ORIGINAL ARTICLE

Idiopathic Hypertrophic Cranial Pachymeningitis

P.N. Sylaja, P.J. Cherian, C.K. Das,* V.V. Radhakrishnan,** K. Radhakrishnan

Departments of Neurology, Radiology* and Pathology** Sree Chitra Tirunal Institute for Medical Sciences and Technology Trivandrum, Kerala, India.

Summary

Idiopathic hypertrophic cranial pachymeningitis is a rare form of fibrosing chronic inflammatory process of unknown etiology, which causes thickening of the intracranial dura mater. We present four patients with hypertrophic cranial pachymeningitis who presented with chronic headache and cranial nerve palsies. The diagnosis of idiopathic hypertrophic cranial pachymeningitis was based on neuroimaging findings of thickened enhancing dura, exclusion of known causes and histopathologic findings compatible with nonspecific inflammation in the meningeal biopsies. Corticosteroid therapy was effective in all cases in inducing a complete or partial remission of the neurologic symptoms and signs. We describe the clinical, radiological and pathological features of idiopathic hypertrophic cranial pachymeningitis and discuss the relationship of this entity with other inflammatory fibrosclerotic disorders to explain the pathogenesis. A high index of suspicion, prompt confirmation of the diagnosis by meningeal biopsy, and early institution and long-term maintenance of steroid therapy may help to prevent irreversible neurologic sequelae, especially blindness.

Key words : Cranial nerve palsy, Headache, Hypertrophic cranial pachymeningitis, Meningitis, Pachymeningitis.

Neurol India, 2002; 50 : 53-59

Introduction common clinical manifestations of patients with hypertrophic cranial pachymeningitis. Numerous Hypertrophic cranial pachymeningitis is a rare clinico-pathological entities produce thickening of the chronic fibrosing inflammatory disease characterized pachymeninges (Table I), hence, idiopathic hyper- by marked diffuse thickening of the cranial dura mater trophic cranial pachymeningitis (IHCPM) is a that causes progressive neurological deficits.9,13 diagnosis of exclusion. A dural biopsy is essential to Chronic headache and cranial neuropathy are the establish the diagnosis of hypertrophic cranial pachymeningitis and to exclude known causes. Correspondence to : Dr. P. N. Sylaja, Deparment of Neurology, Sree Chitra Tirunal Institute for Medical Sciences Only 33 cases of IHCPM were identified in a search and Technology, Trivandrum, Kerala, India. 5 6 E-mail : [email protected] of the literature till 1997. Goyal et al, reported four

Neurology India, 50, March 2002 53 Idiopathic Hypertrophic Cranial Pachymeningitis patients with idiopathic hypertrophic cranial pachymeningitis from India; in only two of them the diagnosis was confirmed by a meningeal biopsy. We document four more patients with biopsy proven IHCPM to elucidate the clinical, radiological and pathological features of this rare disorder.

Case Report

The following four patients were treated in the Neurology services of the Sree Chitra Tirunal Insitute for Medical Sciences and Technology, Trivandrum, Kerala, which is a tertiary referral center for neurological disorders, in southern part of India.

