- [voiceover] so, what is sinusitis? before we can answer that question, we should talk a little bit about anatomy. so, here i've drawn a couple faces, and we're going to superimposethe sinuses on these faces. so, the largest sinusesthat you have in your face are called the maxillary sinuses, and they live on theside of your nose here, right underneath your eye.
if you tap on that boneright underneath your eye, your cheekbone, you're tapping on the frontal wall of the maxillary sinus. when you're looking atsomebody from the front, this is what they look like, and maxillary sinuses from the side are located about right here. so, another set ofsinuses lives at the top of your nasal cavity,
and it's composed ofmultiple little air cells, multiple little bony chambersthat are filled with air. these are a little bit irregular, and everybody's are alittle bit different, but they kind of look about like this. there's usually two layers or so of them, and these are called the ethmoid sinuses. these are also known asthe ethmoid air cells. right behind the ethmoid air cells,
and deeper back in your head, is a pair of larger sinusescalled the sphenoid sinuses, and they live about right here. and another set of sinuseslives in your forehead, about like right here. it's kind of variable in shape, but kind of looks about like this, and these are called your frontal sinuses. and altogether these are knownas the paranasal sinuses.
the reason for that isbecause they're located adjacent to your nasal cavity, and the nasal cavity, as you might guess, sits right in the middle ofyour face, right about here. now your paranasal sinusesand your nasal cavity are all lined by a layerof tissue called mucosa, and that mucosa is contiguous throughout your paranasalsinus and nasal system. in other words, the samemucosa lines everything,
and because of this fact, sinusitis is probably moreaccurately termed rhinosinusitis. and in the medical literature, it's referred to in both ways. so, quickly i'd like to showa real example of this anatomy by using a cat scan. so, i'm going to labelsome of the structures here on these two images of anactual patient's cat scan. the first image is a coronal image,
which means it's like we're looking at a patient's face directly on. the second one is an axial image, and that's like we're taking a slice through the patient's sinuses here and looking only at that slice. so, just like in our cartoon drawing, we have the maxillarysinuses here under your eyes. we have the ethmoid air cells.
we have the nasal cavity. and on our axial image here, you can see the maxillary sinuses here and the nasal cavity here, and the nasal cavityextends all the way forward. so, you can see it going outtowards the patient's nose. so, we'll go back to our cartoon. and now that we have a goodgrasp of the anatomy involved, we can talk about whatexactly rhinosinusitis is.
so, the definition of rhinosinusitis is inflammation in one ormore of these cavities. let's say, for instance,that the sphenoid sinus in this patient in thiscartoon is inflamed. so, that mucosal tissue thatlines that sphenoid sinus is going to become red andirritated and inflamed. and the first thing thatmost patients notice is going to be pain. now, that pain can be localizedto the sinus in question,
but it can also produce general pain, particularly in the caseof the deep sinuses, like the ethmoid air cellsand the sphenoid sinuses. that may just cause headache. with maxillary sinusitis, youcan actually feel the pain in that particular maxillary sinus. in fact, if you tappedon it with your finger, that could produce tenderness. and another thing that happens
when you get inflammation of the mucosa is that mucosa producesmucus, as you might expect. so, going back to oursphenoid sinusitis here, we will draw in a fluid layer here of mucus that's being produced, and that mucus has to go somewhere. and all of these sinuses are connected by little holes to the nasal cavity, and the purpose of those connections
is to actually allow things to drain out. so, that mucus that'sproduced is going to drain out into the nasal cavity. now, there's really onlytwo things that it can do, once it's in the nasal cavity. the first thing is tocome out of your nose. so, people will notice nasal discharge. so, the other place that mucus can go is down into your throat.
so, the back of your nose is connected with the back of your throat, and as that mucus leaks downinto the back of your throat, it's irritating there as well, and that will cause you to cough, and when you lie down,it's particularly bad, and so the cough is often worse at night when you're trying to sleep. now, sometimes theinflammation is bad enough
that patients will get a fever. that's not always the case. you can certainly have sinusitiswithout having a fever, but it is one of the reported things, and it tends to happen moreoften in cases that are worse. and this inflammationin the mucosa can also alter the way your bodysmells and tastes things. let's move this down, to give ourselves a littlebit of space to write here.
so, what are the causes of sinusitis? in adults, the vast majority of cases are caused by viruses. in fact, more than 98 percent of them. the remaining two percent areusually caused by bacteria, the common types of bacteria being streptococcus pneumoniae,haemophilus influenza, often abbreviated h. flu,and moraxella catarrhalis. there's a small population of people
that can get fungal disease. that's not as commonand tends to only happen in people who are immunosuppressed. there are some predisposingfactors that make it more likely that you'll get sinusitis. if you have allergic rhinitis, that could make it easier foran infection to take hold. if you're exposed tocigarette or cigar smoke, either firsthand or secondhand.
and there's certain anatomic variants that make it harder for sinuses to drain. like if the hole to one of the sinuses that leads to the nasalcavity is a little bit small, or if it's blocked byan extra large air cell, that can be a set up to get an infection. so, let's go back to a cat scan. this one's a little bit different. this time, the patienthas acute sinusitis.
here you can see in the maxillary sinus this liquid that's layeringat the bottom here. you can see the fluid, and youcan see sitting in the top, these little round bubbles as well. so, this is kind of a frothyfluid sitting in here. that's a definite sign of acute sinusitis. you can also see some fluid up here, in the ethmoid air cells, anda little bit of fluid sitting in the nasal cavity aswell, but not a lot.
you can also see some mild mucosal edema. i'll outline that for you here and here. sometimes the mucosal edema can get so bad that it will fill up the entire cavity. this particular patient, it's not so bad. but the fact that you can see it at all, at least in the maxillarysinuses and ethmoid air cells, means that it's inflamed. so, we're going to move thispicture up a little bit,
and we're going to use it to illustrate some of the potentialcomplications of sinusitis. now, most of the time sinusitisis a self-limiting disease. the viral type will go away on its own, after a period of time, butthe bacterial type tends to be a little bit more aggressive. so, you can see thesestructures in your face are really located in a prettycentral and important area, and the complications of sinusitis are all
related to spreading infection. so, there's lots of important bones here. so, if this infection was tospread into the maxillary bone, here for instance, or ifit was to spread into here, that complication is called osteomyelitis, and that just means infection of the bone, and that can be a verydifficult infection to treat. let's say this infection traveled from the ethmoid air cell here,
through this very thin bone, and then spread into this cavity here. of course, that's whereyour brain likes to live. that's inside your skull at this point. so, now we're talking aboutan intracranial abscess, and, of course, that's avery major complication. that can cause all sortsof problems with the brain, if it gets up into the brain. if the infection spreads outinto the soft tissues here,
or here, or basically anywhere else, that is termed cellulitis. if the infection spreads this way, through the ethmoid aircells, into this cavity, that's your orbit. that's where your eyeball lives. that can be a supersevere complication too. that can cause an intraorbital abscess or an orbital cellulitis.
and there's all sorts ofimportant arteries and veins that run through your head and neck, and if infection gets into them, it can cause infectedclots or septic clots, and it can also travel toother parts of the body, and those are called septic emboli. now, all of these complicationsare much more common in severe disease, andsevere disease is usually, but not always, bacterial.
so, most people will try and treat bacterial sinusitis pretty aggressively. similarly, if your immunesystem isn't working properly, you can develop severe disease and are more prone toget these complications. but keep in mind thatcomplications are rare. in fact, something on theorder of 30 million people in the united states alone getsinusitis in any given year. that's a huge number, andonly a tiny minority of them
actually get these complications. most of them don't need treatment at all, and those that do get treated,usually respond very well.
