Respiratory Flashcards
What is tuberculosis?
an infectious disease caused by the mycobacterium tuberculosis bacteria
What is the most common cause of TB?
mycobacterium tuberculosis is the most common causative organism and is an aerobic acid-fast bacilli which is turned bright red against a blue background using the Ziehl-Neelson stain
What are some other mycobacteria which cause TB?
M. africans
M. microtis
M.bovis
What are the risk factors for TB?
Immunocompromised (e.g. HIV or immunosuppressive meds)
Close contacts with TB
Recent travel or immigration from areas of high TB prevalence
People with relatives or close contacts from countries with a high rate of TB
Homeless people, drug users, alcoholics
IVDU
Older age
What is active TB?
active infection in various areas within the body
What is latent TB?
where the immune system encapsulates sites of infection and stops the progression of disease
What is miliary TB>
severe, disseminated disease when the immune system is unable to control the spread/progression
What is extrapulmonary TB?
When infection spreads outside of the lungs (most common site of infection) to lymph nodes, pleura, CNS, pericardium, GI system, GU system, bones + joints, skin (cutaneous TB)
What is the immune response to TB?
- TB phagocytosed but resist killing –> formation of granulomas
- T cells are recruited and central region of granuloma undergoes caseating necrosis (primary Ghon focus, in upper parts of the lung)
- Ghon focus spreads to nearby lymph nodes –> Ghon complex (focus + lymph node spread)
- in most cases, infection is contained within granulomas –> latent TB
- If TB spreads systemically –> miliary TB
What are the key presentation sof TB?
chronic, gradual onset of symptoms
lethargy
fever or night sweats
weight loss
cough +/- haemoptysis
lymphadenopathy
erythema nodosum
spinal pain in spinal TB (Pott’s disease of spine)
What are the investigations for TB?
1st line: Purified Protein Derivative (PPD) - intradermal skin test which looks for previous immune response to TB
GS: Interferon Gamma Release Assay
Other: CXR , cultures
What are the CXR signs of primary TB?
patchy consolidation, pleural effusions and hilar lymphadenopathy
What are the CXR signs of reactivated TB?
patchy or nodular consolidation with cavitation typically in the upper zones, disseminates
What are the CXR signs of miliary TB?
‘millet seeds’ distributed uniformly throughout the lung fields
What are the 4 drugs used to treat acute pulmonary TB?
R - rimfampicin (6mo)
I - isoniazid (6mo)
P - pyrazinamide(2mo)
E- ethambutol (2mo)
What is TLCO?
Total lung diffusion capacity for carbon monoxide - shows how much carbon monoxide is taken into body during inhalation/exhalation
What is the BCG vaccination?
intradermal infection of live attenuated Tb which offers protection against severe and complicated TB but is less effective at protecting against pulmonary TB (for patients at higher risk of contact with TB)
What is pneumonia?
infection of the lung tissue which causes inflammation of the lung tissue and sputum filing the airways and alveoli
What are the causes of pneumonia?
streptococcus pneumoniae (50%)
haemophilus influenzae (20%)
moraxella catarrhalis (in immunocompromised patients/pts with chronic disease)
pseudomonas aeruginosa (pts with CF or bronchiectasis)
staphylococcus aureus (pts with CF)
What are the risk factors for pneumonia?
Bronchiectasis
Asthma
Cystic fibrosis
COPD
Malnutrition
Diabetes
Heart failure
Sickle cell disease
Liver or kidney disease
Hospitalisation
Older age
What is pleuritic chest pain?
pain on deep inspiration (feels like sandpaper on lungs during breathing)
What is the definition of hospital acquired pneumonia?
pneumonia which develops more than 48hrs after hospital admission
What are the key presentations of pneumonia?
Shortness Of breath
Cough productive of sputum
Fever
Haemoptysis (coughing up blood)
Pleuritic chest pain (sharp chest pain worse on inspiration)
Delirium (acute confusion associated with infection)
Sepsis
What are the signs of pneumonia?
