Increased intracranial pressure (ICP) often requires invasive monitoring and emergent treatment. Pseudotumor cerebri is the common name for the idiopathic form, which may be due to cerebral venous sinus thrombosis and associated with papilledema and visual loss. The opposite clinical syndrome is intracranial hypotension, which is one of the causes of new daily persistent headache. The magnetic resonance imaging (MRI) shows a sagging brain and pachymeningeal enhancement. Myelography using either computed tomography (CT) or MRI imaging is used to find the cerebrospinal fluid (CSF) leak, sometimes cured with a blood patch. Brain herniation is a complication of increased ICP requiring emergent treatment. False localizing signs are seen due to compression of the contralateral Kernohan notch.
Hydrocephalus can be associated with the normal pressure form, diagnosed by a high-volume lumbar puncture (LP), and treated with ventriculoperitoneal or lumboperitoneal shunting.
White matter diseases include acute disseminated encephalomyelitis, progressive multifocal encephalopathy caused by the John Cunningham (JC) virus, multiple sclerosis, and central pontine myelinolysis.
The total volume of the adult intracranial content is 1400–1700 mL, of which the brain is 80% (1200 mL), and the cerebrospinal fluid (CSF) and the blood are each 10% (150 mL). The choroid plexi form CSF at a rate of 20 mL/hour or 450–500 mL/day. The arachnoid granulations lie along the superior sagittal sinus and return the CSF into the venous system via a one-way valve.
The Monro-Kellie hypothesis states the skull is inelastic, containing a fixed volume. This applies to both intracranial hypertension and hypotension.
Headache (HA) that is worse upon awakening and exacerbated with coughing/sneezing/bending.
Visual changes may include diplopia and transient visual obscurations (TVOs).
Weakness, sensory changes, and myelopathy (compression at the cervical–medullary junction).
Altered breathing patterns, cardiac dysrhythmia, and hiccups.
CT: tumor, stroke, hydrocephalus, subarachnoid hemorrhage (SAH), cysts, abscess, herniation, hematoma, loss of gray–white junction, congenital or developmental anomalies, and lateral displacement of the calcified pineal body
MRI: above plus encephalitis, meningitis, shear, empty sella, edema, and prominence of the optic nerve sheath (optic nerve hydrops)
MRV (venous): cerebral venous thrombosis (do not overlook this important and treatable etiology that is not seen on routine imaging, unless there is associated cerebral venous infarction) (Figure 18-1)
Figure 18-1
(A) Initial MR venography demonstrated partial thrombosis of the superior sagittal sinus, torcula, and proximal transverse sinuses (arrows). (B) Follow-up MR venography at the time of visual worsening showed improvement in venous flow, with mild residual thrombosis. (C) Fast-spin echo T2-weighted axial imaging demonstrated reversed optic nerve cupping in the right eye with posterior scleral flattening and protrusion of optic nerve papilla into the globe (arrow) (subsequent image on MRI demonstrated similar findings in the left eye). (D) Close-up of right eye seen in (C). MRI data: (A and B) repetition time (TR) 33.3 msec, echo time (TE) 6.9 msec, ST 1.5 mm; (C and D) TR 3500 msec, TE 95 msec, ST 5.0 mm. Reproduced with permission from Zimmer JA, Garg BP, O’Neill DP, et al: Teaching neuroImage: MRI visualization of papilledema associated with cerebral sinovenous thrombosis in a child, Neurology. 2008 Aug 12;71(7):e12–e13.
