Systemic Pathology 400 (respiratory pathologies 3-4) Flashcards
allergic rhinitis
..
allegic rhinitis mostly where?
mostly nose and eyes
allergic rhinitis occurs in respones to
occur in response to breathing in allergens
allergens (example)
dust, dander, mold, cockroaches, pollen, grass, trees
allergic rhinitis is …
A collection of signs and symptoms
(mostly in the nose and eyes)
what are those collections of SSx?
Itching nose, mouth
Conjunctivitis (EYES)
Sneezing
Sinus and nasal obstruction
Coughing, wheezing
Coryza
SSx are in
eyes,
nose
throat, respiratory tract
sinuses
allergic rhinitis AKA
AKA HAY FEVER or SEASONAL ALLERGIES
how common is allergic rhinitis
VERY COMMON
not as common 50 years ago (?)
allergic rhinitis commonly co-occurs with …
Asthma
Atopic dermatitis
—> Atopy
atopy define
“Atopy is the tendency to produce an exaggerated immunoglobulin E immune response to otherwise harmless substances in the environment.”
“Atopy refers to the genetic tendency to develop allergic diseases such as allergic rhinitis, asthma and atopic dermatitis (eczema).”
“derived from the Greek words a and topos, meaning “without” and “place,” respectively.”
allergic rhinitis — PATHOGENESIS
ACUTE VASOMOTOR response mediated by HISTAMINE and related vasoactive substances released locally in the nose from mast cells coated with IgE
what is the acute vasomotor response mediated by?
1) HISTAMINE
2) vasoactive substances
—> released locally in the nose
(from mast cells coated with IgE)
allergic rhinitis — Dx
History
Symptoms
Skin test
skin test – allergic rhinitis
“A skin prick test, also called a puncture or scratch test, checks for immediate allergic reactions to as many as 50 different substances at once. This test is usually done to identify allergies to pollen, mold, pet dander, dust mites and foods. In adults, the test is usually done on the forearm.”
allergic rhinitis – Tx
(Avoid triggers)
Antihistamines
Decongestants
Injections
how does decongestant work?
vasoconstrict
“They work by reducing the swelling of the blood vessels in your nose, which helps to open the airways. Examples include pseudoephedrine (sometimes called by the brand name Sudafed.”
ASTHMA
..
what is asthma?
Increased responsiveness of bronchial tree to certain stimuli
how is asthma multi-factorial?
Complex disorder involving…
biochemical,
autonomic,
immunologic,
infectious,
endocrine,
psychological factors
asthma – how is it chronic vs acute?
Chronic inflammatory condition
with acute exacerbations
asthma can be classified as …
Can be classified as reversible COPD
back to allergies —> “hygiene” theory related to allergies, hypersensitivities, autoimmune diseases, etc.
exposure to pathogens and a variety of substances from early age, reduces likelihood of allergies/hypersensitivities developing.
whereas, children who are sheltered, and don’t spend time outside, and around various substances/animals/people, are more likely to develop hypersensitivities/allergies, etc.
Asthma – Incidence
..
HOW COMMON IS ASTHMA?
The MOST COMMON chronic disease in adults and children
asthma, male to female ratio
Male > female 2:1
asthma, male to female ratio IN SEVERE CASES
Severe cases: Male = female
asthma – incidence vs country development level
and incidence vs socioeconomic class
More common in DEVELOPED countries, specifically those who are of LOW SOCIOECONOMIC STATUS
for asthma in developing countries, which group are more likely to have asthma?
In the developing world it is more common in those who are of high socioeconomic standing.
Why?
access to healthcare (?)
rich people living in cities more often in developing countries (?)
related to occupation (?)
Asthma risk factors
Environment
Small families
Lack of pets
Antibiotics
Age
Gender
Smoking while pregnant
Viral infections
other risk factors for asthma
Obesity
Urban settings
Low SE status
Overcrowding
BMI
Family history
Atopy (tendency for allergies)
allergies as risk factor for asthma?
