basic lung disease

8/10/2019 Basic Lung Disease

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Basic concepts in Lung disease


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Contents

Embryology Anatomic concepts Physiologic concepts Pathology Clinical : symptoms

physical signsdisease patterns


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Anatomic Concepts Embryology : lung development starts from the

gut 24 days after conception; diaphragm forms incervical region at 3-4 weeks and moves

progressively downwards carrying the phrenicnerves with; lung lobes are identifiable at 12weeks; bronchial tree is completed at 16 weeksand alveoli and capillaries appear at 24 28weeks; surfactant appears at 35 weeks.

Postnatal Alveolarization: intense first 8-10 y(alveolar buds hyperplastic growth) andenlargement of all structures throughoutadolescence and early adulthood ( hypertrophicgrowth)


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Developmental abnormalities: tracheo-oesophagealfistula, cleft palate, cysts, agenesis, sequestration,cilia dysfunction and abnormal structure,diaphragmatic hernias.

Shared nerve supply (Vagus) between respiratorytract and GI tract Gastro-oesophageal reflux canincrease bronchial secretions (reflexively) andcause bronchial constriction ( together withoesophageal spasm).

Diaphragmatic irritation is often experienced as pain in the cervical region (referred pain) fromwhere it evolved.


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Anatomy

Surface Anatomy: borders of the pleura borders of the lung

fissureslung lobes

Bronchial tree, vascular and nerve supply,

lymphatics. Angle of Louis Histology, cilia, secretory and immunologic cells.


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Physiology

Lung mechanics and Lung functions Airway resistance

Diffusion :Gas laws ( Graham, alveoalar gasequation)

Blood gases: PaO 2, PaCO 2, pH, HCO3, O 2 sat

Hemoglobin, dissociation curve, 2,3DPG Surfactant Control of Breathing


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Pathology

Airway diseases: COPD, asthma, bronchiectasis,cystic fibrosis, obstructive sleep apnoea

Parenchymal disease: pneumonia, ARDS,Interstitial lung disease, pneumoconiosis

Pleural disease: pleural effusion, empyema. Vascular disease: thrombo-embolism, primary

pulmonar hypertension Neoplastic disease: Bronchus Ca, mesothelioma,

adenoma, carsinoid


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Airway diseases

Causes: atopy, cigarette smoking, infection,abnormal lung defense

Effect: obstruction to airflow Mechanism: bronchospasm, inflammation, airway

remodelling, destruction, collapsing airways Consequences: air flow ( FEV1, PEF); work

of breathing resp muscle fatigue respiratoryfailure; PaO 2, PaCO 2 PHT cor pulmonale


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Parenchymal disease

consolidation - infection - typical/atypical Oedema - cardiac vs non-cardiac (ARDS)

interstitial lung disease - idiopathic fibrosis,sarcoidosis, hypersensitivity pneumonitis, pneumoconiosis

Vascular secondary/primary PHT, cor

pulmonale, pulmonary thrombo-embolism(unexplained dyspnea); Virchow triade: stasis, coagulability, blood vessel abnormality, varicoseveins, endothelial dysfunction DVT risk


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Pleural disease

Pleural effusion: alb, LDH, pleural/serum,cholesterol, glucose, ADA, pH.

exudate: infection, inflammation, neoplastic, blood ( permeability)

transudate: hypoproteinemia (renal, liver - oncotic pressure), systemic venous hypertension( hydrostatic pressure - Heart failure)

Empyema Chylothorax, pseudo-chylothorax


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Neoplastic disease

Bronchus Ca: squamous, small cell ca,adeno ca, large cell ca, broncho-alveolar ca

Mesothelioma Metastatic ca Rare tumours: lymphoma, malt-lymphoma Benign tumours


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Control and Mechanism of

breathing Alveolar hypoventilation Sleep-related: central and obstructive sleep

apnoea, Ondines curse Neuro-muscular diseases: polio, Guillain-

Barre syndrome, myasthenia gravis, respmuscle fatigue, polimyositis

Chest wall: kyphoscoliosis, rib fractureswith flail chest


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Complications of Lung disease

Cor pulmonale Respiratory failure: ventilatory failure vs

oxygenation failure hypercapnia, acidosisand hypoxaemia

Endstage lung disease

Pneumothorax


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Clinical Manifestations

Dyspnea, PND, orthopnea, trepopnea, platypneaand orthodeoxia.

Cough: productive vs non-productive, volume,character, blood, post-nasal discharge

Chest pain: ischaemic, pleuritic, chest wall, GEreflux, tearing of tissue

Constitutional: fever, night sweats, weight loss RHF: swelling, pain R hypochondrium, abdominaldistention, palpitations


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Physical signs

General: Cyanosis, anaemia, jaundice,oedema, lymphadenopathy, clubbing

Respiratory examination:1. Observation2. Palpation

3. Percussion4. Auscultation


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Auscultation

Intensity of breath sounds: N, or absent Character of breath sounds: N or bronchial

breathing/ amphoric breathing Intensity of vocal sounds: (one-one, 99)N,

(bronchophony) or or nasal ( aegophony)

Whispering pectoriloquy ( 66) Adventitious sounds: ronchi, creps, rubs,clicks.

