Overwhelming pulmonary blastomycosis associated with the adult respiratory distress syndrome

Battling the breath-stealers: Blastomyces and Pseudomonas triggering acute respiratory distress syndrome (ARDS)

Blastomycosis is an endemic disease in North America and commonly manifests with pulmonary symptoms. Blastomycosis should be consider when patients have persistent infiltrates on imaging in an endemic area. We present a case of a 46-year-old male who presented to the pulmonary clinic with fever, cough with production of yellowish-green sputum and culture of BAL-fluid showed growth of Pseudomonas spp. Antimicrobial therapy was started accordingly, but was not effective. A repeat bronchoscopy was performed and BAL-fluid culture was positive for Blastomyces dermatitidis and liposomal amphotericin B was initiated. Unfortunately, the patient died after withdrawing care.

Case series of dogs with blastomycosis managed with high-flow nasal oxygen therapy (2019-2023): 19 cases

Objective

To describe the clinical presentation, progression, treatment, and outcome of dogs with blastomycosis treated with high-flow nasal oxygen therapy (HFNOT).

Design

Retrospective case review.

Setting

University veterinary teaching hospital.

Animals

Nineteen client-owned dogs with strongly suspected or confirmed blastomycosis treated with HFNOT.

Measurements and main results

The medical records of dogs with strongly suspected or confirmed blastomycosis between October 2019 and May 2023 that received HFNOT were evaluated. Nineteen dogs were included. Nine dogs were started directly on high-flow nasal oxygen therapy. The remaining 10 dogs first received traditional oxygen therapy and were then transitioned to HFNOT 3-142 h later. Of the 19 dogs, 1 survived to discharge from hospital, 12 were euthanized due to progression of disease, and 6 died during the hospitalization period.

Conclusions and clinical importance

The prognosis for survival of dogs with severe blastomycosis requiring therapy beyond traditional oxygen methods was poor to grave in this population. This is the first known documented report of HFNOT use in dogs with confirmed or suspected blastomycosis.

Blastomycosis Complicated by Adult Respiratory Distress Syndrome in an Immunocompetent Adult: A Case Report and Literature Review

Blastomycosis is an endemic mycotic infection caused by inhalation of thermally dimorphic fungi from the genus Blastomyces. Blastomyces dermatitidis is the species most related to human infection in the USA and North America. Adult respiratory distress syndrome (ARDS) is a rare complication of blastomycosis and is associated with high mortality. Due to its rarity, evidence-based guidelines for diagnosing and treating ARDS associated with blastomycosis are scarce. In this case presentation, a 22-year-old male with a history of chronic cannabis use presented with severe respiratory symptoms, initially treated as community-acquired pneumonia. Despite antibiotic treatment, his condition deteriorated, necessitating intubation and resulting in the development of ARDS. A delayed diagnosis of pulmonary blastomycosis was confirmed through polymerase chain reaction testing. Treatment with amphotericin B and corticosteroids proved successful in addressing the fungal infection, leading to the recovery of the patient from his severe clinical condition. This case highlights the challenges associated with diagnosing and treating blastomycosis, particularly when complicated by ARDS, emphasizing the importance of considering fungal infections in the differential diagnosis of non-responsive pulmonary infections. Additionally, it suggests the potential utility of corticosteroids in severe cases and emphasizes the crucial role of early diagnosis and a combination of diagnostic modalities for the timely management of this rare and potentially life-threatening condition.

Use of Venovenous Extracorporeal Membrane Oxygenation in Patients With Acute Respiratory Distress Syndrome Caused by Fungal Pneumonia

Background: Patients with fungal pneumonias sometimes progress to acute respiratory distress syndrome (ARDS). Mortality has been reported as high as 60% to 90% in this group. Venovenous extracorporeal membrane oxygenation (VV-ECMO) can be used to support such patients, however, outcomes are not well understood. Patients and Methods: This was a retrospective study across the four adult ECMO centers in Minnesota for one decade (2012-2022). The outcomes of interest were duration of ECMO, survival rate, and complications. Data were extracted from the electronic medical record and analyzed using descriptive statistics. Results: Fungal pneumonia was the etiology of ARDS in 22 of 422 (5%) adults supported with VV-ECMO during the 10-year study period. Median patient age was 43 years (interquartile range [IQR], 35-56) and 68% were male. By type of fungal infection, 16 (72%) had blastomycosis, five (22%) had pneumocystis, and one (5%) had cryptococcus. Of the 16 patients with blastomycosis two were immunosuppressed whereas all five of the pneumocystis patients were immunosuppressed. The overall survival rate was 73%; most patients with blastomycosis (67%) and pneumocystis (80%) survived to hospital discharge. The duration of ECMO support was greater for the pneumocystis group (median, 30 days; IQR, 21-43) compared with blastomycosis (median, 10 days; IQR, 8-18). Conclusions: Our findings support the use of VV-ECMO for ARDS caused by fungal pneumonias in select immunocompetent and immunocompromised patients. Although survival was high, patients with pneumocystis required longer ECMO runs.

