Disease Flashcards
Asthma
Inflammatory mediators stimulate parasympathetic receptors and bronchial smooth muscle to produce bronchoconstriction, increased capillary permeability allows plasma to escape leading to mucosal oedema.
Inflammatory cells activate and damage airway epithelium which produces mucosal oedema, impairs mucociliary clearance and prolong bronchospasm.
Limited exploratory airflow traps air distal to narrow airway and reduces gas exchange.
Distended alveoli compress alveolar and decreases blood flow further reduces gas exchange
Chronic Bronchitis
Excessive bronchial mucus secretion and productive cough >3mth. CO2 drives respiration
Inhaled irritant leads to chronic inflammation with vasodilation, congestion and oedema of bronchial mucosa, goblet cells increase in number and mucous glands enlarge
Changes in bronchial squamous cells impair ability to clear secretions
Narrow airways obstruct airflow and expiration is affected first then inhalation
Emphysema
Destruction of walls of alveoli with resultant enlargement of abnormal air spaces. Deficiency in a-antitrypsin (prevents lung destruction)
Inflammatory cells that collect in distal airway destroy elastic fibres in bronchioles and alveolar ducts
Destruction causes air space to enlarge reducing capillary bed diffusion and gas exchange
Pneumonia
Microorganisms-(strep pneumonia, mycoplasma pneumonia, haemophilius influenza, legionella, chlamydia, e-Cili, staph Aureus).
Microorganisms colonise in alveoli and inflammatory/immune response is activated. The bodies antigen-antibodies response and endotoxins released by some organisms damage bronchial and alveolar mucous membranes causing inflammation with vascular congestion and oedema.
Infection debris and exudate fill alveoli and affect gas exchange and ventilation
Pulmonary hypertension
5 types-
1- pulmonary arterial hypertension (PAH)
Caused by- inherited, drugs (appetite suppressors, rapeseed oil, methamphetamines, St. John’s wart, dasatinib, interferon), HIV, connective tissue disease-SLE/raynauds/rheumatoid/sclerosis
2- pulmonary hypertension (PH)-Due to left sided heart disease
3- PH due to chronic lung disease/hypoxaemia
4- PH due to pulmonary artery obstruction (tumours, thromboembolic disease, pulmonary artery stenosis)
5- PH due to unidentified mechanisms (haematological disorders, metabolic disorders, sarcoidosis, chronic renal failure, complex congenital heart disease)
Can be pre or post capillary
Pre- due to primary elevation in pressure of pulmonary arterial system ie. (PAH)
Post- elevations of pressure in pulmonary venous and capillary systems
S&S - exertion dyspnoea, fatigue other symptoms relate to causing factors, desaturation during sleep
Right ventricle failure= exertional chest pain, exertional syncope, peripheral oedema, Anorexia/abdominal pain in right upper quadrant due to hepatic congestion
Uncommon symptoms- cough, hemoptysis, hoarseness (compression of left laryngeal nerve by a dilated main pulmonary artery), palpitations, arrhythmias
As progresses will see increased JVP, hepatomegaly , peripheral oedema, ascites, pleural effusion
Diagnosis-
heart causes- TTE (transthoracic echocardiography) looks for tricuspid regurgitant jet velocity (>2.8m.s), pulmonary artery systolic pressure (>35 mmHg young adults, >40 older adults), echo (right ventricle size and function, potential contribution of left sided heart failure), X-ray (enlarged pulmonary arteries, right ventricular enlargement, right atrial dilation, pleural effusions), CT, ECG, brain natriuretic peptide elevated due to right ventricle stretch, right heart catheterisation (if being considered for advanced heart therapies or pre-capillary PH is suspected or no evidence of left heart disease or other etiology, or right heart disease suspected)
Cause Lung disease- pulmonary function tests, 6 minute walk test
Cause pulmonary obstruction- VQ scan, CTPA (CT pulmonary angiogram)
Cause other etiology- right heart cath
Diagnosis criteria for group 1- right heart cath results= mean pulmonary arterial pressure (mPAP) >20mmHg at rest, pulmonary vascular resistance (PVR) >3 wood units, mean capillary wedge pressure <15mmHg (to exclude left side heart cause), no evidence of lung or obstructions
Diagnosis criteria group 2- mPAP >20mmHg, pulmonary capillary wedge pressure (PCWP) >15mmHg and a normal or reduced cardiac output. Left atrial enlargement on echo and left heart cath to confirm elevated ventricular end diastolic pressure.
Classified as LHD-PH due to heart failure with preserved ejection fraction, heart failure with reduced ejection fraction, valvular heart disease, congenital or acquired
Group 3- moderate to severe lung dysfunction and or hypoxaemia.
Classified as PH due to obstructive lung disease, restrictive lung disease, mixed obstructive/restrictive, PH associated with hypoxia without lung disease, PH due to developmental disorders
Group 5-
Haematological disorder (sickle cell, beta thal, sphericytosis)
Systemic or metabolic disorders (sarcoidosis, pulmonary langerhans histiocytosis X, neurofibromatosis, glycogen storage disease, gaucher disease
Complex congenital heart disorder
Chronic kidney disease, fibrosing mediastinitis
