Acute Sinusitis: Definition and Pathology

00:01 Another important subject among respiratory tract infections is that of sinusitis.

00:08 And we can define acute sinusitis as an inflammation of the mucosa of the paranasal sinuses of less than four weeks' duration.

00:22 The main problem in sinusitis is obstruction of the ostia of the paranasal sinuses And of course that can be caused by malfunction of the ciliary apparatus that lines all the sinuses in the mucosa The other thing in evaluating a person with sinusitis or possible bacterial sinusitis is the character of the sinus secretions.

00:51 If they are too thick, normally they can block the ostia.

00:57 So we need to discuss the systemic factors that cause blockage of the ostia of the sinuses.

01:06 And these include most commonly viral upper respiratory tract infection, a common cold for instance, or allergy.

01:15 These are the two most common reasons.

01:19 Then patients can be born with a problem, very mucoid secretions, like cystic fibrosis, and the mucus of the sinuses and the entire respiratory tract is supposed to be of a certain viscosity so that the cilia within it can beat.

01:40 The cilia beat within this mucous lining, and if it’s too viscid they will not beat normally, or if people for example are smoking they will not beat normally.

01:53 There are a variety of immune disorders which affect ciliary action, and then there’s this rather curious entity called ciliary dyskinesia, the most important manifestation of which is Kartagener syndrome.

02:10 Kartagener syndrome is the constellation of sinusitis, situs inversus, and bronchiectasis.

02:21 These patients have all three of those findings.

02:25 And if particularly in somebody with Kartagener syndrome, the heart is on the right side of the chest, not the left.

02:36 Wouldn’t it be embarrassing to not recognize that? So if somebody has ciliary dyskinesia, make sure you would pick out the right side for the heart exam.

02:51 And then as I mentioned tobacco smoke, it’s interesting, you may know several people who smoke and who are always complaining of having sinus problems.

03:03 Then of course there can be some local insults to the face that cause obstruction of the ostia of the sinuses and they can result in bacterial sinusitis, like facial trauma for example, prizefighters.

03:19 People who do a lot of swimming and diving either for recreation or professionally can have sinus problems.

03:26 All of you who have done any swimming recognize the changes in pressure when you go underwater.

03:35 Sinusitis can be a very severe and career-ending problem for high-altitude aviation maneuvers.

03:44 For example, if a pilot develops some problem with the sinuses, that pilot probably shouldn’t fly if he’s flying one of these fighter jets because particularly on descent, the sinus pressures can change so dramatically they can have that sudden onset of very severe facial pain which could result in aircraft accident.

04:11 So high-altitude aviation maneuvers are very important in the military.

04:18 Then there are people who chronically take decongestants or antihistamines and actually they can become rather dependent on those such that their ostia seem to be always blocked.

04:34 And then if a patient has to come in the hospital for surgery or for admission to the ICU, they may have to be intubated and put on a ventilator.

04:46 That can certainly block the ostia of the sinuses if they are nasally intubated.

04:54 There can be mechanical obstruction of the ostia of the sinuses as some people are born with choanal atresia.

05:03 One of the important exams of a newborn is to make sure the external nares are completely patent.

05:12 Some people have deviated nasal septum.

05:15 This is a pretty common problem.

05:17 Most people don’t have enough deviation of their nasal septum to obstruct the sinus ostia, but this is something that has to be examined for.

05:28 Nasal polyps occur.

05:33 Little kids can get foreign bodies like little plastic automobiles and things like that in their nose.

05:41 And then some large bullae may form in the ethmoid sinuses that can block the ostia there.

05:49 So we’ve been talking about blockage of the sinus ostia.

05:54 Well, what are the consequences of that happening? Well, if the sinus gets blocked, then you get initially an increase in sinus pressure, and of course fluid is going to build up behind the blockage.

06:08 Now eventually, the oxygen is going to be absorbed out of the blocked sinus and eventually there’ll be negative pressure in the sinus.

06:20 Now, the other thing is that bacteria, nasal and nasopharyngeal bacteria, can enter the sinus during sniffing.

06:31 Some people have a chronic habit of sniffing, kind of a tic.

06:36 And then a lot of people when they have for example a common cold will blow their nose very hard.

06:44 Some of them sound like a foghorn when they blow their nose.

06:48 Well, they may actually get sinusitis from doing that.

06:52 So if you have a common cold and if you’re advising your patients, you should tell them to blow their nose gently, never blow their nose very hard.

07:04 So the bottom line is that fluid becomes static inside of a blocked sinus, and if there are bugs there, then the bugs can, as we say, set up light housekeeping in the sinus.

07:21 And if the ciliary apparatus doesn’t work properly, that can also complicate problems.

07:30 A typical viral infection can actually eliminate some of the cilia.

07:38 They’ll come back, but during a viral infection sometimes the cilia are destroyed.

07:45 And as I mentioned, if the mucous layer is abnormal, the ciliary action is abnormal.

07:54 You don’t think of this often, but your sinuses are not supposed to be dry.

08:00 There’s supposed to be mucus every day, all day, in your sinuses and that keeps the cilia moving as they are supposed to move and they normally beat toward the posterior pharynx.

08:19 And the secretions are normally swallowed.

08:24 Patients who smoke cigarettes have a change in the viscosity of that mucus.

08:31 And I think you can imagine how that may mess up the motility of the cilia.

08:37 So no wonder they have sinus congestion and no wonder they have frequent episodes of sinusitis.