Gastric mucormycosis: Diagnosis by imprint cytology

Part 1: Mucormycosis: Prevalence, Risk Factors, Clinical Features and Diagnosis

INTRODUCTION

Mucormycosis (MCR) is caused by filamentous molds within the Class Zygomycetes and Order Mucorales. Infections can result from inhalation of spores into the nares, oropharynx or lungs, ingestion of contaminated food or water, or inoculation into disrupted skin or wounds. In developed countries, MCR occurs primarily in severely immunocompromised hosts. In contrast, in developing/low income countries, most cases of MCR occur in persons with poorly controlled diabetes mellitus and some cases in immunocompetent subjects following trauma. Mucormycosis exhibits a propensity to invade blood vessels, leading to thrombosis and infarction of tissue. Mortality rates associated with invasive MCR are high and can exceed 90% with disseminated disease. Mucormycosis can be classified as one of six forms: (1) rhino-orbital-cerebral mucormycosis (ROCM); (2) pulmonary; (3) cutaneous; (4) gastrointestinal or renal (5); disseminated; (6) uncommon (focal) sites.

AREAS COVERED

The authors discuss the prevalence, risk factors and clinical features of mucormycosis.A literature search of mucormycosis was performed via PubMed (up to November 2022), using the key words: invasive fungal infections; mold; mucormycosis; Mucorales; Zyzomyces; Zygomycosis; Rhizopus, diagnosis.

EXPERT OPINION

Mucormycosis occurs primarily in severely immunocompromised hosts. Mucormycosis can progress rapidly, and delay in initiating treatment by even a few days worsens outcomes.

Clinical presentations, diagnosis, management, and outcomes of renal mucormycosis: An overview of case reports

Background

Renal mucormycosis (RM) is a rare presentation of invasive mucormycosis with a high mortality rate. There is no single systematic review of the literature that indicates the different clinical aspects of RM.

Methods

A systematic search of PubMed/Medline was performed to collect individual case reports of RM in patients of all ages published between 2010 and April 2022.

Results

Seventy-one individual cases were detected through PubMed bibliographic database searches, with a final assessment performed on 60 patients with RM. India and Asia had the largest number of reported cases, with 30 (50%) and 42 (70%) reports, respectively. Also, 74 and 26% of the patients with a mean age of 33 years were male and female, respectively. RM showed 44% mortality rate in the analyzed cases. Immunosuppressive agent therapy followed by tissue transplantation (kidney and liver) and diabetes were the most remarkable risk factors in patients. Nevertheless, 22% of the patients were immunocompetent with no apparent underlying condition. COVID-19 positivity was detected in eight adult patients with an 87% mortality rate. The most common signs of infection were fever, flank pain, and oliguria; additionally, isolated RM was reported in 57% of the cases. In 55% of the patients, histopathologic examination alone was sufficient to diagnose RM, whereas molecular methods and culture were used in only 18 and 35% of patients, respectively. Surgery alone, surgery plus anti-infection therapy, and anti-infection therapy alone were used in 12, 60, and 13% of patients, respectively. Furthermore, 15% of the patients died before any treatment.

Conclusion

The early diagnosis of RM is necessary. In this regard, the use of molecular-based diagnostic assays can help identify the fungus at the genus and species levels and use an appropriate treatment in the shortest possible amount of time. Because of the increase in antibiotic resistance in recent years, determining microbial susceptibility tests can lead to the better infection management. Additionally, withdrawal of immunosuppressant, appropriate surgical intervention, and antifungal therapy are the main factors associated with a successful outcome in RM.

Sensitivity of liquid-based cytology in the diagnosis of mucormycosis in COVID-19 treated patients

BACKGROUND

The coronavirus disease 2019 (COVID-19) infection caused by the novel severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) is associated with a wide range of disease patterns, ranging from mild to life-threatening pneumonia. COVID-19 can be associated with a suppressed immune response and/or hyperinflammatory state due to cytokine storm. Reduced immunity, combined with steroid usage to prevent cytokine storm along with various pre-existing co morbidities can prove to be a fertile ground for various secondary bacterial and fungal infection, including mucormycosis. Diagnosis of mucor is a challenging task given high negativity rate of various detection methods. While histopathology is considered the gold standard, the acquisition of necessary tissue biopsy specimens requires invasive procedures and is time consuming.

METHOD

In this study various methods of mucor detection, like conventional cytopathology (CCP), liquid-based cytology (LBC, BD SurepathTM ), potassium hydroxide mount (KOH) preparation, culture and histopathology were analysed. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for various methods.

RESULTS

This study showed that LBC has sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 72.4%,100%,100% and 38.4% respectively.

CONCLUSION

This study showed that, liquid-based cytology (LBC) can be a rapid and effective alternative to histopathology in mucor diagnosis.

