Ruptured Mycotic Aneurysm of the Distal Circulation in a Patient with Mucormycosis Without Direct Skull Base Extension: Case Report

Fungal Endophthalmitis in a Case of Rhino-Orbito-Cerebral Mucormycosis: Successfully Treated With Amphotericin B Colloidal Dispersion

Background

Rhino-orbito-cerebral mucormycosis (ROCM) is an acute, fulminant, opportunistic fungal infection that usually occurs in diabetes or immunocompromised patients. Amphotericin B combined with surgical debridement remains the standard treatment, although it is controversial due to its lager nephrotoxicity. Thus far, no studies have reported the treatment for ROCM-associated fungal endophthalmitis because the exact pathogenesis and transmission routes in ROCM remain unclear. Here, we reported a case of ROCM complicated with fungal endophthalmitis treated favorably with amphotericin B colloidal dispersion (ABCD) in combination with other antifungals and surgical debridement.

Case Presentation

A 34-year-old woman with diabetes was admitted to our hospital owing to right-sided headache for 8 days, blindness with swelling in the right eye for 5 days, and blindness in the left eye for 1 day. MRI showed that the patient had sphenoid sinus, sinuses, frontal lobe lesions, and proptosis of the right eye. Metagenomic sequencing revealed that the patient had Rhizopus oryzae infection. During hospitalization, the patient received intravenous ABCD, oral posaconazole, and topical amphotericin B and underwent surgical debridement. After 67 days of treatment, the patient’s condition was significantly improved, and limb muscle strength showed grade V. Rhizopus oryzae showed negative results, and conjunctival swelling decreased. Additionally, no nephrotoxicity occurred during treatment. After discharge, the patient’s treatment was transitioned to oral posaconazole and she was free of complaints during the 30-day follow-up without any additional treatment for ROCM.

Conclusion

Treatment with ABCD combined with other antifungal drugs and surgical debridement for ROCM complicated with fungal endophthalmitis showed remarkable efficacy and good safety. Hence, this regimen is a promising treatment strategy for this fatal disease.

Blood vessel occlusion by Cryptococcus neoformans is a mechanism for haemorrhagic dissemination of infection

Meningitis caused by infectious pathogens is associated with vessel damage and infarct formation, however the physiological cause is often unknown. Cryptococcus neoformans is a human fungal pathogen and causative agent of cryptococcal meningitis, where vascular events are observed in up to 30% of patients, predominantly in severe infection. Therefore, we aimed to investigate how infection may lead to vessel damage and associated pathogen dissemination using a zebrafish model that permitted noninvasive in vivo imaging. We find that cryptococcal cells become trapped within the vasculature (dependent on their size) and proliferate there resulting in vasodilation. Localised cryptococcal growth, originating from a small number of cryptococcal cells in the vasculature was associated with sites of dissemination and simultaneously with loss of blood vessel integrity. Using a cell-cell junction tension reporter we identified dissemination from intact blood vessels and where vessel rupture occurred. Finally, we manipulated blood vessel tension via cell junctions and found increased tension resulted in increased dissemination. Our data suggest that global vascular vasodilation occurs following infection, resulting in increased vessel tension which subsequently increases dissemination events, representing a positive feedback loop. Thus, we identify a mechanism for blood vessel damage during cryptococcal infection that may represent a cause of vascular damage and cortical infarction during cryptococcal meningitis.

Meningitis is a life threatening form of infection in the brain that is difficult to treat. How infection spreads from the blood to cause meningitis is not well understood. Here we have shown how infection with the fungus Cryptococcus neoformans can be spread from the blood by blocking and bursting blood vessels. Using zebrafish larvae, we were able to follow the same infections over a period of days to understand how this infection behaves in blood vessels. We found that fungal cells become stuck within blood vessels depending on their size. These cells grow within blood vessels, resulting in the blood vessels becoming wider. We measured increased tension in blood vessels suggesting that, with the bloackage and widening of vessels, there was increased local blood pressure. We found that vessel blockage was associated with their rupture and spreading of fungus into the surround tissue. Finally, by increasing the tension in vessels we could increase the number of blood bursting events supporting our conclusion that blood vessel blockage leads to the spread of the infection outside of blood vessels.

