To report the pattern of the clinical features, lab and imaging findings and etiology of hypertrophic pachymeningitis in southern India. Our secondary objective includes investigating the presence of any associations between our findings and the underlying etiology.

Hypertrophic pachymeningitis is an inflammatory condition which causes thickening of the dura mater. The etiology can be classified into primary (idiopathic) and a spectrum of secondary causes whose prevalence and distribution varies based on the study population. According to the best of our knowledge, our report includes the largest sample size among south Indian studies on pachymeningitis.

This is a retrospective study based in a tertiary center. All patients underwent a thorough history and physical examination. All underwent MRI brain, chest X-ray, serological testing, antibody testing and CSF analysis.

We included 21 patients with mean age of 49.76 ± 12.04. The female to male ratio was 3.2:1. Headache was the most common symptom (95.23%), with holocranial headache phenotype being most prevalent. Most of our patients presented with cranial nerve involvement (85.71%) with the optic nerve being most affected.

All patients had dural thickening on MRI. 16 patients (76.19 %) had focal thickening of the dura.15 had focal regular pattern of thickening and 1 had focal irregular (nodular) type. 28.57% had dural sinus involvement and 23.81% had orbital involvement.

61.90% of our patients had idiopathic pachymeningitis. 19.04% had anti IgG4 disease, 9.52% had tuberculosis and 9.52% had Neurosarcoidosis. All patients with tubercular pachymeningitis presented with fever and had predominant occipital and tentorial dural thickening. The one patient with focal irregular type had tubercular etiology. Additionally, patients with Neurosarcoidosis were the only ones with increased CSF proteins.

Headache and cranial nerve involvement is common in hypertrophic pachymeningitis. Our results give insights on patient presentation patterns and etiological distributions in the study population.