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         EDITORIAL COMMENTARY Year : 2023  |  Volume : 69  |  Issue : 3  |  Page : 136-137

Current understanding of role of venous sinus stenosis in management of idiopathic intracranial hypertension

D Muzumdar
Department of Neurosurgery, Seth Gordhandas Sunderdas Medical College and King Edward VII Memorial Hospital, Acharya Donde Marg, Parel, Mumbai, Maharashtra, India

Date of Submission20-Dec-2022Date of Decision16-Jan-2023Date of Acceptance17-Jan-2023Date of Web Publication20-Apr-2023

Correspondence Address:
Dr. D Muzumdar
Department of Neurosurgery, Seth Gordhandas Sunderdas Medical College and King Edward VII Memorial Hospital, Acharya Donde Marg, Parel, Mumbai, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jpgm.jpgm_974_22

How to cite this article:
Muzumdar D. Current understanding of role of venous sinus stenosis in management of idiopathic intracranial hypertension. J Postgrad Med 2023;69:136-7
How to cite this URL:
Muzumdar D. Current understanding of role of venous sinus stenosis in management of idiopathic intracranial hypertension. J Postgrad Med [serial online] 2023 [cited 2023 Jul 11];69:136-7. Available from: https://www.jpgmonline.com/text.asp?2023/69/3/136/374442

Taallapalli et al.[1] report a case of an idiopathic intracranial hypertension (IIH) secondary to right transverse and superior sagittal sinus stenosis in a 23-year-old lady in whom the symptoms of raised intracranial pressure responded to lumbar puncture. The left transverse sinus was hypoplastic. The unique feature in this case is the conversion of intracranial hypertension into intracranial hypotension due to lumbar puncture and resolution of transverse sinus stenosis.

IIH was first discovered more than a century ago. The exact cause of raised intracranial pressure in IIH is still unknown. It predominantly affects young obese women. The glia-neuro-vascular interface has a key role in the pathophysiology. The expansion of the brain and interstitial caused by lymphatic dysfunction may be responsible for the extrinsic venous sinus stenosis of IIH. The diagnosis is more often by exclusion.

Venous sinus stenosis is an important component of IIH. The incidence of transverse sinus stenosis in patients with IIH ranges from 10% to 90%, while the incidence in the general population is 6.8%. There is no direct correlation observed between the degree of venous sinus stenosis and the degree of intracranial pressure (ICP). The use of venous manometry is a gold standard measure to determine whether there is a venous pressure gradient on the stenosis.[2] Three-dimensional (3D) T1-weighted imaging is helpful in the diagnosis.

The venous sinus stenosis can be extrinsic or intrinsic.[3],[4],[5] Extrinsic stenosis may initially result from a small increase in ICP, which leads to a greater increase in ICP. This positive feedback loop is termed the Starling-like resistor. The proportion of extrinsic stenosis in IIH is relatively higher than that of intrinsic stenosis. It is unclear whether venous sinus stenosis is a primary cause of IIH or an epiphenomenon secondary to elevated ICP resulting in focal stenosis.[3],[4],[5] In intrinsic stenosis, the arachnoid granulations cause mechanical obstruction of the venous sinuses causing reduction in the efficiency of the venous cerebrospinal fluid (CSF) outflow pathway. Chronic venous sinus compression leads to local fibrosis and remodeling of the sinus wall, producing inherent stenosis. The occurrence of IIH is a result of the intertwining of various factors.

There are various modalities of treatment for IIH. Weight loss is the mainstay of treatment. Drugs like acetazolamide can reduce production of CSF. Surgery is indicated when there is a rapid or progressive decline in visual function. The treatment options include CSF shunting, optic nerve sheath fenestration, and venous sinus stenting. Venous sinus stenting is an emerging treatment, more effective and involves fewer complications. Patients with extrinsic stenosis need one or two long stents to cover the transverse sinus from the torcula to the sigmoid sinus, while in intrinsic stenosis, a single shorter stent usually seems to be sufficient.[3],[4],[5]

The patient reported by Taallapalli et al.[1] had right transverse and sigmoid sinus stenosis. The MR angiogram revealed that the transverse and sigmoid sinuses had opened following lumbar puncture. However, the MR angiogram after 3 months showed mild stenosis of the right sigmoid sinus without any high or low pressure.

In retrospect it can be postulated that the intrinsic stenosis of the transverse and sigmoid sinuses had caused the initially elevated ICP, which had been further compounded by the extrinsic stenosis. The lumbar puncture provided a buffer for normalization of the ICP and normal MRI in spite of persistent intrinsic stenosis. Thus, the entire process was dynamic, the extrinsic and intrinsic stenosis being intertwined. In the present case, only a long-term follow-up would shed more light on the pathophysiology of the intrinsic and extrinsic sinus stenosis and whether drainage by lumbar puncture alone is sufficient to produce long-term remission.

 

 :: References 
1.Taallapalli AVR, Shivaram S, Gupta M, Kulkarni GB. The ebb and flow of headache: A clue to pathophysiology of sinus stenosis in idiopathic intracranial hypertension? J Postgrad Med 2022;69:179-81.  
    2.Zhao K, Gu W, Liu C, Kong D, Zheng C, Chen W, et al. Advances in the understanding of the complex role of venous sinus stenosis in idiopathic intracranial hypertension. J Magn Reson Imaging 2022;56:645-54.  
    3.Sundararajan SH, Ramos AD, Kishore V, Michael M, Doustaly R, DeRusso F, et al. Dural venous sinus stenosis: Why distinguishing intrinsic-versus-extrinsic stenosis matters. AJNR Am J Neuroradiol 2021;42:288-96.  
    4.Gurney SP, Ramalingam S, Thomas A, Sinclair AJ, Mollan SP. Exploring the current management idiopathic intracranial hypertension, and understanding the role of dural venous sinus stenting. Eye Brain 2020;12:1-13.  
    5.Xu K, Yu T, Yuan Y, Yu J. Current status of the application of intracranial venous sinus stenting. Int J Med Sci 2015;12:780-89.