Gastrointestinal mucormycosis: A periodic systematic review of case reports from 2015 to 2021

BACKGROUND

GI mucormycosis (GI) is a rare but highly lethal infection in patients. There is no single comprehensive review of the literature that demonstrates the various clinical aspects of this infection.

METHODS

A structured search of PubMed/Medline was used to collect case reports of GI mucormycosis in patients of all ages published between 2015 and November 2021.

RESULTS

Eighty-seven cases were identified through PubMed bibliographic database searches, and final analyses were conducted on 70 adults and ten neonatal patients with GI mucormycosis. Asia had the highest number of reported cases, with 46 (57.5%). Neonatal cases had a mortality rate of 70%, while other cases had a mortality rate of 44%. Corticosteroid therapy and diabetes were the most significant risk factors in patients, while 11% were immunocompetent with no apparent underlying condition. COVID-19 positivity was detected in four adult patients. Moreover, neonatal cases included premature and low-weight infants, metabolic acidosis, and malnutrition. Abdominal pain, fever, and GI perforation were the most common signs of infection, while vomiting occurred in 40% of neonatal cases. In 97% of patients, a histopathologic examination was used to detect infection, whereas culture and molecular methods were used in only 28% and 17% of patients, respectively. Surgery plus anti-infection therapy, anti-infection therapy alone, and surgery alone were used in 61%, 28%, and 11% of patients, respectively. Nonetheless, all neonatal patients underwent surgery. Although used in a small number of patients, posaconazole (30%) and isavuconazole (11%) demonstrated high efficacy in treating patients.

CONCLUSION

GI mucormycosis is a rare but highly lethal disease. Treatment of underlying conditions, the use of multiple diagnostic techniques, and appropriate antifungals in conjunction with surgery can all contribute to infection control.

Gastric mucormycosis complicated by a gastropleural fistula: A case report and review of the literature

RATIONALE

Mucormycosis is a rare opportunistic fungal infection with poor prognosis. The incidence of mucormycosis has been increasing, and it is a threat to immunocompromised hosts. We present a case of gastric mucormycosis complicated by a gastropleural fistula during immunosuppressive treatment for adult-onset Still disease (AOSD).

PATIENT CONCERNS

An 82-year-old woman diagnosed with AOSD who developed gastric ulcers during the administration of an immunosuppressive therapy with corticosteroids, cyclosporine, and tocilizumab complained of melena and epigastralgia. Esophagogastroduodenoscopy showed multiple ulcers covered with grayish or greenish exudates.

DIAGNOSES

The patient diagnosed with mucormycosis based on culture and biopsy of the ulcers, which showed nonseptate hyphae branching at wide angles. Mucor indicus was identified using polymerase chain reaction.

INTERVENTIONS AND OUTCOMES

Although liposomal amphotericin B was administered, gastric mucormycosis was found to be complicated by a gastropleural fistula. The patient died because of pneumonia due to cytomegalovirus infection, and autopsy revealed the presence of Mucorales around the fistula connecting the stomach and diaphragm.

LESSONS

Gastric mucormycosis is refractory to treatment and fatal. Surgical resection, if possible, along with antifungal drugs can result in better outcomes.

Case Report: Gastric Mucormycosis- a rare but important differential diagnosis of upper gastrointestinal bleeding in an area of Helicobacter pylori endemicity

A 57 years female from the hills of Nepal presented with upper gastrointestinal bleeding with gastric ulcer evident on endoscopy. Though initially treated with Helicobacter pylori ( H. pylori) eradication therapy alone, biopsy later on revealed both mucormycosis and H. pylori infection. She was then treated with antifungals liposomal amphotericin B followed by posaconazole which led to complete recovery. Mucormycosis is a rare but life-threatening fungal disease of immunocompromised host though our patient was immunocompetent. If recognized and treated at early stage, as in our patient, prognosis is good. A high index of suspicion is required for considering this disease in H. pylori endemic regions such as Nepal, and is crucial for early recognition and treatment.

Case Report: Gastric Mucormycosis- a rare but important differential diagnosis of upper gastrointestinal bleeding in an area of Helicobacter pylori endemicity

A 57 years female from the hills of Nepal presented with upper gastrointestinal bleeding with gastric ulcer evident on endoscopy. Though initially treated with Helicobacter pylori ( H. pylori) eradication therapy alone, biopsy later on revealed both mucormycosis and H. pylori infection. She was then treated with antifungals liposomal amphotericin B followed by posaconazole which led to complete recovery. Mucormycosis is a rare but life-threatening fungal disease of immunocompromised host though our patient was immunocompetent. If recognized and treated at early stage, as in our patient, prognosis is good. A high index of suspicion is required for considering this disease in H. pylori endemic regions such as Nepal, and is crucial for early recognition and treatment.

