Histoplasmosis

A Complex Case of Histoplasmosis in an Immunocompromised Patient: Diagnostic Challenges, Multidisciplinary Collaboration, and Environmental Factors

Histoplasmosis is a systemic fungal infection caused by Histoplasma capsulatum, known for its protean clinical manifestations that often pose diagnostic challenges. Immunocompromised patients, such as those on immunosuppressive therapies or with HIV/AIDS, are particularly susceptible to severe forms of the disease. We present a case of a 55-year-old female with a complex medical history, including a renal transplant, who developed fever, malaise, nausea, and vomiting after a month-long stay in Panama. The patient's history included exposure to a bird with apparent infection and mold in her home. Her clinical presentation featured acute kidney injury, elevated liver enzymes, acalculous cholecystitis, and lung nodules. This intricate constellation of symptoms underscores the diverse nature of histoplasmosis presentations and its potential to mimic other diseases. The patient underwent a stepwise diagnostic approach involving imaging, microbiological tests, and multidisciplinary consultations. The positive Fungitell assay, Histoplasma capsulatum detection in urine, and identification of scattered subcentimeter lung nodules confirmed the diagnosis. This case underscores the significance of considering endemic areas, environmental exposures, and atypical clinical features in immunocompromised patients. The multidisciplinary approach facilitated appropriate management and treatment initiation with liposomal amphotericin B, highlighting the importance of collaboration among various medical specialties in complex cases. As such, this case report emphasizes the complexity of diagnosing and managing histoplasmosis in immunocompromised individuals and highlights the need for a comprehensive evaluation of atypical presentations.

The Current and Future States of Diagnostic Tests for Histoplasmosis with a Focus on People with HIV and Disseminated Histoplasmosis

Histoplasmosis is caused by Histoplasma capsulatum and, although endemic in large parts of the world, is often underrecognized in many locations. In addition to underrecognition, inadequate availability of diagnostic tests is a major contributor to poor outcomes in disseminated disease in people with HIV. For those with advanced HIV and disseminated disease, antibody testing is less useful. Culture and histopathology can be useful in this situation, but each has limitations, including variable sensitivity by site and, in the case of culture, the need for a biosafety level three laboratory and a long period of growth. Antigen testing has proven useful for disseminated histoplasmosis due to the excellent sensitivity of urine. Yet, turnaround is slower than ideal due to use in a limited number of centers. The development of lateral flow assays has the potential to make for true rapid point-of-care assays for histoplasmosis, but in order to meet that promise, the tests must be widely available and affordable.

Mebendazole Inhibits Histoplasma capsulatum In Vitro Growth and Decreases Mitochondrion and Cytoskeleton Protein Levels

Histoplasmosis is a frequent mycosis in people living with HIV/AIDS and other immunocompromised hosts. Histoplasmosis has high rates of mortality in these patients if treatment is unsuccessful. Itraconazole and amphotericin B are used to treat histoplasmosis; however, both antifungals have potentially severe pharmacokinetic drug interactions and toxicity. The present study determined the minimal inhibitory and fungicidal concentrations of mebendazole, a drug present in the NIH Clinical Collection, to establish whether it has fungicidal or fungistatic activity against Histoplasma capsulatum. Protein extracts from H. capsulatum yeasts, treated or not with mebendazole, were analyzed by proteomics to understand the metabolic changes driven by this benzimidazole. Mebendazole inhibited the growth of 10 H. capsulatum strains, presenting minimal inhibitory concentrations ranging from 5.0 to 0.08 µM. Proteomics revealed 30 and 18 proteins exclusively detected in untreated and mebendazole-treated H. capsulatum yeast cells, respectively. Proteins related to the tricarboxylic acid cycle, cytoskeleton, and ribosomes were highly abundant in untreated cells. Proteins related to the nitrogen, sulfur, and pyrimidine metabolisms were enriched in mebendazole-treated cells. Furthermore, mebendazole was able to inhibit the oxidative metabolism, disrupt the cytoskeleton, and decrease ribosomal proteins in H. capsulatum. These results suggest mebendazole as a drug to be repurposed for histoplasmosis treatment.

Comparison of Indirect Fungal Diagnostic Tests in Patients With Proven Histoplasmosis

BACKGROUND

Histoplasmosis is a common cause of invasive fungal infection in endemic regions and accurate diagnosis is difficult without direct tissue culture or pathology. Indirect fungal antigen testing for various fungal pathogens are typically performed to assist with diagnostic workup, though cross-reaction can lead to difficulty in interpreting results. We aimed to compare indirect fungal diagnostic tests and evaluate prevalence of positive antigen testing for non-Histoplasma fungal pathogens in patients with proven histoplasmosis.

METHODS

We performed a single-center retrospective review of adult patients with proven histoplasmosis diagnosed by fungal culture and/or cytology from January 2010 to March 2018. Patient demographics, clinical characteristics, and results of fungal antigen testing for Histoplasma, Blastomyces, Aspergillus, Cryptococcus, and (1→3)-β-D-glucan were evaluated. Two different urine Histoplasma antigen assays were used during the study period.

