Spontaneous subdural effusion in a hospitalized Covid-19 patient: Case report

Abstract

Subdural effusions (SE) have already been associated with several viruses, but there are few associations with Covid-19 reported to date, and all of them had one thing in common: the presence of superimposed bacterial rhinosinusitis. Here we describe the case of a 76-year-old male patient that was transferred to our center due to severe SARS-CoV-2 infection and developed a SE during hospital stay. He presented sensory level impairment during hospitalization, but an initial Head CT scan showed no alterations. A new CT scan performed six days later evidentiated a bilateral SE. The patient had a cardiorespiratory arrest during the night of the same day, resulting in death. Covid-19 as a direct cause of subdural effusion (positive Covid-19 PCR in subdural fluid) has never before been reported in the literature, and, unfortunately, it was not possible to rule out or confirm this phenomenon in our case due to the rapid evolution of the clinical picture. However, our case clearly differs from the literature as the patient did not show any signs of sinus disease or intracranial hypotension, and the possible causes of the effusion boil down to spontaneity and the direct action of Covid-19 in the CNS and subdural space.

Introduction

Covid-19 has already infected more than 664 million people worldwide, leaving 6.7 million dead, [1] and even after all these cases it continues to surprise us with novel and unusual manifestations and complications, such as subdural effusions (SE). SE are the abnormal accumulation of fluid in the subdural space, usually consisting of sterile cerebrospinal fluid (CSF). It is a pathology of bimodal epidemiology, occurring mainly before 5 or after 50 years of age, and it is usually caused by head trauma. However, it can occur in the context of intracranial hypotension, spontaneously and even in infectious diseases, both bacterial and viral 2, 3, 4, 5, 6. Here, we report the occurrence of a non-traumatic SE in an elderly patient hospitalized due to Covid-19, the only case in more than 1,675 Covid-19 patients hospitalized in our center.

Case report

A 76-year-old male patient, obese, with systemic arterial hypertension and diabetes mellitus, presented with cough, anosmia, headache, myalgia and diarrhea, with exacerbation of symptoms and onset of fever 3 days later. He sought care at an emergency service, where he underwent a positive polymerase chain reaction test (PCR) for COVID-19, being admitted to a specific treatment unit. On the 3rd day of hospitalization there was an exacerbation of the respiratory condition and he was referred to our center for ICU admission.

Upon arrival, the patient was conscious and oriented, with no further neurological deficits or new complaints. A chest computed tomography (CT) scan was performed and evidenced bilateral and diffuse ground-glass opacifications, and a course of dexamethasone was started after confirmation of severe COVID-19. In addition, the patient developed acute kidney injury, without the need for dialysis. Two days after admission to the ICU, he presented with hyperactive delirium and further worsening of the respiratory condition, reason why he was submitted to mechanical ventilation. Despite optimized sedation, the patient had several episodes of agitation and ventilatory competition.

During this period, the patient presented difficult-to-control glycemia, worsening of kidney function, hypernatremia and hyperkalemia, all of which received standard management. After improvement in lung function, the patient was extubated and maintained a satisfactory ventilatory pattern afterwards. However, he also kept a depressed and fluctuating sensory level despite the absence of sedation. The initial suspicion was of delirium associated with sensory impairment, secondary to metabolic causes, especially uremia (serum creatinine (SCr) 3.26 mg/dl, urea 288 mg/dl at this time). A brain CT scan was performed for differential diagnosis, but it did not show abnormalities (Fig. 1 ). Quetiapine and haloperidol were administered, along with non-dialytic measures to control acute kidney injury, but, despite the medications and the improvement in the metabolic picture (SCr: 1.84 mg/dl, urea: 88 mg/dl), the patient remained with a depressed level of consciousness.

Fig. 1.

First head CT performed, showing no acute findings or sinus disease.