Tachypnoea
Tachycardia
Hypoxia
Hypotension
Fever
Confusion
What are the characteristic chest signs of pneumonia?
Bronchial breath sounds = harsh breath sounds equally loud on expiration and inspiration caused by consolidation of the lung tissue around the airway
Focal coarse crackles = air passing through sputum in the airways
Dullness to percussion due to lung tissue collapse and/or consolidation
What are the investigations for pneumonia?
CURB 65, CXR, FBC, U+Es, CRP
Sputum cultures, blood cultures, legionella and pneumococcal urinary antigens
What are the implications of CURB 65 scores 0-5?
0-1 = mild, only admit if social circumstances or single worrying feature
2 = moderate, admit to hospital
3-5 = severe, admit and monitor closely
4-5 = consider admission to critical care unit
What are the mortality percentages for CURB 65 scores?
0=0.7%
1=2.1%
3=9.2%
4-5=15-40%
What is the management for pneumonia?
Mild CAP = 5 day course of oral antibiotics (amoxicillin or macrolide)
Moderate - severe CAP = 7-10 day course of dual antibiotics (amoxicillin and macrolide)
What are the potential complications of pneumonia?
sepsis, pleural effusion, empyema, lung abscess, bronchiectasis, death
What is CURB-65?
An algorithm for assessment of pneumonia severity
C - confusion (new disorientation in person, place or time)
U - urea >7
R - respiratory rate ≥ 30
B - blood pressure <90 systolic or ≤ 60 diastolic
65 - age ≥ 65
What is cystic fibrosis?
autosomal recessive genetic condition affecting mucus glands which has multi-systemic effects
What is the prevalence of CF in children?
1 in 2500
What is the aetiology of CF?
Caused by a mutation of the CF transmembrane conductance regulatory gene on chromosome 7 (CFTR)
There are many variants of this mutation, the most common being delta-F508 mutation which codes for cellular channels, particularly a type of chloride channel
What are the risk factors for CF?
FHx
Caucasians
What are is the pathophysiology of CF?
Thick pancreatic and biliary secretion which cause blockage of the ducts, resulting in a lack of digestive enzymes such as pancreatic lipase in the digestive tract
Low volume thick airway secretions that reduce airway clearance, resulting in bacterial colonisation and susceptibility to airway infections
Congenital bilateral absence of the vas deferens in males
What are the key presentations of CF?
Meconium ileus (seen in 20% of babies with CF)
Recurrent lower respiratory tract infections
Failure to thrive (poor weight and height gain)
Pancreatitis
Chronic cough
Thick sputum production
Recurrent respiratory tract infections
Loose, greasy stools (steatorrhoea) due to a lack of fat digesting lipase enzymes
Abdo pain and bloating
What are the signs of CF?
Very salty sweat
Nasal polyps
Finger clubbing
Crackles and wheezes on auscultation
Abdominal distension
What are the investigations for CF?
Newborn blood spot testing
GS: Sweat test (pilocarpine patch and electrodes used to test chloride concentration) - >60mmol/L = CF
Genetic testing CFTR gene can be performed during pregnancy by amniocentesis or chorionic villous sampling
What is the management for CF?
Chest physiotherapy (multiple times daily)
Exercise → improved resp function + reserve, helps clear sputum
High caloric diet
CREON tablets to digest fats in patients with pancreatic insufficiency
Prophylactic flucloxacillin
Treat chest infections
Bronchodilators (salbutamol inhalers)
Nebulised DNase (enzyme which breaks down DNA material in secretions → easier to clear)
Nebulised hypertonic saline
Vaccinations for pneumcoccal, influenza, varicella
Lung transplant in ESRespF
Liver transplant in liver failure
Fertility treatment involving testicular sperm extraction for infertile males
What are some common infections in CF patients?
