Pulmonary Pathology 1 Flashcards
True or False: Any alveolar filling process (pneumonia, alveolar hemorrhage, etc) causes restrictive pattern because it dilutes surfactant and fill alveoli which reduce the compliance of the lung.
True.
What does mucus do in the airways?
Protects the lungs from the things that you’re inhaling. It makes the walls of the airways really sticky so particulates, bacteria, etc. get stuck in the mucus and can be moved up and out of the airway by the epithelium.
In the bronchi, the epithelium is ciliated ____
columnar
True or False: As you get into smaller airways, there are less ciliated epithelial cells.
True. As you get into smaller airways, the air is more or less already sterile.
What is acute bronchitis typically caused by and how is it characterized?
Acute bronchitis is typically caused by bacterial infections that come on quickly and is characterized by neutrophils in the airway lumen and infiltrating wall.
What’s going on here?
This is acute bronchitis. You can see that the airway is occluded by mucus and neutrophils (fragmented/multi-lobar nuclei). Neutrophils are typically responding to bacterial antigens.
When you see acute inflammation in the airways, think acute bronchitis.
What is chronic bronchitis and how is it characterized?
Chronic bronchitis is characterized by chronic inflammation. The inflammation can be caused by many different things (e.g. chronic infections, autoimmune diseases, etc). With chronic inflammation, you have lymphocytes instead of neutrophils.
When you see neutrophils in airways, think of acute bronchitis. When you see lymphocytes, think chronic bronchitis.
Over time, the airway epithelium undergoes squamous metaplasia (much tougher–to try to protect against chronic injury) and you have mucus gland hypertrophy (secreting more mucus to try to protect against chronic injury)
What’s going on here?
Chronic bronchitis.
You can tell that it’s chronic inflammation because the cells there are lymphocytes, not neutrophils. Neutrophils have multi-lobed nuclei and cytoplasm while the lymphocytes are blue without cytoplasm.
What happens to the epithelial layer in chronic bronchitis?
Squamous metaplasia (a reaction to protect against the chronic inflammation)
The cells start to turn into squamous cells that are tougher and more protective. It starts to look a lot like outside skin.
It is thought that squamous metaplasia is an early step leading to cancer.
What happens to mucus glands in chronic bronchitis?
Mucus gland hyperplasia.
There is proliferation of the mucus glands and you get increased secretion of mucus to try to defend the airways against chronic insults.
What is bronchiectasis and how is it characterized?
Bronchiectasis happens when you have things like chronic bronchitis and recurrent infections year after year and is characterized by airway dilation.
It’s often seen in cystic fibrosis as cystic fibrosis patients are more prone to infection.
You can also see this in patients that get infected with tuberculosis (because these infections can last a very long time). When airways are inflammed and injured for a long time, they can become dilated.
In bronchiectasis, as airways get ____, the body has a harder time controlling ______. This can lead to ____.
bigger (dilated), what’s inside of the airways, infection
As the airways get too big, things in the airway become far away from the blood supply so the immune response can’t reach them to control them.
What’s the easiest way to see if there is bronchiectasis?
Compare the airway to its corresponding artery (they almost always run together). They should have lumens about the same size. If the airway is bigger, there is bronchiectasis.
With acute bronchitis, you have neutrophils. With chronic bronchitis, you have lymphocytes. What about for asthma? What WBC do you have?
Eosinophils
What are 4 pathology characteristics of asthma?
- Thickened subbasal lamina
- Eosinophilic inflammation (the eosinophils all go away if treated with steroids, so eosinophils may not be present in a biopsy of a treated patient)
- Mucus hypersecretion
- Smooth muscle hyperplasia (gets bigger bc it’s getting exercised throughout episodes)
What’s going on here?
Asthma. Asthma histology has a pink band-like area under the epithelium that is thickened (subbasal lamina).
What’s going on here?
Allergic asthma (eosinophils present).
They have red cytoplasm and have bi-lobed nuclei
What’s going on here?
This is asthma. You can see the thickened subbasal lamina under the epithelium. There is mucus hypersecretion in asthma in response to the inflammation in the airway.
What’s going on here?
Asthma. You can see the thickened subbasal lamina under the epithelium. Also, you can see smooth muscle hyperplasia. Typically, the smooth mucle is supposed to be the same thickness as the epithelial layer but it is about 8 times thicker in this picture. This shows that the smooth muscles have been built up (exercised by the asthma episodes).
What’s going on here?
(Cellular) Chronic Bronchiolitis
There are lymphocytes infiltrating the wall of the bronchiole (causing squeezing of the airway) which is a sign of chronic bronchiolitis. This is potentially reversible if you can get rid of the inflammation.
What is follicular bronchiolitis?