Six days after the previous head CT scan, the patient presented an abrupt worsening in the level of consciousness, associated with left hemiplegia, without changes in the pupillary reflex. A new head CT scan was requested and no hemorrhagic, ischemic or sinus alteration was identified; however, there was a bilateral SE extending from the temporal region to the calvaria, measuring 0.9 cm at its largest diameter (Fig. 2 ). The effusion was hypodense in relation to the parenchyma, but slightly denser than the CSF. Unfortunately, it was not possible to perform additional tests for diagnostic clarification (magnetic resonance imaging, lumbar puncture, subdural fluid analysis, etc.) because the patient had a cardiorespiratory arrest during the night of the same day, resulting in death. Therefore, it was not possible to confirm or exclude the presence of ischemic stroke and central nervous system (CNS) and/or subdural space infection.

Fig. 2.

Head CT performed 6 days later, evidencing the appearance of a bilateral subdural effusion, 0.9 cm wide at its largest width. The effusion was hypodense in relation to the parenchyma, but slightly denser than the cerebrospinal fluid. There were no signs of sinusopathy or other acute findings.

Discussion

It is a known fact that Covid-19 affects the CNS both directly and indirectly, invading it through the systemic blood flow, through the cribriform plate, causing anosmia/hyposmia and then continuing through a retrograde axonal pathway until it reaches the brain, or through the interaction with the angiotensin-converting enzyme 2 receptor [7]. However, there are no clear pathways on how SARS-CoV-2 could directly cause a SE. SE have already been associated with several viruses, including enterovirus 71 (Coxsackie), HSV-1 and EBV, 4, 5, 6 but there are few associations with Covid-19 reported to date.

In total, 5 cases were found in our literature review, and all of them had one thing in common: the presence of bacterial rhinosinusitis concomitant with Covid-19, confirmed by imaging and/or culture tests 8, 9, 10. In all 5 cases, subdural empyema turned out to be a complication of bacterial superinfection, confirmed by subdural fluid culture, which showed bacterial growth and negative PCR for Covid-19. We believe that this situation can be ruled out in our patient, as he did not have any clinical or imaging evidence of paranasal sinuses infection. Furthermore, there were no other classic radiological features of intracranial hypotension, which led us to discard this diagnosis as well.

Covid-19 as a direct cause of subdural effusion (positive Covid-19 PCR in subdural fluid) has never before been reported in the literature, and unfortunately it was not possible to rule out or confirm this phenomenon in our case due to the rapid evolution of the clinical picture and death. However, as the other diagnostic hypotheses were discarded, the possible causes of the effusion in our patient boil down to spontaneity and the direct action of Covid-19 in the CNS and subdural space. The presence of several neurological manifestations in our patient favors the hypothesis of a Covid-19 infection in the CNS; however, we must consider the effect of the patient's clinical and metabolic state on his neurological status.

Nonetheless, the capability of Covid-19 to surprise us and cause unexpected and new manifestations in all systems of the human body is remarkable, reason why it is always hypothesized as a direct cause and not as a coincidentally concomitant disease.

Funding statement

No funding was received in any phase of the article’s production.

Ethics approval and consent to participate

This case report was extracted from a larger study still in progress, approved by the Ethics and Research Committee of Faculdade Meridional – IMED and registered under CAAE: 60913222.8.0000.5319 (final opinion 5,646,360). The Informed Consent Form was waived by the Research Ethics Committee, as it was a non-interventionist retrospective study, which used only information from medical records, organizational information systems and imaging tests already performed, without changing or interfering in the management of the service research participants and, consequently, without adding risks or harm to their well-being, with anonymous treatment and analysis of the data, without individual identification of the participants.

Author contributions

Each author made significant individual contributions to this manuscript. Martio AE: Development and writing of the article; Literature review; Approval of the final version of the manuscript. Carregosa AL: Writing and Editing; Literature review; Critical review of the intellectual content of the manuscript; Approval of the final version of the manuscript. Karam OR: Physician responsible for the patient’s care; writing revision and editing; approval of the final version of the manuscript. Padua, WL: Physician responsible for the patient’s care; Critical review of the intellectual content of the manuscript; approval of the final version of the manuscript. Mesquita Filho PM: Critical review of the intellectual content of the manuscript; approval of the final version of the manuscript.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.