Respiratory System Flashcards
1
Q
What is inspiratory reserve volume?
A
The extra volume that can be breathed in at rest
2
Q
What is expiratory reserve volume?
A
The extra volume that can be breathed out at rest.
3
Q
Describe Boyle’s law
A
Pressure is inversely proportional to volume
4
Q
Describe Charles’ law
A
Pressure is proportional to temperature
5
Q
What is the significance of vapour pressure?
A
It is when water enters the gas phase. It affects the partial pressure of other substances
6
Q
What are the three bony projections on the lateral wall of the nasal cavity?
A
Superior concha Middle concha Inferior concha
7
Q
What is the function of the conchi in the nasal cavity?
A
Increase surface area
8
Q
What type of epithelia lines the nasal cavity
A
Pseudostratified columnar ciliated epithelium (Except olfactory mucosa)
9
Q
What forms the floor of the nasal cavity?
A
Soft and hard pallet
10
Q
What is the main role of the nose?
A
Filter, humidify and warm the air
11
Q
Where do serous secretions into the nasal cavity come from?
A
Nasoacrimal duct Sinuses
12
Q
What are the four paranasal sinuses?
A
Frontal Ethmoid Maxillary Sphenoid
13
Q
What are the three parts of the pharynx and where do they extend from/to?
A
Nasopharynx - nose to above lower border of soft pallet Oropharynx - border of soft pallet to the epiglottis Laryngopharynx - below tip of epiglottis
14
Q
What is the function of the vocal cords?
A
Valve to the trachea. Close to protect it when swallowing Build pressure for the cough reflex Speech
15
Q
What is the glottis?
A
The two vocal cords with an opening in the middle (rima glottis)
16
Q
What nerve supplies the intrinsic laryngeal muscles?
A
Recurrent laryngeal nerve?
17
Q
Why can the recurrent laryngeal nerve be affected by lung cancer, causing the voice to become hoarse?
A
It arises from the vagus nerve in the neck, curves around the subclavian artery/aortic arch then back up through the thorax to the vocal cords.
18
Q
What type of epithelia is found in the pharynx, larynx and trachea?
A
Pseudostratified epithelium with cilia and goblet cells
19
Q
What type of epithelia is found in bronchioles and terminal bronchioles?
A
Simple columnar with cilia and Clara cells
20
Q
What type of epithelia lines respiratory bronchioles and alveolar ducts?
A
Simple cuboidal with clara cells and sparse cilia
21
Q
What type of epithelia lines alveoli?
A
Simple squamous with type I/II pneumocytes
22
Q
What type of epithelium is found in the olfactory regions of the nasal cavity?
A
Thick pseudostratified epithelium (no goblet cells) with microvilli, and olfactory bipolar neurons whose axons form non-motile cilia. Serous Bowman’s glands to flush the surface clear regularly.
23
Q
What is the function of a Clara cell?
A
Secretes surfactant lipoprotein to stop the walls sticking together
24
Q
What is the clinical relevance of CC16, produced by Clara cells?
A
Protein marker in bronchoalveolar lavage fluid. If low, indicates lung damage. If raised in serum, indicates leakage across the air-blood barrier.
25
What are alveolar sacs?
Composite air spaces which many alveoli open into.
26
Why do patients with emphysema often breathe through pursed lips?
They need to maintain back pressure to open the bronchioles as they are no longer supported by the alveolar walls which have broken down.
27
Give one common causative pathogen in pneumonia.
Streptococcus pneumoniae Haemophilus influenzae Staphylococcus aureus Legionella pneumophilia Mycoplasma pneumoniae
28
What is tidal volume?
The volume of air moving in and out with each breath during quiet respiration
29
What are the three parts of the sternum, from superior to inferior?
Manubrium Body Xiphoid process
30
What part of the sternum is used to find the second rib?
Sternal angle (angle of Louis)
31
What ribs are true ribs?
1-7
32
What ribs are floating?
11-12
33
Describe a 'typical' rib, and what numbers are they?
3-9 Head with two articular facets to articulate with the thoracic vertebra Neck with a tubercle to articulate with the transverse process of the inferior vertebra Costal groove running around to the costal cartilage.
34
What is the difference between rib I and typical ribs?
Rib I is shorter and more curved, with one articular facet for T1. It is flat. Has a scalene tubercle separating the anterior groove for the subclavian vein and the posterior groove for the subclavian artery
35
What is the difference between rib 2 and typical ribs?
