Increaded intracranial pressure

Increaded intracranial pressure

Diffuse brain oedema or swelling
• Meningo-encephalitis
• Subarachnoid haemorrhage
• Idiopathic intracranial hypertension
Disturbance of CSF circulation
Mass lesions
• Obstructive (non-communicating) hydrocephalus: obstruction within ventricular system
• Communicating hydrocephalus: site of obstruction outside ventricular system
• Cerebral tumour
• Infective: Cerebral abscess Tuberculoma, Hydatid cyst
• Intracranial haemorrhage (traumatic or spontaneous):
Extradural haematoma
Subdural haematoma
Intracerebral haemorrhage

Pseudotumor cerebri

Intracranial hypertension without ventriculomegaly, mass lesion, or evidence of infection characterize the pseudotumor cerebri syndrome.
There are many conditions and medications associated with the pseudotumor cerebri syndrome, but the idiopathic form, idiopathic intracranial hypertension, is most commonly encountered in practice.


Intracranial venous drainage obstruction
Endocrine dysfunction
Vitamin and drug therapy

(eg, venous sinus thrombosis, head trauma, polycythemia, thrombocytosis)

(eg, chronic hypercapnia, severe right heart failure, hypertensive encephalopathy, severe iron deficiency anemia)
Other

(eg, obesity, withdrawal from steroid therapy, Addison disease, hypoparathyroidism)

(eg, hypervitaminosis A and 13 cis-retinoic acid in children and adolescents, tetracycline, minocycline, nalidixic acid)

IIH
Women are affected much more commonly than men, with a peak incidence in the third decade. Most patients are obese.

Clinical features

The most common presenting symptom of IIH is visual. The earliest visual symptom of idiopathic intracranial hypertension is transient visual obscurations, which are episodes of visual blackout or dimming lasting seconds to minutes in one or both eyes. The episodes are characteristically provoked by arising after bending over or from eye movement; vision returns to baseline after each episode, but episodes may occur many times daily and indicate the presence of papilledema.

Idiopathic intracranial hypertension generally affects young obese women.

Patients with idiopathic intracranial hypertension sometimes become aware of their physiologic blind spot as it enlarges. As the blind spot, normally located 10 to 15 degrees temporal to fixation, enlarges toward fixation it obscures parts of text or images. Patients often report temporal expansion of the blind spot as seeing ‘‘something moving in my peripheral vision,’’ and constriction of peripheral visual field “tunnel vision”
Diplopia may also occur, usually with images displaced horizontally, reflecting a unilateral or bilateral abducens palsy. The clinician can asses diplopia by asking the patient to close one of his eye as the double image disappear.
Photosensitivity is common, perhaps a manifestation of the headache
Headache.
Pulsatile tinnitus occur in 50 % of patient.

Examination

Visual acuity The examination reveals normal or near-normal visual acuity.
Visual field by perimetry and confrontation reveals enlargement of the blind spot and constriction of peripheral visual field.
Fundoscopy shows papilledema “bilateral optic disc swelling due to raised intracranial pressure”

Young obese women

Visual symptoms of transient visual obscuration, becoming aware of physiological blind spot, diplopia, photosensivity,
headache
Pulsatile
tinnitus

Ocular motility examination may reveal a unilateral or bilateral abducens nerve palsy.

Papilledema is graded using the Frise´n scale. Mild (grade 1 to 2) papilledema include an incomplete and complete, dark peripapillary halo and elevation of the optic disc. Moderate (grade 3) papilledema results in a complete peripapillary halo, obscuration of major vessels crossing the disc, and diffuse nerve head elevation. With severe (grades 4 to 5), two or more major vessels crossing the disc are obscured and the optic cup is obliterated.
NB Hemorrhages, exudates, and retinal edema may be present in acute to subacute papilledema but are not factors that determine severity while Chronic papilledema not show hemorrhages or exudates.

Mild papilledema

Grade 1 and 2


Moderate papilledema
Grade 3

Papilledema Grade 4

Loss of major vessels on the disc
Papilledema Grade 5
Has the criteria of grade 4 plus partial or total obscuration of all vessels of the disc + absence of the optic disc cup +dome shape disc

Diagnostic Criteria for Pseudotumor Cerebri Syndrome

Definite
• Papilledema
• Normal neurologic examination except for cranial nerve abnormalities
• Neuroimaging: Normal brain parenchyma without evidence of hydrocephalus, mass, or structural lesion and no abnormal meningeal enhancement on MRI, with and without gadolinium.
• Normal CSF composition
• Elevated lumbar puncture opening pressure (more than 250 mm CSF in adults and 280 mm CSF in children.
Probable A-D
NB we can diagnose IIH in the absence of papilledema but probable if full the criteria from B-E + three out of following 5:empty sella, flattening of globe, wide periopic SAS, tonsellar decent, transverse sinus stenosis.