RESULTS

Fifty-seven of 182 (31.3%) patients reviewed had proven histoplasmosis and presented with acute pulmonary (n = 10), chronic pulmonary (n = 7), and disseminated (n = 40) disease. Forty-one (72%) of these patients were immunosuppressed. Urine Blastomyces antigen (93%) and serum (1→3)-β-D-glucan (88%) were commonly positive in patients with histoplasmosis, whereas Aspergillus antigen was detected in 50% of patients and Cryptococcus antigenemia was rare (5%). In patients with disseminated disease, the MiraVista urine Histoplasma antigen assay had higher sensitivity than the Viracor urine Histoplasma antigen assay (86% vs 50%, respectively; P = .019).

CONCLUSIONS

Noninvasive fungal antigen assays are helpful diagnostic tools; however, given their low specificity, clinicians must be aware of the various clinical presentations of invasive fungal infections and be aware of the limitations of these tests.

Diagnosis of histoplasmosis: current status and perspectives

Histoplasmosis is a worldwide-distributed systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum. Its clinical manifestations range from subclinical or mild respiratory illness to progressive disseminated histoplasmosis (PDH), a life-threatening disease, whose accurate diagnosis is still challenging and limited in many countries, where this disease is highly endemic. In this regard, Histoplasma antigen testing is now included in the WHO Essential Diagnostics List. The final diagnosis of histoplasmosis is established by culture and/or visualization of the yeast cells by cytology or histopathology using specific stains. However, both procedures have limited sensitivity to detect the disease and cultures are time-consuming. Antibody detection assays are effective for the subacute and chronic clinical forms of histoplasmosis. However, their sensitivity is low in the immunocompromised host. Several molecular "in-house" tests were also developed and showed promising results, but none of these tests are commercially available and their standardization and validation are still pending. Antigen detection assays have high sensitivity in PDH cases and are of great value for the follow-up of patients with histoplasmosis; however, cross-reactivity with other related fungi are common. In addition, this assay is expensive and only performed in few laboratories. Novel protein antigen candidates have been recently identified and produced by DNA-recombinant techniques in order to obtain standardized and specific reagents for the diagnosis of histoplasmosis, as opposed to the unspecific antigens or crude extracts currently used. This review describes the currently available assays, highlighting their strengths and limitations and reports the latest approaches to achieve reliable and rapid diagnostic tests for histoplasmosis. KEY POINTS: • PDH causes thousands of deaths per year globally. • Rapid accurate diagnosis of PDH is unfeasible in many regions. • Fast, accurate, and low-cost diagnostic alternatives are currently under development.

Histoplasmosis: An Emerging or Neglected Disease in Bangladesh? A Systematic Review

Histoplasmosis is uncommon in many parts of the world, including Bangladesh, where, in recent years, cases are increasingly reported. We sought to describe the sociodemographic characteristics, clinical presentation, investigations, treatment, and outcome of histoplasmosis in Bangladesh. We conducted a retrospective data review of published literature from 1962 to 2017, containing information on histoplasmosis in and/or from Bangladesh. Unpublished, well-documented histoplasmosis cases were also included. A total of 26 male patients aged 8–75 years, with a diagnosis of histoplasmosis were included; nine were farmers, seven had diabetes, one was a renal transplant recipient, and four had HIV/AIDS. Fever (n = 20), weight loss (n = 17), anemia (n = 15), lymphadenopathy (n = 9), and hepatosplenomegaly (n = 7) were common. Eleven patients had bilateral adrenal enlargement. Diagnosis was confirmed by histo/cytopathology from skin (n = 1), oropharyngeal ulcers (n = 8), lymph nodes (n = 3), adrenal glands (n = 11), paravertebral soft tissue (n = 2), and bone marrow (n = 4). Cultures of representative samples and antibodies were detected in three and two cases, respectively. Twenty-two patients had disseminated histoplasmosis and four patients had localized oropharyngeal disease. Nine patients were prescribed anti-tuberculosis drugs empirically before establishing the diagnosis of histoplasmosis. Treatment consisted of amphotericin B and itraconazole. Six patients died in hospital, 14 patients recovered with relapse in two cases, and the outcome of the other patients could not be ascertained. Histoplasmosis is thought to be endemic in Bangladesh, but few cases are reported to date, which may be due to many asymptomatic, undiagnosed, misdiagnosed, or under-reported cases. Histoplasmosis should be considered as a differential in appropriate clinical scenarios.

Clinical features and endemic trend of histoplasmosis in China: A retrospective analysis and literature review

INTRODUCTION

Histoplasmosis is a rare mycosis with nonspecific clinical manifestation and a high misdiagnosis rate, which is an epidemic disease that occurred in several endemic areas. Cases of histoplasmosis were sporadic in China.