Case 1 : A 52 year old women had progressive daily headache, hearing impairment, loss of smell, visual deterioration, and dysphagia for one year. She had earlier received a brief course of oral prednisolone, which resulted in a partial amelioration of her symptoms. On clinical examination, the visual acuity in the left eye was 6/12 and she could only perceive Fig. 1 : Cranial MRI of Patient 1 : Gadolinium enhanced light in the right eye. Fundus showed bilateral optic T1WI, coronal sequence, reveals markedly thickened and atrophy. In addition, she had right III, IV, and VI, enhancing falx and tentorium cerebelli. bilateral VII, and left IX, and X cranial nerve palsies. The motor and sensory system examination was biopsy revealed a dense fibrous tissue infiltrated with normal and there were no cerebellar signs. Routine plasma cells and lymphocytes. There was no urine analysis, blood counts and serum chemistry granuloma formation or vasculitis. Specific stains for were normal, except for an elevated erythrocyte fungi and acid fast bacilli were negative. She was sedimentation rate (ESR) of 55 mm/hr. The serum was started on oral prednisolone, 40 mg/day, which was negative for rheumatoid factor, antinuclear antibodies, tapered to 20 mg/day after six months. When last VDRL test, hepatitis B surface antigen (HBsAg) and seen. The headache and most of her cranial nerve anti-double stranded DNA. Work up for sarcoidosis palsies had completely resolved by 11 months after such as chest radiograph, serum calcium and the initiation of steroid therapy. However, the angiotensin converting enzyme were negative. Bone profound vision loss in the right eye remained marrow examination and ultrasound scan of the unchanged. abdomen, to exclude a neoplastic and chronic inflammatory processes, were normal. Cerebrospinal Case 2 : A 38 year old woman, who had hypertension fluid (CSF) analysis after lumbar puncture revealed 2 and daily headache for one year, was hospitalized for lymphocytes/mm,3 protein of 26 mg/dl and sugar of a recent exacerbation of the headache. She had 78 mg/dl. Microbiological evaluation of the CSF for bifrontal, nonpulsatile, daily headache of moderate cryptococcal antigen, VDRL, and cultures for acid fast intensity, which was not associated with phonophobia bacilli (AFB) and fungi yielded no positive results. and photophobia. She had no other neurological Magnetic resonance imaging (MRI) of the brain symptom. The blood pressure at admission was showed thickening of the meninges which was more 130/90 mmHg. Laboratory evaluation revealed a marked along the falx and tentorial edge. Gadolinium normal blood counts, ESR and chemistry. The lumbar enhanced T1WI MRI images showed thickened CSF study showed a clear fluid under normal pressure 3 uniformly enhanced meninges (Fig. 1). There were no with 2 lymphocytes/mm , protein of 96 mg/dl and brain parenchymal lesions. sugar of 58 mg/dl. Examination of the CSF for mycobacteria, fungi and malignant cells was negative. The patient underwent a left parieto-occipital Work up for sarcoidosis, collagen vascular diseases craniectomy. The underlying dura was observed to be and systemic malignancy was negative. MRI brain thickened, grey and grossly fibrotic. A biopsy was showed diffuse thickening and gadolinium obtained from the right parietal dura mater. enhancement of dura of the falx, cranial convexity and Histopathological examination of the meningeal tentorium. A meningeal biopsy taken through a left

54 Neurology India, 50, March 2002 Sylaja et al precoronal frontal burr hole showed a dense enhancement of the thickened meninges and a right collagenous tissue with few inflammatory cells parietal infarct was seen. Through a right frontal comprising lymphocytes and foci of nonspecific craniotomy, biopsy of the anterior falx was done neovascularization. No microorganisms, granulomas which showed dense fibrous tissue with inflammatory or evidence of vasculitis were seen in the biopsy cells consisting of lymphocytes and occasional specimen. The patient was started on oral neutrophils. No granulomas or evidence of vasculitis prednisolone 40 mg/day. Six months later, she was were seen. readmitted with recurrent episodes of left focal seizures and left hemiparesis. Her headache had In view of the profound and rapid deterioration of completely resolved. A blood sugar of 363 mg/dl was vision, he was administered a five-day course of detected. Her blood pressure was controlled on intravenous methylprednisolone 1 gm/day, after amlodipine. A repeat cranial MRI revealed multiple which he was maintained on oral prednisolone 40 lacunar infarcts in the centrum semiovale and an mg/day. At last follow-up, after three months of increase in the thickening of meninges. The steroid treatment, he showed no improvement in the hyperglycemia was corrected with insulin, and visual acuity, but had not developed any additional treatment with diphenylhydantoin was initiated. Her neurologic symptoms. left hemiparesis had partially improved by 18 months and she was still receiving a maintenance dose of Case 4 : A 38 year old lady was admitted with chronic 20 mg prednisolone per day. She had no further headache of two years duration. Two months after the headache or seizures. onset of headache, she was investigated elsewhere. CT scan of the head had shown tentorial enhancement Case 3 : This 30 year old man started developing and CSF examination revealed 10 lymphocytes/mm3 recurrent episodes of neurological dysfunction at the with normal protein and sugar values. The CSF was age of 16 years, in 1985. He first presented with normal. She received antituberculous treatment for a headache, diplopia and left sided hearing loss of three period of nine months. Because of persistent months duration. Examination confirmed left lateral headache, she was referred to us. Clinical examination rectus palsy and a left sensory-neural hearing loss. was normal. Investigations for tuberculosis, CT scan, cerebral angiogram and CSF examination sarcoidosis and collagen vascular diseases were were normal. Investigations for sarcoidosis, collagen negative. A CT head showed thickened enhanced vascular diseases and systemic neoplasms did not tentorial meninges with dilated third and lateral yield any positive results. He was treated with oral ventricles with normal fourth ventricle, suggesting prednisolone for six weeks, which resulted in total aqueductal obstructive hydrocephalus. The CSF study resolution of his symptoms and signs. One year later was normal. She was treated with ventriculo- he developed recurrence of headache and decrease in peritoneal shunt after which her headache subsided. It the vision of the right eye. These symptoms was decided to keep her under follow-up and steroids completely resolved after restarting prednisolone. were not started. Seventeen months later, she Three years after the onset of symptoms, he developed presented with two months history of headache, recurrent right sensorimotor simple partial seizures, dysphagia, stiffness of the lower limbs and which responded to treatment with phenytoin. In unsteadiness of gait. On examination she had bilateral October 1999, nearly 14 years after the onset of his VI, IX, X and XII cranial nerve palsies, and bilateral remitting and relapsing neurological disorder, he had pyramidal and cerebellar signs. The cranial MRI progressive bilateral vision loss and unsteadiness of showed diffuse thickening and enhancement of the gait of two weeks duration. On examination, he only meninges along the floor of the anterior, middle and had light perception in both the eyes and there was posterior cranial fossa and extending inferiorly to the bilateral optic atrophy. The reflexes were normal, and cervical spinal canal upto the fourth cervical vertebral he had gait ataxia. The only abnormal finding on level (Fig. 2a and b). The spinal cord was compressed routine laboratory evaluation was an elevated ESR of and thinned out at the second and third cervical 50 mm/hr. The lumbar CSF study showed a protein vertebral levels. She underwent suboccipital level of 42 mg/dl with 2 lymphocytes/mm3 and craniectomy with a high cervical laminectomy and normal sugar content. Examination of the CSF for biopsy of the dura mater. AFB, fungi and malignant cells was negative. MRI brain showed thickening of dura mater of the falx and Histopathological examination showed dense collagen tentorium. The optic nerves were small and atrophic. tissue with collection of lymphocytes, plasma cells The sagittal sinus was narrow secondary to dural and few eosinophils and macrophages (Fig. 3a and b) thickening. On contrast administration, uniform There was no evidence of granuloma or vasculitis. She

