Resp-TB, RF... Flashcards
What is latent TB?
Infected with the TB bacteria but do not have the signs and symptoms of the active disease. Only 1 in 10 infections result in disease
What is the primary complex of TB?
Lesion (Ghon focus) and draining gland
Usually asymptomatic
Skin text conversion
What are the symptoms of respiratory TB?
Primary infection usually asymptomatic May be non-specific Often constitutional only Tirednedd and malasia Weight loss and anorexia Fever (low grade or hectic) Cough most common Breathlessness indicative of pleural effusion Haemoptysis occasionally
What are the signs of resp TB?
Nonspecific
Pallor
Fever
Evidence of weightless
Clubbing in extensive or longstanding disease only
Often no signs in the chest despite marked radiological abnormality
Localized wheezing if bronchial narrowing
Cervical nodes palpable
Who is at risk of developing active disease after latent infection of TB?
IV drug abusers HIV cases Solid transplant recipients Haematological malignancy Chronic renal failure/haemodialysis Anti TNF alpha treatment Silicosis Underweight Vitamin D deficiency? Iron deficiency?
What is erythema nodosum?
Red nodules beneath the skin, commonly on the shins. Often no trigger but TB can
What are the mechanisms of post-primary TB?
Direct progresion
Reactivation
Haematogenous spread
Exogenous reinfection
What is haemoptysis?
Coughing of blood from the respiratory tract below the level of the larynx
When might haemoptysis occur in TB?
May occur in active cavitating disease More common in post-TB bronchiectasis Rausmussen's aneurysm in old TB cavity Mycetoma in old TB cavity Broncholithiasis
What is a Rasmussen’s aneurysm?
Pulmonary artery aneurysm adjacent or within a TB cavity
Is pleural TB more common in males or females?
Males
What are the mechanisms for pleural involvement in TB?
- Hypersensitivity response in primary infection may cause acute pleuritic price with fever
- TB empyema with ruptured cavity - has tendency to burrow through chest wall
Who is lymph node TB most common in?
Females
Asians
How does Lymph TB present/
Often painles
Most commonly in neck
Discrete swelling to marked inflammation of the rupture
Intra-thoracic node may collapse bronchi
What can osteo-articular TB cause?
Peripheral arthritis Osteomyelitis Dactylitis Tenosynovitis Poncet's disease - aseptic polyarthritis of knees, ankles and elbows. Cultures negative and X-rays normal
What is TB spondylitis?
Most common form of osteo-articuar TB
Starts generally in sub-chondral bone and spreads to vertebral bodies and joint space
Follows longitudinal ligaments
Mainly lower thoracic and upper lumbar spine
What causes miliary TB?
Bacilli spreading through the blood stream, either during primary infection or as reactivation (elderly in low prevalence countries)
What organs are involved in miliary TB?
Lungs always involved, other organ involvement variable.
Headaches sugget meningeal involvement
How doe miliary TB present?
Headache (suggests meningeal involvement) Few resp symptoms Pericardial, pleural effusions small Ascites may be present Retinal involvement (children)
Discuss chronic “cryptic” miliary TB.
Usually in over 60s High mortality Insidious onset Weightloss, lethargy and interittent fever High index of suspicion required Not infrequently found at post-mortem
WHat is the ABC of chest imaging?
Airway - trachea Breathing - lungs Circulation - heart Disability - bones Everything else
WHy might there be no air in the lung?
Removed
Collapsed
Consolidated
Fluid filled
What is the interstitium and what does it do?
Between the alveoli and capillaries. Trafficking of cells between them, inflammatory cells in response
What other structures does interstitial disease effect?
Acini Alveoli lumen Bronchiolar lumen Bronchioles Epithelial, endothelial, mesenchymal, macrophages and recruited inflammatory cells affected
What are the symptoms of interstitial lung disease?
Shortness of breath - gradual
Cough - dry
On examination of someone with suspected interstitial lung disease, what would the signs be on examination?
Clubbing Cyanosis Tachycardia Signs of right heart failure (only if severe) Tachypnoea Decreased chest movement Couse crackles
What are the different types of interstitial lung disease?
Occupational Treatment related Connective tissue disease Immunological Idiopathic - most common
What diseases can asbestos cause?
Asbestos plaques - thickening of the pleura. Not problem
Diffuse pleural thickening
Benign asbestos pleural effusion
Asbestosis - interstitial lung firbrosis due to asbestos
Mesothelioma
Bronchogenic lung cancer
Rounded atelectasis
What is needed to diagnose asbestosis?
Exposure history
Interstitial fibrosis - CXR/CT
Restrictions
Fibrosis
What drugs can cause ILD?
Mehotrexate Bleomycin Amiodarone Nitrofurantoin Drugs often given to treat lung diseases...
What connective tissue diseases can cause ILD?
Dermatomyositis/Polymyositis Sjogren's syndrome Systemic Lupus erythematosis Schleroderma Rheumatoid arthritis - may predate arthritic symptoms Disease or treatment may be cause
What is the cause and symptoms of sarcoidosis?