Flat Poor costal groove Twice as long as rib 1
36
What differentiates ribs 11 and 12 from typical ribs?
A single facet on their head No tubercle Short with little curve Tapering anterior end with floating cartilage
37
What are the two costovertebral joints?
Head of the rib with the body of the vertebrae Costotransverse joint (tubercle of rib with transverse process)
38
From superficial to deep, what muscles are in the intercostal space?
External intercostal Internal intercostal Innermost intercostal
39
What direction do the external intercostal fibres run in?
Downwards and anteriorly
40
What direction do the internal intercostal muscle fibres run in?
Downwards and posteriorly
41
Where does the external intercostal muscle extend from and to?
From tubercles of the ribs to the costal cartilage, then continues as the external intercostal membrane
42
What is the function of the external intercostal muscle?
Elevation of the ribs for inspiration
43
Where do the internal intercostal muscles run from and to?
From parasternal region to the angle of the ribs posteriorly, where they extend to the vertebral column as the internal intercostal membrane.
44
What is the function of the internal intercostal muscles?
Pull down the ribs for forced expiration.
45
Where does the neurovascular bundle of the intercostal space run in relation to the ribs?
In the costal groove between the internal and innermost intercostal muscles.
46
Why would pain be referred to a specific section of skin if some of the parietal pleura was inflamed?
The intercostal nerves each supply a strip of the parietal pleura, skin and corresponding intercostal muscle.
47
What arteries run either side of the stenum?
Internal thoracic arteries
48
What arteries branch from the internal thoracic arteries to the intercostal spaces?
Anterior intercostal arteries
49
What artery do the anterior intercostal arteries branch from in the superior two intercostal spaces?
Superior thoracic artery
50
What artery gives rise to the posterior intercostal arteries?
Thoracic aorta
51
What is shingles?
Reactivation of the varicella zoster virus which lays dormant in the dorsal root ganglia. Reactivation causes a rash with dermatomal distribution.
52
Where do the azygous veins run and what vein do they contribute to?
Down the posterior thoracic cavity Contributes to the superior vena cava
53
What veins do the posterior and anterior intercostal veins contribute to?
External and internal thoracic veins
54
What do the external and internal thoracic veins drain into?
Azygous and hemiazygous veins, respectively
55
What are the attachments of the diaphragm?
Lower 6 ribs Arcuate ligaments (fascia over posterior abdominal muscles)
56
What are the crus of the diaphragm?
Fibrous attachment from the vertebra to the central tendon of the diaphragm.
57
What are the vertebral levels of each opening in the diaphragm and what passes through?
T8 - vena cava T10 - oesophagus T12 - aorta
58
What are the surface markings of the right and left domes of the diaphragm on expiration?
Right - fifth rib, mid-clavicular line Left - fifth intercostal space, mid-clavicular line
59
Why would there be dull percussion in the right fifth intercostal space?
The liver is in the way.
60
What nerve gives motor supply to the diaphragm?
Phrenic nerve (C3,4,5)
61
What does the phrenic nerves give sensory supply to?
Pericardium Adjacent pleura Both sides of the diaphragm
62
What muscles allow quiet breathing?
External intercostals Diaphragm descent
63
What are the accessory muscles used for forced inspiration?
Scalene Sternocleidomastoid Pectoralis major Serratus anterior
64
What allows quiet expiration to be passive?
Elastic recoil of the lungs and chest wall
65
What muscles are involved in forced expiration?
Internal intercostal Innermost intercostal Rectus abdominis External oblique Internal oblique Transverse abdominis
66
What does the parietal pleura line?
Pulmonary cavities, wall, mediastinum and diaphragm
67
What does the visceral pleura line?
Lungs, including fissures
68
What is the function of the pleural seal?
When the parietal pleura is pulled outwards with thorax expansion, the visceral pleura is also pulled, which expands the lungs with it.
69
What is the extra space in the thoracic cavity called, which isn't filled by the lungs?
Costodiaphragmatic recess
70
What vertebral level does the trachea divide into the right and left bronchi?
T4/5
71
What structure at the base of the trachea divides the right and left bronchi?
Carina
72
What muscle forms a ring with the c-shaped cartilage of the trachea
Posterior trachealis muscle
73
Which bronchus is most likely to be the location of an aspirated foreign body and why?