Evidence of head or neck trauma including:
Basilar skull fracture: hemotympanum, Battle sign, raccoon eyes, and CSF drainage from the ears or nose
Ocular trauma: hyphema (blood in the anterior chamber) and retinal detachment (ophthalmoscopy is not an optional part of the examination, the neurologist must carry and be proficient in the use of the ophthalmoscope)
Cervical spine fracture: crepitus or step-off along the cervical spine
Ocular motility and pupillary reaction
CN III compression: ipsilateral inferolateral eye deviation (“down and out”) with a dilated pupil (due to interruption of the parasympathetic fibers carried by CN III)
ipsilateral ptosis, miosis, and anhydrosis represent Horner syndrome due to interruption of the oculo-sympathetic fiber pathway
Papilledema
Variation in the Glasgow Coma Scale (GCS in Figure 18-2)
Observation of spontaneous movement and examination of tone (note that rigidity and cogwheeling suggests injury to the deep nuclei), resistive strength, reflexes, extensor toe sign, posturing (decorticate or decerebrate), and response to a painful stimulus (grimace, withdrawal, localization)
Cushing triad: bradycardia, hypertension, and abnormal respiration due to compression of the medulla
GCS <8
Abnormal CT/MRI
Or normal CT with age >40 years, posturing, and/or SBP <90
CASE 18-1
A 23-year-old woman presents to the emergency department (ED) with a 9-month history of progressive, generalized, unrelenting headache associated with bilateral visual loss and, more recently, diplopia. She had been seen by several physicians and diagnosed with “migraine”; ophthalmoscopy had never been performed. Weight had increased by 65 pounds in the prior year. The complete general and neurological examination was remarkable for obesity, bilateral abducens palsies, and bilateral papilledema. MRI showed optic nerve hydrops and sulcal effacement. CSF opening pressure (OP) was 29 cmH2O with her in the lateral decubitus position and relaxed. Otherwise, CSF composition was unremarkable.
Historically seen in obese females over the age of 40 years.
It has historically been referred to as pseudotumor cerebri and benign intracranial hypertension.
The symptoms vary throughout the day due to variations in ICP.
Headaches, transient visual obscuration, pulsatile tinnitus, photopsias (flashes of light in the lateral visual fields), retrobulbar pain, diplopia (abducens nerve palsy), and sustained visual loss
Other cranial nerve deficits: olfactory, oculomotor, trochlear, trigeminal, facial, and auditory
A high index of suspicion is necessary, as the CSF opening pressure may be normal at the bottom of the fluid wave.
See Table 18-1.
Medications That May Cause Intracranial Hypertension
| Medication Classification | |
|---|---|
| Antibiotics | Tetracycline Minocycline Doxycicline Nalidixicacid |
| Vitamin A and related compounds | Vitamin A (doses>250,000 IU daily) Isotretinoin Trans retinoic acid |
| Hormone and related compounds | Levonorgestrel implant Oral contraceptives Growth hormone |
| Chemotherapy | Cytarabine |
| Immunosuppressants | Cyclosporine Corticosteroids (withdrawal from long-term use) |
| Antiarrythmics | Amiodarone |
| Antipsychotics | Lithium |
Carbonic anhydrase inhibitors slow CSF production.
Acetazolamide, up to 4 gm/day
Weaker inhibitors are topiramate (25–100 mg BID) and zonisamide (50–200 mgQD) which will also reduce the appetite and are often used for weight loss, which has been heralded as the only “cure” for IIH associated with obesity. These medications may be used in combination with acetazolamide.
Ventriculoperitoneal or lumboperitoneal shunting
Optic nerve fenestration (has been shown to be more expedious and efficacious in the preservation of vision)
Serial LPs (check closing pressure to be sure it is now in the normal range of <200mm or 20 cmH2O)
CASE 18-2
A 37-year-old woman developed a headache following a trip to an amusement park, where she had ridden several roller coasters. The pain became persistent and seemed to improve only after assuming a horizontal position. When severe, her vision would blur with intermittent diplopia, there was a feeling of motion, and intermittent tinnitus and hearing change. Her neurological examination and initial brain MRI were normal, but a repeat MRI 3 months later showed a “sagging brain” with the pontomesencephalic angle 39° (defined as the angle between the line drawn along the anterior margin of the midbrain and the anterior superior margin of the pons). The mean value in patients with intracranial hypotension is 41.2° (SD, ±17.4°).
The mammillopontine distance was 4.3 mm (defined as the distance between the inferior aspect of mamillary bodies and the superior aspect of pons. (The mean value in patients with intracranial hypotension is 4.4 mm (SD, ±1.8)).1 MRI of the cervical and thoracic spine was normal; however, intrathecal gadolinium MR myelography demonstrated a CSF leak at T4. A selective epidural blood patch was performed, and the headache resolved over the next 6 weeks.
Headache is usually postural and worse when upright.
Although there may be no headache, or rarely, it is worse when lying flat.
Generalized or localized to the occipital region.
May involve the posterior neck.
Worsened with coughing, laughing, and Valsalva maneuver.
CSF OP <60 mm H2O.
Theorized as a potential etiology of the “new persistent daily headache.”
