Respiratory Lecture 5 Dr Azeem Alam, MBBS BSc (Hons) Surgical AFP - - PowerPoint PPT Presentation

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Respiratory Lecture 5 Dr Azeem Alam, MBBS BSc (Hons) Surgical AFP - - PowerPoint PPT Presentation

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Respiratory Lecture 5 Dr Azeem Alam, MBBS BSc (Hons) Surgical AFP Guys and St. Thomas Hospital Email: admin@bitemedicine.com Website: www.bitemedicine.com Facebook: https://www.facebook.com/biteemedicine Content reviewed on 08/04/2020.

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Respiratory

Lecture 5

Dr Azeem Alam, MBBS BSc (Hons) Surgical AFP Guy’s and St. Thomas’ Hospital

Email: admin@bitemedicine.com Website: www.bitemedicine.com Facebook: https://www.facebook.com/biteemedicine Instagram: @bitemedicine Content reviewed on 08/04/2020.

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Learning objectives

  • 2 respiratory topics: Asthma in adults and Lung cancer
  • Case-based discussion(s) to identify the top differentials and why
  • Theory to cover pathophysiology, diagnostic criteria, investigations and

management

  • Quiz (Mentimeter and multi-step SBAs)

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Case 1

History A 29-year-old male presents with shortness of breath and wheezing after exercise. His symptoms have been getting progressively worse over the last year and he has been struggling to sleep at night. Observations HR 98, BP 134/82, RR 18, SpO2 96%, Temp 37.4°C.

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Pathophysiology

Definition: chronic inflammation resulting in reversible airway obstruction and hyper- reactivity

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Pathophysiology

Inflammatory response is driven by T-helper type 2 (Th2-cells)

  • 1. Bronchial inflammation
  • Terminal bronchioles
  • 2. Bronchial obstruction
  • Increased mucous production and mucosal
  • edema
  • Bronchospasm
  • Smooth muscle hypertrophy
  • 3. Bronchial hyperresponsiveness
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Classifications

Allergic asthma (extrinsic)

  • Allergen
  • IgE-mediated type 1 hypersensitivity
  • Mast cell degranulation and histamine release

Non-allergic asthma (intrinsic)

  • Irritants and other external factors
  • Neutrophil release
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Differentials

Asthma COPD Alpha-1 antitrypsin deficiency Bronchiectasis Aetiology

  • Th2-cells and IgE

type 1 hypersensitivity

  • Macrophages

and neutrophils

  • Genetic
  • Recurrent

pulmonary infections Features

  • Wheezing, cough

and dyspnoea

  • Trigger

(allergens, exercise)

  • Diurnal variation
  • Smoking history
  • Dyspnoea occurs

with or without wheezing

  • Progressive
  • Irreversible

airway

  • bstruction
  • Young onset
  • Wheezing
  • FHx of lung

disease

  • Liver dysfunction
  • Wheezing, cough

and dyspnea

  • High-resolution

CT: bronchial wall thickening

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Investigations: diagnostic

Primary investigations

  • Fractional exhaled nitric oxide (FeNO): inflammatory cells produce nitric oxide (> 40 ppb)
  • Spirometry : FEV1/FVC < 70%

Investigations to consider

  • Bronchodilator reversibility: improvement of FEV1 by ≥ 12%
  • Peak flow rate (PEFR): variability of > 20% throughout the day
  • Airway hyperreactivity testing: histamine or methacholine direct bronchial challenge
  • Allergy testing: for allergic asthma
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Investigations: exacerbation

Bedside

  • PEFR
  • Moderate: 50–75%
  • Severe: 33–50%
  • Life-threatening: < 33%

Bloods

  • FBC: leukocytosis, eosinophilia and neutrophilia may be present
  • Arterial blood gas: may demonstrate acidosis or respiratory failure

Imaging

  • Chest x-ray: hyperexpanded chest, with or without focal signs
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Levels of severity

Moderate Severe (any one of) Life-threatening (any one of) Near-fatal

  • Worsening

symptoms

  • Peak flow 50-75%
  • Peak flow 33-50%
  • RR ≥ 25
  • HR ≥ 110
  • Unable to complete

sentences in one breath Clinical signs

  • Reduced

consciousness

  • Exhaustion
  • Arrhythmia
  • Low BP
  • Cyanosis
  • Silent chest
  • Poor respiratory

effort Measurements

  • Peak flow < 33%
  • SpO2 < 92%
  • PaO2 < 8 kPa
  • 'Normal’ PaCO2

One or both of:

  • High PaCO2
  • Mechanical

ventilation

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Management: chronic (adult >16 years)

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Management: exacerbation

General management for all severities:

  • Oxygen: use in life-threatening asthma or if SpO2 <94%

Inhaled salbutamol +/- ipratropium bromide:

  • Nebulisers are generally used for exacerbations and can be given ‘back to back’

Corticosteroid:

  • Oral prednisolone is given if alert, otherwise, offer IV hydrocortisone
  • Steroids take a few hours to work and a course of 3 days is usually sufficient

Severe or life-threatening exacerbation

  • Intravenous bronchodilation: magnesium sulphate may be needed
  • Other IV bronchodilators: second-line options include IV salbutamol and aminophylline
  • Ventilation: if deteriorating despite the above measures

