Respiratory Flashcards
Characteristics of ARDS
- arterial hypoxia
- reduced thoracic compliance
- normal pulmonary capillary wedge pressure
- diffuse infiltrates on CXR
Management of acute Anaphyllaxis
- adrenaline 0.5ml of 1:1000 (1mg/ml) solution, I.e. 500 micrograms IM.
- repeat after 5mins if no improvement
- early oxygen
- IV fluid challenge if hypotension
- hydrocortisone 200mg slowly IV/IM + chlorphenamine 10mg slowly IV/IM after adrenaline
Differentials in breathless patient with no clinical signs (must exclude these before diagnosing ‘psychogenic’)
- early pulmonary congestion of LVF
- silent multiple pulmonary emboli (?diagnostic lung scan)
- lymphangitis carcinomatosis
- interstitial fibrotic pulmonary infiltrations
- metabolic acidosis e.g. Uraemia, DKA
- respiratory muscle weakness
Conservative treatment of asthma
Check precipitating factors e.g. Cold, exercise
Train to use peak flow and record values for 2w
Remove known allergens
Stop smoking
Step 1 treating asthma (mild intermittant asthma)
ICS low dose regular
(+Inhaled short acting B2 agonist)
SE: tremor and tachycardia (rarely hypokalaemia and lactic acidosis)
Step 2 treat asthma
Add LABA (combo inhaler) OR Increase dose inhaled corticosteroid (ICS) 200-800mcg/day (start e.g. 400mcg) according to severity OR try monteleukast if young.
Step 3 treat asthma
Check response to LABA (long acting B2 agonist)
If good response- continue LABA + increased ICS dose OR Add theophylline.
If response but inadequate control- increase ICS to 800mcg/day
If no response- stop LABA and increase ICS to 800mcg/day.
Step 4 treating asthma (persistent poor control)
Consider trials of
- increased dose of ICS up to 2000mcg/day
- add 4th drug e.g. Leukotriene R-antag; SR theophylline; B2 agonist tablet.
NB. Little evidence of benefit of ICS >800 in asthma. High risk of pneumonia. Warn about adrenal suppression if stop ICS suddenly.
Step 5 treating asthma (with continuous or frequent use of oral steroids)
- Add daily steroid tablet in lowest dose providing adequate control.
- Maintain high dose of ICS 2000mcg/day.
- Consider other treatments to minimise use of oral steroids.
- Refer for specialist care
Management of COPD (conservative)
Stop smoking
Lung rehab/exercise
Prevention: influenza and pneumococcal vaccine
Nutrition/lose weight
COPD management pharmacological
Bronchodilators (symptom management):
- SAB2A e.g. Salbutamol/terbutaline
- Anticholinergic Ipratropium (atrovent)/tiotropium
-?theophylline
- one or combination of above aerosol/Nebs
Inhaled corticosteroids (if documented Spirometry response to ICS) NB. little benefit >800mg ICS.
If chronic severe COPD consider long-term home oxygen >15l/day
COPD management of exacerbation
SHONA
Steroids (oral) v. Baseline. ?bone protection
Heparin (preventing DVT while immobile)
Oxygen (titrate carefully e.g. 24-28% Venturi)
Nebulised bronchodilators (?theophylline)
Antibiotics (amoxicillin & macrolide)
If PaCO2 continues to rise consider NIPPV, think about it early, before the patient tires.
Management of acute severe asthma
Continuous high flow oxygen.
Bronchodilators: SABA (salbutamol/terbutaline) + Ipratropium via oxygen Nebs OR IV infusion if unreliable inhalation.
Corticosteroids: oral prednisolone OR IV hydrocortisone. Continue oral prednisolone 30-50 mg daily >4days or recovery.
IV fluids: for initial dehydration until oral fluids taken, monitor urine output.
?IV Mg 8mmol over 8mins.
?aminophylline (BW dependent)
Consider bacterial infection trigger (?antibiotics) usually strep pneumoniae or H. Influenzae
Consider mechanical ventilation if persisting/increasing high PaCO2 OR worse hypoxia esp if + exhaustion.
Discharge when PEFR >75% of best with
Steriods prescribe for asthma/COPD
Asthma: 30-40 mg prednisolone for 5d.
COPD: 30mg OD 7-14d
NB. If prx high dose steroids for >3weeks you need to implement a weaning period to prevent addisonian crisis (2a addison’s)
SABA example
Salbutamol
-10-30% absorbed, distrib 5-15mins, peak 30min-2h
SE: tremor (skeletal muscle B2) tachycardia (atrial B1) dose dependent.
NB. rarely causes: hypokalaemia (Na-K pump by B2 activation); interaction with steroids (decrease K); lactic acidosis.
LABA
Salmeterol
12h action, enables steroid reduction.
Add LAMA/LABA if stable COPD with SOB or have exacerbations >2y. If FEV1>50%
If FEV1
Qvar?
Beclometasone inhaled
Ipratropium
Muscarinic antagonist (also tiotropium)
Short acting
SE: dry mouth, slow GI, bitter, glaucoma (para block)
Theophylline
Methylxanthine
- competitive non-selective PDE inhibitor, raises ICF cAMP, activate PKA, inhibits TNF-a/LK synthesis/reduce inflam and innate immunity.