Cranial nerve deficits due to nerve compression and/or traction causing blurred vision, diplopia, facial numbness, change in taste, vertigo, hearing impairment, and/or tinnitus
Less common: altered mental status, quadriplegia, parkinsonism, chorea, tremor, radiculopathy, myelopathy, thrombosis of cortical vein or venous sinus, leptomeningeal hemosiderosis, cerebral vasoconstriction syndrome, and/or frontotemporal brain sagging syndrome
CSF leakage from: LP, trauma, surgery, and spinal/epidural anesthesia
Overdrainage from a CSF shunt
Alteration in CSF formation or resorption
Downward displacement of the cerebellar tonsils
Pachymeningeal enhancement
Venous and/or pituitary engorgement
Subdural fluid collections (Monro-Kellie hypothesis) and/or hematoma
C1/C2 sign = high signal intensity between their spinous processes
“Sagging brain” with a reduced pontomesencephalic angle (41.2 ±17.4°)
Short mamillopontine distance (4.4 ± 1.8 mm) (Figure 18-3)
Figure 18-3
Imaging in spontaneous intracranial hypotension. (A) Coronal enhanced T1-weighted MRI shows typical changes of intracranial hypotension with subdural fluid collections (arrows) and meningeal enhancement (arrowheads) in a 35-year-old man with multiple spontaneous spinal CSF leaks. (B) Normal coronal enhanced T1-weighted MRI in a 43-year-old man with spontaneous CSF leaks at the T2 to T3 (C, arrow) and T6 to T7 (D, arrows) levels on CT myelography. (E, F) Following surgical repair, no CSF leak was detected, but symptoms persisted. An arachnoid cyst arising from the left T7 nerve root was ligated with an aneurysm clip (F, arrow). Reproduced with permission from Schievink WI, Maya MM, Louy C: Cranial MRI predicts outcome of spontaneous intracranial hypotension, Neurology. 2005 Apr 12;64(7):1282–1284.
Radionucleotide cisternography
Conventional or CT myelography
Intrathecal gadolinium MR myelography (Figure 18-4)
Figure 18-4
(A) Contrast axial T1-weighted MRI shows intense linear and diffuse dural enhancement. (B) Radionuclide cisternograms show CSF leakage at the level of the bilateral cervico-thoracic junction of the spine and the multiple T spine level. Reproduced with permission from Choi H, Lee J, Koh SH, et al: Teaching Neuro Images: CSF leaks and spontaneous intracranial hypotension, Neurology. 2012 Nov 6;79(19):e176
Empiric lumbar epidural blood patch prior to a more selective area blood patch (using the patient’s own blood, drawn at the time of the procedure)
Caffeine may have the effects of stimulation of CSF production and vasoconstriction
Fibrin glue or muscle patch at the site of the leak
Ligation of meningeal diverticulae
CASE 18-3
A 73-year-old man was found down in his home by neighbors, who had not seen him pick up his newspaper at the end of his driveway for 2 days. His examination showed an abrasion of the L face with swelling of the left globe with hyphema. The right fundus did not show papilledema, and the right pupil was slightly reactive. There was a very slight withdrawal to pain of all limbs, without associated localization. Tone and muscle stretch reflexes were increased in the lower limbs, with sustained ankle clonus and upgoing toes bilaterally. Emergent intubation and stabilization of vital signs were undertaken, which included pressors to maintain blood pressure.
Laboratory studies showed an INR = 17, hemoglobin = 8, hematocrit = 25, and sodium = 130. MRI showed a left panhemispheric subarachnoid hemorrhage measuring 6 mm in width, a small left frontal subdural hematoma, and left pancerebral edema with a subfalcial left to right shift = 3 mm. Video EEG demonstrated nonconvulsive status epilepticus of the left hemisphere only, not responding to loading doses of fosphenytoin, levitiracetam, and lacosamide; burst suppression was achieved with midazolam drip up to 60 mg/hour. Hypertonic saline was infused, maintaining a serum sodium level of 158.
After correction of the INR, repeat CT scans were unchanged and neurosurgical intervention was not required. Although the epileptiform activity remained controlled after weaning off the midazolam, consciousness was never regained.
The causes are multiple and include structural lesions (tumor with vasogenic edema), abcess, hemorrhage (intracerebral, subdural, epidural), stroke (ischemic with cytotoxic edema), pancerebral edema (hepatic encephalopathy, encephalitis), hydrocephalus, and impaired venous outflow (venous sinus thrombosis, superior vena cava syndrome). Another cause is herniation through a breech in the skull.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