OBJECTIVE

We detected the clinical characteristics and endemic trend of histoplasmosis to understand it more profoundly.

METHOD

The clinical data of 34 cases of histoplasmosis hospitalized in Xiangya Hospital of Central South University from 2003 to 2016 were analyzed retrospectively. The relevant literature were reviewed roundly which were about histoplasmosis from 2001 to 2019 reported in the Chinese mainland.

RESULTS

Thirty-four patients were included in the study, male predominance. About 44.1% were combined with underlying disease and HIV infection was observed in eight patients. Common clinical manifestations were fever (94.1%), followed by lymphadenopathy (70.6%) and anemia (67.6%). Organ involvement included lungs (52.9%), oral cavity (5.9%) and intestine (5.9%). Patients were diagnosed by bone marrow smears (44.1%), lymph node biopsy (41.1%), lung tissue biopsy (8.8%) and intestinal tissue biopsy (5.9%). About 70.6% received amphotericin B, while 38.2% received itraconazole therapy and 79.4% were improved. About 611 cases of histoplasmosis in the Chinese mainland were obtained in the study from the related literature, with 217 (37.0%) cases occurred in Yunnan province, 69 (11.9%) cases in Hunan province and 67 (11.6%) cases in Hubei province. All of them were high incidence area of histoplasmosis.

CONCLUSION

Histoplasmosis is a rare mycosis with high diagnosis rate and has a prominent geographical distribution in China, which should be considered highly in clinical work.

Dual Invasive Fungal Infection Presenting with Cervical Myelopathy

Disseminated fungal infections are often seen in immunocompromised patients. Here we present a case of a previously healthy woman presenting with cervical myeloradiculopathy found to have two separate fungal infections in the setting of depressed CD4 cell counts and a genetic mutation predisposing to invasive fungal infections.

A matrix-assisted laser desorption/ionization time of flight mass spectrometry reference database for the identification of Histoplasma capsulatum

The isolation of the pathogenic fungus Histoplasma capsulatum from cultures together with the visualization of typical intracellular yeast in tissues are the gold standard methods for diagnosis of histoplasmosis. However, cultures are time-consuming, require level 3 containment and experienced personnel, and usually call for an additional confirmation test. Matrix-Assisted Laser Desorption Ionization Time of Flight Mass Spectrometry (MALDI-ToF MS) has been established as a suitable tool for microbial identification in several clinical laboratories. A reference database has been constructed for the identification of H. capsulatum by MALDI-ToF MS by using six H. capsulatum strains previously identified by molecular methods. For validation, 63 fungal strains belonging to the Collection of the Spanish National Centre for Microbiology were tested against the new reference database combined with other commercial and in-house databases. In a blind assay, all H. capsulatum strains (n = 30) were correctly identified by the database and 86.6% had scores above 1.7. Considering both phases of the fungus for the same strain, the most reliable results were obtained with the mycelial phase, with only 13.3% of isolates having scores below 1.7. The new database was able to identify both morphological phases of the fungus. MALDI-ToF technology yields a prompt and simple identification from H. capsulatum yeast forms and early mycelial cultures. It allows for reducing response time and decreasing risk in fungus manipulation.

Fulminant Histoplasmosis Presenting as Pyrexia of Unknown Origin in Immunocompetent Adult Diabetic Patient

Opportunistic infections are commonly seen in immunocompromised individuals such as those suffering from HIV infection, organ transplant recipients and connective tissue disorders. Histoplasmosis is one of the fungal opportunistic infections which is usually seen in immunosuppressed individuals but can also be seen in immunocompetent patients with frequent involvement of adrenal glands. We present a case of adult diabetic patient presenting as pyrexia of unknown origin in which bone marrow aspiration and biopsy lead to diagnosis of histoplasmosis without adrenal involvement.

How to cite this article: Shastri P, Gupta P. Fulminant Histoplasmosis Presenting as Pyrexia of Unknown Origin in Immunocompetent Adult Diabetic Patient. Indian J Crit Care Med 2019;23(4):193–195.

Environmental and Wilderness-Related Risk Factors for Histoplasmosis: More Than Bats in Caves

INTRODUCTION

Histoplasma capsulatum is a dimorphic fungus that causes histoplasmosis, a sporadic endemic mycosis with environmental, occupational, and wilderness exposure-related risk factors. The objectives of this review are to describe these risk factors, to alert clinicians to the different presenting manifestations of histoplasmosis, and to recommend effective management and prevention strategies.

METHODS

Internet search engines were queried with keywords to select articles for review over the study period, 1950 to 2018. Articles selected for review included case series, epidemiologic analyses of surveillance data, clinical and laboratory updates, immunologic investigations, and observational and longitudinal studies. Articles excluded from review included systemic mycosis reviews and clinicopathologic conference reports.