“The chemicals released by your immune system lead to allergy signs and symptoms, such as nasal congestion, runny nose, itchy eyes or skin reactions. For some people, this same reaction also affects the lungs and airways, leading to asthma symptoms.”
asthma – etiology
Genetics
Viruses
Risk factors (outlined in previous slide)
EXTRINSIC ASTHMA
(atopic or allergic asthma)
results from?
occurs mostly in?
considered a _____ disorder
Results from an allergy to specific triggers
Occurs mostly in children and young adults
considered part of “Hypersensitivity disorders”
is family history a risk factor for asthma
yes
3-6 times more likely
Intrinsic asthma
((nonallergic asthma)
triggers?
onset age?
possibly d/t … ?
No known triggers
Adult onset
Possibly viral exposure
—> Post-viral asthma
(POST-VIRAL BRONCHOCONSTRICTION)
Occupation Asthma
NARROWING OF AIRWAYS
caused by workplace exposure
exercise-induced Asthma
Bronchoconstriction can occur in those without other forms of asthma
—> Up to 20% of the healthy population
(More common in cold temperatures)
asthma – pathogenesis
An inflammatory response in the airway causes:
Cellular infiltration
Epithelial disruption
Mucosal edema
Mucous plugging
The inflammatory mediators produce:
Smooth muscle spasm
Vascular congestion
Increased vascular permeability
Edema formation
PRODUCTION OF THICK, TENACIOUS MUCOUS
Impaired mucociliary function
Mediators also cause:
Thickening of airway walls
Increased contractile response of bronchial smooth muscle
This leads to airway hyper-responsiveness and, along with swollen airways and mucous plugs, causes trapping of distal air leading to:
HYPOXEMIA/hypoxia
Obstructed airflow
Increased work of breathing
in long run, what can asthma cause
barrel chest – but not as common
asthma – SSx, clinical manife
Cough
SOB
Wheezing
Degree – mild, moderate, severe
Frequency
asthma attacks are usually …
Most attacks are short-lived with asymptomatic periods between attacks.
long term asthma and repeated acute episodes can lead to…
Repeated episodes may leads to …
barrel chest,
elevated shoulders,
hypertonicity of accessory muscles of respiration, etc.
acute severe asthma — aka
formerly known as STATUS ASTHMATICUS:
“a severe condition in which asthma attacks follow one another without pause.”
acute severe asthma is …
Acute severe asthma (formerly status asthmaticus) –
an acute attack that cannot be altered with standard bronchodilators
acute severe asthma requires ____
can be ____
requires emergency medical care
can be fatal
asthma — Dx
History
Clinical manifestation
Pulmonary function tests (FEV-1) — FORCED EXPIRATORY VOLUME
fev-1 diagnostic tool
forced expiratory volume test
“FEV1 helps measure the progression of lung conditions such as chronic obstructive pulmonary disease (COPD) or asthma. FEV stands for forced expiratory volume, which is the air you exhale in 1 second. A low FEV1 suggests a breathing obstruction.”
asthma – Tx
Identify and avoid specific triggers
Medications
—> Corticosteroids
—> Bronchodilators
asthma – Px for children
Asthma resolves in many children, but for as many as one in four, wheezing persists into adulthood or relapse occurs in later years
asthma – mortality rate ?
About 4000 deaths/yr in the US are attributable to asthma, most of which are preventable with treatment. Thus, the prognosis is good with adequate access and adherence to treatment
long term asthma —-> structural effects on lungs
What can prevent these structural changes?
Over time, the airways in some patients with asthma undergo permanent structural changes (remodeling) that prevent return to normal lung functioning.
Early aggressive use of anti-inflammatory drugs may help prevent this remodeling
PNEUMOCONIOSES
Restrictive lung diseases
caused by inhalation of MINERAL DUSTS and various INORGANIC particulate
—> leads to permanent deposition of substantial amounts of particles in the lungs
which substances are commonly involved in PNEUMOCONIOSIS?