Follicular bronchiolitis is a kind of chronic bronchiolitis that forms germinal centers of lymphoid aggregates next to the bronchioles. You have B-cells in the center surrounded by T-cells at the edge. It takes germinal centers a long time to form so this suggests bronchiolitis that has been present for a long time.
What is constrictive and obliterative bronchiolitis?
This is when inflammation of the bronchioles causes fibrosis and scarring which causes the bronchioles to close. Fibrisis/scarring is irreversible. Airways beyond scarring are essentially non-functional.
In the picture, you can see the inflammation present with the WBCs, and under the arrow, the pink stuff is fibroblasts starting to squeeze the airway shut. If you look at the smooth muscle above the arrow, you can see that it is far away from the airway epithelium. That’s because the fibrosis grew in between. Below the airway, you can see the typical distance expected between smooth muscle and airway epithelium.
What’s going on here?
Constrictive bronchiolitis. You can see that the airway was closed by fibrosis
What’s going on here?
Obliterative Bronchiolitis. The airway has closed completely by fibrosis and any airway downstream is useless.
What’s going on here?
This mosaic pattern can happen in constrictive and obliterative bronchiolitis because of air trapping. “mosaic air trapping”
What is granulomatous bronchiolitis?
Granulomatous bronchiolitis is characterized by histiocytes and multinucleated giant cells. It may be necrotizing or non-necrotizing (and it is almost always caused by infection if it’s necrotizing).
In the picture, you can see the multinucleated giant cell surrounded by clustered pink histiocytes (macrophages) with elongated nuclei and abundant cytoplasm.
What’s going on here?
Non-necrotizing granuloma indicates a non-necrotizing granulomatous bronchiolitis
What is acute pneumonia?
Inflammation of airspaces. Presents with neutrophils in the airspaces.
When you see neutrophils, think bacterial (almost all of the time) and think acute.
Airspaces are typically clear of cells except for occasional macrophages.
What is aspiration pneumonia?
Pneumonia from inhaling a forgein material (e.g. food).
This may present with multinucleated giant cells.
In the picture, you can see cooked meat. There are often neutrophils present as well as the food isn’t sterile.
What is eosinophilic pneumonia?
Pneumonia with eosinophils, macrophages, and fibrin in airspaces.
The eosinophils are very sensitive to steroids and will disappear w/ treatment. You can see the eosinophils in the picture and also the fibrin (pink gritty material) around them.
What is organizing pneumonia?
Most commonly idiopathic (looks like it might be from infection but it’s not).
There are fibroblast plugs in the airways and airspaces. Patients with organizing pneumonia actually don’t do that badly. From the histology, it looks like the majority of the airways/airspaces are plugged, but with organizing pneumonia, the patients have areas of the lung that are clear.
Organizing pneumonia can be treated with steroids.
What is diffuse alveolar damage?
Hyaline membranes (pink ribbons of fibrin) fill the airspaces.
Alveolar septa are thickened by inflammation and fibroblastic tissue.
Diffuse alveolar damage is idiopathic.
In the picture, you can see the hyaline membranes (pink ribbons) that are lining the airspaces. This is preventing gas exchange.
DAD has about 50% mortality rate.
What’s going on here?
Diffuse alveolar damage. The hyaline membrane lines the airspaces and prevents gas exchange. Alveolar septa are thickened with inflammation and loose fibroblastic tissue.
50% mortality rate
What’s going on here?
Emphysema. Broken alveolar septa can sometimes have the club formation which lets you know that the septa was broken in the patient and not from the histology procedure.
With smokers, is emphysema worse in the lower or upper part of the lungs?
Upper (think smoke rises… although who knows if that’s actually the reason)
What is this a sign of?
Emphysema.
Blebs can break and cause pneumothorax.
What is respiratory bronchiolitis and how does it appear in histology?
Respiratory bronchiolitis interstitial lung disease refers to a form of idiopathic interstitial pneumonia associated with smoking. It appears with pigmented macrophages in the airspaces near bronchioles.
Tends to be worse in the upper lobes (smoking).
In the picture, you can see the dirty looking macrophages. They turn brown/black because they are trying to clean up the stuff from smoking. These macrophage clusters obstruct airways. The airspaces further away from the airway are spared.
What is desquamative interstitial pneumonia and how does it appear in histology?
Desquamative interstitial pneumonia is a form of idiopathic interstitial pneumonia featuring elevated levels of macrophages. It looks a lot like respiratory bronchiolitis.
There are pigmented macrophages in all airspaces. This is different from respiratory bronchiolitis which had macrophages only near the airways.
*note that DIP is a misnomer. originally it was thought to be squamous cells but later was found just to be macrophages.
