Neurological complications during the course of severe COVID-19: is it just the tip of the iceberg?

Article information

Acute Crit Care. 2022;37(1):124-126
Publication date (electronic) : 2022 February 22
doi :
Division of Intensive Care Medicine, Department of Internal Medicine, Hacettepe University Faculty of Medicine, Ankara, Turkey
Corresponding author: Gulcin Koc Yamanyar Division of Intensive Care Medicine, Department of Internal Medicine, Hacettepe University Faculty of Medicine, Hacettepe st., Ankara 06230, Turkey Tel: +90-312-305-36-27 Fax: +90-312-305-23-81 E-mail:
Received 2021 October 5; Revised 2021 November 29; Accepted 2021 December 1.

Dear Editor:

During the coronavirus disease 2019 (COVID-19) pandemic, expanding data on the presence of neurological complications has increased the interest in neurological involvement of COVID-19 and its possible pathophysiological mechanisms. Recently, many studies have been published showing that COVID-19 may cause neurological disorders [1-3]. The incidence of neurological disorders has been reported higher in severe patients requiring intensive care admission [2]. In COVID-19 patients, timely recognition and intervention of neurological disorders is crucial to improve outcomes. For this reason, we aimed to share the characteristics of neurological diseases in critically-ill COVID-19 patients who were admitted to our COVID-intensive care unit (ICU) between March 21, 2020 and March 21, 2021 for 1-year period.

In our ICU, 16 (4.9%) of 328 critically ill confirmed COVID-19 patients manifested with severe neurological diseases. Neurological findings were present in half of the patients at hospital admission and in the remaining eight patients, neurological problems were detected after ICU admission, in five of them after failure of awakening from cessation of sedation and in three of them after development of hemiparesis. Patients’ characteristics are shown in Table 1. There were 13 cases (81.3%) with ischemic stroke (IS), 10 of these patients had no previous history of IS. There was one case with Guillain-Barre syndrome, one with intracranial hemorrhage, and one with meningitis. IS was the most common neurological disease in our registry similar to other studies. However, when the risk factors of 13 patients regarding IS were evaluated, there was only one patient who did not have any risk factors for IS. Other patients had at least one risk factor for IS. There was hypertension in six patients, diabetes mellitus in five patients, cardiac disease in four patients, cerebrovascular disease in three patients and a long-term intensive care stay with renal failure and septic shock in one patient. Overall mortality was 37.5% in patients with neurological disease, whereas the 1-year mortality was 32.3% in our COVID-19 cohort.

Patient characteristics of COVID-19 patients with neurological diseases

The fact that detailed neurological evaluation could not be performed during a pandemic in the context of ICU, indicates that the incidence of neurological diseases might even be more than that reported, increasing morbidity and mortality. Patients can present with neurological complications before development of respiratory symptoms and signs during the COVID-19 course. Suspicion threshold for neurological complications should be low in cases of encephalopathy even if focal neurological deficits were not detected in COVID-19 patients. Although many studies have been published to reveal the relationship between COVID-19 and stroke, the majority of patients with IS during COVID-19 have advanced age and co-morbidities similar to our patients [4,5]. In a study of a high-volume center examining the relationship between COVID-19 and stroke, usual causes of stroke were found in most of the stroke cases. Moreover, all patients with an acute stroke without a usual etiology presented a severe infection requiring mechanical ventilation [5]. We believe that detailed etiological evaluations will give more accurate results in terms of determining COVID-19 related neurological complications. Therefore, more studies are needed to define the real incidence of neurological complications of COVID-19 and to clarify the underlying mechanism and causality between COVID-19 and neurological diseases.



No potential conflict of interest relevant to this article was reported.


Conceptualization: GKY, BH, AT. Data curation: GKY, BH, MY. Methodology: BH, MY, AT. Project administration: GKY, BH, AT. Visualization: GKY. Writing–original draft: GKY, BH. Writing–review & editing: GKY, BH, AT.


