Aas_Study

Smallpox / Obituary / Variola Definition : It is an acute viral disease caused by variola virus characterised by sudden onset of high grade fever associated with prostration malaise, headache, vomiting and sometime convulsion. Followed by typical rashes ( macule, papule, vesicle, pustule and scab) starting from limbs and face than spread toward the trunk. The disease eradicated now from the world. Last case seen in India - 1975 India was free declare in - 1977 Last case of the world in Somalia - 1978 The disease eradicated from the world - 08/05/1988 FACTOR RESPONSIBLE FOR ERADICATION OF THE DISEASE :- Only single reservoir (Man). No animal reservoir. Vaccine was highly effective (100%). Low infectivity (30-40%). Long incubation period. Easy diagnosis. No sub-clinical cases. International co-operation.  AGENT FACTORS Agents : Variola virus. Reservoir Of Infection : Only man. Source Of Infection : Case - clinical case. Infective Material : N...

Primary Atypical Pneumonia / Viral Pneumonia / Mycoplasmal Pneumonia / Interstitial Pneumonia Viral pneumonia is characterised by patchy inflammatory changes, generally confined to interstitial tissue of the lungs without any alveolar exudate. Most of the cases are mild and momentary but some cases may be severe and fulminant. Etiology :  Interstitial pneumonia occasionally associated with psittacosis (Chlamydia) and Q fever (Coxiella). Viruses that cause viral pneumonia - i. Respiratory Syncytial Virus (RSV) - (Most common). ii. Mycoplasma pneumoniae. iii. Influenza and para-influenza viruses. iv. Adenoviruses. v. Rhinoviruses. vi. Coxsackieviruses. vii. Cytomegaloviruses (CMV). In most cases, the infection of upper respiratory tract remains such as common cold. It may be extend to lower respiratory tract and involve the interstitium of the lungs. Other conditions that may be accelerate to the viral pneumonia i.e. malnutrition, chronic debilitating disea...

Measles / Rubeola Definition : It is an acute highly infectious viral disease caused by paramyxovirus and characterised by fever, cough and coryza. Followed by macular or maculopapular rashes starting from behind the ear and spread to face, trunk and limbs. AGENT FACTORS Agents : RNA paramyxovirus - only one serotype and can't survive outside the body. Reservoir Of Infection : Man is obligate (only) host. Source Of Infection : Case of measles (no carrier state to occur in measles) and sub-clinical cases are few. Infective Material : Nasal secretions and Oropharyngeal secretions. Period Of Communicability : Highly communicable in prolonged stage and early stage. 4-5 days before and after appearance of rashes. HOST FACTORS Age  : It is a childhood disease, common age is 6 month to 3 years in developing countries and 5 year or more in developed countries. Sex : Equal effect in both sexes. Immunity : Single attack or vaccination, gives life long immuni...

Chickenpox / Varicella  Definition : It is an acute viral highly infectious disease caused by varicella-zoster (V-Z) virus. It is characterised by sudden onset of fever followed by appearance of rashes (macule, papule, vesicle and scab), starting from trunk and spread to face and limbs. AGENTS FACTORS  Agents : Varicella-Zoster / Human (alpha) herpes virus 3 Source of infection : Person to person contact or direct contact. Infective material : Nasopharyngeal secretions, Oropharyngeal secretions, Lesions of skin & mucosa and Vesicular fluid. Period of communicability : 1-2 days before and 4-5 days after appearance of rashes.  Secondary Attack Rate : Chickenpox is highly communicable. SAR is 90% HOST FACTORS  Age : Below than 10 years is common. Sex : Equal effects on both sexes. Immunity : One attack gives durable immunity and second attack is rare. Pregnancy : Risk present for fetus. ENVIRONMENTAL FACTORS  Season : Fir...

Pneumonias  Definition :  It is an acute inflammation of lungs parenchyma with consolidation distal to terminal bronchioles ( consisting of the respiratory bronchiole, alveolar ducts, alveolar sacs and alveoli ).It may be infective and non-infective. Pathogenesis :  Microorganism can enter into the lungs by following route after  failure of defensive mechanism  - i. Inhalation of air microbes. ii. Aspiration of the microbes from the nasopharynx or oropharynx. iii. Haematogenous spread from a distant focus of infection such as - vector population, environmental characteristics. iv. Direct spread from a adjoining site of infection. Classification : 1. On the basis of anatomical regions - Lobar Pneumonia Bronchopneumonia or Lobular Pneumonia Interstitial Pneumonia Features of lobar and lobular pneumonia 2. On the basis of clinical aspects - Community-acquire Pneumonia Health care-associated Pneumonia (Hospital acquired Pneumonia) Ve...

Legionella pneumonia or Legionnair's disease It is a epidemic disease caused by gram-negative bacilli, legionella pneumophila that thrives in aquatic environment. It was first recognised in those person that attending American legion convention in Philadelphia in july 1976 and hence the name. Etiopathogenesis : This disease is epidemic occur in summer season due to i. Spread of organism through contaminated water or air conditioning cooling towers. ii. Immunosuppressed person ( corticosteroid therapy, old age) iii. Cigarette smoking MORPHOLOGICAL FEATURES : Grossly :  i. Consolidation of the entire lung. ii. Pleural effusion is frequently present. Histologically :  i. Intra-alveolar exudate, initially of neutrophils later composed mainly macrophages. ii. Alveolar septa shows  foci of hyperplasia of the lining epithelium and thrombosis of vessels in the septa. iii. Special stains shows organism in the macrophages. Features ...

