Respiratory Flashcards
Describe cystic fibrosis in lay terms
An inherited condition that causes sticky mucus to build up in the lungs and digestive system. Causes lung infections and problems with digesting food
Inheritance of cystic fibrosis
autosomal recessive
Gene implicated cystic fibrosis
CFTR
Describe key pathogenesis of cystic fibrosis
High sodium sweat: primary secretion of sweat duct is normal but CFTR does not absorb chloride ions, which remain in the lumen and prevent sodium absorption (therefore sweat testing used in diagnosis)
Pancreatic insufficiency: relative dehydration of pancreatic secretions, causing their stagnation in the pancreatic ducts.
Biliary disease: defective ion transfer across the bile duct causes reduced movement of water in the lumen so that bile becomes concentrated, causing plugging and local damage.
Gastrointestinal disease: low-volume secretions of increased viscosity, changes in fluid movement across both the small and large intestine and dehydrated biliary and pancreatic secretions cause intraluminal water deficiency.
Respiratory disease: dehydration of the airway surfaces reduces mucociliary clearance
What does CFTR gene do
Codes a cAMP-regulated chloride channel
Which chromosome most commonly affected in cystic fibrosis
Delta F508 on long arm of chromosome 7
Carrier rate cystic fibrosis
1 in 25
Why should those with CF minimise contact with each other (what bug(s))
Brukholderia cepacia complex and psudeomonas aeruginosa
Whats first line in those with pseudomonas aeruginosa who have failed eradication with antibiotics?
Nebulised colistimethate sodium
Contraindication to lung transplant in cystic fibrosis
Chronic infection with brukholderia cepacia
Drug used for those homozygous for delta F508 mutation (CF) - explain mechanism
Lumacaftor/Ivacaftor (Orkambi)
Lumacaftor increases the number of CFTR proteins that are transported to the cell surface
Ivacaftor is a potentiator of CFTR that is already at the cell surface, increasing the probability that the defective channel will be open and allow chloride ions to pass through the channel pore
Management COPD acute exacerbation
Pred 30mg
Ipratropium bromide 500mcg 5mg NEB
Salbutamol 5mg NEB
Ipratropium MOA
Blocks muscarinic acetylcholine receptors - relaxes bronchial smooth muscle. Tiotropium long acting
Theophylline MOA
Non-specific inhibitor of phosphodiesterase resulting in an increase in cAMP
Montelukast MOA
Block leukotriene receptors
(apparently useful in aspirin induced asthma) –> antiinflammatory and bronchodilatory properties
Features of eosinophilic granulomatosis (small - medium vessel vasculitis)
Asthma
Blood eosinophilia (e.g. > 10%)
pANCA positive in 60%
Mononeuritis multiplex
Sinusitis
Vasculitis
Dyspnoea
Precipitant of eosinophilic granulomatosis
LTRA
Features of granulomatosis with polyangitis
Renal failure
Epistaxis/haemoptysis
cANCA
Saddle shaped nose deformity
Sinusitis (+nasal crusting)
Vasculitis
Dyspnoea
also: vasculitic rash, eye involvement (e.g. proptosis), cranial nerve lesions,
rapidly progressive glomerulonephritis (‘pauci-immune’, 80% of patients)
Is granulomatosis with polyangitis largely cANCA +ve or pANCA +ve?
cANCA
Renal biopsy granulomatosis with polyangitis
Epithelial crescents in bowman’s capsule
Management granulomatosis polyangitis
Steroids
Cyclophosphamide
Plasma exchange
Median survival 8-9 years
What is idiopathic pulmonary fibrosis?
Lung fibrosis when no underlying cause can be identified
Transfer factor IPF
Reduced
Gold standard investigation IPF
CT - honeycombing
Management IPF
Pulmonary rehab, some evidence for pirfenidone (antifibrotic)
What is kartageners?
Primary ciliary dyskinesia, autosomal recessive problem with impaired mucocilliary clearance
Pathogenesis kartageners
Dynein arm defect results in immotile cilia
Features kartageners
Dextrocardia or complete situs inversus (quiet hear sounds, small volume complexes in lateral leads)
Bronchiectasis
Recurrent sinusitis
Subfertility (secondary to diminished sperm motility and defective ciliary action in the fallopian tubes)
Features of kelbsiella pneumonia
More common in alcoholic and diabetics
May occur following aspiration
‘Red-currant jelly’ sputum
Often affects upper lobes (abscesses, empyema)
Motelukast is associated with development of what syndrome?
Eosinophilic granulomatosis with polyangiitis
What is lofgren’s syndrome?