RESULTS

The principal transmission mechanism of histoplasmosis is by inhalation of spores aerosolized by soil disruption, resulting in pneumonic infections ranging from asymptomatic to disseminated. Although histoplasmosis is more common in endemic regions, nonendemic regions have reported increasing autochthonous and imported cases. Immunocompromised persons are at significantly increased risks of contracting histoplasmosis. Environmental and wilderness-related risk factors for histoplasmosis include bird and bat watching, cave and cave entrance exploration, and bamboo removal and burning. Occupational risk factors for histoplasmosis include road construction, roofing, bridge and water tower work, demolition, and masonry.

CONCLUSIONS

Histoplasmosis can result in considerable morbidity. Increased awareness of disease risk factors among the public and the international healthcare community will improve the timely diagnosis and treatment of histoplasmosis and prevent disease progression and dissemination.

Histoplasmosis of the Head and Neck in the Immunocompetent Patient: Report of 2 Cases

Histoplasmosis of the head and neck is rarely seen in immunocompetent patients. We report 2 new cases of histoplasmosis of the head and neck in immunocompetent patients, one an 80-year-old man and the other a 57-year-old man. The older man presented with oral cavity histoplasmosis; his symptoms included pain, dysphagia, and ulcerative lesions. The younger man had laryngeal histoplasmosis, which resulted in hoarseness and dyspnea. We discuss the methods of diagnosis and the classic findings in histoplasmosis, including the microscopic appearance of caseating granulomas, the results of periodic acid–Schiff staining and Gomori staining, and antibody detection of histoplasmosis. We also review the treatment options with antifungals, including amphotericin B and the oral conazole drugs. With an accurate diagnosis and proper treatment, both of our patients recovered well and their symptoms resolved. Because their symptoms overlapped with those of other, more common disease processes, an accurate diagnosis of these patients was essential to treating their infection.

Sepsis-like histoplasmosis in a kidney transplant patient

Histoplasmosis is a fungus infection that mainly affects immunosuppressed patients. The authors present a case of a kidney transplant recipient who developed sepsis-like histoplasmosis, na atypical but severe manifestation of the disease. The fungus was found in blood and in a skin biopsy, and the treatment with liposomal amphotericin resulted in hepatotoxicity.

Lung Cancer Screening Reveals a Nonspiculated Nodule: Histoplasmosis

We report the case of a middle aged man, 43-pack-years active smoker, who upon radiographic screening for lung cancer found to have a non-spiculated lung nodule concerning for malignancy. Histologic evaluation of this lesion turned out to be a nodule due to Histoplasma capsulatum.

Histoplasmosis mimicking metastatic spinal tumour

Histoplasmosis is an infection caused by a fungus called Histoplasma. Diagnosis of histoplasmosis is based on the culture of biological samples and detection of fungus in tissues. Histoplasmosis can mimic malignant lesions. We report a 65-year-old, immunocompetent, male patient with back pain. We describe the main clinical and radiological characteristics in our patient who had vertebral histoplasmosis that mimicked cancer. A computed tomography scan showed lytic lesions of the right side of T4, T5, and T6 vertebral bodies. Magnetic resonance imaging displayed abnormal marrow signals in T4, T5, and T6 vertebral bodies (low signal on T1, high on T2 and short time inversion recovery (STIR)). Which was mimicking malignancy, such as haematological malignancy and metastatic bone cancer. Therefore, thoracic spinal surgery using the anterior approach was performed. An intraoperative frozen section examination and routine postoperative pathology showed thoracic histoplasmosis infection. Treatment of histoplasmosis was performed with oral itraconazole. The lesions did not progress and the patient symptomatically improved at a follow-up of 26 months.

Laboratory Diagnostics for Histoplasmosis

The diagnosis of histoplasmosis is based on a multifaceted approach that includes clinical, radiographic, and laboratory evidence of disease. The gold standards for laboratory diagnosis include demonstration of yeast on pathological examination of tissue and isolation of the mold in the culture of clinical specimens; however, antigen detection has provided a rapid, noninvasive, and highly sensitive method for diagnosis and is a useful marker of treatment response. Molecular methods with improved sensitivity on clinical specimens are being developed but are not yet ready for widespread clinical use. This review synthesizes currently available laboratory diagnostics for histoplasmosis, with an emphasis on complexities of testing and performance in various clinical contexts.

Presentation and Treatment of Histoplasmosis in Pediatric Oncology Patients: Case Series and Review of the Literature

Histoplasmosis is an endemic fungus in several regions of the United States. The diagnosis and treatment of this infection can be challenging in pediatric oncology patients. We present 5 patients diagnosed with histoplasmosis while receiving treatment at a midsize pediatric oncology center in Iowa. Two cases occurred in patients with acute lymphoblastic leukemia and 3 cases in patients with solid tumors. All patients were treated with antifungal therapy and demonstrated excellent clinical response. Histoplasmosis should be considered as a potential cause of nonspecific febrile illness, pulmonary masses, and bone marrow suppression in immunocompromised patients in endemic regions. Prompt and accurate diagnosis can facilitate timely antifungal therapy and avoidance of prolonged hospital stays, invasive testing, unnecessary antibiotics, and unwarranted anticancer therapies.