Other considerations

  • Antibiotics: indicated if there is a suspected bacterial infection

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Summary 1 – Asthma

  • Asthma classically presents with a history of dyspnoea, wheeze, and cough, with

diurnal variability

  • According to NICE, FeNO and spirometry are the first-line investigations
  • Offer bronchodilator reversibility or PEFR as additional investigations
  • First-line treatment is with a SABA, followed by an ICS. A leukotriene antagonist is

then added if symptoms remain poorly controlled

  • Acute exacerbations are generally managed with bronchodilators and steroids

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Case 2

History A 62-year-old male presents with a one-month history of coughing up blood. He has felt generally lethargic recently and mentions that his clothes are feeling loose. On examination, you note tar staining of his fingernails. Some routine bloods are taken and show the following:

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Hb 135 g/L (135 - 180) WCC 10.9 X 109/L (4.0-11.0) Na 126 mmol/L (135-145) K 4.5 mmol/L (3.5-5.5) Creatinine 70 μmol/L (55-120)

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Aetiology

Majority of lung cancers are primary bronchial carcinomas. Risk factors

  • Smoking (85% of lung cancer cases)
  • Family history
  • Asbestos exposure
  • Pollution
  • Radon exposure
  • Idiopathic pulmonary fibrosis

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Classifications

Small-cell lung cancers (SCLCs)

  • 15% of lung cancers
  • Derived from neuroendocrine Kulchitsky cells
  • Rapid growth and patients present in an advanced stage

Non-small cell lung cancers (NSCLCs)

  • 85% of lung cancers
  • Squamous cell, adenocarcinoma, large-cell, carcinoid tumours and bronchoalveolar

cells

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Pathophysiology

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SCLC NSCLC Small cell (10-15%) Squamous-cell (25-30%) Adenocarcinoma (40%) Large-cell (10-15%) Location Central lesion Central lesion Peripheral lesion Peripheral lesion Smoking Strong link Strong link Lower link Strong link Paraneoplastic syndrome

  • SIADH
  • Cushing’s

syndrome

  • Lambert-Eaton

syndrome

  • Cerebellar

syndrome

  • Hypertrophic

pulmonary

  • steoarthropathy
  • PTHrP:

hypercalcaemia

  • Hypertrophic

pulmonary

  • steoarthropathy
  • Hypertrophic

pulmonary

  • steoarthropathy
  • Ectopic βHCG

secretion

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Cancer referral pathway

Cancer referral (within 2 weeks) if:

  • CXR findings suggestive of lung cancer or
  • > 40 years old and have unexplained haemoptysis

Urgent CXR (within 2 weeks) if:

  • > 40 years old and 2 of the following or PMHx of smoking and 1 of the following:
  • Fatigue
  • Cough
  • SOB
  • Chest pain
  • Weight loss

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Investigations

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Bloods: not diagnostic but may reveal evidence of paraneoplastic syndromes

  • U&Es: hyponatraemia in SIADH
  • Bone profile: hypercalcaemia

Imaging

  • CXR: coin lesion
  • CT chest: if CXR is abnormal, conduct CT chest and image the abdomen for

staging

  • PET-CT: staging

Special tests

  • Biopsy: either percutaneous if peripheral, or EBUS if central
  • Mediastinoscopy: assess for mediastinal lymphadenopathy as CT not always

sensitive

  • Spirometry: assess fitness prior to surgery. FEV1 < 2L is a contraindication for

pneumonectomy

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Investigations

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Investigations

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Investigations

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Investigations

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Management

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In general, NSLC is treated surgically, whereas SCLC is treated with chemoradiotherapy and is often too advanced at diagnosis for surgery. Smoking cessation is key for all patients.

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Management: SCLC

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Limited disease (confined to ipsilateral hemithorax): chemoradiotherapy

  • Surgery is only appropriate for a very small subset of patients with early disease

Extensive disease: chemoradiotherapy Limited disease Extensive disease Chemoradiotherapy with platinum- based agents Surgery for early disease (TI-IIa) Chemoradiotherapy

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Management: NSCLC

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Non-metastatic disease (stage I-IIIa): curative surgery; lobectomy or pneumonectomy

  • Usually with adjuvant chemotherapy
  • Curative radical radiotherapy is an alternative

Metastatic disease (stage IIIb and above): palliative treatment with immunotherapy, chemotherapy, and radiotherapy Non-metastatic disease Metastatic disease Stage I-IIIa: Curative surgery +/- chemotherapy Stage IIIb and above: Palliative treatment

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Summary 2 – Lung cancer

  • NSCLC accounts for 85% of cases
  • Lung cancer is associated with paraneoplastic syndromes
  • Urgent referral: patients with a suspicious CXR or those aged ≥40 with unexplained

haemoptysis

  • Urgent CXR: aged ≥40 with two or more persistent symptoms (e.g. cough, weight

loss, fatigue) or smokers with one or more symptoms

  • Staging involves CT and PET, alongside other specialist investigations
  • SCLC: chemoradiotherapy is the main treatment
  • NSCLC: surgery is the main curative treatment, with adjuvant chemotherapy

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Further information

  • We need your feedback!
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  • Stay up-to-date!
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  • Want to get involved? Contact us at
  • pportunities@bitemedicine.com to get your information pack

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References

1) United States-National Institute of Health: National Heart, Lung, Blood Institute / Public domain. https://upload.wikimedia.org/wikipedia/commons/4/4a/Asthma_attack-illustration_NIH.jpg 2) James Heilman, MD / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). https://upload.wikimedia.org/wikipedia/commons/0/03/LungCACXR.PNG 3) Lange123 / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/). https://upload.wikimedia.org/wikipedia/commons/3/3f/Thorax_CT_peripheres_Brronchialcarcinom_li_ OF.jpg

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