Particularly inorganic DUST such as IRON ore or COAL
—> inhaled and deposited in lung tissue
pneumoconiosis etymology
pneumo – of or related to lungs
konis – dust
osis – condition/disease
pneumoconiosis – commonly as a result of
Most classified as occupational and a consequence of long term exposure in the workplace
“coal worker’s pneumoconiosis”
(aka anthracosis)
etymology:
anthrax/anthrak – coal
osis – condition/disease
3 types of pneumoconiosis
1) coal worker’s pneumoconiosis (anthracosis)
2) silicosis
3) asbestosis
whether or not there is damage to lungs during pneumoconioses, depends on a THREE FACTORS
A) Duration of exposure
B) Concentration of particles
C) Size, shape and solubility of particles
D) Biochemical composition of the inhaled dust
how does size of particles determine whether a risk factor for pneumoconioses?
E.g.
Large dust particles retained in the nasal mucus and do not reach the lower respiratory tract
How does biochemical composition of the inhaled dust determine risk for developing pneumoconioses?
E.g. Inert particles, like coal particles, are less reactive
E.g. silica particles are more reactive and produce more prominent tissue injury
E.g. asbestos particles are insoluble and remain lodged in lungs permanently
pneumoconiosis – incidence and etiology
Occurs most commonly in miners, sandblasters, stonecutters, asbestos works, insulators
Increasing incidence with age because cumulative effects of exposure
Overall incidence decreasing (BETTER OCCUPATIONAL SAFETY STANDARDS)
1) Coal worker’s pneumoconiosis
Amorphous carbon particles retained in nasal mucosa
Ingestion of inhaled coal dust by alveolar macrophages; expectorated
—> Black lung
2) SILICOSIS
Cells membranes of macrophages destroyed; macrophages die and release silica which is ingested by macrophages
Dead macrophages release
biochemically active substances
that stimulate formation of
COLLAGENOUS NODULES
Confluent nodules destroy lung
parenchyma and cause
massive pulmonary fibrosis
____ is a common complication of SILICOSIS
TB common complication
if silicosis is caused by volcanoes it is called ____
Pneumonoultramicroscopicsilicovolcanoconiosis
silicosis define
“Silicosis is a type of pulmonary fibrosis, a lung disease caused by breathing in tiny bits of silica, a common mineral found in sand, quartz and many other types of rock.”
“Silicosis mainly affects workers exposed to silica dust in jobs such as construction and mining. Over time, exposure to silica particles causes scarring in the lungs, which can harm your ability to breathe.”
3) Asbestosis
Asbestos particles engulfed by macrophages
Macrophages activated to release inflammatory mediators
asbestos associated with increased risk of ____
whereas silicosis is associated with increased risk of _____
Associated with increased risk of LUNG CANCER
silicosis is associated with increased risk of TUBERCULOSIS
pneumoconiosis — Clinical manifestations
Progressive dyspnea
Chest pain
Chronic cough
Expectoration of mucus
pneumoconiosis — Dx
workplace exposure,
CXR,
clinical manifestation,
pulmonary function tests (FEV1?)
pneumoconiosis – safety measures
Prevention and safety measures
pneumoconiosis – is there Tx when it happens?
No standard treatment
pneumoconiosis – what about Px ?
Poor prognosis generally
HYPERSENSITIVITY PNEUMONITIS
Hypersensitivity reaction in the alveoli as a response to inhaled ORGANIC particulate
BOTH of these are considered to be OCCUPATIONAL PATHOLOGIES
Hypersensitivity Pneumonitis
Pneumoconiosis
BOTH of these are considered to be RESTRICTIVE LUNG DISEASES
Hypersensitivity pneumonitis
Pneumoconiosis
Hypersensitivity pneumonitis causes
“Hypersensitivity pneumonitis can happen when you repeatedly breathe in bacteria , mold, or chemicals in your environment that cause inflammation in your lungs. These harmful substances may be found in: Air conditioners, humidifiers, and ventilation systems. Bird droppings, feathers, and animal furs.”