Right It is shorter, wider and more in line with the trachea
74
What fissures are present in the right and left lungs?
Right - horizontal and oblique Left - oblique
75
What is the projection called on the lower part of the superior lobe of the left lung?
Lingula
76
Why might a tumour of the lung involve structures in the neck?
The apex of the lung extends into the root of the neck Brachial plexus (especially median branch), sympathetic trunk, subclavian vessels
77
What does the hilum of the lung contain?
Pulmonary vessels Main bronchus Nerves Lymphatics (drain to hilar lymph nodes)
78
Which nerve passes around the arch of the aorta?
Recurrent laryngeal nerve
79
Which nerve runs alongside the trachea?
Vagus nerve
80
Which nerve runs along the pericardium to the diaphragm?
Phrenic nerve
81
What structures are in the middle mediastinum?
Pericardium Heart Origins of the great vessels Nerves Smaller vessels
82
What is the vertebral levels of the superior mediastinum?
T1-4
83
What is in the superior mediastinum?
Thymus Right and left brachiocephalic veins Left superior intercostal vein Superior vena cava Aortic arch Trachea Oesophagus Phrenic nerves Vagus nerves Left recurrent laryngeal nerve Thoracic duct
84
What is in the posterior mediastinum?
Oesophagus and associated nerve plexus Thoracic aorta Azygous veins Thoracic duct and associated lymph nodes Sympathetic trunks Thoracic splanchnic nerves
85
What is in the anterior mediastinum?
Thymus Fat Connective tissue Lymph nodes Mediastinal branches of internal thoracic vessels Sternopericardial ligaments
86
What is the difference between 'dry' air and tracheal air?
Tracheal air is at 37 degrees and is fully saturated.
87
What factors affect the diffusion rate of a gas into a fluid?
Solubility Cross sectional area Distance Pressure Molecular weight Temperature in the environment/fluid
88
Why does carbon dioxide diffuse faster than oxygen when it is a larger molecule?
It is more soluble
89
Is oxygen or carbon dioxide diffusion more impaired when the diffusion distance is increased?
Oxygen
90
What is affected in fibrotic lung disease to change diffusion rates, and how is pO2 and pCO2 changed in plasma?
Barrier thickened pO2 decreased, pCO2 same.
91
How does pulmonary oedema affect gas diffusion in the lungs, and how does pO2 and pCO2 in plasma change?
Increases diffusion distance pO2 low, pCO2 normal
92
Why is it important that oxygen levels in the plasma reach equilibrium with the lungs with 2/3 redundancy?
In exercise, when blood is flowing faster, the rate of exchange isn't limiting
93
What is the alveoli ventilation rate?
The amount of air per minute reaching the alveoli (L/min)
94
If the ventilation:perfusion ratio is low, what is the general issue?
Something is preventing oxygen entering the alveoli, such as a mucus plug.
95
What is the general issue if the ventilation:perfusion ratio is high?
Perfusion occlusion, such as a pulmonary embolus.
96
What is the difference between serial and distributive dead space in the lungs?
Serial - volume in the conducting airways Distributive - parts which don't support exchange (such as dead or damaged alveoli)
97
What is vital capacity?
Maximum inspiration to maximum expiration
98
What properties of the lungs affects vital capacity?
Compliance Force of muscles Airway resistance
99
What is inspiratory capacity?
Largest breath in from the resting expiratory volume
100
What is tidal volume?
The volume of air breathed out after the deepest inhalation
101
What is functional residual capacity?
The volume of air present in the lungs at the end of passive expiration
102
What is inspiratory reserve volume?
The additional air which can be forcibly inhaled after the inspiration of normal tidal volume
103
What is expiratory reserve volume?
The additional air that can be forcibly inhaled after the inspiration of normal tidal volume
104
What is FEV1 in spirometry?
The volume expired in the first second, influenced by how quickly air flow is slowed.
105
In obstructive lung disease, what affect is there on FEV1 and FVC? Explain why.
FEV1 lowered FVC normal (
106
In restrictive lung disease, how are FEV1 and FVC affected? Explain why.
FVC reduced FEV1 normal (\>70%) The lungs are difficult to fill, so the lungs begin less full. No problems exhaling.
107
What type of lung disease is peak expiratory flow rate used to screen for?
Restrictive E.g. Asthma
108
Describe the test used to assess residual volume.