Cannon ball appearance on radiology in a middle-aged diabetic female

Pulmonary tuberculosis is commonly presented as cavitary lesion and infiltrations. It commonly involves upper lobe. Lower lobe involvement is less common. Various atypical presentations of tuberculosis on radiology are reported like mass, solitary nodule, multi lober involvement including lower lobes. Atypical presentations are more commo in patients with immunocompromised conditions like Diabetes Mellitus, anemia, renal failure, liver diseases, HIV infection, malignancy, patients on immunosuppressive therapy. Cannon ball presentation of pulmonary tuberculosis is extremely rare and not so common. Common causes of cannon ball presentation in lung are metastasis, fungal infections, Wegener's grannulomatosis, sarcoidosis, etc. We report here a case of middle year female with diabetes mellitus presented with atypical symptoms with cannon ball appearance on radiology and found to be of tuberculosis in origin. Thus any patients with immunocompromised condition can present with atypical manifestation of tuberculosis either clinically or radiologicaly in high endemic countries for tuberculosis.

Prevalence and lethality among patients with histoplasmosis and AIDS in the Midwest Region of Brazil

Histoplasmosis is a systemic mycosis that is considered an important public health problem. In this work, we performed a descriptive, observational, cross-sectional and retrospective study with a secondary data analysis of medical records from 2000 to 2012 at a tertiary hospital. The study sample consisted of 275 patients with laboratory-confirmed Disseminated Histoplasmosis (DH)/AIDS. The results showed that the prevalence of DH associated with AIDS was 4.4%. The majority of patients were young adult men with fever in 84.2%, cough in 63.4%, weight loss in 63.1%, diarrhoea in 44.8% and skin manifestations in 27.6% of patients. In the overall cohort, the CD4 counts were low, but not significantly different in survivors and non-survivors. Higher levels of urea and lower levels of haemoglobin and platelets were observed in non-survivor patients (<.05). The global lethality was 71.3% (196/275). The results with high prevalence and lethality highlight the need to adopt measures to facilitate early diagnosis, proper treatment and improved prognosis.

Worldwide Phylogenetic Distributions and Population Dynamics of the Genus Histoplasma

Background

Histoplasma capsulatum comprises a worldwide complex of saprobiotic fungi mainly found in nitrogen/phosphate (often bird guano) enriched soils. The microconidia of Histoplasma species may be inhaled by mammalian hosts, and is followed by a rapid conversion to yeast that can persist in host tissues causing histoplasmosis, a deep pulmonary/systemic mycosis. Histoplasma capsulatum sensu lato is a complex of at least eight clades geographically distributed as follows: Australia, Netherlands, Eurasia, North American classes 1 and 2 (NAm 1 and NAm 2), Latin American groups A and B (LAm A and LAm B) and Africa. With the exception of the Eurasian cluster, those clades are considered phylogenetic species.

Methodology/Principal Findings

Increased Histoplasma sampling (n = 234) resulted in the revision of the phylogenetic distribution and population structure using 1,563 aligned nucleotides from four protein-coding regions. The LAm B clade appears to be divided into at least two highly supported clades, which are geographically restricted to either Colombia/Argentina or Brazil respectively. Moreover, a complex population genetic structure was identified within LAm A clade supporting multiple monophylogenetic species, which could be driven by rapid host or environmental adaptation (~0.5 MYA). We found two divergent clades, which include Latin American isolates (newly named as LAm A1 and LAm A2), harboring a cryptic cluster in association with bats.

Conclusions/Significance

At least six new phylogenetic species are proposed in the Histoplasma species complex supported by different phylogenetic and population genetics methods, comprising LAm A1, LAm A2, LAm B1, LAm B2, RJ and BAC-1 phylogenetic species. The genetic isolation of Histoplasma could be a result of differential dispersion potential of naturally infected bats and other mammals. In addition, the present study guides isolate selection for future population genomics and genome wide association studies in this important pathogen complex.

Histoplasmosis is a potentially severe fungal disease of mammals caused by Histoplasma capsulatum. The highest incidence of the disease is reported on the American continent, and approximately 30% of HIV and histoplasmosis co-infections are fatal. Previous studies have suggested at least 7 phylogenetic species within H. capsulatum, however by increasing taxon sampling and using different phylogenetic and population genetic methods, we detect at least 5 additional phylogenetic species within Latin America (LAm A1, LAm A2, LAm B1, LAm B2, RJ and BAC-1). These phylogenetic species are nested in the former LAm A clade. We found evidence that bats may be a cause of speciation in Histoplasma, as well-supported monophyletic clades were found in association with different species of bats. The radiation of the Latin American H. capsulatum species took a place around 5 million years ago, which is consistent with the radiation and diversification of bat species. Previous phylogenetic distribution of Histoplasma is upheld and strong support is indicated for the species delineation and evolution of this important pathogen.