- non-selective adenosine R antagonist (A1,A2,A3) tachycardia, arrhythmia (careful in AF)
ADR: insomnia, palpitations, headache, nausea/vomit HYPOKALAEMIA, diarrhoea.
NB. Narrow therapeutic window! Toxicity: seizures, tachyarrhythmia, CNS stimulation (esp. Resp centre)
Aminophylline
2Theophylline + 1ethylenediamine
Improves solubility.
Less potent, shorter action (vs theophylline)
Clenil inhaler?
Beclometasone
Flixotide
Fluticisone inhaler
Causes of haemoptysis
Common: 1. Bronchitis 2. Bronchial Ca 3. Bronchiectasis 4. Pneumonia
Uncommon: Pulmonary infarction; CF; Abscess; TB; Foreign body; Goodpasture’s; after vigorous coughing.
CV: severe mitral stenosis; acute LVF.
Bleeding diatheses.
Causes of stridor
Congenital- Laryngomalacia (congenital flaccid larynx)
Foreign body
Laryngeal oedema: anaphylaxis, inhalation injury
Infection: epiglottitis, retropharyngeal abscess.
Iatrogenic: post-tracheostomy/intubation stenosis, post-thyroid surgery.
Rheumatoid Arthritis: cricoarytenoid RA
Goitre
Malignancy: intraluminal- larynx, trachea, bronchus; external compression- malignant nodes; bilateral vocal cord palsy- brainstem stroke, thyroid Ca, oesophageal Ca.
Pulmonary fibrosis differentials
BREAST CARDS- Upper lobe: BREAST; Lower lobe: CARDS Berylliosis Radiation Extrinsic allergic alveolitis Ankylosing spondylitis/ ABPA Sarcoidosis/Silicosis Cryptogenic fibrosing alveolitis (IPF) Asbestosis Radiation Drugs Systemic sclerosis and other CTDs
Minimum presentation of normal respiratory examination
On examination of X’s respiratory system I found him to be comfortable at rest with a respiratory rate of 12/minute and pulse of 72 beats per minute. There are no peripheral stigmata of respiratory disease. The trachea is central. Chest shape is normal. Chest movement is equal bilaterally with 6cm expansion. Percussion note is resonant in all areas. Breath sounds are vesicular throughout with no added sounds. In conclusion this patient presents with a normal respiratory examination.
Pleural fluid aspirate findings ‘normal’
Normal
Cytology: macrophages, mesothelial cells, lymphocytes and some erythrocytes
Pleural fluid cytology findings and differentials
- NEUTROPHILIC: acute inflammatory response. Empyema/Pneumonia. NB. May also see reactive mesothelial cells. These may mimic/hide malignancy.
- Eosinophilic (>10%): usually reaction to haemo/pneumothorax.
- Lymphocytic majority
- Malignant cells.
Causes of eosinohphilic pleural aspirate
- Reaction to air/blood in pleural cavity
- Drug reactions
- Parasitic infections
- Churg-Strauss Syndrome (E-GPA, eosinophilic granulomatosis with polyangiitis)
Differentials for a lymphocytic effusion on pleural aspirate
- Inflammatory disease e.g. Rheumatoid
- Infection, including mycobacteria
- Malignancy, solid or lymphoma
- Post CABG and others
Pleuritic chest pain indicates inflammation/irritation of parietal or visceral pleura
Parietal, has sensory innervation for pain. The visceral pleura has no sensory innervation.
Where is pleural fluid secreted and absorbed? Normal volume?
Parietal pleura secretes fluid, it is absorbed by the visceral pleura, draining into the lymphatics and returns to the blood. Normally there is 10-20ml.
Radiological findings of Pleural effusion
- Homogenous density
- density in dependent portion ‘meniscus sign’ (concave upper border)
- ?fissures visible
- loss of normal silhouette e.g. Obscures hemidiaphragm, loss of costophrenic angle
+/- mediastinal shift (contralateral in massive effusions)
Normally confirmed by PA and lateral CXR (more sensitive than PA)
At what size is a pleural effusion visible on CXR
> 200ml on average needed.
Lateral CXR >50ml obliterates ant/post costophrenic angle (CP)
PA CXR >200ml obliterates lateral CP angle
PA CXR >500ml obliterates/elevates ipsilateral hemidiaphragm.
Confirm with lateral decubitus film OR USS (effusions from 5ml)
Signs of pleural effusion on Supine/AP CXR?
- hazy diffuse opacity (but can see normal lung marking through it)
- Ill-defined hemidiaphragm
- capping of apex with pleural shadow >500ml
- apparent elevation of diaphragm.
Variations on pleural effusion presentation on CXR
- Encysted pleural fluid (commonly CCF): obliterates oblique CP angles, ‘vanishing tumour’
- Loculated effusion: fluid doesn’t shift to dependent portion, ?adhesion between pleura. Lenitform opacity against chest wall (convex to lung) mimics chest wall mass. Haemothorax/empyema.
Findings in USS for pleural effusion
Anechoic (Black, echo free) = transudate (sometimes exudate)
Complex non-septated (echogenic/bright material in anechoic fluid) = Exudate
Complex septated (fibrin strand/septa floating in anechoic fluid) = Exudate
Echogenic (homogenous echogenic- bright fluid) = exudate/haemorrhage/empyema/chylothorax.