Helium dilution Breathe in a known volume with a known concentration of helium. The concentration will reduce as it enters a larger volume, adding to the air already in the lungs. Watch the concentration change over a few breaths.
109
Describe the test used to assess serial dead space.
Nitrogen washout Take one normal breath of pure oxygen, then assess nitrogen content at regular intervals. Initially it will only be oxygen expired.
110
Give an example of a condition which increases serial dead space.
Pulmonary embolism Pulmonary oedema Pneumonia with consolidation Pulmonary contusion
111
Describe the test used to assess diffusion conductance.
Carbon monoxide transfer factor Inhale gas with CO to total lung capacity. Hold breath for 10 seconds. Check the CO in the blood to assess rate of diffusion. Can't be used if they're a smoker
112
What shape is a myoglobin dissociation curve?
Hyperbole
113
Why would myoglobin be useless for oxygen transport in the blood?
It is fully saturated at the pO2 in tissues
114
What is the function of myoglobin?
Store oxygen in muscles to be used as a reserve when pO2 drops very low.
115
What is the shape of the haemoglobin O2 binding curve?
Sigmoid
116
What does the pO2 in tissues depend on?
How metabolically active the tissue is
117
Why should tissue pO2 ideally not drop below 3kPa?
To create a large enough gradient to drive oxygen into the cells.
118
Describe the Bohr shift and its relevance in metabolically active tissues.
When pH decreases, it shifts the dissociation curve to the right. pH is lowest in the most metabolically active tissues, due to the production of substances such as lactic acid, sulphuric acid, and carbon dioxide. This allows more oxygen to be taken up by tissues
119
If the temperature in the tissues increases, how does the oxygen dissociation curve shift?
To the right to increase oxygen release
120
What are the bony landmarks of the pleura?
8th rib, mid-clavicular line 10th rib, anterior axillary line 12th rib, posterior scapular line
121
What are the bony landmarks of the lung?
6th rib, mid clavicular line 8th rib, anterior axillary line 10th rib, posterior scapular line
122
What are the bony landmarks of the right oblique fissure of the lung?
Spinous process of T2 to 6th costal cartilage
123
What are the bony landmarks of the right horizontal fissure?
Along the 4th rib from the mid axillary line
124
What are the bony landmarks of the left oblique fissure?
Spinous process of T2 to the 6th costal cartilage
125
Where in the intercostal space would you insert a needle to do a pleural aspiration?
In the inferior portion of the intercostal space to prevent damage to the vessels and nerves which run just below each rib.
126
What type of nerve fibre does the vagus nerve have?
Parasympathetic
127
What structures do the bronchial arteries supply?
From the bronchi to respiratory bronchioles Visceral pleura Structures at the lung roots
128
What could cause damage to the recurrent laryngeal nerve?
Aortic aneurysm Enlarged hilar lymph nodes Lung carcinoma
129
What is the main symptom of damage to the recurrent laryngeal nerve?
Hoarse voice
130
What conditions cause the oxygen dissociation curve for haemoglobin to shift to the right?
Reduced pH Increased temperature High 2,3 BPG
131
What is the significance of only 27% of oxygen being given up at rest to tissues?
Mixed venous blood has a high reserve. When you exercise to the extreme, cardiac output doesn't have to rise as much to deliver enough oxygen to the tissues.
132
How does carbon monoxide affect the oxygen binding curve for haemoglobin?
It loses the sigmoidal shape
133
What is cyanosis?
Blue colouration of skin or mucosal surfaces due to unsaturated haemoglobin near the surface.
134
What is the difference between peripheral and central cyanosis?
Peripheral - poor local circulation, seen in the digits Central - poor systemic saturation of haemoglobin (e.g. CVS shunt), seen in the mouth, tongue and mucus membranes
135
What are two ways of checking oxygen saturation?
Pulse oximetry Arterial blood-gas analysis
136
What can you look at in arterial blood-gas analysis?
pO2 O2 saturation Electrolyte or acid-base disturbances
137
How does an increased respiratory rate affect pH?
Increased pH (low CO2)
138
What is the Henderson-Hasselbach equation?
pH = pK + log10([HCO3-]/pCO2x0.23
139
What is the normal ratio of bicarbonate to dissolved CO2?
20:1
140
What cell is the main producer of bicarbonate?
Red blood cells
141
What enzyme increases the rate of production of bicarbonate from dissolved carbon dioxide?