Endemic mycoses in children in North America: a review of radiologic findings

Clinically significant endemic mycoses (fungal infections) in the United States (U.S.) include Blastomyces dermatitidis, Histoplasma capsulatum, and Coccidioides immitis/posadasii. While the majority of infections go clinically unnoticed, symptomatic disease can occur in immunocompromised or hospitalized patients, and occasionally in immune-competent individuals. Clinical manifestations vary widely and their diagnosis may require fungal culture, making the rapid diagnosis a challenge. Imaging can be helpful in making a clinical diagnosis prior to laboratory confirmation, as well as assist in characterizing disease extent and severity. In this review, we discuss the three major endemic fungal infections that occur in the U.S., including mycology, epidemiology, clinical presentations, and typical imaging features with an emphasis on the pediatric population.

Blastomycosis: A Review of Mycological and Clinical Aspects

Blastomycosis is caused by a thermally dimorphic fungus that thrives in moist acidic soil. Blastomyces dermatitidis is the species responsible for most infections in North America and is especially common in areas around the Great Lakes, the St. Lawrence Seaway, and in several south-central and southeastern United States. Other Blastomyces species have more recently been discovered to cause disease in distinct geographic regions around the world. Infection almost always occurs following inhalation of conidia produced in the mold phase. Acute pulmonary infection ranges from asymptomatic to typical community-acquired pneumonia; more chronic forms of pulmonary infection can present as mass-like lesions or cavitary pneumonia. Infrequently, pulmonary infection can progress to acute respiratory distress syndrome that is associated with a high mortality rate. After initial pulmonary infection, hematogenous dissemination of the yeast form of Blastomyces is common. Most often this is manifested by cutaneous lesions, but osteoarticular, genitourinary, and central nervous system (CNS) involvement also occurs. The diagnosis of blastomycosis can be made by growth of the mold phase of Blastomyces spp. in culture or by histopathological identification of the distinctive features of the yeast form in tissues. Detection of cell wall antigens of Blastomyces in urine or serum provides a rapid method for a probable diagnosis of blastomycosis, but cross-reactivity with other endemic mycoses commonly occurs. Treatment of severe pulmonary or disseminated blastomycosis and CNS blastomycosis initially is with a lipid formulation of amphotericin B. After improvement, therapy can be changed to an oral azole, almost always itraconazole. With mild to moderate pulmonary or disseminated blastomycosis, oral itraconazole treatment is recommended.

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Radical treatment for blastomycosis following unsuccessful liposomal amphotericin

Pulmonary blastomycosis is a respiratory disease that is caused by the fungus Blastomyces spp, which is acquired through inhalation of the fungal spores. Blastomycosis is relatively uncommon, with yearly incidence rate of 1-2 cases per 100 000 people. Blastomycosis is a disease that is endemic to the midwest and southern regions of the USA, most commonly affecting immunocompromised patients. About 50% of patients are asymptomatic, but for those who progress to acute respiratory distress syndrome (ARDS) mortality can be as high as 80%. Patients with severe blastomycosis are initially treated with intravenous amphotericin B, followed by long-term itraconazole maintenance therapy. In this Grand Round, we present the case of an immunocompetent 35-year-old man diagnosed with chronic pulmonary blastomycosis who had a poor response to 10 days of intravenous liposomal amphotericin B (L-AmB). He was endotracheally intubated and eventually cannulated for extracorporeal membrane oxygenation (ECMO), due to worsening respiratory function. L-AmB was replaced with a continuous infusion of intravenous amphotericin B deoxycholate (AmB-d). He improved significantly and was decannulated from ECMO on day 9 of AmBd continuous infusion and extubated on day 12 Although L-AmB is considered first-line treatment for blastomycosis, mortality remains high for patients with ARDS associated with blastomycosis. This case highlights the importance of considering AmB-d continuous infusions for patients with severe blastomycosis who might have poor clinical responses to L-AmB.

Blastomycosis-Some Progress but Still Much to Learn

Blastomycosis, caused by Blastomyces spp., is an endemic mycosis capable of causing significant disease throughout the body. Higher rates of infection are seen in the Mississippi and Ohio River valleys, the Great Lakes region of the United States and Canada, much of Africa, and, to a lesser extent, in India and the Middle East. Limited reporting inhibits our true understanding of the geographic distribution of blastomycosis. An estimated 50% of those infected remain asymptomatic. Of those who present with symptomatic disease, pulmonary involvement is most common, while the most common extrapulmonary sites are the skin, bones, genitourinary system, and central nervous system. Itraconazole is the standard therapy for mild-moderate disease. Data for other azoles are limited. Amphotericin is used for severe disease, and corticosteroids are occasionally used in severe disease, but evidence for this practice is limited. Despite increasing incidence and geographic reach in recent years, there are still significant knowledge gaps in our understanding of blastomycosis. Here, we provide an updated review of the epidemiology, clinical presentations, and diagnostic and therapeutic approaches for this infection. We also discuss areas needing further research.

