【病例】特发性颅内高压1例MR影像表现

History: A 63-year-old woman presents with headaches, nausea, vomiting, and vertigo.(63岁妇女,出现头痛、恶心、呕吐和眩晕。)

【病例】特发性颅内高压1例MR影像表现

【病例】特发性颅内高压1例MR影像表现

【病例】特发性颅内高压1例MR影像表现

Findings

Sagittal T1-weighted MR image shows an empty and expanded sella turcica.

Axial T2  images show the optic nerve sheath is widened and expanded with cerebrospinal fluid (CSF) hyperintensity surrounding the optic nerve.

Axial T2 and axial FLAIR images shows posterior flattening of the globes.

矢状T1加权MR图像显示蝶鞍扩大(空碟鞍)。

轴向T2和轴向FLAIR图像显示视神经鞘扩大和视神经周围的高信号脑脊液。

轴向T2和轴向FLAIR图像显示眼球后部扁平。

正确诊断:Idiopathic intracranial hypertension (IIH)(特发性颅内高压)

Key points

Idiopathic intracranial hypertension (IIH)

Pathophysiology (病理生理学)

As the name suggests, the exact cause of idiopathic intracranial hypertension is not fully understood. The diagnosis is dependent upon exclusion of other causes of intracranial hypertension, including mass lesions and hydrocephalus. Pseudotumor cerebri refers to patients with raised intracranial pressure without hydrocephalus or mass lesion but which may be secondary to findings such as dural sinus thrombosis or dural arteriovenous fistula. There are several theories regarding IIH’s pathophysiology, which include the following:

Impaired CSF homeostasis (reduced CSF reabsorption or excess CSF production)

Altered vitamin A metabolism,  supported by associations with medications including tetracycline and corticosteroids

Venous sinus stenosis, which may cause increased venous pressures, leading to decreased CSF resorption, increased ICP and venous sinus compression

顾名思义,特发性颅内高压的确切原因尚不完全清楚。诊断依赖于排除颅内压增高的其他原因,包括肿l瘤和脑积水。假性脑瘤是指患者无脑积水或肿瘤而是硬脑膜窦血栓形成或硬脑膜动静脉瘘造成的颅内压增高。有关于特发性颅内高压的病理生理学的几个理论,包括:CSF稳态受损(CSF重吸收减少或脑脊液产生过量),维生素A代谢的改变,与包括四环素和皮质类固醇在内的药物相关,静脉窦狭窄可能导致静脉压力增加,导致脑脊液吸收减少,颅内压增高和静脉窦压迫。

Epidemiology (流行病学)

Idiopathic intracranial hypertension is a rare condition, with an incidence of approximately 0.9 cases per 100,000. It is found much more commonly in women with a reported 8:1 female to male ratio. There is a strong association with body mass index (BMI), such that the odds ratio of the condition increases approximately fourfold with a BMI greater than 35 compared with a BMI of 25-29. It occurs most commonly between the ages of 20 and 44. It is also associated with the use of growth hormones, steroids, tetracycline, vitamin A, thyroid replacement, and some systemic diseases, including hypercoagulability disorders, systemic lupus erythematosus, Addison’s disease, and severe iron deficiency anemia.

特发性颅内高压症是一种罕见的疾病,每100000例发病率约为0.9例。据报道这在女性种更为常见,女性与男性的比例为8:1。体重指数有很强的相关性,BMI指数大于35要比BMI指数在25-29之间的风险大约增加四倍。最常见的发生在20岁到44岁之间。这也与生长激素、类固醇、四环素、维生素A、甲状腺替代使用相关的,和一些全身性疾病,包括高凝状态的疾病,系统性红斑狼疮、艾迪生病、严重的缺铁性贫血

Clinical presentation(临床表现)

Classically, idiopathic intracranial hypertension presents with headache and vision changes in obese women of childbearing age. Headaches are usually unremitting, associated with retro-ocular pain and accompanied by nausea. Vision changes usually include tunnel vision secondary to transient ischemia of the optic nerve. Ophthalmologic signs of IIH include diminished visual acuity and visual field losses on formalized testing, as well as papilledema on fundoscopic exam in 40% of patients. Cranial nerve palsies, usually the abducens nerve (CN VI), can occur in as many as 10% to 20% of patients.

典型的特发性颅内高压表现为肥胖育龄妇女出现头痛和视力变化。头痛通常是持续性的,伴随着眼部疼痛和恶心。视觉改变通常包括视神经短暂缺血继发的隧道视觉。IIH的眼科症状包括视力下降和视野损失,以及对40%的患者的眼底检查视乳头水肿。颅神经麻痹,通常是外展神经(CNVI),可在10%至20%的患者中发生。

Imaging features(影像学特点)

“Empty sella sign” — Refers to when the pituitary gland is not visible and is associated with longstanding effects of increased intracranial pressure.

Optic nerve sheath enlargement with widened ring of CSF signal intensity around the side of the optic nerve

Posterior globe flattening, which is associated with increased ocular pressure by transmission of elevated CSF pressure through the optic nerve sheath to the posterior globe, and is associated with the finding of papilledema

Optic nerve tortuosity

Intraocular protrusion of the optic nerve head

Stenosis of the transverse cerebral venous sinuses

“空蝶鞍征”指的是未见正常垂体,与长期颅内压增高有关。

视神经鞘扩大,视神经周围脑脊液信号环形增宽。

眼球后部扁平,脑脊液压力增高通过视神经鞘传递至眼球后部导致眼压增高,视乳头水肿

视神经迂曲

视神经乳头凸向眼内

横窦狭窄

Treatment(治疗)

The main goals of treatment are to alleviate symptoms of increased intracranial pressure (largely headaches) and preserve vision.

治疗的主要目标是缓解颅内压增高(主要是头痛)和保持视力的症状。

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