Skip to main content

Optic nerve sheath diameter in critically ill patients: nuances and interpretation

To the Editor,

We read with great attention the remarkable research letter by Yang and colleagues studying the utility of optic nerve sheath diameter (ONSD) in predicting sepsis-associated encephalopathy (SAE) (surrogate for raised intracranial pressure) in critically ill patients [1]. However, careful reading of the letter raises some concerns that could alter the interpretation of results and overall conclusion. It has been well known that the use of corticosteroids and/or sudden discontinuation can significantly increase the risk of intracranial hypertension and thereby alter the dimensions of the ONSD [2,3,4]. It has been hypothesized that the sudden withdrawal of corticosteroids can reduce the absorption of cerebrospinal fluid (CSF) and can cause increased resistance to the flow of CSF thereby resulting in intracranial hypertension [4]. Prolonged use of corticosteroids can also create a biochemical scenario similar to vitamin A toxicity with increased carotene levels [2]. This may in turn behave like pseudotumor cerebri and thus intracranial hypertension. It is important to know since many of the critically ill patients in the intensive care unit (ICU) require steroids for a plethora of reasons such as stress dose steroids for septic shock. Sepsis itself has been identified as a clinical state with deficiency of intrinsic corticosteroids. Authors while describing the baseline characteristics of patients should shed more light on this, if these patients in all 3 groups were matched in terms of steroid use.

Systemic hypertension itself could be an independent risk factor for increase in ONSD and has been studied in the past [5]. While presenting the baseline characteristics of the 3 groups studied by the authors, they have omitted the important details specifically about the percentage of hypertensive patients (and baseline blood pressure values at the time of assessment of ONSD).

We wish to congratulate the authors for this remarkable work in the critical care setting to risk stratify patients with SAE with the help of ONSD. However, providing further details about the clinical status of the patients in this setting (such as blood pressure readings) and details of past medical background (steroid use and history of endocrinopathies) will provide readers of this journal with much needed clarity and further credibility to this outstanding work.

Availability of data and materials

Not applicable.


  1. Yang Z, Qin C, Zhang S, Liu S, Sun T. Bedside ultrasound measurement of optic nerve sheath diameter in patients with sepsis: a prospective observational study. Crit Care. 2020;24(1):235.

    Article  Google Scholar 

  2. Walker AE, Adamkiewicz JJ. Pseudotumor cerebri associated with prolonged corticosteroid therapy. reports of four cases. Jama. 1964;188:779–84.

    CAS  PubMed  Google Scholar 

  3. Leggio MG, Cappa A, Molinari M, Corsello SM, Gainotti G. Pseudotumor cerebri as presenting syndrome of Addisonian crisis. Ital J Neurol Sci. 1995;16(6):387–9.

    CAS  PubMed  Google Scholar 

  4. Shenouda S, Al-Farawi K, Dolan J, Flesher SL. "Idiopathic intracranial hypertension as a presenting sign of adrenal insufficiency." SAGE Open Med Case Rep. 2018;6:2050313x17753787.

  5. Roque PJ, Barth L, Drachman D, Wu T, LoVecchio F. 85 optic nerve ultrasound in the hypertensive patient. Ann Emerg Med. 2011;58(4):S206.

    Article  Google Scholar 

Download references




Not applicable.

Author information

Authors and Affiliations



AL: conception of idea + manuscript draft + literature review + final review

KKS: conception of idea + manuscript draft + literature review + final review

AKM: conception of idea + manuscript draft + literature review + final review

JA: conception of idea + manuscript draft + literature review + final review

The authors read and approved the final manuscript.

Corresponding author

Correspondence to Amos Lal.

Ethics declarations

Ethics approval and consent to participate

No IRB approval required.

Consent for publication

Not applicable.

Competing interests

Not applicable.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Lal, A., Sahu, K.K., Mishra, A.K. et al. Optic nerve sheath diameter in critically ill patients: nuances and interpretation. Crit Care 24, 343 (2020).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: