| Affiliation |
(AGL) Chairman, Department of Ophthalmology, The Methodist Hospital, Houston, Texas; Professor of Ophthalmology, Weill Cornell Medicine, New York City, New York; (JG) Class of 2021, Baylor College of Medicine, Houston, Texas |
| Description |
Summary: • Key/Distinctive Features o Progressive, painless enophthalmos o Pseudoptosis o Deep superior sulcus o Measurable hypoglobus • Other Features o Typically, an older patient o Possible diplopia, typically binocular and vertical • Work-Up o Coronal MRI/CT: Ipsilateral sinus is smaller compared to contralateral sinus, leading to a vertical drop in the ipsilateral inferior rectus and/or orbit • Pathophysiology o Sinuses are constantly remolding, and remodeling based on pressure gradient o A blocked maxillary sinus ostium, e.g. an asymptomatic sinusitis, will cause negative pressure, decreasing the sinus size o A smaller sinus provides empty space for the ipsilateral inferior rectus and/or orbit to drop down, leading to the key and distinctive features of silent sinus syndrome |
| Transcript |
So today, we're going to be talking about the silent sinus syndrome, and it's a great name because it tells you exactly what it is. It's silent because the patients don't usually have any symptoms of sinusitis. And the cause is: The sinus is actually getting smaller. So, the sinuses are constantly remolding and remodeling in terms of size, and what drives it is the pressure gradient. So, in silent sinus syndrome, when you have the eyeballs here in coronal view, normally, we have extraocular muscles around the eye - So, superior rectus, inferior rectus, medial and lateral rectus - And if you have the maxillary sinus underneath the orbit, the junction of the floor of the orbit and the maxillary sinus is where the problem is. So, if we have a blocked ostium of the maxillary sinus, that will cause negative pressure effects, and then this sinus will get smaller and smaller. So, compared to the other side, what we see radiographically is a smaller sinus. And so, when the sinus gets smaller, the inferior rectus, and in fact the whole orbit, can drop down into the place where the sinus used to be. And so, this causes the distinctive features of the silent sinus syndrome, which are the globus sunken in - "enophthalmos", as opposed to exophthalmos in thyroid with eyes bulging out. They might get a ptosis, but it's more of a pseudoptosis because the whole eye is hypoglobus. So, the whole eye is down - "hypoglobus". And they might have real diplopia, if this inferior rectus muscle is far enough down, and it might not work properly, and all the pulleys and all the actions of the muscles might be disturbed by having this whole eye go down. So, the typical symptom complex is an older patient who has progressive, painless, enophthalmos, ptosis, a deep superior sulcus, and a measurable hypoglobus - and they may have a horizontal, or more commonly vertical, diplopia. And the key and radiographic distinctive feature is: The sinus is smaller on the side of the silent sinus syndrome, and the whole eye, including the inferior rectus muscle and the orbit, is sinking downward. So, it's a silent sinus syndrome: A silent, painless sinusitis leading to negative pressure that makes the sinus smaller, leading to the key and differentiating features - enophthalmos, ptosis, hypoglobus, and binocular, vertical diplopia. And so, it's really important that we look at the coronal MRI in this setting or a coronal CT to compare the maxillary sinus on the ipsilateral-involved side against the contralateral side in the silent sinus syndrome. |