one difference between pneumoconiosis and hypersensitivity pneumonitis
PNEUMOCONIOSIS usually involves inhalation of INORGANIC particles
HYPERSENSITIVITY PNEUMONITIS usually involves inhalation of ORGANIC particles
hypersensitivity pneumonitis – relation to allergies and allergens
“Hypersensitivity pneumonitis causes a different immune reaction in your body than pollen or pet allergies. Unlike common allergies that cause hay fever and asthma, repeated exposure to allergens that cause HP can lead to inflammation that can permanently damage your lungs.”
hypersensitivity pneumonitis — SSx
Fever
Cough
Dyspnea
Headache
Pleuritis
Clubbing (hypoxia?)
Honeycomb lungs
Bronchiolitis
Crackles (aka RALES)
hypersensitivity pneumonitis – Dx
History
Blood tests
X-ray
Biopsy
PFT (e.g. FEV1)
hypersensitivity pneumonitis — Tx
Avoid triggers
Anti-inflammatories
pneumothorax
accumulation of air/gas in the PLEURAL CAVITY
caused by defect in VISCERAL pleura
or defect in PARIETAL pleura (chest wall)
what is result of pneumothorax
COLLAPSE of lung (ATELECTASIS)
atelectasis etymology
ateles (imperfect)
ektasis (extension)
PRIMARY pneumothorax
no underlying pathology
idiopathic
SECONDARY pneumothorax
typically result of COPD (esp emphysema), CF
or other lung pathologies/infections
how does pneumothorax lead to atelectasis (lung collapse) ?
air leaking into pleural cavity causes compressive force on lung –> leading to lung collapse
incidence (pneumothorax) – gender, age
MEN 5x more likely
Can develop at ANY AGE
esp TALL and SKINNY individuals
pneumothorax – risk factors
100x
SMOKING increases risk by up to 100x
(Tobacco or cannabis)
pneumothorax as a result of TRAUMA
IATROGENIC trauma
—> Surgery
or other ACUTE TRAUMA
pneumothorax — pathogenesis
air enters pleural cavity
There is a separation between the visceral and parietal pleura
→ destroys the NEGATIVE pressure of pleural space
→ lung collapses towards the hilum
pleural cavity pressure – typically negative or positive?
typically NEGATIVE
positive pressure means that it will exert pressure/force on the lungs —> leading to lung collapse
what is the effect on mediastinum d/t pneumothorax
air pressure pushes mediastinum in OPPOSITE direction —> towards UNAFFECTED lung
“Result is a mediastinal
shift towards the unaffected side which
will compress the opposite lung”
types of pnuemothorax
1) spontaneous (different from idiopathic)
2) traumatic
3) Iatrogenic (type of traumatic)
spontaneous pneumothorax
generally d/t
blebs and bullae (usually)
TB, lung abscess and other lung disease (also possible)
traumatic pneumothorax
occurs following penetrating or non-penetrating chest trauma (rib fracture, stab, bullet)
iatrogenic pneumothorax (type of traumatic pneumothorax)
occurs during medical procedure
(biopsy, CPR, etc.) –
is considered to be traumatic
other types of pneumothorax
1) Open & closed
2) tension pneumothorax
open pneumothorax
air is drawn into lungs via hole
forced out of hole during expiration
____
a type of traumatic pneumothorax that occurs when air is drawn into the lungs upon inspiration and is forced out upon expiration.
This is the opposite of a closed pneumothorax.
open pneumothorax is AKA
“sucking chest wound”
closed pneumothorax
hole does not open to exterior
2) TENSION PNEUMOTHORAX
any pneumothorax that leads to significant respiratory impairment or issues with blood circulation.
This is a medical emergency.