Childhood histoplasmosis in Colombia: Clinical and laboratory observations of 45 patients

Histoplasmosis is an important mycosis in the Americas; and in children with no immune system abnormalities, histoplasmosis is typically a self-limited process. In contrast, in children with immune problems, disease manifestations are frequently more severe and include dissemination. From 1984 to 2010, a retrospective study of paediatric patients who had been diagnosed with histoplasmosis was performed. A total of 45 pediatric cases of histoplasmosis were identified. The most important risk factor was malnutrition (37%), followed by environmental exposure (33%). The patients exhibited pulmonary infiltrates (83%), fever (76%), cough, constitutional symptoms (38%), headache (35%), and lymph node hypertrophy (33%). Concerning the clinical forms, 64% of the patients presented with the progressive disseminated form that frequently affected the central nervous system (48%). Diagnostic laboratory tests indicated that the cultures were positive for 80% of the patients, the agar gel immunodiffusion was reactive in 95%, the M band of the precipitate was more commonly observed (81%), and the complement fixation tests were reactive in 88% of the patients. The timely diagnosis of histoplasmosis is important, and for this reason, it is hoped that the results of this study will lead pediatricians toward a better understanding of this mycosis in children.

Cutaneous presentation of disseminated histoplasmosis as a solitary peri-anal ulcer. Case report and discussion

Disseminated histoplasmosis has a diverse and non-specific range of clinical signs and symptoms. In a significant minority of patients, cutaneous lesions are apparent at the time of initial presentation, affording an opportunity to establish the diagnosis from a skin biopsy. The most frequently reported clinical scenario in immunocompromised patients with cutaneous involvement is that of multiple papulo-nodular lesions on the face, trunk or extremities. The following report features an immunocompetent patient who presented with a solitary ulcerated plaque on the buttocks close to the anal verge. This case presentation underscores the broad spectrum of clinical presentations as well as the potential for diagnostic confusion with protozoa such as Leishmania or Trypanosoma species during histopathologic examination if special stains for fungal organisms are not performed.

Disseminated histoplasmosis presenting as pelvic inflammatory disease

A 39‐year‐old female patient was presented with acute abdominal pain. Diagnostic laparoscopy revealed extensive granulomas throughout the abdomen. Disseminated TB was suspected, but the biopsies were negative. Due to a high degree of suspicion, a urine antigen test was performed and was strongly positive for histoplasmosis.

Diagnosis of HIV infection on the basis of histoplasmosis-related oral ulceration

Histoplasmosis is an endemic systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum. In immunocompromised patients, histoplasmosis generally occurs as an opportunistic disease, with dissemination to various organs. Cutaneous involvement is observed in 38% to 85% of cases, with oral mucosal involvement in 30% to 60% of cases. This article describes the case study of a 32-year-old woman who presented an extensive tongue ulcer due to histoplasmosis and had the HIV infection diagnosis based on laboratory tests requested by the dentist.

Disseminated histoplasmosis in an immunocompetent haweli dweller: A diagnosis and follow-up by endoscopic ultrasound-guided fine-needle aspiration

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is nowadays widespread minimally invasive procedure for diagnosing a large number of benign as well as malignant lesions. We report a case of a 62-year-old immunocompetent elderly male, who presented with high-grade fever, hepatosplenomegaly and mediastinal and intra-abdominal lymph nodes. He was residing in an old haweli with bats infestation. EUS-FNA of the subcarinal and the preaortic lymph node clinched the diagnosis. A rapid on-site evaluation of the cytology material revealed organisms conforming to the morphology of Histoplasma capsulatum. The patient was immediately started on amphotericin B and itraconazole and responded well. In this case, we found the role of EUS-FNA not only in diagnosis, but also in the follow-up of the patient.

Challenges in the management of disseminated progressive histoplasmosis in human immunodeficiency virus-infected patients in resource-limited settings

The diagnosis of histoplasmosis in patients with human immunodeficiency virus in southern Africa is complicated by the nonspecific presentation of the disease in this patient group and the unavailability of sensitive diagnostics including antigen assays. Treatment options are also limited due to the unavailability of liposomal amphotericin and itraconazole, and the inability to perform therapeutic drug monitoring further confounds management. We present 3 clinical cases to illustrate the limits of diagnosis and management in the southern African context, and we highlight the need for additional diagnostic tools and treatment options in resource-limited settings.

