Mucormycosis-associated intracranial hemorrhage

Rhizopus microsporus and Mucor racemosus coinfection following COVID-19 detected by metagenomics next-generation sequencing: A case of disseminated mucormycosis

Mucormycosis is an invasive opportunistic fungal infection, which may be lethal and mostly affects patients with immunodeficiency or diabetes mellitus. Among Mucorales fungi, Rhizopus spp. is the most common cause of mucormycosis, followed by genera such as Mucor and Lichtheimia. Here we report a patient with severe COVID-19 infection who developed nasal pain, facial swelling, prominent black eschar on the nasal root. CT scan revealed pansinusitis along the maxillary, ethmoidal, and sphenoid sinuses. Mixed mold infection with Rhizopus microsporus and Mucor racemosus was detected by blood metagenomics next-generation sequencing (mNGS) and later nasal mucosa histological investigation confirmed mucormycosis. Severe COVID-19 infection led to the patient's thrombocytopenia and leukopenia. Later disseminated mucormycosis aggravated the infection and sepsis eventually resulted in death. It is the first case report of mucormycosis in which R. microsporus and M. racemosus as the etiologic agents were found simultaneously in one patient. COVID-19 infection combined with disseminated mucormycosisis can be fatal and mNGS is a fast, sensitive and accurate diagnostic method for fungi detection.

Cerebrovascular Involvement in Mucormycosis in COVID-19 Pandemic

Background

Many countries have seen an unprecedented rise of cases of coronavirus disease 2019 (COVID-19) associated mucormycosis (CAM). Cerebrovascular involvement in CAM has not been studied so far. We describe clinico-radiological manifestations of cerebrovascular complications observed in CAM.

Methods

In this multicentric retrospective observational study from India, patients with CAM who developed cerebrovascular involvement were studied. Their demographics, risk factors, clinical manifestations, imaging, laboratory profile and outcomes were noted.

Results

Out of 49 subjects with cerebrovascular involvement, 71.4% were males while average age was 52.9 years. Ischemic stroke was commonest (91.8%) followed by intracranial haemorrhage (6.1%) and subarachnoid haemorrhage (2%). The incidence of cerebrovascular complications in CAM was found to be 11.8% in one center. Cerebrovascular symptoms appeared a median of 8.3 days from the onset of mucormycosis. Commonest presentation of mucormycosis was rhino-orbito-cerebral syndrome in 98%. Diabetes mellitus was present in 81.7%. Forty percent developed stroke despite being on antiplatelet agent and/or heparin. Amongst subjects with ischemic strokes, location of stroke was unilateral anterior circulation (62.2%); bilateral anterior circulation (17.8%); posterior circulation (11.1%) and combined anterior and posterior circulation (8.9%). Vascular imaging revealed intracranial occlusion in 62.1%; extracranial occlusion in 3.4% and normal vessels in 34.5%. Mortality was 51% during hospital stay.

Conclusions

Cerebrovascular involvement was seen in 11.8% patients of CAM. Angio-invasive nature of the fungus, prothrombotic state created by COVID-19, and diabetes were important causative factors. Subjects with CAM should be screened for involvement of the brain as well as its vessel. Antiplatelet agents/heparin did not seem to provide complete protection from this type of stroke.

Comparative host transcriptome in response to pathogenic fungi identifies common and species-specific transcriptional antifungal host response pathways

Candidiasis, aspergillosis, and mucormycosis cause the majority of nosocomial fungal infections in immunocompromised patients. Using an unbiased transcriptional profiling in PBMCs exposed to the fungal species causing these infections, we found a core host response in healthy individuals that may govern effective fungal clearance: it consists of 156 transcripts, involving canonical and non-canonical immune pathways. Systematic investigation of key steps in antifungal host defense revealed fungal-specific signatures. As previously demonstrated, Candida albicans induced type I and Type II interferon-related pathways. In contrast, central pattern recognition receptor, reactive oxygen species production, and host glycolytic pathways were down-regulated in response to Rhizopus oryzae, which was associated with an ER-stress response. TLR5 was identified to be uniquely regulated by Aspergillus fumigatus and to control cytokine release in response to this fungus. In conclusion, our data reveals the transcriptional profiles induced by C. albicans, A. fumigatus, and R. oryzae, and describes both the common and specific antifungal host responses that could be exploited for novel therapeutic strategies.