Acute form sarcoidosis
Characteristics of logren’s syndrome
Bilateral hilar lymphadenopathy (BHL), erythema nodosum, fever and polyarthralgia
RF for lung abscess
Poor dental hygiene, prev stroke, reduced consciousness
Rarer causes lung abscess
Haematogenous spread eg 2ndary to IE, direct extension from empyema, bronchial obstruction eg lung tumour
Monomicrobial causes of lung abscess
Staphylococcus aureus
Klebsiella pneumonia
Pseudomonas aeruginosa
What is carcinoid lung ca?
NE tumours, arising from the amine precursor uptake and decarboxylation (APUD) system, like small cell tumour. Account for 1% of carcinoid tumours
Features lung carcinoid
Slow growing - long history. Often central and not seen on CXR. “Cherry red ball” often seen on bronchoscopy
What is carcinoid syndrome
Seen in those who have a carcinoid tumour when it spreads to the liver releasing serotonin - skin flushing, facial lesions, diarrhoea, dyspnoea, tachycardia
Contraindications to lung ca surgery
Stage IIIb or IV (i.e. metastases present)
FEV1 < 1.5 litres is considered a general cut-off point*
Malignant pleural effusion
Tumour near hilum
Vocal cord paralysis
SVC obstruction
Small cell lung ca paraneoplastic features
ADH -> hypoN
ACTH - (cushings) not typical, hypertension, hyperglycaemia, hypokalaemia, alkalosis and muscle weakness are more common than buffalo hump etc
Lambert-Eaton syndrome (antibodies to voltage gated calcium channels causing myasthenic like syndrome)
Squamous cell lung ca paraneoplastic features
Parathyroid hormone-related protein (PTH-rp) secretion causing hypercalcaemia
Clubbing
Hypertrophic pulmonary osteoarthropathy (HPOA)
Hyperthyroidism due to ectopic TSH
Adenocarcinoma lung ca paraneoplastic feautres
Gynaecomastia
Hypertrophic pulmonary osteoarthropathy (HPOA)
Is coal dust a RF for lung ca?
No
What cell type does small cell lung ca arrise from?
APUD cells
(Amine - high amine content
Precursor Uptake - high uptake of amine precursors
Decarboxylase - high content of the enzyme decarboxylase)
Fibrosis affecting upper zones
C - Coal worker’s pneumoconiosis
H - Histiocytosis/ hypersensitivity pneumonitis (Extrinsic allergic alveolitis)
A - Ankylosing spondylitis
R - Radiation
T - Tuberculosis
S - Silicosis/sarcoidosis
Fibrosis affecting lower zones
IPF
Most connective tissue disorders (except ankylosing spondylitis) e.g. SLE
Drug-induced: amiodarone, bleomycin, methotrexate
Asbestosis
Microscopic polyangitis features (small vessel ANCA vasculitis)
renal impairment: raised creatinine, haematuria, proteinuria
fever
other systemic symptoms: lethargy, myalgia, weight loss
rash: palpable purpura
cough, dyspnoea, haemoptysis
mononeuritis multiplex
pANCA/cANCA microscopic polyangitis
pANCA (against MPO) - positive in 50-75%
cANCA (against PR3) - positive in 40%
What causes Middle East respiratory syndrome?
Betacoronavirus MERS-CoV
Risk factor for MERS-CoV
Contact with camels (including camel products such as milk)
Indications for non-invasive ventilation
COPD with respiratory acidosis pH 7.25-7.35
(pH<7.25 it can be used with increased monitoring, but lower threshold for intubation and ventilation)
Type 2 resp failure
Sleep apnoea
Cardiogenic pulmonary oedema unresponsive to CPAP
Weaning from tracheal intubation
Recommended initials settings for bi-level pressure support in COPD
Expiratory Positive Airway Pressure (EPAP): 4-5 cm H2O
Inspiratory Positive Airway Pressure (IPAP): RCP advocate 10 cm H20 whilst BTS suggest 12-15 cm H2O
back up rate: 15 breaths/min
back up inspiration:expiration ratio: 1:3
Predisposing factors sleep apnoea
Obesity
Macroglossia: acromegaly, hypothyroidism, amyloidosis
Large tonsils
Marfan’s syndrome
Consequences of sleep apnoea
Daytime somnolence
Compensated respiratory acidosis
hypertension
Management sleep apnoea
Weight loss
CPAP
Intra oral devices eg mandibular advancement
DVLA should be informed if excessive
What is olamizumab used for?
Severe persistent confirmed allergic IgE-mediated asthma as an add on to optimised standard therapy in people aged 6 years and older:
who need continuous or frequent treatment with oral corticosteroids (defined as 4 or more courses in the previous year)a, given as an injection every 2 to 4 weeks
What type of drug is olamizumab?
Monoclonal antibody
Adverse effects olamizumab
Abdominal pain
Headache
Fever
Churg-Strauss syndrome: may present with eosinophilia, vasculitic rash, worsening respiratory symptoms and peripheral neuropathy
What is the oxygen dissociation curve?
