A new-found cause of “guitar pick sign”: IGG4 related disease

Abstract

A 62-year-old female presented first in 2016 with recurrent right-sided frontal headaches, nasal block and seizures of seven years duration. There was no history of any systemic disease. Clinical examination was unremarkable. The evaluation showed rhino-sinusitis and right frontal pachymeningitis on magnetic resonance imaging (MRI), normal cerebrospinal fluid analysis, serum angiotensin-converting enzyme levels and negative antinuclear antibodies. Serum immunoglobulin-G4 (IgG4) level was 2410 mg/dL (< 135 mg/ dL-normal). Dural biopsy was conclusive of IgG4-related disease (IgG4-RD). She was treated with intravenous Rituximab (three cycles of 2-g each 6-months apart). Oral prednisolone was also given for the initial two months. She improved symptomatically and was lost to follow-up. She again presented in September 2021 with a history of rightsided constant ocular pain, proptosis, with an intact vision of one-month duration. MRI of the brain and orbits showed abnormal soft tissue enhancing lesions in ethmoidal and sphenoidal sinuses extending into the right medial orbital cavity abutting the medial rectus and compressing the optic nerve along with abnormal enhancing duramater overlying the floor of the anterior cranial fossa (Fig. 1a, b). The rightsided globe is deformed with posterior scleral tenting, giving an appearance of a "guitar pick" (Fig. 1c, d). Her symptoms resolved after treatment with oral prednisolone and rituximab. Confirmatory histopathology is shown (Fig. 1e, f)."Guitar pick sign", also referred to as posterior globe tenting, is a radiological sign seen in acute and subacute orbital pathologies with a rapid increase in intraorbital pressure. These changes cause anterior displacement and

Decoding “guitar pick sign” in COVID-19–associated mucormycosis: A case series

“…[ 1 ] in diverse disease conditions such as orbital cellulitis, subperiosteal abscess, hemorrhage into a lymphangioma, orbital varix, traumatic carotico-cavernous fistula, thyroid orbitopathy, IgG4-related disease, and multiple epithelial implantation cysts. [ 8 ] In 2011, Theoret et al . [ 2 ] described a similar phenomenon on orbital ultrasonography in an elderly patient of traumatic retrobulbar hemorrhage and named it the guitar pick sign due to the resemblance of the posterior globe to a guitar pick.…”