COVID-19-related diffuse posthypoxic leukoencephalopathy and microbleeds masquerades as acute necrotizing encephalopathy.

BACKGROUND: The complications of coronavirus disease 2019 (COVID-19), the clinical entity caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are not limited to the respiratory system. Leukoencephalopathy with microbleeds is increasingly seen in patients with COVID-19. New information is needed to delineate better the clinical implications of this infectious disease. CASE REPORT: A 46-year-old man with confirmed SARS-CoV-2 infection was admitted to the intensive care unit (ICU) with severe COVID-19. After transfer to the general wards, the patient was noted drowsy, disorientated, with slow thinking and speech. A brain MRI showed bilateral symmetrical hyperintense lesions in the deep and subcortical whiter matter, involving the splenium of the corpus callosum, as well as multiple microhemorrhages implicating the splenium and subcortical white matter. No contrast-enhanced lesions were observed in brain CT or MRI. CSF analysis showed no abnormalities, including a negative rtRT-PCR for SARS-CoV-2. An outpatient follow-up visit showed near-complete clinical recovery and resolution of the hyperintense lesions on MRI, without microbleeds change. CONCLUSION: We present the case of a survivor of severe COVID-19 who presented diffuse posthypoxic leukoencephalopathy, and microbleeds masquerading as acute necrotizing encephalopathy. We postulate that this kind of cerebral vasogenic edema with microbleeds could be the consequence of hypoxia, inflammation, the prothrombotic state and medical interventions such as mechanical ventilation and anticoagulation.

Radiotherapy for the treatment of pituitary adenomas: A dosimetric comparison of three planning techniques.

AIM: Our goal was to compare conformal 3D (C3D) radiotherapy (RT), modulated intensity RT (IMRT), and volumetric modulated arc therapy (VMAT) planning techniques in treating pituitary adenomas. BACKGROUND: RT is important for managing pituitary adenomas. Treatment planning advances allow for higher radiation dosing with less risk of affecting organs at risk (OAR). MATERIALS AND METHODS: We conducted a 5-year retrospective review of patients with pituitary adenoma treated with external beam radiation therapy (C3D with flattening filter, flattening filter-free [FFF], IMRT, and VMAT). We compared dose-volume histogram data. For OARs, we recorded D2%, maximum, and mean doses. For planning target volume (PTV), we registered V95%, V107%, D95%, D98%, D50%, D2%, minimum dose, conformity index (CI), and homogeneity index (HI). RESULTS: Fifty-eight patients with pituitary adenoma were included. Target-volume coverage was acceptable for all techniques. The HI values were 0.06, IMRT; 0.07, VMAT; 0.08, C3D; and 0.09, C3D FFF (p < 0.0001). VMAT and IMRT provided the best target volume conformity (CI, 0.64 and 0.74, respectively; p < 0.0001). VMAT yielded the lowest doses to the optic pathway, lens, and cochlea. The position of the neck in extreme flexion showed that it helps in planning mainly with VMAT by allowing only one arc to be used and achieving the desired conformity, decreasing the treatment time, while allowing greater protection to the organs of risk using C3D, C3DFFF. CONCLUSIONS: Our results confirmed that EBRT in pituitary adenomas using IMRT, VMAT, C3D, C3FFF provide adequate coverage to the target. VMAT with a single arc or incomplete arc had a better compliance with desired dosimetric goals, such as target coverage and normal structures dose constraints, as well as shorter treatment time. Neck extreme flexion may have benefits in treatment planning for better preservation of organs at risk. C3D with extreme neck flexion is an appropriate treatment option when other treatment techniques are not available.