S. aureus
H. influenzae
P. aeruginosa
What are the complications of CF?
90% CF patients develop pancreatic insufficiency
50% develop diabetes
30% develop liver disease
Most males are infertile due to absent vas deferens
What is bronchiectasis
permanent dilation of bronchioles (+ excessive mucus in them)
What are the causes of bronchiectasis?
Recurrent pulmonary infection leads to progressive bronchial damage
Post infectious (18% of adult patients)
COPD (15% of adult patients)
Asthma (7%)
Connective tissue disorders (9%)
Allergic bronchopulmonary aspergillosis (5%)
Immunodeficiency (5%)
Aspiration or inhalation injury (4%)
Genetic
IBD
Focal bronchial obstruction
Idiopathic (29%)
Other (e.g. Marfan, Ehlers-Danlos…)
What are the risk factors for bronchiectasis?
Post infection (e.g. TB, pneumonia)
CF
HIV
ABPA (allergic bronchopulmonary aspergillosis - fungal infection of lung)
Congenital airway disorders
What is the pathophysiology of bronchiectasis ?
Irreversible dilation, loss of cilia + mucus hypersecretion ↑risk of infection (as ↓mucociliary clearance)
What are the key presentations of bronchiectasis?
Productive cough with lots of sputum + dyspnoea
Fever
Fatigue
Haemoptysis
Wheezing
What are the signs of bronchiectasis on auscultation?
Crackles, high pitched inspiratory squeaks and rhonchi (low pitched wheezes)
What is the management for bronchiectasis?
Non-curative
conservative : chest physio (+stop smoking)
Drug: bronchodilators
Consider abx if infection
What is pleural effusion?
Collection of fluid in the pleural cavity which can be exudative (high protein count >35g/L)
Or transudative (lower protein count <35g/L)
What are the exudative causes of pleural effusion?
Exudative causes are related to inflammation which leads to protein leakage out of tissue into the pleural space:
Lung cancer
Pneumonia
Rheumatoid arthritis
Tuberculosis
WHat are the transudative causes of pleural effusion?
Transudative causes relate to fluid moving across into the pleural space:
Congestive cardiac failure
Hypoalbuminemia
Hypothyroidism
Meigs syndrome
What are the key presentations of pleural effusion
SOB
Dullness to percussion over the effusion
Reduced breath sounds
Tracheal deviation away from the effusion if it’s massive
What are the signs of pleural effusion?
Reduced chest wall expansion
Quiet breath sounds
Stony dull percussion
Reduced tactile/vocal fremitus
Mediastinal shift away from affected side
WHat are the investigations for pleural effusion?
CXR (blunting of costophrenic angle, fluid in the lung fissures, larger effusions have a meniscus, tracheal and mediastinal deviation)
Thoracocentesis (sample of pleural fluid, pH, lactate, WCC, microscopy, transudate or exudate)
What are the signs seen on CXR in pleural effusion?
Blunting of costophrenic angle
Fluid in the lung fissures
Larger effusions have a meniscus
Tracheal and mediastinal deviation
What is Light’s criteria?
measurements of a number of factors including protein used to show whether pleural effusion is transudative or exudative)
What are the different appearances of fluid aspirate taken from lungs in pleural effusion and what do they indicate?
Straw coloured/clear - transudate/exudate
turbid /foul smelling - empyema/parapneumonic effusion
Milky - chylothorax
Blood stained - trauma/cancer/PE
Food particles - esophageal rupture
What is the management for pleural effusion?