Carbonic anhydrase
142
What organ is the main control of bicarbonate levels?
Kidneys
143
Why can more carbon dioxide dissolve in venous blood than arterial blood?
There is slightly greater pO2 More H+ reacts with haemoglobin as there is less oxygen, so more CO2 can be dissociated.
144
What is the carbonic acid-bicarbonate buffering system?
The more CO2 dissolved into the blood, the more HCO3- is produced and reabsorbed by the kidney. The ratio of 1:20 is what maintains the pH, rather than actual amounts.
145
How can the kidneys compensate for respiratory acidosis?
Increasing reabsorption of bicarbonate
146
Why can altering respiration only partially compensate for metabolic alkalosis?
Respiration must decrease to release more carbon dioxide, but too much will cause hypoxia.
147
Interpret the following: Low pH High pCO2 Normal HCO3-
Respiratory acidosis
148
Interpret the following: Low pH Low pCO2 Low HCO3-
Metabolic acidosis (partially compensated)
149
Interpret the following: High pH Low pCO2 Normal HCO3-
Respiratory alkalosis
150
Interpret the following: High pH Normal pCO2 High HCO3-
Metabolic alkalosis
151
What receptors have control over breathing?
Central chemoceptors Peripheral chemoceptors Pulmonary receptors (stretch) Joint and muscle receptors
152
Where are peripheral chemoreceptors found?
Aortic and carotid bodies
153
What do peripheral chemoreceptors detect changes in?
pO2
154
What change in conditions makes peripheral chemoceptors more sensitive?
Decreased flow rate
155
What effect do peripheral chemoceptors have when they detect a change in pO2?
Stimulate the ANS to redistribute blood flow
156
What do central chemoceptors detect changes in?
pCO2
157
Where are central chemoceptors found?
Medulla
158
What stimulates the central chemoceptors?
Acidification of the cerebrospinal fluid and ECF
159
What produces cerebrospinal fluid?
Choroid plexus
160
What separates cerebrospinal fluid from plasma?
Blood-brain barrier
161
How do central chemoceptors detect changes in plasma carbon dioxide levels?
Carbon dioxide diffuses across the blood brain barrier and carbonic anhydrase in the CSF produces hydrogen ions. As bicarbonate cannot diffuse but is produced by the choroid plexus, the increased proton levels can't be buffered, so the chemoceptors detect the change.
162
What changes in the brain to adjust to persistent hypoxia?
Ventilation increases to correct for the hypoxia, but this causes pCO2 to fall. The choroid plexus must reduce the production of bicarbonate to prevent activation of the central chemoceptors
163
What is hypoxia?
Oxygen deficiency at a tissue level
164
What is hypoxaemic hypoxia?
Low oxygen in the blood, usually due to poor oxygen exchange on the lungs. Low saturated oxygen and pO2
165
What is anaemic hypoxia?
Insufficient haemoglobin to carry oxygen. Eg. Anaemia or CO poisoning
166
What is circulatory hypoxia?
Poor perfusion, reducing oxygen delivery
167
What is cytotoxic hypoxia?
Oxygen delivery is adequate but tissues are unable to use it.
168
What is the difference between type I and type II respiratory failure?
Type i - not enough oxygen in the blood. Low pO2 and SaO2, normal or low CO2 Type ii - not enough carbon dioxide leaving or oxygen entering. Low pO2 and SaO2, high CO2
169
What type of respiratory failure is hypoventilation?
Type ii
170
Give some causes of type 2 respiratory failure.
Respiratory centre depression Muscle weakness Chest wall problems Stiff lungs High airway resistance
171
What type of respiratory failure can be caused by fibrosis thickening the alveolar walls?
Type 1
172
What is emphysema?
Elastin breakdown in the alveoli, reducing elastic recoil and allowing the alveoli to dilate. This increases compliance and allows hyperinflation.
173
What are the clinical features of hypoxia?
Exercise intolerance Tachypnea Confusion (cerebral hypoxia) Central cyanosis
174
How can chronic hypoxia cause cor pumonale?
Hypoxic vasoconstriction is widespread in the lungs, causing pulmonary hypertension. This increases the afterload on the right side of the heart, eventually leading to heart failure.
175
What are the symptoms of hypercapnia?
Warm hands Flapping tremors
176
In chronic type 2 respiratory failure, how can oxygen administration worsen hypercapnia?
