PE, sarcoidosis and cystic fibrosis Flashcards
Pulmonary embolism
A thrombus that dislodged from a deep vein to form an embolus: Leg, arms, pelvis
This blocks the pulmonary artery.
Signs and symptoms of PE
Dyspnoea
Syncope
Pleuritic chest pain
Calf pain and swelling
Haemoptysis
Cough
Hypoxaemia
Risk factors of PE
Hypercoagulability: OCP, genetic conditions, pregnancy, malignancies.
Vascular damage: Smoking, surgery (iatrogenic), hypertension.
Circulatory stasis:
Prolonged immobility, pregnancy
D-dimer test
Used to diagnosis PE.
D-dimers are created when clots are broken down.
This test screens the blood and rules out the presence of inappropriate blood clots when negative.
Excludes thromboembolic disease when probability is low
Duplex ultrasound
Ultrasound that looks into the blood vessels and calculates the velocity of blood moving.
Used in investigating PE.
The ultrasound will show the blood clot and also the blood being occluded.
CT pulmonary angiography
CT scan that images of the pulmonary arteries. The blood vessels are filled with contrast which will appear.
It is used to diagnose PE- it will show dark masses in the arteries.
V/Q scan
Medical imaging that uses isotopes to analyse the circulation of air and blood in the lungs.
Ventilation= looks at air flow Perfusion= looks at blood flow.
Each scan done separately to calculate a V/Q ratio.
Mismatch is seen in patients with PE BUT does not exclude other underlying pulmonary diseases.
Diagnostic tests used to diagnose PE
CT pulmonary angiogram.
Duplex ultrasound.
V/Q scan
CXR
D-dimer test
Well’s criteria
Used to assess the likelihood of PE.
Certain signs observed are assigned to ‘points’.
If the sum of the points >4, definitive testing is carried out.
If the sum <4, D-dimer test is carried out.
Typical ABG result of PE
Hypoxaemia- O2 will be below 95%.
PAO2= low, lot less than 14/15 kPa / 95 mm Hg.
There is an increase in PAO2 due to hyperventilation= 15 kPa
Decrease in PaO2 due to perfusion obstruction- 11.3 kPa
Causes the A-a gradient increases.
Hypoxic pulmonary vasoconstriction does not happen- it is dysregulated by inflammation.
Blood pH in PE
Alkalemia: pH will be 7.49
Due to hyperventilation, there is depletion in CO2, causing hypocapnia.
CO2 levels: 30 mm Hg/ 4 kPa
Normal CO2 levels vs PE CO2 levels in blood.
Normal: 5kPa/ 40 mm Hg
PE: 4 kPa/ 30 mm Hg.
Anticoagulants used to treat PE
Warfarin
Heparin
DOACs: Dabigatran (direct thrombin inhibitor), Rivaroxaban ( direct Xa inhibitor)
Non- pharmacological treatment of PE
Removable inferior vena cava filter
Screening for pro-coagulable conditions
Screening for cancers in certain patients.
Sarcoidosis
Inflammatory pulmonary disease that has heterogeneity. It causes both restriction and obstruction.
Granulomas primarily form in the lungs but the condition spreads to the skin and lymph nodes, as well as the eyes, liver, heart and brain.
The clinical course is variable but most patients go into remission.
Pathogenesis of sarcoidosis
Unidentified antigen in inhaled and presented by APCs.
This activates CD4+ T cells causing them to release cytokines- IFN-g, IL-2, IL-12.
Macrophages also release TNF-alpha and form granulomas.
Granulomas are sterile as inflammation is not triggered by pathogens- therefore the granuloma has to be biopsied.
Chronic sarcoidosis
This occurs when chronic inflammation of the lungs turn into fibrosis.
Symptoms of sarcoidosis
Can be asymptomatic in some cases.
Cough, Dyspnoea
Systemic symptoms- fatigue, weight loss, fever.
Imaging of sarcoidosis in CXR
Lymphadenopathy.
Triad of adenopathy: swollen lymph nodes in three locations.
Bilateral hilar
Right paratracheal
Lung nodules: grow in size during progression.
Fibrosis: mainly in the airways.
Pharmacological management of sarcoidosis
Corticosteroids- immunosuppressants
Non-pharmacological management of sarcoidosis
Screening for multiorgan diseases: eye exam, ECG, blood tests for liver, kidney function.
Baseline PFT data
Example of corticosteroid used to treat sarcoidosis
Prednisolone- immunosuppressant drug.
Cystic fibrosis
Autosomal recessive disorder caused by a deletion of a nucleotide in CFTR protein.
This prevents transportation of chloride and thiocyanate ions across cell membranes.
Hence, fluid transport is disrupted and there is an excess production of thickened mucus that obstruct exocrine glands.
CFTR
Cystic fibrosis transmembrane conductance regulator- 1480 amino acids
Protein channel in epithelial membranes that allows conductance of Cl- and thiocyanate ions.
In CF, this protein is dysfunctional.
Most common gene alteration in CF
Delta-F508
Loss of phenylalanine
Systems affected by CF
Lungs
Pancreas- enzyme secretion inhibited.
Intestines- causes malnourishment, nutrients not absorbed.
Meconium Ileus- when newborn faeces is obstructed and thickened.
Male infertility
Osteoporosis: more intake of vitamin D from diet.
Diagnosis of CF
Screening- genetic screening. Finding the mutation.
Sweat test- will show increase Na+ and Cl- because Cl- is not excreted into the dermis.
Signs of CF
Wheezing
Haemoptysis
Rhonchi- low rumbling noise in lungs, like snoring. Heard when large airway is obstructed.
Imaging of CF
Bronchiectasis- both CT and CXR
Opacities- mucous plugging
Hyperinflation
Shrunken, fibrotic lungs
Acute infections in CF
Infections by:
Pseudomonas aeruginosa
MRSA
Normal flora changes to resistant gram negatives with age.
Chronic infections in CF
Pseudomonas
B cepacia- gram negative species of bacteria
Allergic bronchopulmonary aspergillosis (ABPA)- hypersensitive reaction of the immune system to fungus.
Complications of CF
Acute and chronic infections
Haemoptysis- due to inflamed BVs in bronchiectasis
Respiratory failure
Social restrictions
Treatment of CF
Bronchodilators
Airway clearance techniques
Mucus thinners
Corticosteroids
Antibiotics
CFTR potentiators
Lung transplant
Pancreatic enzyme replacement.
Airway clearance techniques
Postural drainage
Chest physical therapy
Mucus thinners for CF
Hypertonic nebuliser