Conservative ; small effusions will resolve with treatment of the underlying cause
Pleural aspiration (needle into lungs to remove fluid)
Chest drain (drain the effusion, prevents recurrence)
What is empyema?
infected pleural effusion
- suspected when the patient has improving pneumonia but new or ongoing fever
- plueral effusion shows pus, acidic pH, low glucose and high LDL
What is the treatment for empyema?
chest drain to remove pus
6 weeks antibiotics
What is the treatment for malignant effusions?
depends on symptoms, treatment for underlying cancer and prognosis
drain + pleurodesis –> chest drain (talc via drain), thoracoscopy (spray talc)
if recurrent and problematic –> indwelling pleural catheter
WHat is haemothorax?
blood in pleural cavity
What are the causes of haemothorax?
trauma, post-operative, bleeding disorders, lung cancer, PE, aortic rupture, thoracic endometriosis
What is the management for haemothorax?
large bore chest drain, possible vascular intervention, surgical opinion
What is hydropneumothorax?
air and fluid in pleural space
WHat are the causes of hydropneumothorax?
iatrogenic, gas forming organisms, thoracic trauma
What is pneumomediastinum?
where air from the lungs/trachea/oesophagus escapes into neck/face and abdomen
What causes pneumomediastinum?
surgical emphysema/pneumothorax
oesophageal rupture (Boerhaave’s syndrome)
What are the causes of pleural thickening?
related to asbestos exposure
following infection/empyema/chest trauma/haemothorax
cancer (consider if nodular /1 cm depth)
What is pneumothorax?
excess air accumulation in the pleural space, causing ipsilateral collapse
What is the aetiology of pneumothorax?
Can be primary (spontaneous (rupture of apical pleural bleb), no underlying cause) or secondary (to trauma or pathology)
Secondary pathological causes:
Known lung disease
-60% COPD
-Asthma/ILD/CF/Lung cancer
-Cystic lung disease
Infection
-PCP/TB
-lung abscess
Genetic predisposition
-Marfan’s syndrome, Birt-Hogg Dube
-LAM - Lymphangioleiomyomatosis
Catamenial Pneumothorax
Traumatic causes:
Penetrating chest wall injury
Puncture from rib
Rupture bronchus/oesophagus
What are the risk factors for primary spontaneous pneumothorax?
male, smokers, tall, age 20-40yrs, previous occurrence
What is the pathophysiology of pneumothorax?
Pleural space is normally a vacuum (no air)
Breach in pleura (trauma/CT disorders) e.g. subpleural bullae burst –> fistula between pleural space + airways → air in the pleural space
THis causes intrapleural pressure to be negative which leads to air being sucked into cavity leading to partial or total lung collapse
What are the key presentations in pneumothorax?
SOB
One sided sharp pleuritic chest pain
Decreased breath sounds
Hyperresonant percussion ipsilaterally (increased air)
Can be asymptomatic
What are the signs of pneumothorax?
Often no clinical signs except in severe cases
Tachypnoea
Hypoxia
Unilateral chest wall expansion
Reduced breath sounds
Hyper-resonant percussion note
Red flags (tension pneumothorax)
Deviated trachea
Surgical emphysema
Distended neck veins
Cardiovascular compromise
WHat are is the management for pneumothorax?
Small = self-resolving
Larger - needle decompression (remove air with syringe), chest drain
Surgical (if recurrent) - pleurodesis (insertion of a mildly irritant drug into pleural space to close space and prevent further collection of air or fluid)
What is tension pneumothorax?
air can flow into pleural space but can’t leave –> intrapleural pressure increases with every breath (can even press on heart –> cardiac disorder symptoms)
What are the signs of a tension pneumothorax?
tracheal deviation away from side of pneumothorax, reduced air entry to affected side increased resonance to percussion on affected side, tachycardia, hypotension
What is the treatment for tension pneumothorax?
insert large bore cannula into 2nd intercostal space at the midclavicular line, needle decompress and then chest drain
What forms the triangle of safety for chest drains?
The 5th intercostal space (inferior nipple line)
Mid-axillary line (or the lateral edge of the latissimus dorsi)
Anterior axillary line (lateral edge of the pectoralis major)
What is pulmonary hypertension?
Resting mPAP >25mmHg measure with right heart catheterisation
*often results in RHS heart failure; cor pulmonale