Blastomycosis-Induced Acute Respiratory Distress Syndrome

Blastomycosis is a systemic mycosis endemic to the Midwestern and South Central United States. Infection is caused by inhaling spores of Blastomyces dermatitidis (B. dermatitidis) that inhabit soil. Acute respiratory distress syndrome (ARDS) is a rare complication of pulmonary blastomycosis with a significantly high mortality rate. We present a case of blastomycosis associated with severe ARDS treated with traditional prone position ventilation (PPV) and neurally adjusted ventilator assist (NAVA) along with antifungal therapy, steroids, and supportive care in a rural setting with no access to extracorporeal membrane oxygenation (ECMO). This case demonstrates that traditional therapies such as prone position ventilation can help patients with blastomycosis-associated ARDS especially in rural settings where advanced therapies such as ECMO are lacking. The use of NAVA in blastomycosis-associated ARDS needs further research.

Outcomes With Severe Blastomycosis and Respiratory Failure in the United States

BACKGROUND

Outcomes of patients with severe pulmonary blastomycosis requiring mechanical ventilation (MV) are not well understood in the modern era. Limited historical case series reported 50-90% mortality in patients with acute respiratory distress syndrome caused by blastomycosis. The objective of this large retrospective cohort study was to describe the risk factors and outcomes of patients with severe pulmonary blastomycosis.

METHODS

We performed a retrospective cohort analysis utilizing the Nationwide Inpatient Sample from 2006-2014. Patients aged >18 years with a diagnosis of blastomycosis who received MV were included.

RESULTS

There were 1848 patients with a diagnosis of blastomycosis included in the study. Of these, 219 (11.9%) underwent MV with a mortality rate of 39.7% compared with 2.5% in patients not requiring ventilatory support (P < .01). The median (IQR) time to death for patients requiring MV was 12 (8-16) days. The median length of hospital stay for survivors of MV was 22 (14-37) days. The rate of MV was higher for patients treated in teaching hospitals (63.4% vs 57.2%, P = .05) and lower for those receiving care at a rural hospital (12.3% vs 17.2%, P = .04). In a multivariate model, female gender was associated with increased risk of mortality (OR, 1.84; 95% CI, 1.06-3.20; P = .03) as was increasing patient age (10-year age increase OR, 1.64; 95% CI, 1.33-2.02; P < .01).

CONCLUSIONS

In the largest published cohort of patients with blastomycosis, mortality for patients on MV is high at ~40%, 16-fold higher than those without MV.

Clinical Manifestations and Outcomes in Immunocompetent and Immunocompromised Patients With Blastomycosis

BACKGROUND

Blastomyces is a dimorphic fungus that infects persons with or without underlying immunocompromise. To date, no study has compared the clinical features and outcomes of blastomycosis between immunocompromised and immunocompetent persons.

METHODS

A retrospective study of adult patients with proven blastomycosis from 2004-2016 was conducted at the University of Wisconsin. Epidemiology, clinical features, and outcomes were analyzed among solid-organ transplantation (SOT) recipients, persons with non-SOT immunocompromise (non-SOT IC), and persons with no immunocompromise (NIC).

RESULTS

A total of 106 cases met the inclusion criteria including 74 NIC, 19 SOT, and 13 non-SOT IC (malignancy, HIV/AIDS, idiopathic CD4+ lymphopenia). The majority of patients (61.3%) had at least 1 epidemiologic risk factor for acquisition of Blastomyces. Pneumonia was the most common manifestation in all groups; however, immunocompromised patients had higher rates of acute pulmonary disease (P = .03), more severe infection (P = .007), respiratory failure (P = .010), and increased mortality (P = .02). Receipt of SOT primarily accounted for increased severity, respiratory failure, and mortality in immunosuppressed patients. SOT recipients had an 18-fold higher annual incidence of blastomycosis than the general population. The rate of disseminated blastomycosis was similar among NIC, SOT, and non-SOT IC. Relapse rates were low (5.3-7.7%).

CONCLUSIONS

Immunosuppression had implications regarding the acuity, severity, and respiratory failure. The rate of dissemination was similar across the immunologic spectrum, which is in sharp contrast to other endemic fungi. This suggests that pathogen-related factors have a greater influence on dissemination for blastomycosis than immune defense.

Varied Presentation of Fulminant Blastomycosis with Prostatitis and Acute Respiratory Distress Syndrome in a Patient With High Inoculum Inhalation: A Review of Diagnosis and Management

Blastomycosis is an uncommon granulomatous disease caused by infection with thermally dimorphic fungi of the genus Blastomyces. Although pulmonary infections from Blastomyces dermatitidis are uncommon, it is important to understand the geographical distribution, presentation, diagnosis, and management of treating this condition. We report a case of fulminant blastomycosis after high inoculum inhalation, with involvement of the prostate on presentation, which progressed to acute respiratory distress syndrome.

