A Swollen Optic Disc in a Patient with Headaches
A 34-year-old woman with a body mass index of 36 presents with 3 weeks of daily headaches, transient visual obscurations lasting seconds on standing, and pulse-synchronous tinnitus. Acuity is 6/6 both eyes. Pupils are equal with no afferent defect. Fundoscopy shows bilateral disc swelling with obscured margins, hyperaemia, and peripapillary haemorrhages; there are no spontaneous venous pulsations. Visual fields show enlarged blind spots with a mild inferior nasal step on the right. Blood pressure is 128/80. She takes a combined oral contraceptive and has no other medication. She is worried about a brain tumour and asks why she cannot just have a lumbar puncture to 'relieve the pressure'.
1. Explain the diagnostic pathway and the reasoning that must precede any lumbar puncture.
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The presentation is classic for raised intracranial pressure, and the leading diagnosis is idiopathic intracranial hypertension given the demographics, symptoms, and bilateral swollen discs. But 'idiopathic' is a diagnosis of exclusion, and the pathway must exclude secondary causes before any lumbar puncture.
Step 1 - Neuroimaging. Urgent MRI brain and orbits with venography, or CT venography if MRI is unavailable. The purpose is to exclude a mass lesion, hydrocephalus, or - critically - cerebral venous sinus thrombosis, which can present identically and is a contraindication to immediate lumbar puncture. The combined oral contraceptive is a risk factor for venous thrombosis. Look for empty sella, flattening of the posterior globes, distension of the optic nerve sheaths, and transverse sinus stenosis, which support the diagnosis.
Step 2 - Why not lumbar puncture first. Performing a lumbar puncture in the presence of a space-occupying lesion risks fatal herniation. Imaging must precede the tap. Also, a 'normal' opening pressure does not exclude the diagnosis - pressure can be normal in some patients, especially if the tap is done in a relaxed lateral decubitus position and the diagnosis rests on the whole picture.
Step 3 - Lumbar puncture. Once imaging excludes a mass and venous thrombosis, do the tap in the lateral decubitus position with legs extended, measuring opening pressure; send CSF for cells, protein, glucose, and cytology. An opening pressure above 25 cm CSF in a non-obese patient or above 25–30 cm in an obese patient supports the diagnosis.
Step 4 - Other tests. Blood pressure to exclude malignant hypertension, full blood count, and a drug history. She should be asked about tetracyclines, vitamin A derivatives, and growth hormone.
2. She asks whether the lumbar puncture will fix her vision and whether she needs to stop the contraceptive pill. Discuss the treatment strategy and the prognostic factors.
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Will the tap fix it? A single lumbar puncture lowers pressure transiently and may relieve headache for days, but it is diagnostic, not curative. Repeated taps are not a sustainable treatment. The therapeutic aim is to protect vision, which is threatened by papilloedema, not to cure the headache.
Vision-threatening features. Her field loss - enlarged blind spots and an inferior nasal step - is early but real. Risk factors for progressive visual loss include high-grade papilloedema, field loss at presentation, obesity, and a short history of severe symptoms. She needs formal perimetry (Humphrey 24-2 and 10-2) and OCT retinal nerve fibre layer now, and regular monitoring.
Weight and the pill. Obesity is the strongest modifiable risk factor; weight loss of 5–10% improves the condition. Refer to a dietitian. The combined oral contraceptive is a risk factor for venous thrombosis and is often stopped, but this is a shared decision with her general practitioner or gynaecologist, weighing pregnancy risk; a progestogen-only or non-hormonal method is often preferred. It is not an emergency to stop it, but it should be addressed.
Medical therapy. Acetazolamide is first-line, titrated by tolerance; monitor for paraesthesias, taste disturbance, and renal stones. Topiramate is an alternative and aids weight loss.
Surgical options. If vision deteriorates despite medical therapy, or if papilloedema is severe, offer optic nerve sheath fenestration (protects the eye operated on) or a CSF diversion procedure such as a ventriculoperitoneal or lumboperitoneal shunt, or venous sinus stenting if a significant pressure gradient is found. The choice depends on whether headache or vision is the dominant problem and on local expertise.
Monitoring. Review every 4–8 weeks initially with acuity, fields, and OCT; escalate if field loss progresses. Reassure her that most patients retain good vision with treatment, but emphasise that surveillance is lifelong while the condition is active.