APPLICATION OF ADVENTITIOUS LUNG SOUNDS


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Lung sounds Possible mechanism Characteristics Causes

Wheezes Rapid airflow through obstructedairways caused by

bronchospasm, mucosal edema

High-pitched; mostoften occur duringexhalation

Asthma, congestive heartfailure, bronchitis

Stridor Rapid airflow through obstructedairway caused by inflammation

High-pitched; oftenoccurs duringinhalation

Croup, epiglottitis, postextubation

Crackles

I nsp & exp Excess airway secretions movingwith airflow

Coarse and often clearwith cough

Bronchitis, respiratoryinfections

Earl y in sp Sudden opening of proximal

bronchi

Scanty, transmitted to

mouth; not affected bycough

Bronchitis, emphysema,

asthma

L ate insp Sudden opening of peripheralairways

Diffuse, fine; occurinitially in dependentregions

Atelectasis, pneumonia, pulmonary edema,fibrosis



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Respiratory system

signs of respiratory distress, hyperinflation,

consolidation, pleural effusion, pneumothorax, sup vena cava obstruction

Abnormality Initial Inspection Palpitation Percussion Ausculation Possible


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impression causesAcute airwaysobstruction

Appears acutelyill

Use ofaccessorymuscles

Reducedexpansion

Increasedresonance

Expiratorywheezing

Asthma, bronchitis

Chronic airways

obstruction

Appears

chronically ill

Increased

antero-posteriordiameter, use ofaccessorymuscles

Reduced

expansion

Increased

resonance

Diffuse reduction

in breath sounds;early inspiratorycrackles

Chronic

bronchitis,emphysema

Consolidation May appearacutely ill

Inspiratory lag Increasedfremitus

Dull note Bronchial breathsounds; crackles

Pneumonia,tumor

Pneumothorax May appearacutely ill

Unilateralexpansion

Decreasedfremitus

Increasedresonance

Absent breathsounds

Rib fracture, openwound

Pleural effusion May appearacutely ill

Unilateralexpansion

Absent fremitus Dull note Absent breathsounds

Congestive heartfailure

Local bronchialobstruction

Appears acutelyill

Unilateralexpansion


Mucous plug

Diffuse intersitialfibrosis

Often normal Rapid shallow breathing

Often normal;increasedfremitus

Slight decrease inresonance

Late inspiratorycrackles

Chronic exposureto inorganic dust

Acute upperairwayobstruction

Appears acutelyill

Laboured breathing

Often normal Often normal Inspiratory orexpiratory stridoror both

Epiglottitis,croup, foreign

body aspiration


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Functions of the lung

Respiration: ventilation and gas exchange Non-respiratory functions:

synthesis, activation and inactivation of vasoactivesubstances, hormones, neuropeptides, eicosanoids,lipoprotein complexes.

Hemostatic functions Lung defense: complement activation, leucocyte

recruitment, cytokines and growth factors


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Lung sounds Possible mechanism Characteristics Causes

Wheezes Rapid airflow through obstructedairways caused by

bronchospasm, mucosal edema

High-pitched; mostoften occur duringexhalation

Asthma, congestive heartfailure, bronchitis

Stridor Rapid airflow through obstructedairway caused by inflammation

High-pitched; oftenoccurs duringinhalation

Croup, epiglottitis, postextubation

Crackles

I nsp & exp Excess airway secretions movingwith airflow

Coarse and often clearwith cough

Bronchitis, respiratoryinfections

Earl y in sp Sudden opening of proximal

bronchi

Scanty, transmitted to

mouth; not affected bycough

Bronchitis, emphysema,

asthma

L ate insp Sudden opening of peripheralairways

Diffuse, fine; occurinitially in dependentregions

Atelectasis, pneumonia, pulmonary edema,fibrosis


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Abnormality Initialimpression

Inspection Palpitation Percussion Ausculation Possiblecauses


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Acute airwaysobstruction

Appears acutelyill

Use ofaccessorymuscles

Reducedexpansion

Increasedresonance

Expiratorywheezing

Asthma, bronchitis

Chronic airwaysobstruction

Appearschronically ill

Increasedantero-posteriordiameter, use ofaccessorymuscles

Reducedexpansion

Increasedresonance

Diffuse reductionin breath sounds;early inspiratorycrackles

Chronic bronchitis,emphysema

Consolidation May appearacutely ill

Inspiratory lag Increasedfremitus

Dull note Bronchial breathsounds; crackles

Pneumonia,tumor

Pneumothorax May appearacutely ill

Unilateralexpansion

Decreasedfremitus

Increasedresonance

Absent breathsounds

Rib fracture, openwound

Pleural effusion May appearacutely ill

Unilateralexpansion


Congestive heartfailure

Local bronchialobstruction

Appears acutelyill

Unilateralexpansion


Mucous plug

Diffuse intersitialfibrosis

Often normal Rapid shallow breathing

Often normal;increasedfremitus

Slight decrease inresonance

Late inspiratorycrackles

Chronic exposureto inorganic dust

Acute upperairwayobstruction

Appears acutelyill

Laboured breathing

Often normal Often normal Inspiratory orexpiratory stridoror both

Epiglottitis,croup, foreign

body aspiration


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basic lung disease

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