It reverses the hypoxic vasoconstriction, opening the airways which aren't working
177
What are the physical features of a person suffering an acute asthma attack who is struggling to breathe?
Tracheal tug Subcostal recession Nasal flaring
178
What are the structural changes to the lungs in asthma and why do they occur?
Increased smooth muscle Structural changes are due to chronic inflammation (mast cells, cytokines, leukotrienes)
179
What is asthma?
A disease of the airway wall/lamina due to inflammation, which causes restructuring. Leads to increased airway response to stimuli, causing reversible airway obstruction.
180
Give some triggers of an acute asthma attack.
Muscarinic agonists Leukotrienes Histamine Arachadonic acid Cold air Prostaglandins
181
Describe the diagnosis of a asthma.
Low FEV1 Spirometry Peak flow Bronchial hyperresponsiveness History
182
Describe the history of someone with asthma.
Tight chest Cough worse at night Reversible/variable airway obstruction Wheeze Shortness of breath with exercise Breathless
183
Give two types of chronic obstructive pulmonary disease.
Chronic bronchitis Emphysema
184
What are the features of chronic bronchitis?
Inflammation of the large airways causing them to narrow. Excessive mucus production with a chronic productive cough Increased risk of infection.
185
Give 2 causes of COPD
Smoking Alpha-1 antitrypsin deficiency Occupational exposure
186
What are the symptoms of COPD?
Sputum production Breathlessness Cough
187
What are the signs of COPD?
Tachypnoea Pursed lip breathing Low FEV1% Limited airflow in spirometry Use of accessory muscles CO2 retention flap Cor pulmonale Wheeze
188
What are some long term impacts of inhaled steroid use?
Osteoporosis Diabetes Addison's crisis if stopped suddenly (adrenal glands stop production)
189
What is the management for COPD?
Pulmonary rehab Smoking cessation Bronchodilators (beta-2 agonist) Muscarinic antagonist Education about disease, nutrition, exercise Inhaled steroids Mucolytics Long term oxygen therapy Lung volume reduction (if eligible) Flu vaccine Lung transplant if under 60
190
What is the management for an acute exacerbation of COPD?
Oral steroids (IV if unable to swallow) Nebulised bronchodilators Titrated oxygen therapy Antibiotics (if purulent sputum, high CRP + WCC) BIPAP if all else failing
191
What are the defences we have against pneumonia?
Submucosa with lymphoid tissue Mucociliary escalator Cough Sneeze
192
Give two causative agents of pneumonia
Haemophilus influenzae Streptococcus pneumoniae Adenovirus Respiratory syncytial virus Chlamydia Coxiella Mycoplasma Legionella
193
What are the symptoms of pneumonia?
Cough Malaise Yellow sputum Fever Nausea and vomiting Shortness of breath Pleuritic chest pain if pleuritis
194
How can pneumonia be classified?
Clinical setting (hospital/community) Lung pathology (interstitial/broncho/lobular) Organism Acute/chronic Aspiration
195
What investigations would you order in suspected typical pneumonia?
Chest x-ray Urea and electrolytes Full blood count Arterial blood gas Sputum and/or blood culture
196
What extra investigations would you order for a patient with suspected atypical pneumonia?
Bronchial alveolar lavage fluid Nose/throat swab (looks for viral) Urine (for antigen) Serum antibodies
197
What are the potential outcomes in pneumonia?
Resolution (with scarring) Bronchiectasis Lung abcess, maybe with empyema
198
What antibiotic would you use to treat mild to moderate pneumonia?
Amoxicillin
199
What antibiotic would you use to treat moderate to severe pneumonia?
Co-amoxiclav
200
Give an example of an organism which commonly causes acute bronchitis?
Streptococcus pneumoniae Haemophilus influenzae Moraxella catarrhalis
201
How do you treat bronchitis?
Fluid and rest Bronchodilators Physiotherapy
202
What are the symptoms of bronchitis?
Cough Sputum Fever Shortness of breath
203
What organism causes the majority of human TB infections?
Mycobacterium tuberculosis
204
Describe Mycobacterium tuberculosis.
Non motile rod bacteria Obligate aerobe Lots of lipid and fatty acid in the cell wall to allow rigidity and prevent destruction. Stops digestion by macrophages. Acid fast staining Slow growing
205
How is tuberculosis transmitted?
