Pneumonia: Etiology and Pathophysiology (Pediatric Nursing)

00:01 Now let's talk about pediatric pneumonia.

00:04 Pneumonia is an infection that inflames the air sacs in one or both lungs.

00:09 The lungs may fill with fluid or pus- this is called purulent material - causing a cough, fever, chills, and difficulty breathing.

00:17 Pneumonia can affect any part of the lung.

00:20 A patient can have inflammation in the upper lobe of their lung, in the middle lobe of their lung, or in the lower lobe of their lung.

00:27 Sometimes, they even have multiple portions of their lung involved, and it can either be unilateral, on one side, or bilateral, both sides.

00:35 Here's an example of an upper lobe pneumonia.

00:38 Here in the middle, you'll see inflammation and pneumonia in the middle lobe of the lung.

00:42 And remember, the right lung has 3 lobes, the left lung has 2.

00:46 And here you'll see pneumonia in the lower lobe of the lung.

00:51 Childhood pneumonia is an important cause of morbidity in the developed world, and also a cause of morbidity and mortality in the developing world.

00:59 UNICEF estimates that pediatric pneumonia kills about 3 million children worldwide each year, and these deaths occur almost exclusively in children with underlying conditions: children with chronic lung disease, or prematurity, congenital heart disease, or immunosuppression.

01:15 Although most fatalities occur in developing countries, pneumonia still remains a significant cause of morbidity in industrialized nations.

01:22 Now, pneumonia can range in seriousness from mild to life threatening.

01:26 It is most serious for infants and young children, people older than 65, and people with health problems or weakened immune systems.

01:35 The treatment of the pneumonia infection depends on the cause.

01:39 So, pneumonia can be caused by a lot of different things: bacteria, viruses, and fungi.

01:46 In this lecture, we're going to talk about bacterial and viral causes because those are the most common.

01:52 In 2-5 year old population, the most common causes are respiratory syncytial virus or other respiratory viruses, Strep pneumoniae, and now, this is the most common cause of bacterial pneumonia across the spectrum.

02:05 And this is the reason we have the pneumococcal vaccine.

02:07 It's called the Prevnar.

02:08 And that's where a child will receive a 4-dose series given at 2 months, 4 months, 6 months, and at 12-15 months of age.

02:17 Haemophilus influenza, for which children receive their HIB vaccine, is another common cause.

02:22 And they'll receive that at the same milestones: 2 months, 4 months, 6 months, and again, at 12- 15 months.

02:29 Mycoplasma pneumoniae, which is the cause of atypical pneumonia, is also pretty common, and this is a different, sort of, clinical presentation.

02:37 These children will develop their pneumonia much slower than a typical infection.

02:42 Chlamydia pneumoniae is another type of atypical pneumonia.

02:45 Now let's move down into the older population, the 5-18 year olds.

02:49 Pneumonia is typically caused by Mycoplasma, which remember is atypical, Streptococcus pneumoniae, which is the most common cause of pneumonia across the board, Chlamydia pneumoniae, Haemophilus influenza, the flu viruses A and B, adenoviruses, and other respiratory viruses.

03:09 Although anyone can develop pneumonia, some children are more likely than others to get these infections.

03:14 There are certain risk factors.

03:16 These include prematurity, and this is because the lung development is immature in these children and they're more likely to develop respiratory complications.

03:25 Another risk factor is children who are exposed to second-hand smoke.

03:30 Children who are not up to date on vaccinations or are not fully immunized as some immunizations protect against pneumonia-causing infections.

03:38 These are the HIB vaccine, the Prevnar, the DTaP, and the influenza vaccines.

03:44 This could be because maybe the kids are too young to get these vaccines or maybe they have absolute contraindications and they can't receive the vaccines, but either way, they're not protected.

03:55 Children with chronic lung disease such as bronchiectasis or cystic fibrosis are also at an increased risk for developing pneumonia.

04:02 Children with feeding problems are at an increased risk for pneumonia because they can aspirate, and this happens when a child inhales food, stomach acid, saliva, or even vomit into their lungs.

04:13 None of these items belong in the lungs and can cause massive amounts of inflammation and infection.

04:20 Children with chronic lung conditions such as bronchiectasis or cystic fibrosis are also at an increased risk.

04:27 Children with feeding problems are at an increased risk as well because they can aspirate, and this happens when a child inhales food, stomach acid, saliva or even vomit into their lungs.

04:37 None of these items belong in the lungs and can cause a lot of inflammation and resulting infection.

04:44 Children with conditions that decrease their immune system's ability to fight are also at an increased risk for pneumonia.

04:52 How do we prevent pneumonia? Well, it starts with good hand washing, right? Good hand hygiene has been proven to decrease disease transmission.

04:59 We all know this.

05:01 The viruses and some bacteria that cause pneumonia are contagious and they're spread easily from person to person and via fomites, such as doorknobs, utensils countertops, and then these get contaminated with the viruses and the bacteria.

05:16 If you touch these, they get on your hands, and then you end up touching your eyes, mouth, and nose, and this is how you get the viruses and bacteria that cause pneumonia.

05:24 Good hand washing can prevent this transmission.

05:27 Most bacterial causes for pneumonia are not contagious.

05:30 But pertussis, which is whooping cough, is one that is contagious.

05:34 It's always difficult to tell whether pneumonia is viral or bacterial when you're treating a patient, so it's wise to keep these patients away from others and under droplet isolation until the cause can be determined.

05:48 Childhood immunizations have helped greatly in the prevention of pneumonia in children.

05:53 Pneumonia is a known complication of measles, Haemophilus influenza, pertussis, Strep pneumonia, varicella, and influenza and all of these conditions are vaccine preventable.

06:07 So, now, what is it? What's the pathology? Well, pneumonia is an infection down in the lung.

06:12 The patient may also present with pathology in their upper airway because, remember, it's the same tube.

06:18 Here, you see the main airway going down into the normal lung, and then over on the side, you'll see a lung that has pneumonia.

06:26 The pathophysiology of pneumonia involves the infection moving down completely into the lung.

06:32 This is going to start a massive inflammatory response in the body.

06:36 The inflammatory response is going to trigger alveolar edema and exudate to form.

06:41 The alveoli and respiratory bronchioles fill with the serous exudate, blood cells, fibrin, and bacteria, and this is the gunk and the junk that gets in the lung.

06:52 Now, when you look at a chest X-ray of a patient with pneumonia, you're going to see a consolidation on the X-ray.

06:57 This mixture composes the consolidation in the lung tissue, and that's referred to as pneumonia.