Introduction of Respiratory Diseases pdf - D. Majeed

Dr.Majeed M.Al-Hamammi

lectures

year

Medical college

Thi- Qar 2019-2020

Respiratory disease

•

Pulmonary medicine

•

Pulmonology

•

Respiralogy

Objectives

• At the end of this lecture we should be Know

and familiar with

Respiratory physiology
Respiratory anatomy
-Respiratory symptoms.
-Respiratory signs.
-Investigation of respiratory diseases.

Respiratory disease

Is responsible for a major burden of morbidity

and mortality, and conditions such as

• tuberculosis,
• pandemic influenza
• pneumonia

are the most important conditions in world

health terms.

• The increasing prevalence of allergy, asthma

and chronic obstructive pulmonary disease
(COPD) .

• By 2025, smokers world-wide is anticipated to

increase to 1.5 billion.

FUNCTIONAL ANATOMY AND

PHYSIOLOGY

• The lungs occupy the upper two-thirds of the

bony thorax, bounded medially by the spine,
the heart and the mediastinum and inferiorly
by the diaphragm.

Inspiration

• downward contraction of the dome-shaped

diaphragm .

• contraction of the external intercostal

muscles.

Expiration

• largely passive, driven by elastic recoil of the

lungs.

• The increased demand in inspiration and

expiration operate accessory muscles.

The conducting airways

• from the nose to the alveoli connect the

external environment with the extensive, thin
and vulnerable alveolar surface.

• In the glottis and trachea, obstruction by

foreign bodies and tumours.

• in the third-generation respiratory, very slow

flow rates.

Control of breathing

• The respiratory motor neurons in the medulla

oblongata sense the pH of the cerebrospinal fluid (CSF)
and are indirectly stimulated by a rise in arterialPCO2.

• The carotid bodies sense hypoxaemia but are mainly

activated by arterial PO2 values below 8 Kpa (60
mmHg). They are also sensitised to hypoxia by raised
arterial PCO2..

• Muscle spindles in the respiratory muscles sense

changes in mechanical load.

• Cortical influences can override the automatic control

of breathing.

Ventilation/perfusion matching and the pulmonary

circulation

• Gravity determines the distribution of ventilation

and blood flow in the lungs.

• Hypoxia constricts pulmonary arterioles
• Hypercapenia dilates bronchi.
• Lung disease

which disturb the physiological

matching of regional ventilation and perfusion,

causing respiratory failure .

• Diseases that destroy or thicken the alveolar

capillary membrane (e.g. emphysema or fibrosis)

can impair gas diffusion directly.

Model of airway branching in human lung by regularized

dichotomy from trachea (generation z = 0) to alveolar ducts and sacs

(generations 19–23). The first 14 generations are purely conducting; transitional

airways (generation 15) lead into the acinar airways with alveoli

that branch over 8 generations (z′).

Location of major upper andlower airway receptors

Functional anatomy of the lungs

Lung defences

• Upper airway defences
• nasal hairs.
• the columnar ciliated epithelium.
• cough.
• The larynx.

Lower airway defences
Non specific defences
• mucociliary escalator.
• Airway secretions contain an array of

antimicrobial peptides.

Macrophages.

Adaptive immune defence
• Lung dendritic cells.
• CD4 T-helper

Surface view of bronchiolar epithelium shows tufts of

cilia (Ci) forming on individual ciliated cells and microvilli (MV) on

other cells. Note secretion droplet in process of release from goblet

cell (arrow).

Mucociliary escelator

PRESENTING PROBLEMS IN RESPIRATORY

DISEASE

Cough

• The most frequent symptom of respiratory

disease.

• Sputum production is common
• Acute   less than 3 weeks.
• Subacute 3 -8   weeks.
• Chronic    more than 8 weeks.

Acute transient cough

• Viral lower respiratory tract infection.
• post-nasal drip resulting from rhinitis or sinusitis,
• aspiration of a foreign body,
• laryngitis
• pharyngitis.
 Cough occurs in the context of more serious diseases,

pneumonia.

• Aspiration.
• Congestive heart failure.
• pulmonary embolism.

chronic cough

1. cough-variant asthma.
2. post-nasal drip secondary to nasal or sinus

disease.

3. gastro-oesophageal reflux with aspiration.
4. angiotensin-converting enzyme (ACE)

inhibitors .

5. Bordetella pertussis infection in adults .

Respiratory stimuli contributing to breathlessness. Mechanisms by which disease can

stimulate the respiratory motor neurons in the

medulla. Breathlessness is usually felt in proportion to the sum of these stimuli.

Further explanation is given on page 543. (V / Q = ventilation/perfusion

match)

Breathlessness

Pathophysiology :

• Respiratory diseases can stimulate breathing and

dyspnoea by:

• stimulating intrapulmonary sensory nerves .
• increasing the mechanical load on the respiratory

muscle.

• causing hypoxia, hypercapnia or acidosis,

stimulating chemoreceptors.

Differential diagnosis of acute breathlessnss

Chest pain :differential diagnosis

Haemoptysis

Coughing up blood.

Many episodes of haemoptysis remain
unexplained even after full investigation

Causes of haemoptysis

Bronchial disease

 Carcinoma
 Bronchiectasis
 Acute bronchitis
 Others.

Parenchymal disease
• Tuberculosis
• Others.

• Lung vascular disease
• Pulmonary infarction
• Goodpasture's syndrome
• Others.

• Cardiovascular disease
• Acute left ventricular failure.
• Mitral stenosis .
• Others.

• Blood disorders
• Leukaemia
• Others

pleural effusion

• Causes of pleural effusion Common causes

Pneumonia ('para-pneumonic effusion')

• Tuberculosis
• Pulmonary infarction*
• Malignant disease
• Cardiac failure*
• Subdiaphragmatic disorders (subphrenic

abscess, pancreatitis etc.)

Uncommon causes

• Hypoproteinaemia*

(nephrotic syndrome, liver failure, malnutrition)

• Connective tissue diseases* (particularly systemic lupus

erythematosus (SLE) and rheumatoid arthritis)

• Acute rheumatic fever
• Post-myocardial infarction syndrome
• Meigs' syndrome (ovarian tumour plus pleural effusion)
• Myxoedema*
• Uraemia*
• Asbestos-related benign pleural effusion

Sputum

Signs in respiratory disease

INVESTIGATION OF RESPIRATORY DISEASE

• Imaging

• The 'plain' chest X-ray
• A postero-anterior (PA) film
• lateral film.

Normal lateral CXR

Computed tomography (CT)
CT provides detailed images of the pulmonary

parenchyma, mediastinum, pleura and bony
structures .

• High-resolution CT (HRCT)
• CT pulmonary angiography (CTPA)
Positron emission tomography (PET)
The radiotracer taken up by malignant tissue.