exposure. It is not sufficient to await normalization of a single biomarker while anatomy or general condition worsens.

Among acute complications, recurrent tamponade may result from residual or newly produced fluid. Sepsis may progress to multiorgan failure, whereas myocardial involvement may cause ventricular dysfunction and arrhythmias. Embolic or neurologic events require investigation for endocardial or disseminated involvement. Acute-phase management should therefore remain multidisciplinary even after apparently effective drainage, because relief of compression does not eliminate the risks of invasive infection.

Post-infectious constriction should be suspected when venous congestion, edema, ascites, or functional limitation persist without another explanation. Doppler, CT, and magnetic resonance help distinguish pericardial constraint, still-active inflammation, and myocardial disease. Persistent thickening alone does not prove constriction, just as sterilization of cultures does not guarantee mechanical recovery. In stabilized symptomatic cases with irreversible constraint, pericardiectomy may be required in an experienced center.

Treatment toxicities may complicate a prolonged course: nephrotoxicity and electrolyte abnormalities, liver injury, interactions, and absorption problems require planned monitoring. In transplant recipients, changes in antirejection drug concentrations may have consequences independent of the infection. New symptoms arising during therapy should not automatically be attributed to the fungus; drug toxicity must also be considered. Correct management aims to maintain effective exposure without accepting avoidable toxicity as an inevitable cost of treatment.

Long-term follow-up includes symptoms, cardiac function, residual collections, and immune recovery. Duration and intensity are individualized according to organism, associated sites, and response, without a single deadline valid for everyone. Before new immunosuppression, the risk of reactivation and any need for a specific preventive strategy should be discussed. Recovery must be described in terms of infection control and functional outcome: a stable scar, residual effusion, and still-active mycosis are different conditions requiring different decisions.

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