A 78 y.o. male with dementia presents with two months of rhinorrhea unresponsive to antihistamines.

What do you notice?

Our patient had a perforation of the cribriform plate with CSF leak.  The plate is at the  posterior portion of the ethmoid bone located at the base of the skull. Defects in the cribriform plate occur most frequently in trauma and should be considered with septal hematomas, olfactory dysfunction, and  LeFort fractures. The dura over the cribriform plate is thin and tightly adherent to the skull so it can tear easily.  This can cause a CSF leak leading to meningitis or even herniation of the brain.

the cribriform plate

because of its proximity to the frontal and ethmoid sinuses infection can cause erosion of the cribriform plate

The olfactory tract is a major route of infection of the brain after inhalation of certain viruses. Rift valley fever behaves in this way while other inhaled viruses infect the upper  and lower respiratory tract like COVID-19.  In addition to infection, defects of the cribriform plate can lead to tension pneumocephalus with a one way valve effect increasing the air in the head. This leads to the development of the Mount Fuji sign; separation of the frontal lobes by air. This ends in brain herniation and is a surgical emergency.

The mt fuji sign of tension pneumocephalus

TAKE HOME POINT

80-90%  of cribriform plate fractures are caused by blunt force trauma to the face but sinusitis has also been reported to cause erosion of the cribriform plate. Our patient had a previous nasal injury. 

Our patient had endoscopic CSF leak repair which was done with a middle turbinate free graft and bone chips. His rhinorrhea resolved and he was discharged.

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