Neurology India, 50, March 2002 55 Idiopathic Hypertrophic Cranial Pachymeningitis

Fig. 3 : Histopathology of patient 4. (A) Photomicrograph showing collagenous tissue in which mononuclear cells are seen (Hematoxylin and eosin x 150). (B) Photomicrograph showing perivascular aggregates of mononuclear cells (Hematoxylin and eosin x 250).

hypertrophic pachymeningitis is rarer than the spinal form. Early reports of cranial hypertrophic pachymeningitis were due to tuberculosis or syphilis.2,3 Naffziger and Stern4 described the first case of idiopathic hypertrophic cranial pachy- meningitis. Since then, till 1997, 33 patients with Fig. 2 :(A) Post contrast T1WI, mid sagittal MRI of Patient 4, hypertrophic cranial pachymeningitis have been shows thickened and enhancing dura at the base of the skull 5 extending to the upper cervical spinal canal. (B) Contrast documented. To our knowledge, four patients, two enhanced, fat suppressed axial T1 weighted MRI done 17 biopsy proven, reported by Goyal et al,6 appear to be months after ventriculoperitoneal shunting shows intense the only documentation of idiopathic hypertrophic enhancement of the tentorium and the dura along the cranial pachymeningitis from India. We report four cavernous sinus. more biopsy confirmed south Indian patients, with IHCPM. was treated with a three-day course of methyl prednisolone 1gm/day followed by maintenance of 5 oral prednisolone 60 mg/day. During the two weeks of Clinical features : Parney et al reported headache, treatment, her dysphagia and ataxia had improved. cranial nerve palsy and ataxia in 88%, 62% and 32% of the cases, respectively. Headache may be the only Discussion symptom for many years in a small percentage of patients.7 Cranial nerve palsies are due to compression of the exit zone of nerve roots by the Hypertrophic pachymeningitis is a rare disorder of hypertrophic basal pachymeningitis.8 The eighth diverse etiology (Table I). Charcot and Joffroy1 first cranial nerve is most frequently involved, followed in described it in relation to spinal meninges. Cranial equal frequency by the optic, ocular and lower cranial

