Intracranial Hypotension

Question 1

Spontaneous Intracranial Hypotension

Answer 1

Spontaneous intracranial hypotension

Key features
strong postural relationship with the headache generally much worse when upright. Patients may therefore be bed-bound

Diagnosis is confirmed by MRI with gadolinium that demonstrates distinctive dural gadolinium enhancement and downward displacement of brain on sagittal views.

In some cases of spontaneous intracranial hypotension, investigations such as MRI whole spine with STIR sequences or digital subtraction myelography may be used to identify the location of CSF leak in order to guide blood patch treatment.

Example Question:
A 48-year-old woman presented to the emergency department with a severe headache. Symptoms had started early that day while the patient had been walking around her office with the headache reaching maximal intensity within a few minutes. The pain was felt across the entirety of the patient’s head and was much improved when she lay down flat. There were no associated symptoms and the patient had been constitutionally well in the preceding days.

The patient had no past medical history and was nulliparous. She was a non-smoker who consumed 15 units of alcohol per week.

Clinical examination demonstrated no evidence of focal neurological deficit and no signs of meningism. Simple analgesia given in the emergency department had limited impact on the patient’s headache.

CT brain with venogram: no evidence of intra-axial or extra-axial bleeding; no space occupying lesion; no hydrocephalus; no evidence of venous sinus thrombosis

Lumbar puncture: opening pressure 5 mmHg; red cells 8 mm³; white cells 1 / mm³; no xanthrochromia

What is the next best investigation to confirm the likely diagnosis?

	Digital subtraction myelography
	Cerebral angiography
	CT brain with contrast
	MRI whole spine with STIR
	> MRI brain with gadolinium

The clinical presentation and initial investigations are suggestive of spontaneous intracranial hypotension. The key aspect of the history is the strong postural relationship to pain with the headache worsening within a few seconds of upright posture and easing within a minute of lying horizontal. Spontaneous intracranial hypotension can cause either a headache of insidious or rapid onset. A low opening pressure on lumbar puncture (< 6 cmCSF) is one of the diagnostic criteria.

Diagnosis is confirmed by MRI with gadolinium that demonstrates distinctive dural gadolinium enhancement and downward displacement of brain on sagittal views.

In some cases of spontaneous intracranial hypotension, investigations such as MRI whole spine with STIR sequences or digital subtraction myelography may be used to identify the location of CSF leak in order to guide blood patch treatment.

Question 2

Spontaneous Intracranial HypOtension

Answer 2

The key aspect of the history is the strong postural relationship to pain with the headache worsening within a few seconds of upright posture and easing within a minute of lying horizontal.

Spontaneous intracranial hypotension can cause either a headache of insidious or rapid onset.

A low opening pressure on lumbar puncture (< 6 cmCSF) is one of the diagnostic criteria.