Idiopathic hypertrophic pachymeningitis with complication of obstructive hydrocephalous

65-year-old male.

Headache since 5-6 months.

Gait disturbance increasing gradually since 5-6 months.

Left eye blurred vision and Right eye watery discharge since 2 days.

No other significant relevant past medical history.

The patient’s routine biochemistry was normal and CSF showed normal cell count, sugar and protein levels. Patient’s HIV, HBsAG, VDRL, Rheumatoid factor and Antinuclear antibodies were negative.

Patient was undergoing corticosteroid therapy and had improved vision and headache.

There is diffuse symmetric marked thickening of dura appearing hypointense on T2 and FLAIR images and near homogenous enhancement noted along bilateral tentorium cerebelli extending anteriorly upto the cavernous regions, anterior temporal convexities and inferiorly along cerebellar convexities into the upper cervical canal below the level of foramen magnum.

Lateral and third ventricles are mildly prominent with periventricular white matter hyperintensities probably due to obstructive hydrocephalous.

Hypertrophic pachymeningitis is a condition where there is localized inflammatory thickening of the dura mater. These changes in the meninges can be identified in a variety of neoplastic, autoimmune, and infectious disease processes. If an exhaustive work-up fails to identify the cause of the meningeal changes, a diagnosis of IHP is made.

IHP affects men with peak prevalence in the 6th decade of life [1].

Chronic headaches: Most common presenting symptom of IHP [2].

Neurologic complications of IHP include venous sinus thrombosis, obstructive hydrocephalus, and cerebral oedema [3].

Typical MRI findings

T1WI and T2WI - uniform diffusely thickened pachymeninges seen as hypointense areas to brain parenchyma.

T1WI post contrast- shows significant dural enhancement.

These signal intensity characteristics are due to the fibrosis and necrosis of the dura mater.

Take-Home Message/Teaching Points

Headache is commonest presenting symptom with ophthalmological complaints probably due to involvement of cavernous regions and raised intracranial pressure secondary to CSF obstruction.

Once diagnosed on radiology imaging, detail work up needs to be done to rule out other causes of pachymeningeal thickening most importantly lymphoma, sarcoidosis and other infective inflammatory conditions.

IHP is diagnosis of exclusion after all the investigations turn out negative for any particular aetiology.