0:00 Hello, in this video we're going to talk about Stridor and Children. 0:07 Stridor is a sound predominantly heard during inspiration. 0:10 It is caused by partial obstruction of the large airways that result in 0:14 turbulent airflow 0:14 in the respiratory passage. 0:17 Stridor is defined as a high-pitched monophonic sound and is usually loud and 0:22 can be heard. 0:24 Stridor is defined as a high-pitched monophonic sound that is usually loud and 0:27 can be heard 0:28 without a stethoscope. 0:30 The differential diagnosis of stridor is vast with crew being the most common 0:34 cause of acute 0:35 stridor and then laryngeal malaysia being the most common chronic or congenital 0:39 cause 0:40 of stridor. 0:41 When thinking about the pathophysiology of stridor, it's good to think about 0:45 the respiratory 0:46 tract in terms of extra thoracic and intrathoracic regions. 0:51 So as a general rule, inspiratory stridor occurs in the extra thoracic region 0:57 and expiratory 0:58 stridor occurs from obstruction in the intrathoracic region. 1:03 During inspiration, air flows from the extra thoracic region into the intrathor 1:08 acic region. 1:09 When there is some airway obstruction anywhere in the extra thoracic region, 1:12 this will cause 1:13 an inspiratory stridor. 1:16 Most causes of stridor are found in the extra thoracic region. 1:20 During expiration, air flows from the intrathoracic to extra thoracic region. 1:26 If there is any obstruction in the small airways of the intrathoracic region, 1:31 it can cause 1:32 an expiratory stridor. 1:35 Expiratory stridor is much less common. 1:38 The causes of stridor can be divided into anatomical regions, extra thoracic 1:42 region, 1:43 which is anywhere from the nose to the larynx and the trachea, and then intrath 1:48 oracic region, 1:49 which includes the distal trachea and the bronchi, for example. 1:55 Let's focus on the extra thoracic causes of stridor. 1:59 Adenoids here is a lymphatic tissue that can become enlarged during an 2:04 infection. 2:05 Hypertrophy of the adenoids means potentially obstructing the airway, causing 2:09 turbulent 2:09 air flow, causing a stridor. 2:13 The tonsils are also lymphoid tissues that are commonly enlarged during viral 2:16 and bacterial 2:17 infections. 2:19 Tonsal hypertrophy due to inflammation is common in infections such as 2:23 infectious mononucleosis 2:24 caused by Epstein-Bau virus. 2:27 But also important to keep in mind other causes of enlarged tonsils, such as 2:31 malignancy or 2:32 complications of tonsillitis, such as peritonsal abscess. 2:36 And this is much more common in adults. 2:39 Macroglossia, which means an enlarged tongue, causes partial or complete 2:43 obstruction of 2:44 the airway, depending on the cause. 2:47 Causes of macroglossia to remember or consider include allergic reactions, 2:51 causing angioedema, 2:53 amyloedosis, ludewigs, and gyne, and many congenital causes of macroglossia. 3:00 Moving down the respiratory tract, focusing on the laryngopharynx, the larynx, 3:05 and trachea, 3:06 these structures are still within the extra thoracic region, and so it will 3:10 cause an inspiratory 3:11 stridor if partially obstructing. 3:14 Here is the larynx, and here is the epiglottis, not the esophagus, this is a 3:19 spelling mistake, 3:20 please, this is the epiglottis. 3:23 So again, here is the larynx, and above it is the epiglottis, which closes the 3:29 entrance 3:30 to the lower airways during swallowing, and this is to prevent food from 3:34 entering the 3:35 airways. 3:36 The trachea bifurcates into the right and left main bronchus. 3:39 We are looking at the lower respiratory tract from an anterior view. 3:44 Now let us cut a cross section of the larynx and look at it from a superior 3:48 view from the 3:48 top. 3:49 To orientate ourselves, this is the anterior region of the cross section, and 3:53 here is a 3:53 posterior area, therefore in the front in the anterior part, here we have the 3:59 tonk, which 3:59 continues all the way back down posteriorly to the epiglottis. 4:05 These are your vocal cords and the larynx, which can open and close during phon 4:10 ation. 4:11 This is continuation here of the lower respiratory tract, here is the trachea. 4:17 Notice the posterior aspect is the arid tonoid cartilage, and posterior to this 4:22 is the esophagus, 4:23 which I have not drawn. 4:25 This cross section might be confusing, it is essentially a cross section of 4:30 this area, 4:31 and we are looking at it from the top, but the cross section here, when you 4:34 think about 4:35 it, is rotated 180 degrees. 4:38 This is done, this view we have done, is because this is the view that doctors 4:41 see during intubation. 4:45 A life-threatening cause of inspiratory strata to remember is anaphylaxis, 4:48 which is 4:49 a multi-system, severe allergic reaction, usually occurring within 20 minutes 4:54 or so 4:54 of an exposed allergen. 4:56 Anaphylaxis is characterized by hypotension from systemic vasodilation, early 5:03 tail rash, 5:04 and upper airway obstruction from edema, angiodeema, from cytokine release. 5:10 This is an emergency as the edema can cause upper respiratory tract obstruction 5:15 , and 5:15 a flatter should be treated quickly with adrenaline or epinephrine. 