Idiopathic Intracranial Hypertension Investigation and Treatment

Transcription

1 Idiopathic Intracranial Hypertension Investigation and Treatment Dr CP White Consultant Paediatric Neurologist Abertawe Bro Morgannwg UHB January 2011

2 Definition a condition of increased intracranial pressure without clinical, laboratory or radiological evidence of intracranial pathology. Unknown pathogenesis Increased CSF secretion Increased venous sinus pressure Reduced CSF absorption

3 Updated Modified Dandy Criteria 1. If symptoms are present, they may only reflect those of generalised increased intracranial pressure or papilloedema. 2. If signs are present, they may only reflect those of generalised increased intracranial pressure or papilloedema. 3. Elevated opening pressure (in lateral decubitus position) 4. Normal CSF composition 5. Normal CT/MRI findings without evidence of hydrocephalus, mass, structural or vascular lesion 6. No other explanation for the raised intracranial pressure

4 Current Controversies in IIH What (level of) pressure is high? Which associations mean that IIH is no longer idiopathic? Should paediatric IIH only include prepubertal children? (Rangwala and Lui 2007)

5 Controversies What (level of) pressure is high? >20 cm H2O in the non-obese >25 cm H2O in the obese >25 cm H2O in all adults > 18cm H2O in < 8yr old children with papilloedema (Rangwala and Lui 2007)

6 Avery et al NEJM(2010) 363; normal children 1-18yrs 90% centile = 28cm H2O No relationship to age Slighly higher with deep sedation Some relationship to BMI 90% for non sedated, non obese = 25cm H2O

7 Cause or Association? Obesity/rapid weight gain Iron deficiency and other anaemias Lupus Obstructive sleep apnoea Renal impairment Various infections Malnutrition and refeeding Menarche Endocrine Thyroid disease Adrenal disease Parathyroid disease Hypocalcaemia Prescription medications Tetracyclines Nitrofurantoin Nalidixic acid Oral contraceptives Growth hormone Vitamin A Steroids Desmopressin Retinoic acid Excludes IH associated with venous sinus thrombosis

8 Adult IIH Childhood IIH Annual incidence 1-2 cases per 100,000 All ages but more common in obese women of childbearing age (20 cases per 100,000) Female: male ratio 4:1 to 15:1 Annual incidence per 100,000 Lessell s review 1992 No association with obesity No sex predilection BPSU Study of Childhood IIH 0.5 per 100,000

9 BPSU Study of Childhood IIH Prospective national survey of newly diagnosed IIH cases aged 1-16 years. Via monthly notification to British Paediatric Surveillance Unit (BPSU) by all reporting paediatricians in the UK & Ireland. Surveillance period: July 2007 to July 2009 Aims to determine: Contemporary national incidence of childhood IIH Spectrum of clinical presentation Incidence of clinical associations, especially obesity Current clinical management Clinical course of headache and visual outcome at 1 year

10 Changing Demography Distribution of age and sex M F No. of IIH cases Age in years BPSU Study of Childhood IIH - Jul 2007 to Dec children 66% girls 3-9y: N = 18 (9M:9F) vs 10-16y: N = 70 (21M:49F (70%F)) Median age at diagnosis: 12 years in both female and male

11 Changing Demography Distribution of age groups, gender and obesity No. of IIH cases years Males 3-9 years Females years Males years Females Non-obese Obese BPSU Study of Childhood IIH - Jul 2007 to Dec 2008 Obese (BMI 98th centile): 46/71 (65%) Age 3-9y: 5/13 (38%, 4M:1F) Age 10-16y: 41/58 (71%, 13M:28F) UK incidence of childhood obesity -13.7% (2003)

12 Presenting Symptoms Common Headache - 86% Nausea/vomiting Transient Visual obscurations Blurred vision Diplopia Photophobia?visual loss Less Common Pulsatile tinnitus Neck stiffness Back/shoulder pain Irritability Lethargy Increasing head size Asymptomatic

13 Presenting Signs Papilloedema 89% VIth nerve palsy 9-48% IVth nerve palsy - rare IIIrd nerve palsy - rare Visual deficit 25% (up to 91%)

14 Early Investigations Neuroimaging MRI preferable MRV Lumbar puncture diagnostic therapeutic FBC ESR U+Es Bone profile TFTs

15 Neuroimaging Excluding other causes of RICP Non specific abnormalities

16 (Partially) empty sella Adults with IIH 70-94% Lim et al % of children (cf 5% of normals)

17 Flattening of the posterior globe Adults with IIH - 80% Lim et al % of children (cf 40% of normals)

18 Prominence of CSF signal in peri-optic sheath Adults with IIH - 45% Lim et al % of children (cf 35% of normals)

19 Tortuosity of the optic disc sheath Adults with IIH - 40% Lim et al % of children (cf 5% of normals)

20 MR Venography

21 Lateral venous sinus stenoses 2004AAN Enterprises, Inc. 2

22 Lumbar puncture Diagnostic Pressure Normal composition Practicalities Ambience Position Therapeutic Anaesthesia Agent 1kPa increase in end tidal pco2 increases CSF pressure by cm H2O