Mortality associated with Blastomyces dermatitidis infection: A systematic review of the literature and meta-analysis

Published case fatality in blastomycosis patients ranges between 4% and 78%. This study aimed to assess mortality associated with blastomycosis and identify its associated risk factors. We conducted a systematic review of publications related to Blastomyces dermatitidis available in PubMed and Scopus databases. Studies that reported data on blastomycosis mortality and that were published from inception through February 2018 were assessed and included in the analysis. Using the R meta package, a random-effect model meta-analysis was used to calculate pooled and stratified estimates of case-fatality proportions and risk ratios. Of 1553 publications, we included 20 studies reporting on a total of 2820 cases of blastomycosis between 1970 and 2014 and three case series reports with 10, 21, and 36 patients. The mean or median ages ranged from 28 to 59 years. Mortality was defined as attributable mortality caused by blastomycosis in 13 studies. Among 14 studies with a standard error ≤0.05, the overall pooled mortality was 6.6% (95% confidence interval [CI], 4.9-8.2) with 57% heterogeneity. The mortality rate was 37% (95% CI, 23-51) in immunocompromised patients and 75% (95% CI, 53-96) in patients who developed an acute respiratory distress syndrome (ARDS) (n = 3 studies each). ARDS was the only identified risk factor in general patients (risk ratio = 10.2). The overall mortality was significantly higher in studies involving immunocompromised patients and ARDS patients. Our analysis showed considerable heterogeneity among studies. Inconsistent mortality definitions may have contributed to the observed heterogeneity. Further research is needed to assess potential risk factors for mortality.

The importance of skin exam in chronic pulmonary blastomycosis

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-Blastomycosis is a chronic granulomatous disease that usually starts as a pulmonary infection.

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-A high percentage of patients will develop a disseminated disease if the initial lung infection is left untreated.

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-Cutaneous blastomycosis is the most common extrapulmonary manifestation.

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-Definitive diagnosis requires direct visualization of the yeast at staining or positive fungal culture.

Cutaneous blastomycosis is the most common extrapulmonary manifestation of disseminated blastomycosis, a disease caused by Blastomyces dermatitidis, a dimorphic fungus endemic of North America. Initially, the organism enters the respiratory system by inhalation of the infectious conidia and produces an acute pulmonary infection that may eventually disseminate if it is left untreated. Blastomycosis may represent a diagnostic challenge and its definitive diagnosis requires direct visualization of the distinctive yeast or a positive fungal culture. The objective of this case report is to highlight the importance of the skin exam and tissue biopsy in the diagnosis of blastomycosis. We present a previously healthy patient with chronic pneumonia, evaluated at Pulmonary clinic with non-diagnostic thoracentesis and bronchoscopy, found to have disseminated blastomycosis after biopsy of a scalp lesion in Dermatology clinic.

Altered Pharmacokinetics and Dosing of Liposomal Amphotericin B and Isavuconazole during Extracorporeal Membrane Oxygenation

Drug pharmacokinetics may be significantly altered in patients receiving extracorporeal membrane oxygenation (ECMO). Ensuring the optimized effective dosing of antimicrobials on ECMO remains a challenge. To date, limited data are available regarding the optimal use of amphotericin and triazoles during ECMO. We report a case of altered pharmacokinetics, insufficient liposomal amphotericin B and isavuconazole levels, and the need for escalated doses during ECMO in a patient with severe acute respiratory distress syndrome secondary to pulmonary blastomycosis. A 2-fold increase in the standard total daily dose of both drugs was necessary to overcome low serum concentrations thought to be secondary to drug loss from ECMO circuit sequestration. These findings have important implications for optimizing antimicrobial therapy in patients receiving ECMO to maximize therapeutic efficacy. The use of therapeutic drug monitoring for patients receiving antimicrobial therapy with concurrent ECMO may facilitate appropriate drug dosing to achieve adequate serum concentrations and optimize favorable patient outcomes. Further studies exploring antimicrobial pharmacokinetics during ECMO are needed to inform dosing recommendations in critically ill patients.

How Environmental Fungi Cause a Range of Clinical Outcomes in Susceptible Hosts

Environmental fungi are globally ubiquitous and human exposure is near universal. However, relatively few fungal species are capable of infecting humans, and among fungi, few exposure events lead to severe systemic infections. Systemic infections have mortality rates of up to 90%, cost the US healthcare system $7.2 billion annually, and are typically associated with immunocompromised patients. Despite this reputation, exposure to environmental fungi results in a range of outcomes, from asymptomatic latent infections to severe systemic infection. Here we discuss different exposure outcomes for five major fungal pathogens: Aspergillus, Blastomyces, Coccidioides, Cryptococcus, and Histoplasma species. These fungi include a mold, a budding yeast, and thermal dimorphic fungi. All of these species must adapt to dramatically changing environments over the course of disease. These dynamic environments include the human lung, which is the first exposure site for these organisms. Fungi must defend themselves against host immune cells while germinating and growing, which risks further exposing microbe-associated molecular patterns to the host. We discuss immune evasion strategies during early infection, from disruption of host immune cells to major changes in fungal cell morphology.

Treatment of pulmonary blastomycosis with high-dose liposomal amphotericin B in a patient receiving extracorporeal membrane oxygenation

Blastomycosis-associated acute respiratory distress syndrome (ARDS) has a rare incidence. We report the case of a 29-year-old man with blastomycosis-associated ARDS receiving extracorporeal membrane oxygenation and managed with high-dose liposomal amphotericin B. This case illustrates the importance of timely diagnosis of pulmonary blastomycosis and appropriate dosing of antifungal therapy.