An unusual cause of massive upper gastrointestinal bleeding-gastric mucormycosis

Mucormycosis of the gastrointestinal tract is a life threatening infection most commonly seen in patients with severe immunosuppression. A 42-year-old male with history of choriocarcinoma was admitted to the intensive care unit with septic shock. He developed massive hematemesis requiring upper endoscopy which showed multiple deep gastric ulcers. Due to uncontrollable bleeding he underwent an emergent gastrectomy which revealed necrotic ulcers with evidence of angioinvasion in the ulcer bed with mucor organisms. The PCR revealed the mucor to be Mycotypha microspora which is extremely rare. We discuss the challenges involved in the diagnosis and treatment of gastric mucormycosis.

Liquid-Based Cytopathology Test: A Novel Method for Diagnosing Pulmonary Mucormycosis in Bronchial Brushing Samples

Background: Pulmonary mucormycosis, a relatively rare but severe pulmonary fungal disease with a high mortality rate, is difficult to diagnose in immunocompromised patients. Conventional cytopathology (CCP) examination of respiratory samples can help detect Mucorales, but its diagnostic sensitivity is poor. The aim of this study was to assess the first application of liquid-based cytopathology test (LCT) to detect Mucorales.

Methods: A total of 33 pairs of bronchial brushing samples from 27 patients diagnosed as pulmonary mucormycosis by fiberoptic bronchoscopy biopsy were prepared as slides using both CCP and LCT. LCT and CCP used the same cytology brush to obtain samples at the same site during the same time as the fiberoptic bronchoscopy biopsy. All samples were stained with Papanicolaou, GMS and PAS. CCP and LCT slides were evaluated from the rate of positive detection, 8 cytomorphological features and 7 background features.

Results: LCT-prepared slides showed a higher positive rate of Mucorales detection than CCP-prepared slides for Papanicolaou’s staining [28/33 (84.85%) vs. 15/33 (45.45%), p = 0.001] and for “special staining” with GMS and PAS [29/33 (87.88%) vs. 18/33 (54.55%), p = 0.003]. Clearer smear background and more distinct stereoscopic cytopathological features were observed in LCT. Messy yarn-like necrosis observed in conventionally prepared 75.76% (25/33) samples was cytomorphological suggestive for the diagnosis of mucormycosis.

Conclusion: This retrospective study suggests that LCT may be better than CCP to detect Mucorales in bronchial brushing samples from patients with pulmonary mucormycosis.

Rhinocerebral mucormycosis, risk factors and the type of oral manifestations in patients referred to a University Hospital in Tabriz, Iran 2007-2017

Inadequate data are available on the global epidemiology of mucormycosis, mainly derived from the evaluation of specific population groups. Rhinocerebral mucormycosis is an invading and fatal mycosis, particularly among diabetic patients. In the present study, patients hospitalised in Imam Reza Hospital in Tabriz, from 2007 to 2017, were evaluated. The hospital information system (HIS) was used to collect the records of the patients. A total of 42 patients with a diagnosis of mucormycosis were included in the study, 40 cases (95%) of which had a diagnosis of the rhinocerebral form. Of these 40 patients, 21 (52.5%) and 19 (47.5%) were male and female, respectively. Seven cases (17.5%) of rhinocerebral mucormycosis were due to dental procedures. The most predisposing factor in the patients was diabetes with 36 (90%) cases. In our study, the role of tooth extraction in patients with uncontrolled diabetes was identified as an important factor. It may show the important role of dentists in preventing of the disease in diabetic patients.

Gastric mucormycosis: A case report

Mucormycosis is a rare fungal infection which is largely diagnosed in immune-compromised patients. The infection can cause pulmonary, rhinocerebral, skin and soft tissue, central nervous system and gastrointestinal system. The gastrointestinal involvement is the rarest presentation, especially the stomach. We present a 38 years old HIV positive female seen in Steve Biko Academic Hospital with 2 wk history of cough, shortness of breath and lethargy. She was clinically found to be pale, pyrexial, dyspnoea and had severe oral thrush. Blood tests revealed hemoglobin of 6 g/dL CD4 count of 63 cells/uL. Chest X-ray showed multi-lobe pneumonia and gastroscopy confirmed esophageal candidiasis and nodular gastritis. She continued to deteriorate despite antibiotics, antifungal and antituberculous treatment. She developed upper gastrointestinal bleed on day 34, and gastroscopy showed a plaque like lesion in the stomach, histology of which confirmed mucormycosis. She improved on Amphotericin B but subsequently deteriorated and demised a few days later. These cases illustrate the occurrence of a rare fungal infection of the stomach and the poor mortality when diagnosis is delayed. Mucormycosis can co-exist with candidiasis and clinicians should have a high index of suspicion especially in patients not responding to appropriate treatment.