—> LEADS TO PRESSURE ON MEDIASTINUM
open, closed, tension pneumothorax
VS.
pleural & atmospheric pressure
in CLOSED pneumothorax:
—> pleural cavity pressure is LESS THAN atmospheric pressure
in OPEN pneumothorax:
—> pleural cavity pressure is EQUAL TO
atmospheric pressure
in TENSION pneumothorax:
—> pleural cavity pressure is GREATER THAN atmospheric pressure
—> LEADS TO PRESSURE ON MEDIASTINUM
pneumothorax – CLINICAL MANIFESTATIONS
Dyspnea
Sharp, pleuritic chest pain
Tachypnea
TRACHEAL DEVIATION
(when pleural cavity pressure is high enough to push against mediastinum)
Fall in blood pressure (?)
Weak (?) and rapid pulse
why does PNEUMOTHORAX (esp TENSION pneumothorax) cause LOW BP & weak pulse?
“As the intrapleural pressure increases, the mediastinum shifts and the venous return to the superior vena cava is impaired. Tension pneumothorax causes hypotension, increases the central venous pressure, decreases cardiac output, and ultimately produces cardiovascular collapse.”
which type (stage) of pneumothorax is more likely to cause CV Sx (low BP, weak pules) ?
TENSION PNEUMOTHORAX
—> increased pressure in pleural cavity exerts pressure on mediastinum (including structures such as vena cava)
pneumothorax Dx
Patient history
Chest films
—> CT, CXR, US
pneumothorax – Px
Good
However, recurrence is likely
pneumothorax – treatment
Administration of oxygen
Repair and closure of defect
Chest tube insertion may be necessary
Surgery to control bleeding, remove large clots, and treat trauma
Not a good idea to travel on plane or do lung function tests at least 2 weeks after treatment
Watch and wait
pneumothorax – Asherman chest seal (TREATMENT)
“This chest seal includes a one-way valve, intended to let air and blood escape as needed, while keeping both out of the pleural cavity. Features. Circular design with 1-way valve. Pressure-sensitive adhesive that offers effective seal (even on hairy areas)”
pleurodesis (treatment for pneumothorax)
“Pleurodesis is a medical procedure in which part of the pleural space is artificially obliterated. It involves the adhesion of the visceral and the costal pleura. The mediastinal pleura is spared.”
“Pleurodesis is a procedure that sticks your lung to your chest wall. This procedure removes the space between your lung and your chest wall (pleural space)”
pleurodesis etmyology
The term ‘pleurodesis’ comes from the Greek words pleurá (pleura) and desmos (bond)
refers to a procedure undertaken to create the symphysis between the parietal and visceral pleura in order to eliminate the pleural space.
pleurodesis – flaws, risks, complications
“Sometimes patients experience chest pain from pleurodesis. Painkillers are given as needed to help relieve this.”
“Some patients experience fever for the first day or two after the procedure. This is usually controlled with paracetamol and is short-lived.”
“Sometimes pleurodesis can cause breathlessness due to too much inflammation in the lung. This usually settles down over a few days with oxygen treatment, although very rarely (about 1 in 1000) it can be serious.”
PLEURISY
AKA pleuritis
pleurisy is
An inflammation of the pleura
caused by infection (USUALLY VIRAL), injury, tumor, other lung pathologies
pleurisy can be a complication of
pneumonia, TB, influenza, pneumothorax
SLE, RA, cancer
etc.
pleurisy can also be
idiopathic
(PRIMARY?)
pleurisy — clinical manifestations
Sharp, sticking pain when breathing
—> Can also be dull, constant pain
Cough
Fever
SOB
Tachypnea
pleurisy symptoms develop quickly or slowly?