Veno-venous extracorporeal life support for blastomycosis-associated acute respiratory distress syndrome

BACKGROUND

Blastomyces is a dimorphic fungus endemic to regions of North America, which can lead to pneumonia and fatal severe acute respiratory diseases syndrome in up to 89% of patients. Extracorporeal life support can provide adequate oxygenation while allowing the lungs to rest and heal, which might be an ideal therapy in this patient group, although long-term clinical and radiological outcomes are not known.

CLINICAL FEATURES

We report on five consecutive patients admitted to Toronto General Hospital intensive care unit between January 2012 and September 2016, with progressive respiratory failure requiring veno-venous extracorporeal life support within 24-96 hours following mechanical ventilation. Ultra-lung protective mechanical ventilation was achieved within 24 hours. Recovery was the initial goal in all patients. Extracorporeal life support was provided for a prolonged period (up to 49 days), and four patients were successfully discharged from the intensive care unit. Long-term radiological assessment in three patients showed major improvement within 2 years of follow-up with some persistent disease-related changes (bronchiectasis, fibrosis, and cystic changes). In two patients, long-term functional and neuropsychological outcomes showed similar limitations to what is seen in acute respiratory distress syndrome patients who are not supported with extracorporeal life support and in acute respiratory distress syndrome patients without blastomycosis, but worse pulmonary function outcomes in the form of obstructive and restrictive changes that correlated with the radiological imaging.

CONCLUSION

Veno-venous extracorporeal life support can effectively provide prolonged support for patients with blastomycosis-associated acute respiratory distress syndrome that is safe and associated with favorable long-term outcomes.

Endemic fungal infections in solid organ transplant recipients-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention and management of blastomycosis, histoplasmosis, and coccidioidomycosis in the pre- and post-transplant period. Though each of these endemic fungal infections has unique epidemiology and clinical manifestations, they all share a predilection for primary pulmonary infection and may cause disseminated infection, particularly in immunocompromised hosts. Culture remains the gold standard for definitive diagnosis, but more rapid diagnosis may be achieved with direct visualization of organisms from clinical specimens and antigen-based enzyme immunoassay assays. Serology is of limited utility in transplant recipients. The mainstay of treatment for severe infections remains liposomal amphotericin followed by a step-down azole therapy. Cases of mild to moderate severity with no CNS involvement may be treated with azole therapy alone. The newer generation azoles provide additional treatment options, but supported currently with limited clinical efficacy data. Azole therapy in transplant recipients presents a unique challenge owing to the drug-drug interactions with immunosuppressant agents. Therapeutic drug monitoring of azole levels is an essential component of effective and safe therapy. Infection prevention centers around minimizing epidemiological exposures, early clinical recognition, and azole prophylaxis in selected individuals.

Blastomycosis in Southern Saskatchewan 2000-2015: Unique presentations and disease characteristics

In the literature, cases of blastomycosis in Canada have been documented in provinces bordering the Great Lakes, including Ontario and Quebec, as well as Manitoba. This is the first study to our knowledge reporting cases of mycosis seen in southern Saskatchewan suggesting a broader area of endemicity. We searched the Regina Qu'Appelle Health Region (RQHR) Microbiology Laboratory for all culture-confirmed cases of Blastomyces from January 2000 to December 2015 and identified 15 cases. Thirteen cases were reviewed, identifying common presenting symptoms, misdiagnosis, comorbidities, travel history, time from presentation to diagnosis, diagnostic specimen, treatment, and clinical outcome. Nine patients had no travel to areas known to be endemic to environmental blastomycosis. Eight patients presented with respiratory symptoms, four with skin lesions, four with constitutional symptoms, and one presented with chest pain after a fall. Initial misdiagnosis occurred in nine (69%) of the 13 cases, and all six patients that died of the disease were misdiagnosed. These six patients (46%) were acutely ill with refractory disseminated disease, leading to respiratory failure. It is probable that Blastomyces is present as an endemic fungus in the soil of southern Saskatchewan. Possibly due to a lack of awareness of this pathogen in the area, initial misdiagnoses were common and likely contributed to significant morbidity and mortality.

Severe acute respiratory distress syndrome in a liver transplant patient

This case report presents a 46-year old man with a failed liver transplant who presented with malaise and dyspnea. Imaging studies revealed diffuse reticulonodular infiltrates and innumerable miliary nodules and a left upper lobe consolidative mass. Examination of bronchoalveolar lavage fluid demonstrated yeast cells with broad-based budding. He was diagnosed with pulmonary blastomycosis and started therapy with liposomal amphotericin. In spite of therapy, he clinically worsened, developing acute respiratory distress syndrome (ARDS) and eventually expired.