Describes the relationship between the percentage of saturated haemoglobin and partial pressure of oxygen in the blood. It is not affected by haemoglobin concentration.
If oxygen dissociation curve shifts left what does this mean? What causes this?
For given oxygen tension there is increased saturation of Hb with oxygen i.e. decreased oxygen delivery to tissues.
Shifts to L → Lower oxygen delivery, caused by
Low [H+] (alkali)
Low pCO2
Low 2,3-DPG
Low temperature
If oxygen dissociation curve shifts right what does this mean? What causes this?
For given oxygen tension there is reduced saturation of Hb with oxygen i.e. enhanced oxygen delivery to tissues
‘CADET, face Right!’ for CO2, Acid, 2,3-DPG, Exercise and Temperature
Oxygen management in COPD patients
Prior to availability of blood gases, use a 28% Venturi mask at 4 l/min and aim for an oxygen saturation of 88-92% for patients with risk factors for hypercapnia but no prior history of respiratory acidosis.
Adjust target range to 94-98% if the pCO2 is normal
Transudate pleural effusion causes
Heart failure (most common transudate cause)
Hypoalbuminaemia (liver disease, nephrotic syndrome, malabsorption)
Hypothyroidism
Meigs’ syndrome
Transudate = failures of organs + meigs
Exudate pleural effusion
Infection: pneumonia (most common exudate cause), TB, subphrenic abscess
Connective tissue disease: RA, SLE
Neoplasia: lung cancer, mesothelioma, metastases
Pancreatitis
Pulmonary embolism
Dressler’s syndrome
Yellow nail syndrome
Pleural aspiration from pleural effusion - what is sent for?
pH, protein, lactate dehydrogenase (LDH), cytology and microbiology
What criteria differentiates transudate and exudate causes?
Exudates have a protein level of >30 g/L, transudates have a protein level of <30 g/L
If the protein level is between 25-35 g/L, Light’s criteria should be applied.
An exudate is likely if at least one of the following criteria are met:
pleural fluid protein divided by serum protein >0.5
pleural fluid LDH divided by serum LDH >0.6
pleural fluid LDH more than two-thirds the upper limits of normal serum LDH
Pleural fluid with low glucose might indicate
rheumatoid arthritis, tuberculosis
Pleural fluid with raised amylase might indicate
pancreatitis, oesophageal perforation
Pleural fluid with heavy blood staining might indicate
mesothelioma, pulmonary embolism, tuberculosis
When should a chest drain be placed pleural effusion?
If the fluid is purulent or turbid/cloudy a chest tube should be placed to allow drainage
If the fluid is clear but the pH is less than 7.2 in patients with suspected pleural infection a chest tube should be placed
Management options of recent pleural effusion
Recurrent aspiration
Pleurodesis
Indwelling pleural catheter
drug management to alleviate symptoms e.g. opioids to relieve dyspnoea
Describe CRB65 (primary care)
C: Confusion (abbreviated mental test score <= 8/10)
R: Respiration rate >= 30/min
B: Blood pressure: systolic <= 90 mmHg and/or diastolic <= 60 mmHg
65: Aged >= 65 years
What score of CRB 65 merits hospital admission
Considered if >2, Urgent if 3 or above
Management of severe CAP
Amox+macrolide dual therapy
What findings may block a person’s discharge with pneumonia
Temperature higher than 37.5°C
Respiratory rate 24 breaths per minute or more
Heart rate over 100 beats per minute
Systolic blood pressure 90 mmHg or less
Oxygen saturation under 90% on room air
Abnormal mental status
Inability to eat without assistance
Over what time periods should patients expect to feel better post pneumonia?
1 week - fever should have resolved
4 weeks - chest pain and sputum production reduced
6 weeks - cough and breathlessness should have reduced
3 months - most symptoms should have resolved, may be fatigued
6 months - most back to normal
Following pneumonia when should a repeat CXR be done?
6 weeks after clinical resolution
RF for pneumothorax
Pre-existing lung disease (secondary)
Connective tissue disease
Ventilation including non invasive
What is a catamenial pneumothorax?
Cause of 3-6% of spontaneous pneumothorax, occurring in menstruating women
Management of primary penumothorax
If rim of air <2cm and patient not short of breath then consider discharge, otherwise aspiratino
If fails or >2cm chest drain insertion
Management of a secondary pneumothorax
Admit all
If >50 years old and rim of air is >2cm or SOB then chest drain
If rim of air 1-2cm then aspiration attempted
If <1cm O2
Management of iatrogenic pneumothorax
Most will resolve with observation, can aspirate if not
Ventilated and some with COPD may need chest drains