5:21 Continuing on with the extra thoracic cause of strata, focusing on the larynx, 5:26 the larynx 5:26 also known as the voice box is a common site for congenital strata. 5:32 Congenital cause of strata are not acute causes of strata, but rather chronic 5:35 because it is 5:36 ongoing. 5:38 Pringle malaysia is the most common cause of chronic strata in children younger 5:41 than 5:42 two years, and occurs more commonly in males. 5:46 It is a congenital cause of strata and is due to intrinsic deficits in the m 5:50 aturation 5:51 of the laryngeal structures. 5:54 The airway is partially obstructed during inspiration by the prolapse of the fl 5:58 accid 5:58 structures here. 6:00 The inspiratory strata is usually worse when the child is in a supine position, 6:05 so laying 6:06 down when crying or agitated. 6:10 When looking at the larynx here in laryngeal malaysia, there is a 6:14 characteristic omega 6:15 sign of the epiglottis, and this is seen during inspiration. 6:21 Another cause of strata is a laryngeal web, which is a fibrous layer of tissue 6:26 that stretches 6:27 between the vocal cause. 6:29 This obviously causes partial obstruction of the airways, resulting in an 6:34 inspiratory 6:34 strata. 6:37 Vocal cord paralysis is another cause. 6:39 Now vocal cord paralysis can be unilateral or bilateral. 6:45 The most common cause of acute strata in childhood is laryngo tracheobromcitis, 6:50 or croup. 6:52 As the name suggests, it is inflammation of the larynx trachea and the bronchus 6:58 . 6:58 Despite being both extrathratic and intrathratic cause of strata, it is usually 7:06 an inspiratory 7:08 strata because mostly the larynx and trachea are involved. 7:13 The main cause of croup are viruses, specifically para-influenza virus. 7:19 Croup is slightly more common in males, and is usually preceded by an upper 7:23 respiratory 7:23 tracting infection, which evolves into a barking cuff, inspiratory strata, and 7:28 hoarseness due 7:29 to inflammation of the vocal cords. 7:33 Like anaphylaxis, epiglottitis is a medical emergency. 7:37 Epiglottitis is mainly caused by hemophilus influenza type B. Its incidence has 7:43 decreased 7:43 thanks to vaccination. 7:46 Epiglottitis usually occurs in children between the ages of 2 and 7, and 7:50 infectious epiglottitis 7:51 may present with a viral progerum, fever, or dentophasia, muffled voice, and 7:57 drooling. 7:58 The older child may prefer to sit leaning forward with the mouth open and 8:02 tongue somewhat 8:03 protruded. 8:05 There is no spontaneous cuff, and strata is a late sign. 8:10 The risk of airway obstruction in children with epiglottitis is high, and so 8:15 prophylactic 8:16 intubation may be necessary. 8:19 Here is an image, on the left you can see a normal epiglottis with its 8:23 surrounding structures, 8:25 and on the right you can see epiglottitis, where you can see swelling and edema 8:30 of the 8:31 epiglottis. 8:32 And here the airway is being intubated, because you can see the tube running 8:39 down. 8:40 The infectious cause of strata so far we have discussed is epiglottitis and c 8:45 roup. 8:46 Other infection along the same area is bacterial tracheitis. 8:52 Here is a cross section of the trachea. 8:54 You can see that the esophagus runs posteriorly to the trachea. 8:58 The trachea is made up of cartilaginous rings, and here is the lumen of the tr 9:02 achea continuing 9:03 to lower airways. 9:05 The adventitia is shared between the esophagus and the trachea. 9:12 Tracheitis is infection of the trachea. 9:15 Strata here is caused by subglottic edema and mucopurlant secretions in the air 9:21 way, and 9:21 this is due to infection, most commonly a staphylococcus aureus. 9:28 Other tracheal causes of strata are congenital causes, including tracheomolacia 9:32 and tracheo 9:33 esophageal fisture. 9:36 Tracheomolacia, which means basically soft trachea, is characterized by an 9:39 abnormal tracheal 9:41 collapse, secondary to inadequate cartilaginous and elastic elements supporting 9:46 the trachea. 9:48 Tracheal narrowing occurs with expiration and causes an expiratory strata, 9:53 because remember 9:55 this area we're already starting to head towards the intraturassic region. 10:02 Trachea esophageal fisture is another cause of congenital strata, and a fisture 10:06 is basically 10:07 an abnormal passage between two hollow spaces, and this being the trachea and 10:13 the esophagus 10:14 posterior to this. 10:17 Inhalation or aspiration of a foreign body is another common cause of acute str 10:21 ata. 10:22 The foreign body is usually food. 10:24 It can obstruct anywhere along the respiratory tract and can thus present as an 10:29 inspiratory 10:29 strata or both. 10:34 In summary, inspiratory strata is caused by extra thoracic obstruction, because 10:40 during 10:41 inspiration the pressure here drops and causes collapse. 10:46 So if you think about it, if you have obstruction anywhere in the extra thorac 10:50 ic region, it 10:51 will further amplify the obstruction, and thus you get inspiratory strata. 11:00 In summary, the most common cause of acute strata in children is croup, and l 11:22 uringamylatia 11:23 is the most common cause of congenital strata. 11:30 In summary, the most common cause of acute strata is the most common cause of 11:36 acute