Genetic predisposition Often asymptomatic Cough and breathlessness normal chest examination May get better, remain static, worse - unpredictable
What does a biopsy of sarcoidosis look like?
Non-caseasting granulomatous (same as TB except non-caseating
What are the sections of the pleura?
Parietal pleura
Visceral pleura
Pleural space
What is the function of the pleural space?
Allow movement of lung and chest wall
Coupling of chest wall and lung - inward lung recoil, outward chest wall recoil
Pleural fluid circulation
What is the blood supply to the parietal and visceral pleura?
Parietal:
- Costal pleura - intercostals and IMA
- Mediastinal - Bronchial, upper diaphragmatic and IMA
- Pleural dome - subclavian artery
- Venous drainage - peribronchial anad venae cavae
Visceral:
- Bronchial arteries and pulmonary circulation
- Venous drainage - Pulmonary venous circulation
What is the innervation of the parietal and visceral pleura?
Parietal: Somatic, sympathetic and parasympathetic. Phrenic and intercostal nerves
Visceral pleura - devoid of somatic innervation
Where does pleural fluid turnover occur?
Production - Capillary filtration (starling forces. Parietal only)
Absorption - Lymphatic drainage, parietal pleural lymphatics - via stomata on parietal pleural surface (mainly mediastinal, diaphragmatic regions)
Why might there be increased pleural fluid production?
Lung interstitial fluid increase
Hydrostatic pressure increase
Permeability increase
Oncotic pressure decrease
Why might there be decreased absorption of pleural fluid?
Lymphatic blockage
Elevated systemic venous pressures
What treatment is done for pleural effusion?
Thoracocentesis
What might be a cause of pleural effusion?
Empyema - commonly associated with pneumonia
Haemothorax
Chylothorax
What might cause pleural malignancy?
Metastatic
Mesothelioma - primary. Asbestos exposure, pain, breathlessness, effusion, mediastinal pleural enhancement
What are the common congenital chest wall diseases?
Pectus deformities
Scoliosis
Kyphosis
Muscular dystrophy
What are common acquired chest wall disease?
Trauma
Iatrogenic
ANkylosing spondylitis
Motor neurone disease
What problems are associated with chest wall disease?
Ventilation Sleep disordered breathing Poor clearance secretions Atelectasis Pneumonia
What does the respiratory system do?
Ensures oxygen enters the blood at the same rate as metabolism utilises it
Carbon dioxide leaves the blood at the same rate as metabolism produces it
What is the oxygen transport chain?
Air -> airway -> alveolar gas -> alveolar membrane -> arterial blood -> regional arteries -> capillary blood -> tissues
What is respiratory failure?
Not enough oxygen enters the blood or
Not enough CO2 leaves it
Do not necessarily occur together
What is type 1 resp failure?
Not enough oxygen enters CO2 loss not compromised pO2 of arterial blood low pCO2 normal or low (Most commonly perfusion problem) Problem with alveolar membrane, either some or all
What is type 2 resp failure?
Not enough oxygen enters the blood Not enough CO2 leaves it pO2 low pCO2 high aka pump failure ventilation problem
WHat are the symptoms of type 1 resp failure?
Breathlessness
Exercise intolerance
Cyanosis - deoxygenated blood so patient appears blue
What can cause type 1 resp failure?
Ventilation perfusion mismatch Pulmonary embolism Pneumonia Consolidation Pulmonary oedema Fibrosis - fibrosing alveolitis, extrinsic allergic alveolitis, pneumoconiosis
What is acute hypoxia?
pO2 < 8.0 kPa
Detected by peripheral cheomreceptors -> increase ventilation
Effects on pCO2 (decrease - reason for pCO2 drop in resp 1 failure), detected by central chemoreceptors
What is chronic hypoxia?
Renal correction of acid base balance
Increased ventilation, increased oxygen transport capacity, Hb increased by erythropoietin
What are the causes of type 2 resp failure?
Ineffective resp effort:
Poor resp effort - resp depression (narcotics), muscle weakness (upper/lower neurone)
Chest wall problems - scoliosis/kyphosis, trauma, pneumothorax
Hard to ventilate lungs - high airway resistance, COPD, asthma
What is emphysema?
Destruction of ling tissue Changes in compliance Ventilation perfusion mismatch Affects oxygen supply Type 1 failure initially
What are the acute effects of resp failure?
pCO2 rises, pO2 falls
Central chemoreceptors
Breathlessness - some compensation
What are the results of CO2 retention in chronic resp failure?
CSF acidity corrected by choroid plexus Initial acidosis Initial acidosis corrected by kidney Reduction of resp drive Persisting hypoxia
What are the effects of chronic resp failure on the pulmonary circulation?
Effects of hypoxia on pulmonary arterioles
Pulmonary hypertension
Right heart failure (Cor pulmonare)
What is the management of resp failure?
Oxygen therapy - be careful not too much - can cause further decrease in ventilation, increased CO2 etc
Removal of secretions
Assisted ventilation
Treat acute exacerbation