1. Whittaker A, Anson M, Harky A. Neurological manifestations of COVID-19: a systematic review and current update. Acta Neurol Scand 2020;142:14–22.
2. Taquet M, Geddes JR, Husain M, Luciano S, Harrison PJ. 6-Month neurological and psychiatric outcomes in 236 379 survivors of COVID-19: a retrospective cohort study using electronic health records. Lancet Psychiatry 2021;8:416–27.
3. Misra S, Kolappa K, Prasad M, Radhakrishnan D, Thakur KT, Solomon T, et al. Frequency of neurologic manifestations in COVID-19: a systematic review and meta-analysis. Neurology 2021;97:e2269–81.
4. Li Y, Li M, Wang M, Zhou Y, Chang J, Xian Y, et al. Acute cerebrovascular disease following COVID-19: a single center, retrospective, observational study. Stroke Vasc Neurol 2020;5:279–84.
5. Requena M, Olivé-Gadea M, Muchada M, García-Tornel Á, Deck M, Juega J, et al. COVID-19 and stroke: incidence and etiological description in a high-volume center. J Stroke Cerebrovasc Dis 2020;29:105225.

Article information Continued

Table 1.

Patient characteristics of COVID-19 patients with neurological diseases

Variable P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 P15 P16 Median (IQR)
Age (yr) 55 78 71 54 55 19 51 82 22 57 82 65 48 73 72 67 61 (52–73)
Sex M M M M M M M M M M M M M F M M NA
Comorbidity Renal transplant HT, DM, stroke HT, DM None HT, DM Bicuspid aortic valve None HT, DM None Malignancy TIA, AF, HT HT, DM, CAD Malignancy HT DM, HT, stroke AF, CAD NA
SOFA score on admission 7 6 2 6 2 7 2 2 6 3 2 5 6 3 4 0 3.5 (2–6)
APACHE II score 30 23 11 15 11 20 10 13 16 14 15 15 22 15 10 10 15 (11–19)
ECOG 2 2 1 0 0 2 0 1 0 1 3 0 3 3 3 3 1·5 (0–3)
CFS 3 6 2 1 1 4 3 4 1 3 7 2 7 2 7 4 3 (2–5.5)
Neurological complication IS IS IS IS IH IS GBS IS MEN IS IS IS IS IS IS IS NA
Length of stay in the ICU (day) 61 3 8 87 7 2 10 24 7 15 25 96 34 46 8 2 12.5 (7–43)
Length of stay in hospital (day) 67 4 8 87 13 6 16 31 18 45 25 96 34 46 16 8 21.5 (9.3–45.8)
ICU mortality Yes Yes No No No Yes No Yes No No Yes No Yes No No No NA
Hospital mortality Yes Yes No No No Yes Yes No No Yes Yes No Yes No No No NA
Cranial MRI/MRA Acute right ACA and MCA territory infarcts Acute right MCA territory infarct Acute left hemipontine infarct Bilateral multiple acute ischemic lesions Right thalamic hematoma Acute right MCA territory infarct/right distal MCA occlusion - Acute right PCA territory infarct Diffuse leptomeningeal contrast enhancement Bilateral multiple acute infarcts Left ACA-MCA watershed zone, left pontine paramedian, right cerebellar acute infarcts Acute left PCA territory infarct Acute complete right MCA territory infarct/MCA M2 occlusion Bilateral multiple acute infarcts Acute right thalamic infarct Acute right SCA territory infarct NA

COVID-19: coronavirus disease 2019; P: patient; IQR: interquartile range; NA: not applicable; HT: hypertension; DM: diabetes mellitus; TIA: transient ischemic attack; AF: atrial fibrillation; CAD: coronary artery disease; SOFA: Sequential Organ Failure Assessment; APACHE : Acute Physiology and Chronic Health Evaluation; ECOG: Eastern Cooperative Oncology Group; CFS: Clinical Frailty Scale; IS: ischemic stroke; IH: intracranial haemorrhage; GBS: Guillain-Barre syndrome; MEN: meningitis; ICU: intensive care unit; MRI: magnetic resonance imaging; MRA: magnetic resonance angiography; ACA: anterior cerebral artery; MCA: middle cerebral artery; PCA: posterior cerebral artery; SCA: superior cerebellar artery.