150 Pseudotumor cerebri

Youmans Neurological Surgery

1. Pseudotumor cerebri Youmans,Neurological surgery 6 th edition Chapter 150 Neil R Miller 07/03/59

2. Terminology pseudotumor cerebri (PTC) idiopathic intracranial hypertension (IIH ) secondary pseudotumor cerebri for the rare cases in which a cause ( e.g., drug induced) is identified

3. Terminology increased intracranial pressure (ICP) without evidence of dilated ventricles or a mass lesion by imaging normal cerebrospinal fluid (CSF) content papilledema occurring in most cases (but not all) young, obese women without any clear explanation

4. Epidemiology infants , children, and young adults 90 % of cases, is typically a disorder of obese females of childbearing age

5. Symptoms and Signs Asymptomatic and discovered during a routine ophthalmic examination when papilledema is found Headache(90%) generally different from previous headaches and is severe bifrontal or generalized, pressure-like, and often associated with neck pain migrainous features, including unilateral pain, nausea , vomiting, photophobia, and phonophobia “brain tumor headache” that is worse in the morning and aggravated when cerebral venous pressure is increased by v alsalva maneuvers (e.g., coughing, sneezing)

6. Symptoms and Signs Transient obscurations of vision (TOVs)(70%) partial or complete unilateral or bilateral few seconds precipitated by a change in posture (e.g., bending over, arising from a stooped position) or rolling the eyes indicate the presence of optic disc swelling not a sign of a poor prognosis Visual loss enlarged dark spot in the temporal visual field

7. Symptoms and Signs Diplopia(40 %) ho rizontal diplopia results from unilateral or bilateral abducens nerve paresis nonlocalizing feature of increased ICP Pulsatile tinnitus : uncommon whooshing sound, hearing a heartbeat in the head, or a high-pitched noise reflect flow disturbances within the cerebral venous system unilateral or bilateral often more prominent at night or in quiet surroundings

8. Symptoms and Signs Papilledema diagnostic hallmark almost always bilateral and symmetrical but it may be asymmetric or, occasionally, unilateral crucial in determining the appropriate management of any patient with papilledema

9. Frisen Scale

10. Diagnosis no intracranial or spinal mass no evidence of hydrocephalus MRI is recommend documented increased ICP Normal lumbar CSF pressure in both obese and nonobese adult : 20-25 cmH2O Prepupertal : greater than 20 cmH2O is abnormal monitoring normal CSF contents glucose and protein concentration, presence of cells, cytology, and atypical infections (e.g., syphilis, cryptococcus , fungus)

11. Secondary Pseudotumor cerebri

12. Secondary Pseudotumor cerebri

13. Complication Permanent visual loss CSF pressure remained elevated

14. Pathophysiology Unclear mechanism,both IIH or secondary PTC Plasma levels of ghrelin a hormone that appears to be involved in the regulation of body weight found no difference between obese patients with and without evidence of IIH

15. Monitoring Visual field defect Similar to that occurring in patients with chronic open-angle glaucoma progressive visual field constriction , color vision loss, and finally, loss of central vision Most visual deficits associated with papilledema are reversible if ICP is lowered before severe visual loss or optic nerve ischemia develops Ophthalmologist

16. Monitoring

17. Monitoring At disease onset, some patients require an evaluation every 1 to 2 weeks until a pattern of progression or stability is established Other patients can be examined every 1 to 3 months without fear that they will lose vision in the interim Patients with stable vision and mild or moderate papilledema may need to be examined only every 4 to 12 months

18. Treatment Neurologist, ophthalmologist , primary care physician, and neurosurgeon Presence and severity of symptoms such as headache Degree of visual loss at initial examination Rate of progression of visual loss Presence of an identifiable underlying cause (e.g., medication induced , venous sinus thrombosis, Chiari malformation) Detection of factors known to be associated with a poorer visual prognosis(e.g., African American heritage, pubescent child, male gender , high-grade papilledema with macular edema)

19. Treatment Related to Obesity Weight loss , restrict food and exercise Decreasing food intake while increasing water consumption and sodium restriction When weight loss efforts fail, bariatric surgery may be considered Weight reduction should not be used as the only treatment in patients with PTC

20. Medical Treatment Most appropriate when the primary problem is headache in the setting of good visual function Carbonic anhydrase inhibitors decrease the production of CSF and thereby result in decreased sodium ion transport across the choroidal epithelium mild diuretic effect dose of 1 g/day given in divided doses of either 250 mg four times a day or 500-mg Sequels twice a day maximum dose 4g/day side effect : paresthesias of the extremities, lethargy, and altered taste sensation

21. Medical Treatment Repeated Lumbar Puncture “high-volume” LP, with removal of 20 mL of CSF or more low-pressure headaches may develop after this procedure in patients in whom this is done Pressure into the normal range (target closing pressure range of 14 to 18 c m H2O)

22. Surgical Procedures Severe optic neuropathy or when other forms of treatment have failed to prevent visual loss It is not recommended for the treatment of headaches alone

23. Surgical Procedures Cerebrospinal Fluid Diversion Procedures In the past : lumboperitoneal shunt Often malfunction and infection Now : stereotactic devices for place shunt Complication spontaneous obstruction of the proximal or distal ends of the shunt excessively low pressure i nfection migration of the distal end of the catheter resulting in chest or abdominal pain

24. Surgical Procedures Optic Nerve Sheath Fenestration(ONSF) Procedure in which the optic nerve just posterior to the globe is exposed Several slits or some other type of opening is made in the dura and arachnoid sheaths of the nerve to allow CSF to escape , thus decompressing the nerve long-term effectiveness of ONSF may be fibrous scar formation between the dura and optic nerve, thus creating a barrier that protects the proximal optic nerve from the effects of increased ICP

25. Surgical Procedures Complication : infection, transient or permanent diplopia, and transient or permanent loss of vision from central retinal artery occlusion or ischemic optic neuropathy

26. Special Circumstances Pregnancy treated similarly to nonpregnant women no special provisions are required for delivery unless other medical complications are present acetazolamide can use If a surgical procedure is required, prefer ONSF

27. Special Circumstances Fulminant Pseudotumor Cerebri A small subgroup of patients with PTC experience a rapid onset of symptoms and precipitous visual decline requires rapid and aggressive treatment Ddx : cerebral venous sinus thrombosis