Risk factors of intracranial infection in patients after intracranial aneurysm surgery: Implication for treatment strategies

Postoperative intracranial infection after intracranial aneurysm is relatively common in clinical setting; it is necessary to analyze the clinical risk factors of postoperative intracranial infection, to provide reliable evidence to the management of aneurysm.Patients with intracranial aneurysm admitted from January 1, 2016, to November 30, 2020, are included. We collected the patient's personal and treatment data, and analyzed the risk factors of intracranial infection by multivariate logistic regression analysis. We compared the cerebrospinal fluid (CSF) indicators and serological indicators and analyzed their correlation with intracranial infection by spearman analysis.A total of 236 patients with intracranial aneurysm were included; the incidence of postoperative intracranial infection was 12.71%. There were significant differences in the diabetes, intraoperative aneurysm rupture, intraoperative CSF leakage, duration of surgery, and estimated blood loss between infection and non-infection group. Logistic regression indicated that diabetes [odds ratio (OR) 2.053, 95% confidence interval (95% CI) 1.092∼3.385], intraoperative aneurysm rupture (OR 2.239, 95% CI 1.173∼4.312), intraoperative CSF leakage (OR 2.168, 95% CI 1.033∼3.451), duration of surgery ≥360 minutes (OR 1.926, 95% CI 1.108∼2.655), and estimated blood loss ≥125 mL (OR 2.459, 95% CI 1.854∼3.447) were the independent risk factors of postoperative intracranial infection in patients with aneurysm surgery (all P < .05). Klebsiella pneumoniae, Escherichia coli, and Staphylococcus epidermidis were the top 3 commonly seen pathogens. Spearman analyses indicated that PCT, CRP, LA, LDH were all correlated with intracranial infection (all P < .05).There are multiple factors for the postoperative intracranial infection in patients with aneurysm. Coping strategies should be formulated targeted on those risks to improve the prognosis of patients.

Pulmonary mucormycosis in systemic lupus erythematosus: successful management of a case along with review of literature

Pulmonary mucormycosis is rare in systemic lupus erythematosus. A 20-year-old lady with lupus nephritis and neuropsychiatric lupus was treated with injection methylprednisolone and cyclophosphamide. After few days, she developed fever, breathlessness, and hoarseness of voice. After neck and chest imaging, possibility of mucormycosis was considered which was later confirmed on microbiological test. Patient was treated with conventional amphotericin B. Literature review was done, and 8 patients with disseminated or pulmonary mucormycosis were identified with SLE. In patients with high index of suspicion, early imaging can help in diagnosis and early and aggressive management even with conventional amphotericin B can result in favorable outcome.

Key Points • Pulmonary mucormycosis in systemic lupus erythematosus is rare. • Radiological investigation can guide towards diagnosis. • Early and aggressive treatment can lead to good outcome.

Cerebral mucormycosis: neuroimaging findings and histopathological correlation

INTRODUCTION

Mucormycosis are infections caused by molds of the order Mucorales. These opportunistic infections are rare, difficult to diagnose, and have a poor prognosis. We aimed to describe common radiographic patterns that may help to diagnose cerebral mucormycosis and search for histopathological correlations with imaging data.

METHODS

We studied the radiological findings (CT and MRI) of 18 patients with cerebral mucormycosis and four patients' histopathological findings.

RESULTS

All patients were immunocompromised and/or diabetic. The type of lesions depended on the infection's dissemination pathway. Hematogenous dissemination lesions were most frequently abscesses (59 lesions), cortical, cortical-subcortical, or in the basal ganglia, with a halo aspect on DWI for lesions larger than 1.6 cm. Only seven lesions were enhanced after contrast injection, with different presentations depending on patients' immune status. Ischemia and hemorrhagic areas were also seen. Vascular lesions were represented by stenosis and thrombosis. Direct posterior extension lesions were bi-fronto basal hypodensities on CT and restricted diffusion without enhancement on MRI. A particular extension, perineural spread, was seen along the trigeminal nerve. Histopathological analysis found endovascular lesions with destruction of vessel walls by Mucorales, microbleeds around vessels, as well as acute and chronic inflammation.

CONCLUSIONS

MRI is the critical exam for cerebral mucormycosis. Weak ring enhancement and reduced halo diffusion suggest the diagnosis of fungal infections. Involvement of the frontal lobes should raise suspicion of mucormycosis (along with aspergillosis). The perineural spread can be considered a more specific extension pathway of mucormycosis.