pathophysiology

 Pathophysiology of Asthma:

                                                           Asthma


defination: Asthma is a chronic inflammatory disease of the airways in which variable periodic symptoms occurs, along with air flow obstruction,and bronchial hyper-responsiveness, is termed asthma.

Types:

1.Extrinsic:This type is initiated by a type-1 hypersensitivity(atopic) response to an extrinsic antigen.

2.Intrinsic: This type is initiated by non-immune mechanisms,such as respiratory tract infections,exercise,aspirin,emotional upset and exposure to bronchial irritants

Asthma was reclassified in to following type:

1.Atopic Asthma: This Asthma is of type I IgE-mediated hypersensitivity reaction.The attack of atopic asthma is caused by allergens in dust,pollen,animal dander,food etc.

2.Non-atopic Asthma: The asthmatic pateints do not show allergen sensitisation, and the skin tests for diagnosis are negative.Non-atopic asthma is caused by viral respiratory infections i.e, rhinovirus and parainfluenza virus and inhaled air pollutants i.e sulphur dioxide,ozone and nitrogen dioxide

3.Drug- induced Asthma:This type of asthma is caused by certain pharmacological agents like aspirin sensitive patients,bronchospasm.

4.Occupational Asthma: This type of asthma is caused by fumes,organic and chemical dust and other chemicals .

Etiology:Genetic factors along with environmental exposure to inhaled allergens result in allergens result in allergic reactions or irritate the airways.

1.Indoor allergens

2.Outdoor allergens

3.Tobacco smoke

4.Chemical irritants in workplace

5.Air pollution

Pathogenesis:When the type2 helper T cells are activated,they produce cytokines responsible for most of the features of atopic asthma; for example production of IgE by IL-4 and IL-13,activation of esonophils by IL-5, and production of mucus by IL-13.The submucosal mast cells when get exposed to allergens,release their granules content,cytikines and other mediators,two types of reactions are produced by these mast cell derived mediators

1.Early phase or intermediate reaction: Bronchoconstriction,increased mucus production,and vasodialation are the chief characteritics of this reaction

2.Late-phase reaction:This reaction is inflamatory,and the mediators stimulate production of chemokines by the epithelial cells.





                                                                  Fig:1  Airway of asthma



                                                               Fig:2 Triggering of Asthma



Signs and symptoms:

1.Coughing( worse at night)

2.Wheezing

3.Breathlessness

4.Feel of tightness,pain,pressure in chest

Complications:

1. Status asthmaticus is a sustained state of asthma which results when airways remain blocked for prolonged periods and also do not respond to any treatment.

2.Pneumonia is a bacterial or viral lung infection.

3.Respiratory failure occurs when the blood oxygen levels declines markedly or the carbon dioxide levels inclines.

4, Anxiety,depression,stress



Comments

Post a Comment

Popular posts from this blog

BPPK QUESTION PAPER SET FOR PRACTICE

  SET-1 SECTION-A  very short answer.                                                                          (2-mark x 10= 20) 1.         Explain pore transport mechanism. 2.          What is first pass effect? 3.        What do you mean by apparent volume of Distribution? 4.        IVIVC 5.          What do you mean by onset of action and AUC ? 6.          What do you mean by rate constant and order of reaction? 7.     ...
Read more

NON-LINEAR PHARMACOKINETICS

Image
  Difference between Linear and non linear pharmacokinetics LINEARPHARMACOKINETIC a. Change in plasma concentration due to ADME process is proportional to dose of drug administered (single or multiple) b.Follow First order kinetics c. Semilog plot for concentration vs time is super imposable (Principle of superimposition) d.No change in F, Ka, Ke, Vd, Clearance etc. NONLINEAR PHARMACOKINETIC a.Rate process of ADME are dependent on carrier or enzymes having definite capacity and subjected to saturation. b.Change in concentration is no more proportional to dose administered during the total process of ADME. c.Follow First order + Zero order kinetics d.Change in different pharmacokinetic parameters. Stages where non-linearity occurs: Non-linearity can occur at any of the following stage during the fate of drug in body: a.Absorption b.Distribution c.Biotransformation/Metabolism d.Excretion Causes of non-linearity a.During absorption i.Absorption is solubility or dissolution rate limite...
Read more

PRESCRIPTION

Image
  Prescription: Definition : Prescription is a written order from a registered medical practitioner  or other licensed practitioners, such as dentist, veterinarian etc to a registered pharmacist to compound and dispense a specific medication for the patient. Types of prescription : 1. Compounded prescription :  These precriptions are also known as formula magistralis, Each required drugs in the prescription is written on a separate line in a sequence. Ingredients in the prescription are written in the following pattern. i) Basis: This includes the principal drug which gives its primary action to the prescription. ii) Adjuvant: This includes the substance which helps in increasing the action of main ingredient. iii) Vehicle: This is used as a solvent in the solution in order to increase the size and volume or dilute the mixture. 2. Non compounded Prescription : These prescriptions are also called formula officinalis. It is a pre-compounded order comprising of either a sing...
Read more