Immunological assays employed for the elucidation of an histoplasmosis outbreak in São Paulo, SP

Several reports showed outbreaks of histoplasmosis acquired while bat-inhabited caves were visited by tourists, miners or researchers. We evaluated the performance of double immunodifusion (DI) and immunoblotting (IB) assays, employed for the histoplasmosis outbreak elucidation occurred in Vale do Paraíba, São Paulo. The existence of epidemiologic link, four patients with clinical signs suggestive of histoplasmosis and mycological confirmation has made that all 35 individuals involved to the cave visit were subjected to serological evaluation. By DI, we observed reactivity against H. capsulatum antigen in a single serum examined nearly 20 days after exposure to fungal propagules. On the other hand, IB showed reactivity against H and M fractions in 50% of samples evaluated. The analysis of the second sample batch, collected two months after the exposure showed that 96.7% were reactive by DI with antibodies titers ranging from 1 to 16 and 100% of reactivity against H and M fractions, by IB, suggesting an acute infection. The analysis of the overall agreement between the methods showed to be reasonable (κ = 0.37). This study confirms the importance and efficacy of more sensitive methodologies, such as IB assay, to early elucidation of disease, especially in cases of patients without mycological information.

Chronic infections of the small intestine

PURPOSE OF REVIEW

Chronic infections of the small intestine cause significant morbidity and mortality globally. This review focuses on the recent advances in the field of our understanding of selected intestinal infections.

RECENT FINDINGS

Primary and secondary immunodeficiency increase the susceptibility to many chronic intestinal infections. Endoscopy and intestinal biopsies are central to establishing a diagnosis of these conditions. Tuberculosis (TB) remains a major global health challenge. Emerging therapeutic agents to counteract multidrug-resistant strains have shown clinical efficacy, but concerns regarding mortality remain. PCR-based diagnostic TB tests have the potential to reduce diagnostic delays, but remain to be validated for intestinal infections. Adjunctive diagnostic imaging modalities can differentiate infections from Crohn's disease with increasing accuracy. Whipple's disease remains rare, but there have been substantial advances in our understanding of the causative organism Tropheryma whipplei. Extended treatment with broad-spectrum antibiotics is effective in most cases. The narrow therapeutic window and limited armamentarium for treating invasive filamentous fungal infections contribute to their significant morbidity and high rates of mortality.

SUMMARY

The speed and accuracy of diagnosing chronic intestinal infections have improved with recent imaging and laboratory methodologies. Significant research opportunities remain for clinicians and scientists to improve the diagnostic accuracy and clinical outcomes of chronic intestinal infections.

Cutaneous ulcer in an immunosuppressed patient with adult onset Still's disease: primary cutaneous histoplasmosis?

Histoplasmosis is caused by the dimorphic fungus Histoplasma capsulatum.Primary infection occurs through inhalation of spores from the air. Immunocompetent individuals are usually asymptomatic, but may develop pulmonary disease. Immunocompromised patients tend to present systemic histoplasmosis with cutaneous lesions occurring by secondary invasion. In this case report, we describe a probable primary cutaneous histoplasmosis (PCH) in a patient with adult onset Still's disease under immunosuppression.

Progressive disseminated histoplasmosis in the HIV population in Europe in the HAART era. Case report and literature review

INTRODUCTION

In highly endemic areas, up to 20 % of human immunodeficiency virus (HIV)-infected persons will develop progressive disseminated histoplasmosis (PDH). Europe is not endemic to histoplasmosis, and the disease is mainly found in immigrants often co-infected with HIV.

METHODS

We present a case of a patient with HIV and PDH highlighting the possible diagnostic difficulties that may arise in a non-endemic area and review the literature of histoplasmosis in the context of HIV infection with special focus on Europe.

DISCUSSION

When cellular immunity wanes (usually at CD4 T-lymphocyte counts <150 cells/μL) histoplasma infection, acquired earlier, can reactivate and disseminate. PDH is an acquired immune deficiency syndrome(AIDS)-defining disease and a life-threatening infection, with a clinical spectrum ranging from an acute, fatal course with lung infiltrates and respiratory failure, shock, coagulopathy and multi-organ failure, to a more subacute disease with focal organ involvement, pancytopenia and hepatosplenomegaly. Mortality rates remain high for untreated patients, but early diagnosis, proper antifungal treatment and early initiation of antiretroviral therapy have improved the prognosis.

CONCLUSION

European infectious diseases physicians, microbiologists and pathologists must be aware of histoplasmosis, particularly when facing HIV-infected immigrants from endemic areas. This is increasingly important due to migration and travel activities from these areas.

Disseminated histoplasmosis in HIV-infected patients: determinants of relapse and mortality in a north-eastern area of Brazil

Many relapses and deaths resulting from disseminated histoplasmosis (DH) in acquired immunodeficiency syndrome (AIDS) patients have been observed in an endemic area in north-eastern Brazil. The objective of this study was to evaluate the risk factors associated with the clinical outcomes of DH/AIDS coinfection in patients from the state of Ceará, Brazil. A retrospective cohort of AIDS patients, after their hospital discharge due to first DH episode in the period 2002-2008, was followed until December 31, 2010, to investigate the factors associated with relapse and mortality. A total of 145 patients were evaluated in the study. Thirty patients (23.3%) relapsed and the overall mortality was 30.2%. The following variables were significantly (P < 0.05) associated with relapse and overall mortality (univariate analysis): non-adherence to highly active antiretroviral therapy (HAART), irregular use of an antifungal, non-recovery of the CD4+ count and having AIDS before DH; histoplasmosis relapse was also significantly associated with mortality. In the multivariate analysis, non-adherence to HAART was the independent risk factor that was associated with both relapse (Adj OR = 6.28) and overall mortality (Adj OR = 8.03); efavirenz usage was discovered to be significant only for the overall mortality rate (Adj OR = 4.50). Adherence to HAART was the most important variable that influenced the outcomes in this specific population.

