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Fungal Infections
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Uwe Wollina, Pietro Nenoff, Shyam Verma, Uta-Christina Hipler
Clinical presentation: This is a subacute or chronic infection caused by dimorphic fungi. Lymphocutaneous sporotrichosis starts as a painless purple or blackish nodule on exposed skin that erodes into a small ulcer (sporotrichotic chancre) with swollen edges, a painful granulomatous center, and minimal discharge. This is followed by lymphangitis with secondary nodules along the line of lymphatic drainage that can progress to ulcers (sporotrichoid spread). Fixed sporotrichosis characterized by the presence of a solitary lesion. The disease is limited and presents as a slow growing verrucous plaque.
Myocarditis
Published in Mary N. Sheppard, Practical Cardiovascular Pathology, 2022
The incidence of invasive fungal disease has dramatically increased over the past few decades corresponding to the rising number of immunocompromised patients linked mostly to HIV and cancer. The major risk factors for severe cardiac fungal disease are prolonged administration of antibiotics, corticosteroids and cytotoxic agents, invasive medical procedures, and transplant recipients. Invasive fungal infection often affects multiple organs and cardiac involvement frequently occurs in disseminated disease. The most frequently diagnosed opportunistic invasive fungal infection of the myocardium are Candida, Aspergillus and Cryptococcus. Others are dimorphic fungi such as Histoplasma, Blastomyces and Coccidioides. These fungi are ubiquitous, usually acquired from host surroundings (Cryptococcus neoformans, Aspergillus fumigatus) or are components of the normal endogenous flora (Candida albicans). The mortality of the infected patients remains high even after intensive antifungal therapy attributed to the patient's immunodeficiency, belated diagnosis or fungal disease resistance.
Basic Microbiology
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Fungal cells are eukaryotic, containing membrane-bound intracellular organelles, but also possess cell walls. However, rather than peptidoglycan (bacterial) or cellulose (plants), the fungal cell wall is composed of glucans, mannans, glycoproteins, trehalose, and chitin (a strong and flexible polysaccharide). Single-celled microscopic fungi are referred to as “yeasts” and contain a single nucleus and ovoid morphology. Yeasts are commonly larger than bacteria and lack extracellular fibers like flagella or fimbriae. Multicellular fungal forms are called “molds” comprising long branching filaments called hyphae with many individual cells where the cytoplasm in the hyphae are contiguous with neighboring cells. The hyphae of molds generally form a tangled mass called a mycelium. “Dimorphic” fungi are those that can alternate between yeast and mold forms depending on environmental conditions. For example, Histoplasma capsulatum grows in the environment as a mold but upon infection of the lung grows exclusively as a yeast form (3).
Histoplasmosis presenting as colitis and blood dyscrasias in a patient with systemic lupus erythematosus
Published in Baylor University Medical Center Proceedings, 2022
Dua Noor Butt, Muhamad Sheharyar Warraich, Akshay Machanahalli Balakrishna, Mahmoud Ismayl, Sumbul Liaqat, Kanza Noor Butt, Joseph Thirumalareddy, Manasa Velagapudi
Histoplasmosis is the most common endemic mycosis in the United States.1,2 There is a wide spectrum of disease manifestations, ranging from asymptomatic infections to acute pulmonary infections to devastating progressive disseminated disease.3 The causative organism H. capsulatum is a dimorphic fungus. It grows as a mold in the environment at cooler temperatures and as a yeast at 37°C at body temperature. Most patients infected with this fungus experience asymptomatic hematogenous dissemination throughout the reticuloendothelial system via parasitized macrophages. Progressive disseminated histoplasmosis is common in patients with impaired cell-mediated immunity. AIDS, hematologic malignancy, solid organ transplantation, hematopoietic stem cell transplantation, corticosteroid use, tumor necrosis factor antagonist therapy, congenital T-cell deficiency, and infancy and old age have been reported as risk factors.4
Endemic mycoses: epidemiology and diagnostic strategies
Published in Expert Review of Anti-infective Therapy, 2020
Andrés Tirado-Sánchez, Gloria M. González, Alexandro Bonifaz
Dimorphic fungi predominating in several geographic environments produce endemic mycoses. The most common or major endemic mycosis are coccidioidomycosis (CDM), histoplasmosis (HPL), paracoccidioidomycosis (PCM), blastomycosis (BLM). Talaromycosis (TLM), adiaspiromycosis (ADM), and emergomycosis (EME) are emerging endemic mycoses [1,2]. The frequency of these infections has increased worldwide in recent decades [3]. This increase has been associated with immigration, tourism, and professional trips. Global warming has also increased the prevalence of fungal infections predominantly by adaptive thermo-tolerant species with significant pathogenic potential [4]. The increasing prevalence of immunocompromised populations in recent decades [5], mainly concerning human immunodeficiency virus (HIV), has dramatically augmented the incidence of endemic mycoses that were once considered rare, such as talaromycosis and disseminated histoplasmosis [6,7].
Spontaneous pneumothorax secondary to chronic cavitary pulmonary histoplasmosis
Published in Journal of Community Hospital Internal Medicine Perspectives, 2020
Histoplasma capsulatum is a dimorphic fungus that is classically endemic to the Midwestern and Central USA [1]. This includes the Mississippi and Ohio River Valleys in which parts of North Texas are included [2]. It typically enters hosts through the respiratory tract and only causes symptoms in a small number of patients [3]. Infection with Histoplasma capsulatum, termed histoplasmosis, can present in a variety of ways, including both acute and chronic forms. Symptoms are somewhat non-specific, and include chest pain, productive cough, dyspnea, fever, and fatigue [3]. Chronic cavitary pulmonary histoplasmosis is one of the rarest presentations of histoplasmosis, and typically manifests as apical cavitary lesions in patients with pre-existing chronic obstructive pulmonary disease [3]. These apical cavitary lesions are frequently mistaken for malignancy or pulmonary tuberculosis. It is important to remember that chronic pulmonary infection with Histoplasma capsulatum can cause apical cavitary lung disease, it is often misdiagnosed, and lack of appropriate treatment portends a poor prognosis [4,5].