Person to person in airborne droplets Prolonged contact required
206
Describe what happens after the tuberculosis bacterium is inhaled.
M. tuberculosis is engulfed by macrophages Drains to the local lymph nodes Primary complex formed (Ghon's focus and draining lymph node) Can then form primary tuberculosis (immune destruction of lungs) or is initially contained before healing or causing post-primary TB
207
Describe the differences between latent TB and TB disease.
Latent - inactive bacteria, CXR normal, sputum smear and culture negative, no symptoms, not infectious, not a case of TB. Disease - active bacteria, CXR abnormal, sputum smear and culture positive, symptomatic, infectious, a case of TB BOTH will have positive TST and IFNG
208
What does hilar shadowing in a CXR of someone with TB indicate?
Spread to the hilar lymph nodes
209
Who is at high risk of post-primary TB?
HIV Substance abuse Immunosuppressive therapy TNF-alpha antagonist (used in RA) Chronic kidney disease Diabetes mellitus Haematological malignancy
210
What are the characteristic cells of a caseating granuloma?
Langhans giant cells Epithelioid cells Lymphocytes
211
What are the symptoms of tuberculosis?
Low grade pyrexia Anorexia Cough Haemoptysis Breathlessness (if pleural effusion)
212
What investigations should you do for a patient with suspected tuberculosis?
Chest x-ray (cavitation within consolidation Sputum samples Bronchioscopy (if no sputum)
213
Where is a tuberculosis infection most likely to be seen and why?
Apex of the lungs Best aerated (they are obligate aerobes)
214
Describe the tuberculin sensitivity test.
Injected intradermally and measured 48-72 hours later. Measures cellular immune response to the TB antigen Will show a false positive if the person has the BCG vaccine or infection with a bacteria with similar proteins
215
Describe an interferon gamma assay when testing for tuberculosis exposure
Put a blood sample on an ELIZA plate with TB specific antigen. Amount of interferon gamma indicates the response. Has no cross reaction with BCG or other organisms.
216
What are the first line drugs for tuberculosis?
Rifampicin Isoniazid Pyrazinamide Ethambutamol
217
Why is combination treatment in tuberculosis so essential?
To stop establishment of drug resistance
218
What is miliary TB?
Tuberculosis with multiple organ involvement
219
Give some examples of extrapulmonary tuberculosis.
Lymphadenitis - scrofula, abcesses and sinuses Gastrointestinal Genitourinary - slow progresssion to renal disease, spread to lower urinary tract Bones and joints - haematogenous spread, most common in the spine, causes Pott's disease Tuberculosis meningitis - chronic headache and fever, CSF has raised protein and lymphocytes
220
Give some risk factors for lung cancer.
Smoking Asbestos Radium Occupational carcinogens Genetic or familial factors
221
Describe the TNM staging for lung cancer.
T - tumour size, location and number N - lymph node involvement M - metastasis
222
Where are some locations which lung cancer will typically spread to?
Other parts of the lung Pericardium Liver Adrenals Lymph nodes Brain Bone Pleura
223
What are the main imaging techniques used when lung cancer is suspected?
Chest x ray Staging chest CT scan PET scan
224
What are the symptoms of a primary tumour in the lungs?
Cough Dyspnoea Wheezing Haemoptysis Lung infection Chest or shoulder pain Weight loss Malaise Face swelling if SVC obstruction Hoarse voice if left recurrent laryngeal nerve palsy Dysphoea Dysphagia Chest pain Thirst or constipation (hypercalcaemia) Seizures (hyponatraemia)
225
What are some signs of lung cancer?
Cachexia Pale conjunctiva Cervical lymphadenopathy Horners syndrome Consolidation Signs of pleural effusion Muffled hear sounds Liver enlargement Skin metastases
226
What are the types of lung cancer?
Non small cell: Squamous cell carcinoma Adenocarcinoma Large cell carcinoma Small cell
227
Describe the grades of WHO performance status for lung cancer.
0 - fully active, carry out pre-disease activity 1 - restricted when strenuous, can do light work 2 - ambulatory can do self care, cant work or carry shopping 3 - confined to a bed or chair 4 - completely disabled 5 - dead
228
What are the options for treatment in lung cancer?
