CONTRIBUTION OF IMAGING IN CHRONIC MENINGITIS

1. CONTRIBUTION OF IMAGING IN CHRONIC MENINGITIS A. BEN MILED, F. JABNOUN, M. BEN ALI, K. BOUZAIDI, I. KECHAOU, A. KHELIL NEURORADIOLOGY : NR 21

2. INTRODUCTION • The contribution of slice imaging in the chronic meningitis diagnosis process is considerable allowing often a confirmation of the positive diagnosis, and an etiological orientation. • Exclusion of abscess tumors and parameningeal focus of infection in cranial sinusis or paravertebral location are important objectives of imaging in the setting of chronic meningitis. • Most patients with a chronic meningitis, however will have normal imaging or non specific findings.

3. SUBJECTS AND METHODS • A retrospectivestudy of 7 patient observations comprising of 3 men and 4 womenwith a meanage of 43 years. • Investigated by CT scan and/or MRI for headachesassociatedwithpolyuro-polydipsia syndrome (3 cases), convulsions (2 cases) and headacheswithfever (2 cases). • In thispresentation, we are illustrating the different CT scan and MRI aspects of thesechronicmeningitis.

4. RESULTS • The radiological explorations involving CT scan and MRI show and conclude to: • Metastaticleptomeningitis (3) • Neurosarcoidosis (2) • Idiopathichypertrophicpachymeningitis (1) • LangerhansCellhistiocystosis (1)

5. CHRONIC MENIGITIS SYMPTOMS Pleomorphicclinical manifestations encompassingsymptomsand signs in 3 domains of neurologic function: • The cerebral hemispheres: Headache, decrease in mental abilities, confusion. • The cranial nerves: loss of feeling in the face, diplopia, trigeminalsensory or motor loss, cochlear dysfunction, and optic neuropathy. • The spinal cord and roots: disturbances in the ability use the legs and arms, back pain, weakness, burning or prickling sensations.

6. CHRONIC MENIGITIS IMAGING FINDINGS • MRI have a higher sensitivity than CT • Bettercontrastresolution • Avoid the artefact beneath the inner table that limits the visualization of meningeal enhancement with CT. • Imaging shouldbeobtainedpreferablyprior to the lumbarpuncturewhichmay cause a meningealreaction

7. CHRONIC MENIGITIS IMAGING FINDINGS • MRI • CTscan canbesufficientevidencing: • Hyper dense aspect of leptomeningis • Important enhancement, sometimes diffuse in othersnodular.

8. CHRONIC MENIGITIS IMAGING FINDINGS MRI • Leptomeningesthikening and enhancement: • Fine signal-intense layer that follows the gyri , superficial sulci, ependymallining and perivascularspaces(appearance of intraparenchymal lesion) • Cranial nerve enhancementin the subarachnoidcisterns. • Enhancing dural based mass. • Intraduralextramedullary enhancing nodules on spinal MR

9. CHRONIC MENIGITIS IMAGING FINDINGS MRI • Hydrocephalus: • may the first and only sign of leptomeningeal spread of disease. Axial T2 image shows hydrocephalus with transependymal seepage of CSF.

10. CHRONIC MENIGITIS IMAGING FINDINGS MRI • FLAIR images may depict evidence of leptomeningeal lesion: • An hyperintensity in the subarachnoid space resulting from elevations in CSF cellularity and protein concentrations.) FLAIR MR image shows extensive sulcalhyperintensity.

11. CHRONIC MENIGITIS • Imaging signs of leptomeningeal damage are common regardless of the etiology • Etiologic diagnosis is guided by: • The clinical and biological context • A particular distribution of leptomeningeal damage • Other brain locations non leptomeningeal • Other non cerebral locations

12. Case n° 1 • 40 yearoldwoman. • Antecedent of operated breast cancer. • Consulting for seizures. Axial without and withcontrast CT images showingwidespreadleptomeningealenhancementinvolvingsurfaces of cerebellumhemispheres in connectionwithmetastaticorigin. Subarachnoid enhancement over cerebral surfaces and contrast gain in mass of the falxcerbri.

13. Case n° 2 • 62 year old men. • Antecedent of lung cancer. • Convulsions. Axial enhanced CT imagesshowing diffuse linear and nodular meningeal enhancement.

14. Metastaticleptomeningitis • Leptomeningealcarcinoma, is a form of metastatic cancer that has spread to the lining of the brain and spinal cord. • The most meningealmetastasing cancers: leukemia, lymphoma, melanoma, breast, lung and gastrointestinal cancers. • Carcinomas of unknownprimaryconstitute 1% to 7% of all cases of leptomenigeal carcinoma. • Diagnosis: Detection of malignant cells in the cerebrospinal fluid.

15. Metastaticleptomeningitis IMAGING FINDINGS MRI • Non specific • Leptomeningesenhancement, Cranial nerve enhancement, enhancing dural based mass. • The leptomeninges of spinal cord damage ismostfrequently seen in the caudaequina.