Bronchopneumonia (Lobular Pneumonia) Definition : Lobular pneumonia is the infection of the terminal bronchioles that extends into the surrounding alveoli resulting in patchy consolidation of the lung. Founds in extreme of ages ( infants and old age). Etiology : The common organism that responsible for bronchopneumonia is - 1. Staphylococci 2. Streptococci 3. Pneumococci 4. Klebsiella pneumoniae 5. Haemophilus influenzae 6. Gran-negative bacilli ( pseudomonas and caliform bacteria ). MORPHOLOGICAL FEATURES : Grossly : Lobular pneumonia is identified by patchy areas of red and grey consolidation at the affected part. Frequently found bilaterally and more common in lower zone of the lungs. Cut surface shows patchy, consolidated lesions are dry, granular, firm, red or grey in color, 3-4 cm in diameter, slightly elevated over the surface and are commonly centred around a bronchiole.  Histologically :  i. Acute bronchiolitis. ii. Suppurative exudate...

Pneumonias  Definition : It is an acute inflammation of lungs parenchyma with consolidation distal to terminal bronchioles ( consisting of the respiratory bronchiole, alveolar ducts, alveolar sacs and alveoli ).It may be infective and non-infective. Pathogenesis : Microorganism can enter into the lungs by following route after failure of defensive mechanism - i. Inhalation of air microbes. ii. Aspiration of the microbes from the nasopharynx or oropharynx. iii. Haematogenous spread from a distant focus of infection such as - vector population, environmental characteristics. iv. Direct spread from a adjoining site of infection. Classification : 1. On the basis of anatomical regions - Lobar Pneumonia Bronchopneumonia or Lobular Pneumonia Interstitial Pneumonia Features of lobar and lobular pneumonia 2. On the basis of clinical aspects - Community-acquire Pneumonia Health care-associated Pneumonia (Hospital acquired Pneumonia) Ventilator-associated Pne...

How To Failed Lungs Defense Mechanism The lungs are bacteria free in normal condition because presence of high defense mechanism such as-  Nasopharyngeal filtering action Mucociliary action of the lower respiratory airways The presence of alveolar macrophages and immunoglobulins.  Failure of these defense mechanism in certain conditions and may developed pneumonia - 1. Altered consciousness :  The oropharyngeal contents may be aspirated and causing unconsciousness such as in - Coma Cranial Trauma Seizures Cerebrovascular accidents Drugs overdose Alcoholism 2. Depressed cough and glottic reflexes :   In this condition aspirated gastric contents in to the lungs such as in - Old age Traumatic pain or Thoracoabdominal surgery Neuromuscular disease Weakness due to malnutrition Kyphoscoliosis Severe Obstructive Pulmonary Disease Endotracheal intubation Tracheostomy 3. Impaired mucociliary transport :  The normal protection offer...

Pneumothorax An accumulation of air in the pleural cavity called pneumothorax. Classification :  1. Spontaneous pneumothorax 2. Traumatic pneumothorax 3. Therapeutic or artificial pneumothorax 1. Spontaneous Pneumothorax : It occur due to spontaneous rupture of alveoli in any disease of lungs. Causes : Most commonly associated with -  i. Emphysema ii. Asthma iii. Tuberculosis Other causes are :  i. Chronic bronchitis, Bronchiectasis, Pulmonary infarction and Bronchial cancer ( in old patient). ii. Recurrent spontaneous rupture of peripheral subpleural blebs without any cause called Spontaneous Idiopathic Pneumothorax ( in young patient ). 2. Traumatic Pneumothorax : It is occur due to traumatic cause called traumatic pneumothorax. Causes :  i. Chest wall or lungs trauma. ii. Ruptured oesophagus or stomach. iii. Surgical operation of the thorax. 3. Therapeutic or artificial Pneumothorax : It is the first positive t...

Chylothorax Accumulation of milky fluid of lymphatic origin into the pleural cavity called chylothorax. It is occur mostly left side. Chylous effusion is milky due to high content of finely emulsified fats in the chyle.  Causes :  i. Most common cause are rupture of the thoracic duct by trauma. ii. Obstruction of the thoracic duct by malignant tumors and malignant lymphomas. Source : Textbook of pathology (Harsh Mohan) 7th edition

Haemothorax Accumulation of pure blood in the pleural cavity called haemothorax. Causes :  i. Trauma to the chest wall or thoracic viscera. ii. Rupture of aortic aneurysm. ANEURYSM : an excessive localized enlargement of an artery cause by weakening of the artery wall. Complications : Remove the blood from the pleural cavity early as soon as possible. Otherwise the blood will be clot and organise, resulting in fibrous adhesions and obliteration of the pleural cavity. Source : Textbook of pathology ( Harsh Mohan) 7th edition 

Hydrothorax Accumulation of serous fluid within the pleural cavities called hydrothorax. It may be unilateral or bilateral depending upon the causes. Causes : i. Congestive heart failure (most common cause of bilateral hydrothorax). ii. Renal failure iii. Cirrhosis of liver iv. Meig's syndrome (triad of benign Ovarian tumor with Ascites and Pleural effusion) v. Pulmonary Oedema vi. Primary and secondary tumours of the lungs. On Examination : i. color of serous fluid are clear and straw-colored with characteristically  transudate. ii. Specific gravity is under 1.012 iii. Protein contents below 1gm/dl and find little cellular content also. Clinical Features :  If the fluid collection in pleural cavity is less than 300 ml ( normal less than 15 ml) no signs or symptoms are produced and may be appear in chest X-rays in standing posture as obliterated costodiaphragmatic angle. If fluid collection in pleural cavity is more than 300 ml that is the...