Surgery Radiotherapy (radical or palliative) Combination chemotherapy (neo-adjuvant, adjuvant) Biological therapy (targeting mutations) Palliative care with active symptom management
229
What is your role as a healthcare professional in supporting people to give up smoking? (3 A's)
Ask Advise Act (refer)
230
What three things should you be able to see in a chest x-ray to show that it encompasses enough area?
First rib Costophrenic angle Lateral margin of the rib
231
What do you look at in a chest x-ray to check for rotation?
Alignment of spinous processes Clavicles
232
How do you check for normal inspiration on a chest x-ray?
5-7 anterior ribs in the mid clavicular line
233
What would you see differently if someone didn't inspire enough for a chest x-ray?
Large heart Increased lung markings
234
What feature would you see on a chest x-ray of someone with overexpanded lungs?
Flattened diaphragm
235
How can you check for the right penetration in a chest x-ray?
Vertebrae just visible Complete left hemidiaphragm visible
236
What does a blunt costophrenic angle on a chest x ray show?
Pleural effusion
237
What is the ABC approach to assessing a chest x ray?
Patient demographics Projection adequacy Airway Breathing Circulation Diaphragm Bones Review
238
What is the importance of the silhouette sign in a chest x ray?
Adjacent structures of differing density have a crisp silhouette. If the contour is lost, it indicates pathology
239
What can cause a mediastinal shift?
Changed volume or pressure E.g. Tension pneumothorax, consolidation, collapsed lung
240
What changes to a chest x ray would you see in a pleural effusion?
Uniform white areas Loss of costophrenic angle Meniscus at the upper border May have mediastinal shift
241
What changes to an x ray would you see in lobar collapse?
Elevation of the ipsilateral hemidiaphragm Crowding of ipsilateral ribs Shift of mediastinum Crowded pulmonary vessels
242
What are the classic symptoms of interstitial lung disease?
Insidious onset Gradual decline in shortness of breath Terrible dry cough
243
What could you find on examination of someone with interstitial lung disease.
Clubbing Cyanosis Tachycardia Tachypnoea Reduced chest movement Course crackles Signs of cor pulmonale (raised jvp, pitting oedema, hepatomegaly)
244
Give some causes of interstitial lung disease
Idiopathic Sarcoidosis Hypersensitivity pneumonitis (granulomatous) Scleroderma Rheumatoid arthritis Systemic lupus erythematosis Radiation Methotrexate Amiodarone Nitrofurantoin Chemotherapy Asbestos Coal workers pneumoconiosis
245
What would you see on a biopsy in interstitial lung disease caused by sarcoidosis?
Non caseating granuloma
246
What is the difference in somatic innervation between the parietal and visceral pleura?
Parietal - phrenic and intercostal nerves Visceral - no somatic innervation
247
What can cause increased production of pleural fluid?
Increased hydrostatic pressure (heart failure) Increased interstitial fluid Increased permeability (septic shock) Decreased oncotic pressure (liver failure) Peritoneal fluid Thoracic duct disruption
248
What causes decreased production of pleural fluid?
Lymphatic blockage Increased systemic venous pressure
249
What problems or diseases would cause transudate in the pleural space?
Heart failure Cirrhosis Hypoalbuminaemia Atelectasis Nephrotic syndrome Constructive pericarditis Meigs syndrome
250
What problems or diseases would cause exudate in the pleural space?
Infection, e.g. TB Malignancy Rheumatoid arthritis Pulmonary embolism Asbestos related disease Pancreatitis
251
What is a chylothorax?
Lymphatic interruption causing milky fluid to enter the pleural space
252
What is the difference between a primary and secondary pneumothorax?
Primary - otherwise healthy. More common in smokers (particularly cannabis), generally tall and skinny Secondary - underlying lung disease. E.g. Cancer/ COPD
253
What are the signs of a tension pneumothorax and why is it a medical emergency?
Tachycardia Hypertensive Hyperresonant Shifted mediastinum Hypoxaemia The increased pressure stops filling of the heart
254
What are some congenital chest wall diseases?
Pectus deformities Scoliosis Kyphosis Muscular dystrophy
255
What are some acquired chest wall diseases?
Ventilation Sleep disordered breathing Poor clearance of secretions Pneumonia Atelectasis
256
What do you look for in an examination of a patient with suspected interstitial disease?
Clubbing Cyanosis Tachycardia Tachypnoea Reduced chest movement Course crackles Raised JVP, pitting oedema, hepatomegaly (cor pulmonale)