16. Case n° 3 • 33 years old women • Headaches • Polyuro-polydipsia syndrome Axial, sagittal and coronal Contrast-enhancedT1-weighted MR images: Diffuse and nodularleptomeninges thickening and enhancement. Reached basilar and frontal leptomeninges. Hypothalamus and pituitarylesions

17. . Contrast-enhancedsagittal T1-weighted image in the same patient shows enhancing lesion in spinal cordand an abnormallinearleptomeningealenhancement

18. Neurosarcoidosis • Sarcoidosis is an idiopathic systemic disease. • Formation of non-caseatinggranuloma affecting all parts of the body: lungs and lymph nodes+++. • Women affected more than men. • Third and fourthdecades. • In the head and spin: • The leptomeninges damage +++is specially observed in the base of the brain+++ • May involve bone, dura mater, nerve roots and parenchyma, individually or in combination.

19. Neurosarcoidosis • Symptoms depend on the site of granuloma involvement, non specific; we note specially: • Facial nerve paralysis, vision loss, paresis, paresthesia, diplopia, and dysarthria… • Diabetes insipidus (involvement of the hypothalamus or pituitary gland). • Hydocephalusis rare.

20. Neurosarcoidosis IMAGING FINDINGS • Leptomeningeal involvement : • The most typical manifestation of central nervous system sarcoidosis (40%) • Diffuse or nodular • Basilarmeninges +++: suggestive of diagnosis (cisterns around the base of the brain) • Differential diagnosis: tuberculosis; lymphoma

21. Neurosarcoidosis IMAGING FINDINGS • May involve: • Parenchymaof the brain and spine, nerve roots, dura mater,hypothalamus and pituitary.

22. Case n°4 • 26 year old man • Headache, polyuro-polydipsiasyndrome, visualdisturbances Coronal CT (A) and MRI (B) after injection of contrast through the facial mass. (A)Tissularlesion developed at the upper wall of the maxillary sinus withintraorbitalextension. (B) Thickening of the frontal meningesenhancedwithcontrast. He also has a marked pituitary infiltration and a lytic lesion of the skull base. Bronchoalveolar lavage: positif CD1a .

23. LangerhansCellhitiocystosis • LangerhansCellhitiocystosis (LCH) is a raredisease • SystemicIdiopathicgranulomatousprocess, composed of a particular histiocytic contingent: the Langerhans cell . • More common in children. • Sites of involvement: Bone :90% (skull+++), Lung, lymph nodes, Skin, Soft tissue.

24. LangerhansCellhitiocystosis • Sites of involvement: Bone :90% (skull+++), Lung, lymph nodes, Skin, Soft tissue. • The neuroimaging of LCH is, in most of the cases non specific and it can vary depending to the location, specially on MRI. • The most common CNS locations are: • Hypothalamus and pituitary axis (diabetes insipidus) • Cerebellum • Meninges, parenchyma, pineal gland, choroid plexus are rarely included.

25. Case n° 5 • 41 yearoldwoman • Chronicheadache, polyuro-polydipsiasyndrome • Anosmia, decreasein visualacuity. Sagittal and Frontal T2-weighted images: Duremerien thickening spreadingform the frontal base of the crane up to the anteriorfossa, next to the clivus in a frank hyposignal T2.

26. Case n° 5 Sagittal and coronal contrast-enhanced T1-weighted : Peripheral enhancement of the Dura thickening.

27. IdiopathicHypertrophicPachymeningitis • Hypertrophic pachymeningitis is a clinical disorder characterized by localized or diffuse enlargement of the duramater. The underlying and neighboring leptomeninges (pia mater, arachnoidea mater) become opaque and thickened as well. • If an exhaustive work-up fails to identify the cause of the meningeal changes, a diagnosis of IHP is made. • Rare disorder, affecting men more often than women • Peak prevalence occurring in the 6th decade of life.

28. IdiopathicHypertrophicPachymeningitis • Most common manifestations:cerebellarataxia, seizures, and neuroophthalmicsymptoms (visual field loss, complete blindness, optic neuropathy). • Chronicheadaches resembling chronic migraines: focal meningeal irritation or possibly to localized arachnoiditis. • Cranial nerve palsies(cranial nerves IV–VIII) attributed to compression of cranial nerves at the skull base by enlarged dura mater. • Increased intracranial pressure withpapilledema.

29. IdiopathicHypertrophicPachymeningitis Imaging Findings • Smoothor nodular dural thickening isointense or hypointense with both T1- and T2-weighted sequences (fibrosis and necrosis of the dura mater). • Avidenhancementafterintravenous administration of contrast material. • Peripheral hyperintensitycan be seen on T2-weighted images active inflammation or increased vascularity of the dura mater and underlying parenchyma).

30. IdiopathicHypertrophicPachymeningitis Complications • Venous sinus thrombosis • Obstructive hydrocephalus • Cerebral edema Associated syndromes: • Tolosa-Hunt syndrome (granulomatousinflammation of the wall of the cavernous sinus resulting in painful ophthalmoplegia). • Cranial polyneuritis (especially with involvement of the 7th–12th cranial nerves), • Multifocal fibrosclerosis(chronicgranulomatous inflammation consisting of retroperitonealfibrosis). • Riedel thyroiditis. • Sclerosingcholangitis. • Pseudotumor oculi • Diabetesinsipidus.

31. CONCLUSION • The contribution of slice imaging in the chronic meningitis diagnosis process is considerable • Allowing often a confirmation of the positive diagnosis, and an etiological orientation. • The MRI is the examination of choice, however the CT scan could be sufficient in some particular clinical contexts.