Session 8 Flashcards

Question

Describe the blood supply and innervation of the pleura

Answer 1

[\*] Blood Supply of the Parietal Pleura * Costal pleura – intercostals and IMA * Mediastinal – Bronchial, upper diaphragmatic and IMA * Pleural dome – subclavian artery * Venous drainage – peribronchial and venae cavae [\*] Blood Supply of the Visceral Pleura * Bronchial arteries and pulmonary circulation * Venous drainage – pulmonary venous circulation [\*] Pleura innervation * Parietal pleura – somatic, sympathetic and parasympathetic (phrenic and intercostal nerves) * Visceral pleura – devoid of somatic innervation

Answer 2

[\*] 15ml turnover per day (can increase to 300ml) [\*] Produced by capillary filtration at the parietal pleura only (Starling forces). Pleural fluid volume will increase if: * Lung interstitial fluid increases * Increased Hydrostatic (pulmonary intravascular) pressure (e.g. in heart failure) * Increased Permeability of pleural capillaries (e.g. inflammation, sepsis or malignancy) * Decreased Oncotic pressure (e.g. liver failure) (fall in plasma osmotic pressure) [\*] Absorbed via lymphatic drainage (by parietal lymphatic vessels). Pleural fluid volume will increase if there is decreased absorption: * Lymphatic blockage (an obstruction to lymphatic flow in the lungs. * Systemic venous pressure rises [\*] The intrapleura pressure is normally below atmospheric expect during a forced expiration, because of the elastic recoil of the lungs.

Answer 3

[\*] Pleural Effusion: any collection of extra fluid in the pleural space is known as a “Pleural Effusion” [\*] Blood – Haemothorax [\*] Chyle (Lymph with fats in it) – Chylothorax (if thoracic duct is involved) [\*] Pus – Empyema [\*] Serous Fluid – Simple Effusion

Answer 4

Early: lung is squashed, can’t expand properly * Trapped lung * Fistula Late: * Fibrothorax (fibrosis of the pleural space) * Chronic empyema * Empyema necessitatis (extension of the pleural infection out of the thorax and into the neighbouring chest wall and surrounding soft tissues) * Functional restriction

Answer 5

[\*] Simple pleural effusions (Serous Fluid) is further characterised by protein content: * Transudates have low protein content - \<30g/Litre * Exudates have high protein content - \>30g/Litre [\*] `Transudates * Increased hydrostatic pressure - Cardiac Failure * Decreased capillary oncotic pressure Hypoalbuminaemia Nephrotic Syndrome * Increased capillary permeability Sepsis [\*] Exudates * Neoplasma: Cancer involving pleural surface Secondary metastases from breast, lung, ovarian, GI, lymphoma Primary tumour of pleura * Infection Pneumonia, TB * Immune Disease - Connective tissue diseases: rheumatoid arthritis, lupus * Abdominal Disease Pancreatitis (Diaphragmatic inflammation) Ascites (exudate transverses the diaphragm) Subphrenic abscess

Answer 6

[\*] Pleursy, or pleuritis, is an inflammation of the pleura [\*] Sharp pain on inspiration [\*] Pain worse with coughing, sneezing, laughing etc (large breathing moments) [\*] Patients take small breaths and hold affected side of chest [\*] Involvement of diaphragmatic pleura causes pain in the shoulder on the same side (Referred pain) [\*] Characteristic physical sign is Pleural Rub, a creaking nose heard through a stethoscope with respiratory movements

Answer 7

* Infection is the most common cause (TB, pneumonia etc) * Autoimmune (lupus, rheumatoid arthritis) * Lung Cancer * Pneumothorax * Pulmonary Embolism

Answer 8

Unabsorbed pleural effusion may lead to fibrosis of the pleura. A small degree of thickening has no effects, but widespread fibrosis restricts expansion with a measurable reduction in lung volumes and compliance.

Answer 9

* Secondary deposits of tumours are not uncommon in the pleura * The commonest primary tumour is a malignant mesothelioma Almost all victims exposed to asbestos 20-40 years before Early symptoms are those of pleural effusion but with a duller pain and more diffuse than that of pleurisy As the disease progresses pain (due to parietal pleura inflammation) and breathlessness become increasingly severe and there is increasing weight loss. The physical signs are those of a large pleural effusion. Prognosis is very poor with rare survivors two years after diagnosis [\*]

Answer 10

[\*] Congenital Abnormalities of the Chest Wall: deformity of the ribs, sternum and thoracic spine * Sternal abnormalities e.g. pectus carcinatum, pectus excavatum, rarely produce functional impairment though cosmetic impact is considerable. * Scoliosis and kyphosis may produce significant functional impairment of the thoracic cage and are sometimes congenital.

Answer 11

* Trauma: Broken ribs produce pain and possible underlying lung contusion. There may be a pneumothorax. If a large number of ribs are fractured a segment of the thoracic cage may become disengaged mechanically producing a ‘flail’ segment. * Iatrogenic - Some old patients may have had surgery for TB, designed to collapse underlying lung * Kyphosis * Scoliosis * Ankylosing spondylitis

Answer 12

* In addition, the muscles involved in breathing may be affected by generalised muscular disease such as muscular dystrophy or by neurological disease such as motor neurone disease or polio. * The effects of muscle weakness are to produce respiratory failure with a propensity to lower resistance to respiratory tract infections because of poor clearance of secretions.