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Table I cause diffuse thickening of the dura mater (Table I). Varied clinical presentations of these disorders and the Known Causes or Associations with difficulty in establishing the etiology can lead to Hypertrophic Pachymeningitis diagnostic dilemmas. IHCPM is a diagnosis of exclusion. An elevated ESR was present in 24 out of Inflammatory and infective Tuberculous meningitis 27 patients with hypertrophic cranial pachy- Tuberculoma en plaque meningitis.5 Three of our patients had an ESR of over Sarcoidosis 50 mm/1h. The CSF protein may be elevated in two- Mycosis: Cryptococcus, Histoplasma, Coccidioides third, lymphocytic pleocytosis may occur in one- Lyme disease fourth, and the CSF may be normal in one-fourth of Syphilis patients with hypertrophic cranial pachymeningitis.5 HTLV 1 The CSF was normal in our patients, except for an Neoplastic Carcinomatous meningitis elevated protein in patient no. 2. Lymphomatous meningitis Meningioma en plaque IHCPM is being increasingly recognized with the Collagen vascular disorders advent of CT and MRI. MRI is superior to CT in the Rheumatoid arthritis diagnosis of hypertrophic cranial pachymeningitis. Wegener’s granulomatosis Unenhanced CT shows thickened hyperdense dura, Mixed connective tissue disease typically involving the tentorium, falx, and prepontine Orbital pseudotumor region, which enhances markedly after contrast Tolosa-Hunt syndrome administration. On MRI, the thickened dura mater Multifocal fibrosclerosis Miscellaneous appears isointense or hypointense on T1WI and Spontaneous intracranial hypotension hypointense on T2WI often associated with a Chronic hemodialysis hyperintense edge.15 Thickening is better appreciated Mucopolysaccharidosis in the coronal and sagittal images. Contrast Chronic intrathecal drug administration administration reveals uniform enhancement of the thickened meninges. The low MRI signal represents nerves.5,9 Papilledema was noted among 9 of 33 dense fibrosis, and enhancement suggests patients (26%).5 Ischemia caused by tight, thickened inflammation. Rarely, nodular pseudotumoral and adherent pachymeninges of the posterior fossa is thickening of dura mater, mimicking multiple presumed to be responsible for the cerebellar meningioma may occur.16 dysfunction.9 There are isolated reports of dural venous sinus occlusion,6,10,11 internal carotid artery A meningeal biopsy is usually required to establish the diagnosis of IHCPM and to exclude other causes occlusion,12 intracranial hemorrhage26 and of hypertrophic pachymeningitis. Pathological obstructive hydrocephalus13,14 among patients with findings consist of thick fibrous dura often associated IHCPM. with chronic inflammatory cell infiltrate consisting of lymphocytes and plasma cells. Granulomatous 5 Age ranges from 20 to 78 years (mean 51 years). findings have been noted in about 10% of the reported Three of our four patients (mean age 40 years, range cases of hypertrophic cranial pachymeningitis.9,17,18 30 to 52 years) were females. All our patients Biopsy from an accessible site with CT or MRI presented with chronic headache. While three of them documented enhancing and thickened dura mater is had multiple cranial nerve palsies, gait disturbance more likely to yield a positive etiological diagnosis.19 related to cervical myelopathy dominated in patient The varied meningeal biopsy sites in our patients are no. 4. Two of our patients (patients 1 and 3) had due to our practice of selecting the optimal site of profound irreversible vision loss. Symptomatic biopsy based on neuroimaging findings. cervical hypertrophic pachymeningitis as observed in patient no. 4, and cerebral parenchymal infarcts and In developing countries, a majority of patients focal seizures as noted in patients no. 2 and 3 in presenting with clinical and investigative features association with idiopathic hypertrophic cranial suggestive of a chronic meningitic process will pachymeningitis is seldom documented in the appropriately receive a trial of antituberculous literature.9,13 chemotherapy before alternate diagnostic possibilities are considered, as in our patient no. 4. Tuberculous Diagnosis : A variety of infectious, inflammatory, meningitis is a diagnosis very difficult to exclude. infiltrative, neoplastic and other disease processes can