Mucormycosis Leading to Cerebral Edema and Cerebellar Tonsillar Herniation after Allogeneic Bone Marrow Transplant: A Case Report

INTRODUCTION

Mucormycosis following hematopoietic stem cell transplant (HSCT) carries a very high mortality rate. Pulmonary mucormycosis often leads to systemic dissemination and eventual death. It is imperative for transplant providers to have a high level of suspicion for mucormycosis and initiate early treatment. Here, we present a 64-year-old woman who died of disseminated mucormycosis 13 days following her allogeneic HSCT.

CASE PRESENTATION

A 64-year-old female with a history of acute myeloid leukemia (AML) presented for allogeneic HSCT and passed away from intracerebral hemorrhage secondary to mucormycosis infection 13 days following her transplant. On autopsy, it was found she had angioinvasive mucormycosis in her frontal lobe leading to cerebral edema which eventually led to tonsillar herniation and brainstem infarction. Her lungs were the likely source of infectious dissemination.

DISCUSSION

This case represents an unusual course of events following HSCT in that no other published case shows tonsillar herniation resulting from mucormycosis-related intracerebral swelling. We also report this case because it is believed mucormycosis in HSCT patients is underreported. Additionally, our case highlights the importance of increased vigilance for mucormycosis in patients with prolonged neutropenia prior to HSCT and the potential link of voriconazole prophylaxis and increased risk for mucormycosis.

Klebsiella pneumoniae associated extreme plasmacytosis

Infection-associated plasmacytosis is not uncommon; however, marked plasmacytosis in both peripheral blood and bone marrow that mimicks plasma cell leukemia is a very rare condition. We encountered a case of extreme plasmacytosis associated with Klebsiella pneumoniae sepsis in an aplastic anemia patient. A 42-year-old man presented with high fever of 5 days' duration. Hematological analysis revealed severe neutropenia and thrombocytopenia; his white blood cell count was 900/mm³, with 26% of plasma and plasmacytoid cells in peripheral blood. Bone marrow biopsy and aspiration showed 25% cellularity with marked plasmacytosis (80%), highly suggestive of plasma cell leukemia. On the eighth hospital day, K. pneumoniae was identified in blood and sputum cultures. Fever improved after switching antibiotics, although his hematological condition worsened. His bone marrow cellularity (plasma cell proportion) progressively decreased: the values were 25% (80%), 10% (26%), 10% (11%), and < 10% (< 4%) on the 8th, 30th, 60th, and 90th hospital day, respectively. His plasmacytosis was extremely severe but was confirmed to be reactive with polyclonality. The present case represents the first report of strong suspicion of K. pneumoniae sepsis-associated marked plasmacytosis in an aplastic anemia patient.

Pathophysiology and management of thrombocytopenia in bone marrow failure: possible clinical applications of TPO receptor agonists in aplastic anemia and myelodysplastic syndromes

Aplastic anemia is a bone marrow failure syndrome that causes pancytopenia and can lead to life-threatening complications. Bone marrow transplantation remains the standard of care for younger patients and those with a good performance status but many patients may not have a suitable donor. Immunosuppressive therapy is able to resolve cytopenias in a majority of patients with aplastic anemia but relapses are not uncommon and some patients remain refractory to this approach. Patients may require frequent blood and platelet transfusion support which is expensive and inconvenient. Life-threatening bleeding complications still occur despite prophylactic platelet transfusion. Thrombopoietin (TPO) mimetics, such as romiplostim and eltrombopag, were developed to treat patients with refractory immune thrombocytopenia but are now being investigated for the treatment of bone marrow failure syndromes. TPO is the main regulator for platelet production and its receptor (c-Mpl) is present on megakaryocytes and hematopoietic stem cells. Trilineage hematopoietic responses were observed in a recent clinical trial using eltrombopag in patients with severe aplastic anemia refractory to immunosuppression suggesting that these agents can provide a new therapeutic option for enhancing blood production. In this review, we discuss these recent results and ongoing investigation of TPO mimetics for aplastic anemia and other bone marrow failure states like myelodysplastic syndromes. Clonal evolution or progression to acute myeloid leukemia remains a concern when using these drugs in bone marrow failure and patients should only be treated in the setting of a clinical trial.