Answer 13

Inadequate ventilation Sleep disordered breathing Poor clearance of secretions Atelectasis Pneumonia

Answer 14

[\*] Progressive inflammatory condition of the lungs whose cause is unknown [\*] Unclear pathogenesis [\*] Histologically there is increased numbers of activated alveolar macrophages – perhaps triggered by an infection or pollutant. [\*] Activated macrophages attract neutrophils and eosinophils which produce local lung damage by generation of reactive oxidant species and proteases =\> tissue destruction and fibrosis. [\*] In the early stages, these processes can be restrained by treatment with steroids. Once fibrosis has developed, steroids are less effective. [\*] Condition is relatively rare (3-5 per 100,000). It presents about twice as often in males than in females, most commonly in middle age. [\*] Patients report a progressive shortness of breath on exercise (exertional dyspnoea) often with a non-productive cough. Most patients have finger clubbing. Bilateral inspiratory fine ‘crackles’ can be detected on listening to the chest. The condition progresses at different rates in different patients. [\*] Occasionally the disease progresses rapidly to death in a few months but the more usually progression is slow. [\*] The chest x-ray shows small lungs with micro’nodular shadowing predominating in the lower lobes, with ragged heart borders . [\*] Diagnosis of Fibrosing alveolitis may be confirmed by CT scan, which normally reveals changes predominantly in the lower zones; initially subpleural distribution of fibrosis and may show areas of ‘ground glass’ shadowing indicating alveolitis. The treatment is by high dose oral steroids. The effectiveness of treatment is monitored by repeated lung function tests.

Answer 15

[\*] This is a term for a number of conditions in which the inhalation of organic material triggers a diffuse allergic reaction in the walls of alveoli and bronchioles. [\*] The condition may be acute (sudden onset, rapidly progress) or chronic (develop gradually and persist). [\*] A typical acute form is ‘Farmer’s Lung’, where exposure to an antigen derived from Thermophilic actinomycetes found in mouldy hay produces an influenza-like illness 4-9 hours later with a dry cough and exertional dyspnoea. Sometimes breathless can be severe. On listening to the chest you would expect to hear fine mid and late respiratory crackles. There may also be a wheeze. [\*] A chronic form is ‘Bird Fancier’s Lung’. Here long term exposure to antigens derived from pigeons or budgerigars leads to insidious malaise (feeling persistently unwell), dry cough and breathlessness over months or years. Again you will hear inspiratory crackles. [\*] Finger clubbing odes not occur in either acute or chronic presentation. [\*] In acute disease the chest x-ray shows a diffuse micro-nodular infiltrate denser towards the hila. In the chronic disease, the chest x-ray may be almost normal but the disease may progress to pulmonary fibrosis affecting the upper zones. [\*] In the acute disease: the lung function tests will show small lungs with reduced compliance and reduced gas transfer.

Answer 16

[\*] Inhalation of asbestos fibres can lead to a number of conditions which often develop long after the exposure and so still appear today. [\*] Asbestos inhalation is associated with 3 forms of disease: * Benign pleural plaques * Asbestosis (pulmonary fibrosis) * Mesothelioma * There is also a markedly increased incidence of lung cancer. [\*] Asbestos fibres which penetrate to the alveoli produce an alveolitis with an influx of macrophages coating the fibres to produce characteristic ‘asbestosis bodies’ – this alveolitis progresses to fibrosis. [\*] Clinical features: history of asbestos exposure, exertional dyspnoea and a dry cough. There are inspiratory crackles at the lung bases, which rise as the disease advances. [\*] Pulmonary function tests: shows small lungs, reduced compliance and impaired gas transfer. [\*] There is no treatment for asbestosis per se.

Answer 17

[\*] This is a condition which affects many systems of the body, most commonly the lungs, skin and eyes. [\*] The characteristic feature is the presence of non-caseating granulomata. [\*] Fluid collected by ‘lavage’ (washing-out) of the airways and alveoli contains lots of cells, including macrophages and lymphocytes. [\*] Clinical features: almost any organ system can be affected but the commonest sites are the hilar glands and the lungs. Incidence varies with ethnic background, being commoner in Afro-Caribbean and Asians than in Whites (17-20/100,000 as opposed to 1.5/100,000). The highest incidence is in the 30’s and 40’s with a female preponderance. [\*] Thoracic sarcoid may be graded by chest x-ray into 4 stages from hilar adenopathy through to irreversible pulmonary fibrosis. [\*] Clinical history: may present acutely with hilar gland enlargement or less acutely, usually with stage II or III disease visible on x-ray but asymptomatic. Generally the chest x-ray is much worse than the condition of the patient. The CXR appearance is variable but commonly includes military and nodular shadowing and diffuse fibrosis. [\*] Lung Function tests: patients have small lungs with reduced compliance and reduced gas transfer. There may be some evidence of air flow obstruction. [\*] In stages I to III steroids are usually effective in suppressing the disease.

Answer 18

* revise radiology lecture * revise radiology groupwork presentation * look online at radiologymasterclass.co.uk