Symptoms develop suddenly
pleurisy Sx worse when …
Worse on …
inspiration,
coughing, sneezing,
movement
pleurisy pathogenesis
If serous fluid between the visceral and parietal layers
is unchanged, it is said to be “DRY”
Two layers get congested and swollen and rub against each other → PAIN
DRY pleurisy
If serous fluid between the visceral and parietal layers is unchanged, it is said to be “DRY”
Two layers get congested and swollen and rub against each other → PAIN
WET PLEURISY (pleurisy with effusion)
If serous fluid between visceral and parietal layers is increased, it said to be “wet” or “pleurisy with effusion”
Less likely to cause pain because there is no chafing
May interfere with breathing by compressing the lung
Can become infected - “purulent pleurisy” or “empyema”
DIAPHRAGMATIC PLEURISY
Inflammation of part of the pleura reaches the diaphragm, called diaphragmatic pleurisy
→ secondary to pneumonia
→ sharp pain referred to the neck, upper traps or shoulder
pleurisy types
dry pleurisy
wet pleurisy
diaphragmatic pleurisy
pleurisy Treatment
Aspirin
NSAIDS
Antibiotics
Thoracentesis if effusion is present
PLEURAL EFFUSION
..
pleural effusion vs hydrothorax (?)
“When unspecified, the term ‘pleural effusion’ normally refers to hydrothorax.”
NOTE that if pleural effusion is blood it is hemothorax; if pus, empyema.
—> pleural effusion is more general term, doesn’t specify what is in excess in pleural cavity
pleural effusion is
Increased fluid between visceral and parietal pleura
I.e.
In PLEURAL CAVITY
(pleural effusion) fluid can be
blood, pus, serous fluid, urine
how urine (pleural effusion)
kidney disease (?)
pleural effusion — secondary vs primary
Can be secondary to any pathologies that cause pleural edema
is pleural effusion an issue with DRAINAGE?
or is it an issue with SECRETION?
can be d/t DECREASED DRAINAGE
INCREASED SECRETION
or BOTH
secondary pleural effusion – pathologies
E.g. congestive heart failure, liver disease, kidney disease, trauma, malignancy, PE, infection, etc.
pleural effusion – clinical manifestations DEPEND ON
amount of fluid,
the degree of lung compression,
underlying health condition,
etc.
pleural effusion – Sx may include …
progressive dyspnea on exertion,
pain,
etc.
pleural effusion — Dx
history,
imaging,
biopsy
pleural biopsy define
“Pleural biopsy is a procedure to remove a sample of the pleura. This is the thin tissue that lines the chest cavity and surrounds the lungs. The biopsy is done to check the pleura for disease or infection.”
“Pleural biopsy is often done to find the cause of a collection of fluid around the lung (pleural effusion) or other abnormality of the pleural membrane. Pleural biopsy can diagnose tuberculosis, cancer, and other diseases.”
ventilatory failure
various mechanisms
E.g.
muscle issues
—> E.g. diaphragm not contracting
neural issues
acute alcohol poisoning – medullary rhythmicity centre (DRG)
interferes with DRG
—> inhibits neural activity to lungs/diaphragm
ventilatory failure is secondary to
Secondary to alveolar hypoventilation
—-> Gas isn’t being exchanged properly in the lungs for some reason, which leads to ventilatory/respiratory failure
ventilatory failure occurs in several conditions that can affect …
1) Mechanical respiration
—> (neural control, muscular issues)
2) Lung circulation
3) Airways
4) Gas exchange
neural control of respiration
Respiratory centers in the brainstem have chemoreceptors to measure the content of carbon dioxide
Brainstem lesions can depress spontaneous breathing
respiratory muscles
Consist of the diaphragm, SCMs, intercostals, pec. minor, scalenes
→ are striated muscles controlled by cranial and spinal nerves
how can respiratory muscles become dysfunctional?
Can become dysfunctional under several conditions
→ affect the nerves, the NMJ or muscles themselves
various conditions and respiratory failure
Poliomyelitis
Spinal cord injury
Tetanus toxin
Myasthenia gravis
Muscular dystrophy
Poliomyelitis vs respiratory failure
affects the SPINAL CORD can cause RESPIRATORY PARALYSIS
Spinal cord injury and ventilatory failure
damage to nerves
Tetanus toxin
muscle spasm
—>
“Respiratory failure because of muscle spasms is a major sequela of tetanus. Spasms can be controlled with sedation and adjunctive treatment, albeit at the expense of respiratory drive and weakness. Invasive ventilation under deep sedation with intensive care unit admission is the best practice.”
what percentage of polio patients experience paralysis?
