Etiology of respiratory system

Written by Dr.Md.Redwanul Huq (Masum)
Saturday, 03 March 2012 05:58

Causes of ARI:

I) Bacterial:

* Streptococcus pneumonae

* Haemophilus influenzae

* Staphylococcus aureus.

II) Viral:

* Respiratory syncytial virus

* Influenza A and B viruses

* Parainfluenza viruses

* Adenoviruses

* Rhinoviruses.

Causes of chest pain:-

1) Central causes:

a) Cardiac – Angina, MI, Pericarditis

b) Aortic- Dissecting aneurysm

c) Pulmonary/ mediastinum- Massive embolus, tracheitis, mediastinal malignancy

d) Esophageal- Esophagitis, esophageal spasm

e) Neurological/ skeletal- Herniated intervertebral disc

f) Psychogenic- Anxiety.

2) Peripheral causes:

a) Lungs/ pleura: Lobar pneumonia, pneumothorax, pulmonary infarction, malignancy

b) Chest wall disorder related causes of chest pain: Rib fracture or injury, intercostal muscle injury, costochondritis

c) Neurological/ skeletal: Herniated intervertebral disc.

d) Psychogenic- Anxiety.

Causes of Cheyne- Stokes breathing:


Cyclical repetition of hyperapnea followed by apnea.


1) LVF (Left ventricular Failure)

2) Central respiratory depression

3) Narcotic drug poisoning

4) In infants.

Causes of Chronic bronchitis:

1. Air pollution

a) Outdoor

b) Indoor (due to solid fuel used for cooking and heating)

2. Cigarette smoking

a) Active

b) Passive

3. Hyper responsiveness of the airway.

Causes of Dyspnea:


Abnormal, unpleasant awarness of breathlessness.


A) Acute dyspnea-

1) Cardiovascular cause- Pulmonary edema

2) Respiratory causes- Severe acute bronchial asthma, acute exacerbation of COPD, Acute pulmonary embolism, pneumonia

3) Miscellaneous- Metabolic acidosis, psychogenic dyspnea.

B) Chronic dyspnea-

1) Cardiovascular causes- CCF, Ischemic heart diseases (IHD)

2) Respiratory causes- Bronchial asthma, COPD, large pleural effusion, bronchogenic carcinoma, interstitial lung disease (e.g. Sarcoidosis)

3) Miscellaneous- Severe anemia, obesity.

Causes of Emphysema:

  1. Cigarette smoking

a. Active

b. Passive

2. Alpha-1-anti trypsine deficiency:

a. Family history of emphysema- positive

b. May be associated with liver disease.

Most important causes of hemoptysis:-

1) Pulmonary TB

2) Bronchiectasis

3) Bronchogenic carcinoma

4) Pulmonary infarction

5) Mitral stenosis.

Causes of pleural effusion:

According to the nature of fluid:

1. Exudative:

a) Tuberculosis

b) Pneumonia

c) Bronchogenic carcinoma

d) Lymphoma

e) SLE

f) RA

g) Pulmonary infarction

2. Transudative:

a) Congestive cardiac failure (CCF)

b) Cirrhosis of liver

c) Nephrotic syndrome

d) Malnutrition

e) Dressler’s syndrome

f) Meig’s syndrome

According to the site:


a) Tuberculosis

b) Pneumonia

c) Bronchogenic carcinoma

d) Pulmonary infarction

e) Rheumatoid arthritis

f) SLE

g) Lymphoma

2.Unilateral causes of pleural effusion:

a) Any of the side:

i) Tuberculosis

ii) Pneumonia

iii) Bronchogenic carcinoma

iv) Pulmonary infarction

v) Meig’s syndrome

b) Only in the right side:

Subphrenic abscess (e.g. Liver abscess)

c) Only in the left side:

i) Acute pancreatitis

ii) Pancreatic pseudo cyst

iii) Dressler’s syndrome

iv) Esophageal perforation.

Causes of restricted movement of either side of the chest:

1.Pneumonic consolidation

2.Pleural effusion





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