TREATMENT

Treatments of papilledema in idiopathic intracranial hypertension include
• weight loss,
• Acetazolamide “Carbonic Anhydrase Inhibitors”
• surgical options “optic nerve sheath fenestration and shunting”
weight loss
There was a relationship between weight loss and improvement of papilledema grade, with approximately 6% of body weight loss being associated with resolution of marked papilledema.
Carbonic Anhydrase Inhibitors
It has an inhibitory effect on CSF production by the choroid plexus.
The most common practice is starting with 1 g/d in divided doses, gradually increasing the dose as needed or tolerated to a maximum of 4 g/d.



side effects are paresthesia, gastrointestinal symptoms, and fatigue, Acetazolamide (category C) may be used during pregnancy after the first trimester, hypokalemia occur only when used with other diuretics, Renal stones and elevated transaminase levels occur uncommonly.
NB The sulfa moiety in acetazolamide is different from the sulfa component in antibiotics, so an allergy to sulfa antibiotics does not preclude a trial of acetazolamide.
Therapeutic Lumbar Puncture
Therapeutic lumbar puncture may be useful during pregnancy to buy time while awaiting a surgical intervention, or to avoid acetazolamide in the first trimester.
Optic Nerve Sheath Fenestration
about one-third of patients experiencing visual deterioration over 3 to 5 years after an initially successful procedure.
Postoperative diplopia is usually transient.

Shunting

Various types of shunts have been used to treat the pseudotumor cerebri syndrome, including ventriculoperitoneal lumboperitoneal, ventriculoatrial, and ventriculopleural shunts; ventriculoperitoneal and lumboperitoneal shunts are more frequently employed.
The initial effectiveness (95%) for headache immediately after the shunts.
Complications of shunting procedures include infection, valve malfunction or obstruction and migration of the distal catheter.

BRAIN ABSCESS

Brain abscess is an uncommon disorder, accounting for only 2% of intracranial masses.
Etiology
The common conditions predisposing to brain abscess, in approximate order of frequency, are
• blood-borne metastasis from distant systemic (especially pulmonary) infection,
• direct extension from parameningeal sites (otitis, cranial osteomyelitis, sinusitis),
• unknown source,
• infection associated with recent or remote head trauma or craniotomy,
• infection associated with cyanotic congenital heart disease.

Causative microorganisms

Clinical Findings
The course is that of an expanding mass lesion, usually presenting with headache and focal neurologic deficits in a conscious patient.
Coma may develop over days but rarely over hours.
Common presenting signs and symptoms are shown in this table
Temperature is normal in 40% of patients, and the peripheral white blood cell count is below 10,000/μL in 20%.

Investigative Studies

The diagnosis is strongly supported by finding a mass lesion with a contrast-enhanced rim on CT scan or MRI or an avascular mass on angiography.
Marked clinical deterioration may follow lumbar puncture in patients with brain abscess; therefore, lumbar puncture should not be performed if brain abscess is suspected.
Examination of the CSF reveals an opening pressure greater than 200 mm water in 75% of patients, pleocytosis of 25 to 500 or more white cells/μL (depending on the proximity of the abscess to the ventricular surface and its degree of encapsulation), and elevated protein level (45-500 mg/dL) in approximately 60% of patients. CSF cultures are usually negative.


Right temporal cerebral abscess (arrows), with surrounding edema and midline shift to the left.
A. B
Without contrast CT image
Contrast enhanced CT image.


Treatment
Treatment of pyogenic brain abscess can be with antibiotics alone or combined with surgical drainage.
Surgical therapy should be strongly considered when there is
• significant mass effect
• the abscess is near the ventricular surface, because catastrophic rupture into the ventricular system may occur.
Medical treatment alone is indicated for
• surgically inaccessible,
• multiple,
• early abscesses.
If the causal organism is unknown, broad-spectrum antibiotic coverage is indicated. The first-line recommendation is ceftriaxone 2 g every 12 hours plus metronidazole.


Glucocorticoids may reduce edema surrounding the abscess. The response to medical treatment should be assessed by clinical examination and serial CT or MRI scans.
When medically treated patients do not improve, needle aspiration of the abscess is indicated to identify the organisms present.