23 Goals of Management Relief of symptoms Preservation of vision Not to keep the pressure down Concept of the normal pressure for person

24 Management Multidisciplinary Correct initial diagnosis Of underlying predisposition Therapeutic lumbar puncture Medical therapy Surgical intervention

25 Treatment Underlying predispositions Weight loss Drug withdrawal Management of associated conditions Could this be enough? Therapeutic Lumbar puncture CSF removal to lower closing pressure to 15cm water 10-20% resolve after initial LP (BPSU -12%)

26 First Line Medical Treatment Wait 48hrs after LP Acetazolamide - strong carbonic anhydrase inhibitor - inhibits CSF production - mild diuretic Children Adolescents 25mg/kg/day Twice daily Increase by 25mg/kg/day Maximum - 100mg/kg/day or 2g Start at 1g/day Increase by 250mg/day Maximum 4g/day

27 Acetazolamide Bicarbonate therapy if symptomatic 1-2mmol/kg/day Monitoring Electrolytes -?frequency renal ultrasound after 6m Wean after 2 months headache free Efficacy 47-67%

28 Second Line Treatment Topiramate Weak carbonic anhydrase inhibitor 1.5-3mg/kg/day, max. 200mg/day Increase by 25mg/kg/week Weight loss Treatment of chronic headache syndromes Adult studies only

29 Other Medical Treatment Furosemide Depletion of total body extracellualr fluid Weak carbonic anhydrase inhibitor Dose 1-2mg/kg/day Max. 2mg/kg tds Side effects Monitoring Electrolytes -?frequency Additional potassium Second line or adjuvant? Success rates?

30 Other Medical Treatment Steroids?mechanism of action Dose Prednisolone 2mg/kg/day for 2 weeks wean over 2 weeks Beware rapid withdrawal and weight gain Second line or adjuvant? No studies of efficacy Use limited by side effects Steroids

31 Other Medical Treatment Serial LPs Other diuretics Zonisamide Octretide

32 Fulminant IIH Definition Acute onset of symptoms and signs of IIH (<4wks) Rapid visual loss Normal imaging Rare?commoner in secondary cases Invariably obese women Mean opening pressure=54.1cm Monitor vision daily 50% persisting visual loss Treatment Acetazolamide Repeat LPs Steroids IV methylprednisolone Surgery ONSF Shunt proceedure

33 Headache management Reduction of raised pressure Symptomatic headache relief Conventional analgesics 68% adults have other headaches Migraine Tension headache Analgesia overuse Low pressure headache Often recognised as different from high pressure headache

34 Surgical Treatment Indications Severe visual loss at onset Progressive visual loss despite therapy Refractory symptoms Frequency 5-20% BPSU Study 5% LP Shunt 1 ONSF

35 Surgical Treatment CSF Diversion procedures Lumboperitoneal shunting (LPS) Ventriculoperitoneal shunting (VPS) Optic Nerve Sheath Fenestration (ONSF) Dural Venous Sinus Stenting

36 Surgical treatment LPS Requires more revisions (RR 2.5) Increased risk of obstruction (RR 3.5) Low pressure headache (difficult to treat may be avoided by programmable shunt) No need for craniotomy VPS Requires less revision Lower risk of obstruction Low pressure headache controlled by programmable shunt Requires craniotomy

37 Surgical treatment LPS Infection CSF leak Abdominal pain Radicular pain Iatrogenic chiari malformation Treatment failure (30-50%) VPS Infection Abdominal pain Risk of stroke, haemorrhage, infection etc Treatment failure (up to 30%)

38 Optic nerve sheath fenestration Variably available Limited duration Protects vision Relieves headache in 2/3

39 Outcome Remission in 1wk to 6m?worse in pubertal children than others?related to degree of papilloedema Worse in those without headache Recurrence rate 6-22% Early and late Permanent loss of acuity 0-10% Permanent loss of visual fields <17%

40 Long Term Follow up and Monitoring No consensus/guidelines What to monitor and how? Headache Visual acuity and fields Optic nerve assessment

41 Follow up/ Monitoring If normal visual acuity and responding to treatment Initial frequency of follow up will depend on visual parameters and symptoms 3/12 follow up neurology/ophthalmology when stable How long to follow up? If no response Weekly monitoring neurology/ophthalmology Plan for sudden deterioration in vision

42 Summary Correct diagnosis Confirm papilloedema Correct LP technique Exclude venous sinus thrombosis Good imaging Good communication Agree local protocol for follow up Beware loss of acuity +/field loss Symptoms may not be a good guide