Pyoderma Gangranosum-Like Blastomycosis

Blastomyces dermatitidis is typically contracted through inhalation of the dimorphic conidia, resulting in pulmonary infection as well as extrapulmonary disease through hematogenous spread. Blastomycosis is considered one of the great mimickers in medicine, with verrucous cutaneous blastomycosis resembling skin malignancy and B dermatitidis pulmonary infections often confused with lung cancer. Cutaneous blastomycosis can also often mimic pyoderma gangrenosum and should be considered in the differential diagnosis in any suspected case. This case involves a cutaneous blastomycosis lesion of the leg that was initially diagnosed as squamous cell carcinoma, which was excised. Within a month, the atypical lesion recurred in the area and was unresponsive to antibiotic therapy, rapidly progressing in size and inflammation. We discuss the eventual diagnosis of this blastomycosis infection and the importance of ruling out cutaneous blastomycosis when managing pyoderma gangrenosum.

Blastomycosis in Mammals

Blastomycosis is a serious fungal disease of dogs, humans, and occasionally other mammals caused by geographically restricted, thermally dimorphic Blastomyces species. Blastomycosis is primarily a canine disease, with approximately ten dogs diagnosed for every human case. Dogs also develop disease more rapidly, thus becoming sentinels for possible human disease. Human and canine blastomycosis may differ according to epidemiology/epizoology, clinical features, performance and use of diagnostics, and management.

Clinical Manifestations and Treatment of Blastomycosis

The causal agents of blastomycosis, Blastomyces dermatitidis and Blastomyces gilchristii, belong to a group of thermally dimorphic fungi that can infect healthy and immunocompromised individuals. Following inhalation of mycelial fragments and spores into the lungs, Blastomyces spp convert into pathogenic yeast and evade host immune defenses to cause pneumonia and disseminated disease. The clinical spectrum of pulmonary blastomycosis is diverse. The diagnosis of blastomycosis requires a high degree of clinical suspicion and involves culture-based and non-culture-based fungal diagnostic tests. The site and severity of infection, and the presence of underlying immunosuppression or pregnancy, influence the selection of antifungal therapy.

Blastomyces gilchristii as Cause of Fatal Acute Respiratory Distress Syndrome

Since the 2013 description of Blastomyces gilchristii, research describing the virulence or clinical outcome of B. gilchristii infection has been lacking. We report molecular evidence of B. gilchristii as an etiologic agent of fatal acute respiratory distress syndrome. B. gilchristii infection was confirmed by PCR and sequence analysis.

New Horizons in Antifungal Therapy

Recent investigations have yielded both profound insights into the mechanisms required by pathogenic fungi for virulence within the human host, as well as novel potential targets for antifungal therapeutics. Some of these studies have resulted in the identification of novel compounds that act against these pathways and also demonstrate potent antifungal activity. However, considerable effort is required to move from pre-clinical compound testing to true clinical trials, a necessary step toward ultimately bringing new drugs to market. The rising incidence of invasive fungal infections mandates continued efforts to identify new strategies for antifungal therapy. Moreover, these life-threatening infections often occur in our most vulnerable patient populations. In addition to finding completely novel antifungal compounds, there is also a renewed effort to redirect existing drugs for use as antifungal agents. Several recent screens have identified potent antifungal activity in compounds previously indicated for other uses in humans. Together, the combined efforts of academic investigators and the pharmaceutical industry is resulting in exciting new possibilities for the treatment of invasive fungal infections.

Management and Outcomes of Acute Respiratory Distress Syndrome Caused by Blastomycosis: A Retrospective Case Series

Acute respiratory distress syndrome (ARDS) is an uncommon, highly fatal, and poorly understood manifestation of blastomycosis. Optimal management remains unknown, including the roles of adjunctive corticosteroids and extracorporeal membrane oxygenation (ECMO).We conducted a retrospective chart review of patients with ARDS caused by blastomycosis, managed in intensive care units in Manitoba, Canada, from 1992 to 2014. ARDS was defined using the Berlin definition. Corticosteroid therapy was defined as ≥150 mg cortisol equivalent in 24 hours. Logistic regression was used to identify determinants of a fatal outcome, and bootstrap resampling was used to assess sample size requirements.Forty-three patients with ARDS caused by blastomycosis were identified. ARDS was mild, moderate, and severe in 2 (5%), 12 (28%), and 29 (67%) patients, respectively. Management included amphotericin B (n = 42, 98%), vasopressors (n = 36, 84%), corticosteroids (n = 22, 51%), renal replacement (n = 13, 30%), and ECMO (n = 4, 11%). Seventeen patients (40%) died. All patients treated with ECMO survived (P = 0.14). Corticosteroids were not associated with survival benefit in univariate (P = 0.43) or multivariate analyses (odds ratio 0.52, 95% confidence interval 0.11-2.34). Bootstrap studies indicated that almost 500 patients would be needed to confirm a significant reduction in mortality from corticosteroids (type I error = 0.05, power = 80%).Blastomycosis is an uncommon, albeit important, cause of ARDS in this geographic area. Given the rarity of disease and the large cohort needed to demonstrate mortality benefit, the role of adjunctive therapies, including corticosteroids and ECMO, may remain unconfirmed, and clinical judgment should guide management decisions.