In less than 1% of cases, polio causes permanent paralysis of the arms, legs or breathing muscles.
Myasthenia gravis and ventilatory failure
affects the NMJ to cause depression in breathing
(among other muscles of course)
Muscular dystrophy & respiratory failure
esp. in Duchennes → causes muscle wasting → respiratory muscle failure
Chest wall lesions & ventilatory failure
Restrict the expansion of the chest during inspiration
Happens in deformities of chest cage:
—>
(kyphoscoliosis),
pleural fibrosis,
pleural tumours,
extreme obesity
airway pathologies and ventilatory failure
E.g. CF (with bronchial mucus plugs), COPD, asthma, etc.
ARDS (acute respiratory distress syndrome)
Acute respiratory distress syndrome
Changes that occur in the lungs that cause acute respiratory failure
ARDS vs NRDS
“Despite having a similar name, NRDS is not related to acute respiratory distress syndrome (ARDS).”
ARDS causes
Shock – trauma, burns, acute cardiac failure
Pneumonia
Toxic lung injury – fumes, drugs, bacterial endotoxins
Aspiration of fluids – e.g. drowning
ARDS etiology / pathogenesis
Can be due to a variety of conditions
is ARDS to do with alveoli or capillaries?
EITHER / BOTH (?)
Can be either an injury to endothelial cells in pulmonary capillaries or injury to the alveolar lining cells
as a result
—>
Alveolar walls are affected and gas exchange is severely impaired
what happens if impaired gas exchange?
Impaired oxygenation of blood results in hypoxia
what can long term impaired gas exchange lead to?
fatal systemic conditions including
—>
shock,
sepsis,
SIRS
and/or respiratory acidosis
SIRS
Systemic inflammatory response syndrome
—>
“In immunology, systemic inflammatory response syndrome is an inflammatory state affecting the whole body. It is the body’s response to an infectious or noninfectious insult.”
cancer – primary vs secondary
not idiopathic
primary means it arose from lungs itself (E.g. lung cancer)
secondary means it was d/t metastasis
lung cancer – AKA
AKA bronchogenic carcinoma
lung cancer is malignancy of ____
epithelium
of the respiratory tract
are most lung cancers primary or secondary?
Most PRIMARY
lung cancer epidemiology
Leading cause of cancer death worldwide (men and women)
One of the world’s leading causes of preventable death
Up to 90% due to smoking cigarettes
lung cancer deaths more than ___ + ___ + ___ (THREE CANCERS) combined
More deaths than from
—->
colon, breast, and prostate cancer combined
when is lung cancer diagnosis most common?
Diagnosis typically occurs after 50 years old
5 year survival (lung cancer, esp later stages)
5 year survival rate from diagnosis is 10-15%
—>
Largely because at diagnosis, 50% of lung cancer is already stage IV
lung cancer etiology / risk factors
Cigarette smoking
—> More than 20 per day
Occupation
Environmental exposures
Industrial living
Asbestos
Radon gas
Age
Family history
Radon gas
“Radon is a radioactive gas that has no smell, colour or taste. Radon is produced from the natural radioactive decay of uranium, which is found in all rocks and soils. Radon can also be found in water. Radon escapes from the ground into the air, where it decays and produces further radioactive particles.”
types of lung cancers ?
1) Small cell lung cancer (SCLC)
—> AKA Oat cell lung cancer
2) Non-small cell lung cancer (NSCLC)
1) small cell lung cancer (SCLC)
aka oat cell lung cancer
20% of all lung cancers
SCLC is highly aggressive and almost solely occurs in smokers.
sclc & metastasis @ time of diagnosis (?)
It is rapidly growing, and roughly 60% of patients have widespread metastatic disease at the time of diagnosis.
note that small cell cancer is not unique to lungs, and can occur elsewhere?