Histoplasmosis mimicking primary lung cancer or pulmonary metastases

OBJECTIVE

To describe the main clinical and radiological characteristics of patients with histoplasmosis mimicking lung cancer.

METHODS

This was a retrospective descriptive study based on the analysis of the medical records of the 294 patients diagnosed with histoplasmosis between 1977 and 2011 at the Mycology Laboratory of the Santa Casa Sisters of Mercy Hospital of Porto Alegre in the city of Porto Alegre, Brazil. The diagnosis of histoplasmosis was established by culture, histopathological examination, or immunodiffusion testing (identification of M or H precipitation bands). After identifying the patients with macroscopic lesions, as well as radiological and CT findings consistent with malignancy, we divided the patients into two groups: those with a history of cancer and presenting with lesions mimicking metastases (HC group); and those with no such history but also presenting with lesions mimicking metastases (NHC group).

RESULTS

Of the 294 patients diagnosed with histoplasmosis, 15 had presented with lesions mimicking primary neoplasia or metastases (9 and 6 in the HC and NHC groups, respectively). The age of the patients ranged from 13 to 67 years (median, 44 years). Of the 15 patients, 14 (93%) presented with pulmonary lesions at the time of hospitalization.

CONCLUSIONS

The clinical and radiological syndrome of neoplastic disease is not confined to malignancy, and granulomatous infectious diseases must therefore be considered in the differential diagnosis.

A case in Europe of feline histoplasmosis apparently limited to the skin

BACKGROUND

Histoplasma capsulatum has a worldwide distribution, but reports in Europe remain rare. We present the second report of histoplasmosis in a cat in Europe and, to the best of our knowledge, the first case of feline histoplasmosis infection apparently limited to the skin.

CASE REPORT

A 6-year-old male castrated outdoor cat was presented to the dermatology service with a history of skin lesions evolving over 1 month and consisting of multiple papules and nodules on the head and neck. General examination was unremarkable. Cytological examination of the ulcerated nodules revealed a pyogranulomatous infiltrate, with numerous macrophages containing oval yeast-like cells, 2-5 μm in size, with a central, lightly basophilic core surrounded by a clear halo. A tentative diagnosis of fungal infection was made, and skin biopsy specimens were taken. Histological examination confirmed the cytology findings, and Grocott staining showed numerous organisms suggestive of Histoplasma within macrophages. Thoracic radiographs, abdominal ultrasound and routine laboratory testing were unremarkable. Fungal culture of a nodule was negative. PCR of total DNA extracted from the infected tissue and subsequent sequencing confirmed the diagnosis of H. capsulatum var. capsulatum. Surgical excision of the other nodules was performed, and the cat was treated with oral itraconazole 5 mg/kg once daily; 12 weeks after initial consultation, no lesions were visible. No recurrence was observed during an 8 month follow-up period.

CONCLUSIONS AND CLINICAL IMPORTANCE

Histoplasmosis should be included in the differential diagnosis of nodular diseases of cats worldwide.

Co-infection of disseminated histoplasmosis and tuberculosis in an AIDS patient

Histoplasmosis is a fungal disease caused by the dimorphic fungus Histoplasma capsulatum, recognized as an AIDS-defining illness since the Center for Disease Control's revision criteria in 1985. This infection is reported to be present in 5-20% of AIDS patients, and in 95% of the cases it is manifested in its disseminated form. Serum antibodies and/or antigen research can make diagnosis, but the demonstration of the agent by culture or histopathological examination remains the gold standard methods. Co-infections in patients with AIDS are well known; however, reports on disseminated tuberculosis and histoplasmosis are scarce. The authors report the case of a female patient who presented a short-course history of weight loss, fever, and mild respiratory symptoms, with hepatosplenomegaly and lymphadenopathy. Laboratory workup called attention to anemia, altered liver, canalicular enzymes, liver function tests, high titer of lactate dehydrogenase (LDH), and pulmonary nodules on thoracic computed tomography. Incidental finding of yeast forms within the leukocytes during a routine blood cell count highlighted the diagnosis of histoplasmosis. The patient started receiving amphotericin B but succumbed soon after. The authors emphasize the possibility of this co-infection, the diagnosis of severe infection through the finding of yeast forms within peripheral leukocytes, and for the high titer of LDH in aiding the differential diagnosis.