Hypercoagulability in dogs with blastomycosis

BACKGROUND

Blastomycosis is a potentially fatal fungal disease that most commonly affects humans and dogs. The organism causes systemic inflammation and has a predilection for the lungs. The inflammation might lead to a hypercoagulable state with microemboli in the pulmonary circulation which could contribute to inadequate oxygen exchange in infected dogs.

HYPOTHESIS/OBJECTIVES

Dogs with blastomycosis will be hypercoagulable compared with healthy case-matched controls.

ANIMALS

Client-owned dogs with a diagnosis of blastomycosis (n = 23) and healthy case-matched controls (n = 23).

METHODS

Prospective case-controlled study of client-owned dogs presented to a veterinary teaching hospital with clinical signs compatible with blastomycosis. Complete blood counts, fibrinogen, PT, aPTT, thromboelastometry (TE), thrombin antithrombin complexes (TAT), and thrombin generation were evaluated.

RESULTS

Cases had a leukocytosis compared with controls [mean (SD) 16.6 (7.6) × 10(3)/μL versus 8.2 (1.8) × 10(3)/μL, P < .001], hyperfibrinogenemia [median 784 mg/dL, range 329-1,443 versus median 178 mg/dL, range 82-257, P < .001], and increased TAT concentrations [mean (SD) 9.0 (5.7) μg/L versus 2.0 (2.8) μg/L, P < .001]. As compared to controls, cases were also hypercoagulable as evaluated by thromboelastometry and had increased in vitro thrombin generation on calibrated automated thrombography.

CONCLUSIONS AND CLINICAL IMPORTANCE

Hypercoagulability occurs in dogs with systemic blastomycosis. Additional studies are needed to explore a possible contribution of thrombogenicity to the clinical manifestations of systemic blastomycosis.

A 66-year-old woman with fever, cough, and a tongue lesion

A 66-year-old woman presented with acute onset of fever, chills, and productive cough associated with right-sided chest pain. During a recent hospitalization for dyspnea, she had been diagnosed with Coombs-positive autoimmune hemolytic anemia and had been taking a tapering dose of prednisone starting approximately 6 weeks prior to admission. In the interim, her dyspnea had resolved on treatment with steroids. At the time of presentation, her prednisone dose was 40 mg. Additional medical history included VTE, for which the patient was receiving anticoagulation therapy, and steroid-induced diabetes mellitus. Many years earlier, she had been treated for TB in her home country. The patient had immigrated to Queens, New York, from a Nepalese village 8 years prior. While still in Nepal, she had worked on a farm and had been in close proximity to cows. In Queens, she lived with her family in a house with a small garden but had no pets. Recent travel included a visit to Nepal 9 months ago and a trip to Syracuse, New York, one month prior to presentation. She was a never smoker and did not consume alcohol.

Extracorporeal membrane oxygenation for blastomycosis-related acute respiratory distress syndrome: a case series

PURPOSE

Blastomyces dermatitidis is a dimorphic fungus endemic to North America capable of causing fatal respiratory failure. Acute respiratory distress syndrome (ARDS) complicates up to 10% of pulmonary blastomycosis in hospitalized patients and carries a mortality of 50-90%. This report describes the clinical course of four consecutive patients with blastomycosis-related ARDS treated with venovenous extracorporeal membrane oxygenation (ECMO) during 2009-2014.

CLINICAL FEATURES

Four adults were referred from northwestern Ontario, Canada with progressive respiratory illnesses. All patients developed diffuse bilateral opacities on chest radiography and required mechanical ventilation within 6-72 hr. Patients satisfied Berlin criteria for severe ARDS with trough PaO2/F i O2 ratios of 44-61 on positive end-expiratory pressure of 12-24 cm H2O. Wet mount microscopy from respiratory samples showed broad-based yeast consistent with B.dermatitidis. Despite lung protective ventilation strategies with maximal F i O2 (patients A-D), neuromuscular blockade (patients A-D), inhaled nitric oxide (patients A and D), and prone positioning (patient D), progressive hypoxemia resulted in initiation of venovenous ECMO by hours 24-90 of mechanical ventilation with subsequent de-escalation of ventilatory support. In all four cases, ECMO decannulation was performed (7-23 days), mechanical ventilation was withdrawn (18-52 days), and the patients survived to hospital discharge (31-87 days).

CONCLUSION

This report describes the successful application of ECMO as rescue therapy in aid of four patients with refractory blastomycosis-associated ARDS. In addition to early appropriate antimicrobial therapy, transfer to an institution experienced with ECMO should be considered when caring for patients from endemic areas with rapidly progressive respiratory failure.

Hidden killers: human fungal infections

Although fungal infections contribute substantially to human morbidity and mortality, the impact of these diseases on human health is not widely appreciated. Moreover, despite the urgent need for efficient diagnostic tests and safe and effective new drugs and vaccines, research into the pathophysiology of human fungal infections lags behind that of diseases caused by other pathogens. In this Review, we highlight the importance of fungi as human pathogens and discuss the challenges we face in combating the devastating invasive infections caused by these microorganisms, in particular in immunocompromised individuals.