Can have small cell cancer in other tissues not related to the lungs (cervix, prostate, etc)
2) Non-small cell lung cancer (NSCLC)
80% of all lung cancers
NSCLC includes …
a) squamous cell carcinoma,
b) adenocarcinoma (most common),
c) large cell carcinoma
lung cancer where does it commonly metastasize?
brain
breast cancer – where commonly metastasize?
ovaries
which type of lung cancer do non-smokers usually get?
Lung cancer that occurs in non-smokers is almost always NON-small cell lung cancer (NSCLC)
—> However, most cases of NSCLC are still smokers
what percentage of NSCLC patients have metastasis @ time of diagnosis?
Clinical behavior more variable and depends on histologic type;
about 40% of patients will have metastatic disease at the time of diagnosis.
metastasis @ diagnosis – SCLC vs NSCLC
60% vs 40%
lung cancer pathogenesis
Various chemicals in tobacco smoke act as primary carcinogens
A)
DNA mutating agents
—>
ACTIVATE ONCOGENES
B)
and/or
—>
DEACTIVATE TUMOR SUPRESSOR GENES
C)
as well as
—>
mutate genes that detoxify (oxidative stress) and assist in DNA repair
lung cancer, invasiveness & metastasis
Lung cancer is highly invasive and metastasizes early
→ extends into the mediastinum and spreads into pleural cavity and lymph nodes
lung cancer Dx can be challenging …
A)
not many SSx until late stage
____
B)
can mimic symptoms of other disease
—> E.g. hyperproduction of cortisol
(PARANEOPLASTIC SYNDROME)
I.e.
—> Doesn’t necessarily indicate an issue with lungs
—> Also why websites like WEBMD always list CANCER as potential for MANY, MANY symptom types
where does lung cancer metastasize?
liver and brain (most often),
bones, kidneys and adrenals
where is lung cancer metastasis common?
brain (m/c)
lung cancer and mass effect
Local extension of tumor into the mediastinum or pleural cavity (mass effect)
lung cancer, mass effect, and ATELECTASIS
Cause obstruction → atelectasis → lung infection
lung cancer, mass effect, and PLEURAL EFFUSION
yes
mass effect & dyspnea (?)
Progressive dyspnea from lung compression
lung cancer and pain/paralysis of diaphragm & vocal cords
(d/t MASS EFFECT?)
Pain and paralysis of muscles of diaphragm and vocal cords
___
“Diaphragmatic paralysis may be caused by tumor compression upon or invasion into the phrenic nerve or the C3–5 nerve roots.”
lung cancer – SSx (esp late?)
Hemoptysis
Cachexia
SOB
Cough
Anorexia
Paraneoplastic syndromes
Digital clubbing
Paraneoplastic syndromes
“A paraneoplastic syndrome is a syndrome that is the consequence of a tumor in the body. It is specifically due to the production of chemical signaling molecules by tumor cells or by an immune response against the tumor. Unlike a mass effect, it is not due to the local presence of cancer cells.”
“Paraneoplastic syndromes are rare conditions that can occur with cancerous tumors.”
clinical manifestations of liver metastasis (lung cancer)
Liver → hepatomegaly
clinical manifestations of bone metastasis (lung cancer)
Bone → fractures, pain
clinical manifestations of adrenal gland metastasis (lung cancer)
“Cancer that has spread to the adrenal glands doesn’t usually cause any symptoms.”
“The adrenal glands produce hormones and if cancer has spread to both adrenal glands you might have low levels of adrenal hormones. This might cause: loss of appetite.”
clinical manifestations of brain metastasis (lung cancer)
neurologic symptoms and high mortality
lung cancer – Dx
Diagnosis includes chest x-ray and biopsy (best)
—> CT positives are 95% false positive
___
“One potential risk of low-dose CT is that it results in many false-positive findings, such as a lung nodule, that, upon further testing, turns out not to be cancer.”
lung cancer – Tx
surgery (resection), chemotherapy, radiation
lung cancer prognosis
Prognosis is very poor
(esp later dx, which is the most common dx d/t few clinical manifestations in early stage)
most important thing for lung cancer is ____
prevention
not smoking