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Parney et al5 described a patient with hypertrophic of the pachymeningitic process. Early institution and pachymeningitis, who responded to antituberculous long-term maintenance of steroid therapy may prevent therapy in whom exhaustive investigations, including the neurologic sequelae associated with idiopathic a meningeal biopsy, failed to establish an underlying hypertrophic cranial pachymeningitis. cause. Polymerase chain reaction (PCR) of CSF may be helpful in such cases. We recently reported a case Etiopathogenesis : Idiopathic hypertrophic cranial in whom a diagnosis of en-plaque meningeal pachymeningitis is histologically similar to its spinal tuberculoma based on MRI findings was confirmed by counterpart and they are presumed to be different a Mycobacterium tuberculosis complex-specific PCR presentations of a single disease. As noted in patient assay of the CSF.20 no. 4, these two entities may overlap. There are clinical and pathological similarities between IHCPM, Treatment : The optimal treatment of IHCPM is Tolosa-Hunt syndrome, polyneuritis cranialis, orbital unknown. Spontaneous resolution of both clinical pseudotumor and multifocal fibrosclerosis.9,25 symptoms and signs, and dural thickening has been Clinically, all these disorders can result in reported.21 A variety of therapeutic approaches have pachymeningitis with associated overlap in the been tried alone or in combination. Corticosteroid symptoms and signs. All have a tendency to respond therapy is often effective in ameliorating the to corticosteroids. Chronic nonspecific noncaseous symptoms and signs, and in arresting the progress of inflammatory processes characterizes all. While the disease.8,13,22,23 In some patients, serial imaging Tolosa-Hunt syndrome may be a focal manifestation studies have shown a reduction in the thickness and of pachymeningitic process involving the walls of the cavernous sinuses, IHCPM may be a localized degree of enhancement of the meninges.9 Rarely manifestation of multifocal fibrosclerosis. Although patients have worsened while on steroid therapy.6 In an immunological basis is suspected, the those who do not respond to steroids or those who etiopathogenesis of this group of chronic fibrosing develop steroid dependence with attended side effects, inflammatory disorders at present unknown. cyclophosphamide and azathioprine have been tried 9,13,16 with benefit. References Surgical excision is an option for patients with mass 1. Charcot JM, Joffroy A : Deux cas d’atrophie musculaire effect due to thickening of skull base dura, progressive avec lesions de la substance grise et des unresponsive to steroid therapy.9 Symptomatic faisceaux anterolateraux dela moelle epiniere. Arch Physiol hydrocephalus requires ventriculoperitoneal shunting Norm Pathol 1869; 2 : 354-367, 744-769. as in our patient no. 4. Decompression of the optic 2. Mott FW : A case of localized syphilitic pachymeningitis nerve has resulted in dramatic improvement in a cerebri. Arch Neurol Psychiatry 1909; 4 : 63-69. patient with rapidly deteriorating vision.24 3. Hassin GB, Zeitlin H : Syphititic cerebral hypertrophic pachymeningitis: clinicopathologic studies in a case. Arch Neurol Psychiatry 1940; 43: 362-371. Natural history : The natural course of idiopathic 4. Naffziger HC, Stern WE : Chronic pachymeningitis : report of hypertrophic cranial pachymeningitis is poorly a case and review of the literature. Arch Neurol Psychiatry understood. Spontaneous resolution, response to 1949; 62 : 383-411. steroids, steroid dependency, and remitting and 5. Parney IF, Johnson ES, Allen PB : Idiopathic cranial relapsing course have been documented.9,13,21 hypertrophic pachymeningitis responsive to antituberculous Among the 33 patients with IHCPM gathered from the therapy : a case report. Neurosurgery 1997; 41 : 965-971. 6. Goyal M, Malik A, Mishra NK et al : Idiopathic hypertrophic literature by Parney et al,5 26% experienced full cranial pachymeningitis : spectrum of disease. remission without steroid dependence, 15% Neuroradiology 1997; 39 : 619-623. experienced steroid dependent partial or complete 7. Wouda EJ, Vannesta JAL : Aspecific headache during 13 remission, 15% experienced progressive course years as the only symptom of idiopathic hypertrophic inspite of steroid therapy, and 32% died regardless of pachymeningitis. J Neurol Neurosurg Psychiatry 1998; 64 : treatment. 408-409. 8. Hashimoto M, Ohtsuka K, Nakamura et al : Abducens nerve In retrospect, our initial decision to withhold steroid as a initial sign in a case of hypertrophic cranial therapy for patient no. 4, when her headache pachymeningitis. Jpn J Clin Ophthalmol 1997; 51 : 1893- 1896. ameliorated after ventriculo-peritoneal shunt, was 9. Mamelak AN, Kelly WM, Davis RL et al : Idiopathic inappropriate. Within the next two years, she hypertrophic cranial pachymeningitis. Report of 3 cases. developed neurologic deterioration due to progression J Neurosurg 1993; 79 : 270-276.

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