Pulmonary blastomycosis: a new endemic area in New York state

We describe three cases of pulmonary blastomycosis in patients from central New York State (NYS). Two of these cases occurred in 2012, and in patients who resided in the same county. Moreover, two of these cases manifested with acute respiratory distress syndrome and survived. Interestingly, one of the two received corticosteroids and was extubated within 1 week. To the best of our knowledge, these are the first cases of human blastomycosis to be reported from NYS and we propose that corticosteroids administration might reduce hospitalisation time and ventilator-associated complications, even though it is not currently recommended in standard treatment.

Human and canine blastomycosis: A common source infection

In fall 1993 a man and a dog developed blastomycosis after visiting an island off Bayfield Inlet, Georgian Bay, located near Parry Sound, Ontario. The man recovered but the dog died of blastomycosis. It was hypothesized that the common source of exposure was the island since the permanent residences of the two cases were in different cities. One further case of human infection, based on positive serology, and four additional cases of probable canine blastomycosis were identified. All cases had travelled to Bayfield Inlet during summer and early fall 1993. To the authors' knowledge this is the first Canadian report of a common source of infection of human and canine blastomycosis. This report also provides evidence for a new endemic area of blastomycosis infection.

Fatal septic shock due to a disseminated chronic form of paracoccidioidomycosis in an aged woman

Once rare, septic shock (SS) due to disseminated fungal infections has been increasingly reported due to a growing number of immunocompromised patients, but remains rare in non-immune-compromised individuals. In paracoccidioidomycosis, it has been described in only three patients with the severe, acute form of the disease. We describe the development of a refractory, fatal septic shock due to a severe disseminated chronic form of paracoccidioidomycosis in an older woman without any other microbial insults. A striking event in the evolution of her case was the severe depletion of lymphocytes from the peripheral blood and lymphoid organs. Lymphocyte depletion due to apoptosis is described in the late phase of sepsis and can contribute both to immunosuppression and the progression of SS. The possible mechanisms involved in the induction of SS in the chronic form of paracoccidioidomycosis are discussed.

Antigen detection in bronchoalveolar lavage fluid for diagnosis of fungal pneumonia

PURPOSE OF REVIEW

The purpose of this review is to describe important findings published during the past 18 months using bronchoalveolar lavage (BAL) for diagnosis of pulmonary mycoses.

RECENT FINDINGS

Clinical studies and meta-analysis have established a high sensitivity and specificity for Aspergillus galactomannan testing of BAL specimens for diagnosis of invasive aspergillosis, superior to that observed with other diagnostic methods. Similar findings have been reported in histoplasmosis and blastomycosis.

SUMMARY

Fungal antigen testing of BAL specimens is recommended if bronchoscopy is performed for diagnosis of pulmonary infiltrates in patient groups at risk for aspergillosis or the endemic mycoses if the diagnosis cannot be established by evaluation of sputum specimens or detection of antigen in the urine or serum.

Computed tomographic scan evaluation of pulmonary blastomycosis

BACKGROUND

Blastomycosis is an uncommon granulomatous pulmonary and extrapulmonary infectious disease caused by the thermally dimorphic fungus Blastomyces dermatitidis. Diagnosis may be delayed or difficult because of varied presentation. The characteristics of blastomycosis on computed tomographic (CT) scan of the chest are not well characterized.

METHODS

The images from 34 chest CT scans from patients with confirmed pulmonary blastomycosis were retrospectively reviewed.

RESULTS

The most common CT findings were air bronchograms in 22 patients (65%), consolidation in 21 patients (62%), nodules (smaller than 3 cm) in 21 patients (62%) and lymph node enlargement (mediastinal and hilar nodes combined) in 12 patients (35%). Only four patients (12%) had a miliary pattern.

CONCLUSIONS

A specific abnormality characteristic of pulmonary blastomycosis was not identified on CT scanning. The diagnosis can only be made in the context of a high index of clinical suspicion with histological or culture confirmation.

Clinical and laboratory update on blastomycosis

Blastomycosis is endemic in regions of North America that border the Great Lakes and the St. Lawrence River, as well as in the Mississippi River and Ohio River basins. Men are affected more often than women and children because men are more likely to participate in activities that put them at risk for exposure to Blastomyces dermatitidis. Human infection occurs when soil containing microfoci of mycelia is disturbed and airborne conidia are inhaled. If natural defenses in the alveoli fail to contain the infection, lymphohematogenous dissemination ensues. Normal host responses generate a characteristic pyogranulomatous reaction. The most common sites of clinical disease are the lung and skin; osseous, genitourinary, and central nervous system manifestations follow in decreasing order of frequency. Blastomycosis is one of the great mimickers in medicine; verrucous cutaneous blastomycosis resembles malignancy, and mass-like lung opacities due to B. dermatitidis often are confused with cancer. Blastomycosis may be clinically indistinguishable from tuberculosis. Diagnosis is based on culture and direct visualization of round, multinucleated yeast forms that produce daughter cells from a single broad-based bud. Although a long course of amphotericin B is usually curative, itraconazole is also highly effective and is the mainstay of therapy for most patients with blastomycosis.