Hypersensitivity pneumonitis

IT IS AN ALLLERGIC DISORDER .

1. HYPERSENSITIVITY PNEUMONITIS BY HARSHAD KHAN SIRAJ GROUP 16 TBILISI STATE MEDICAL UNIVERSITY

2. HYPERSENSTITVITY PNEUMONITIS (HP) IS REFERRED TO EXTRINSIC ALLERGIC ALVEOLITIS, IS A PULMONARY DISEASE OCCURS DUE TO INHALLATION OF A VARIETY OF ANTIGENS LEADING TO AN INFLAMMATORY RESPONSE OF ALVEOLI AND SMALL PASSAGES. DEFNITION

3. THE INCIDENCE AND PREVALENCE OF HP IS VARIABLE DEPENDING ON, GEOGRAPHY OCCUPATION IN US 420-3000 PEOPLE ARE AFFECTED IN 100000 PEOPLE. IT IS UNEXPLAINED THAT THERE IS A DECREASED RISK OF DEVELOPING HP IN SMOKERS. STATISTICS AND EPIDYMOLOGY

4. HP CAN BE CAUSED BY A LARGE NUMBER OF OFFENDING INHALLED ANTIGENS VARIOUS ANTIGEN AND ENVIRONMENTAL CONDITIONS IS ALSO INVOLVED ANTIGEN DERIVED FROM BACTERIA, FUNGI, BIRD DERIVED, CHEMICAL SOURCES IS ALSO IMPLICATED TO CAUSE HP. IN US FARMERS,BIRD OWNERS,INDUSTRIAL WORKERS,HOT TUBE WORKERS IS ALSO AFFECTED. ETIOLOGY

5. BIRD OWNERS : BIRD FEATHRES, DROP PING, SERUM PROTEINS FARMERS: GRAIN, MOLDY HAY, SILAGE INDUSTRIAL WORKERS : CHEMICAL WORKERS : FOAM,VARNISH DETERGENT WORKERS : DETERGENT MACHINE OPERATOR : METAL WORKING FLUID SOURCES AFFECTING

6. THE PATHOPHYSIOLOGY OF HP HAS NOT BEEN CHARACTERIZED UPTO THE LEVEL OF IMMUNOLOGY. BUT IT HAS BEEN CHARACTERIZED AS A CONDITION WITH TH1 INFLAMMATORY PATTERN. HOWEVER EMERGING EVIDENCES SHOW THAT TH17 LYMPHOCYTES IS ALSO INVOLVED. THERE ARE IgG ANTIBODIES PARTICIPATING AGAINST HP ANTIGENS IN ADAPTIVE IMMUNITY. BUT THE ROLE OF INNATE IMMUNITY IS ALSO IMPORTANT. IT IS OBSERVED THAT TOLL LIKE RECEPTORS (TLR) AND DOWN STREAM REGULATORY PROTEINS SUCH AS MYD88 IS ALSO ACTIVATED. MHC CLASS 2 IS ALSO OBSERVED. PA THOGENESIS

7. THERE IS A HETEROGENECITY AMOUNG PATIENTS, VARAIBILITY IN ANTIGEN EXPOSURE AND DURATION OF ANTIGEN EXPOSURE. CLASSIFICATION ACUTE SUB ACUTE CHRONIC ACUTE HP MANIFESTS 4-8 HRS AFTER EXPOSURE TO ANTIGEN,OFTEN INTENSE IN NATURE. SYMPTOMS RESOLVE IN HOURS TO DAYS IF THERE IS NO EXPOSURE TO ANTIGEN. IN SUBACUTE HP IS TYPICALLY GRADUAL OVER A COURSE OF WEEK 10-14 DAYS RESULTING IN ANTIGEN EXPOSURE ,ONSET OF RESPIRATORY AND SYSTEMIC SYMPTOMS. CHRONIC HP MAY PERSIST MORE GRADUAL SYMPTOM EXISTING FROM MONTHS TO YEARS WITH SYMPTOMS LIKE CLINICAL PRESENTATION

8. PROGRESSIVE DYSPNEA COUGH FATIGUE WEIGHT LOSS CLUBBING OF FINGERS UNLIKE OTHER TYPE OF HP, IN CHRONIC HP THERE IS AN IRREVERSIBLE COMPONENT TO THE IMPAIRMENT THAT IS NOT RESPONSIBLE, EVEN AFTER THE REMOVAL OF THE ANTIGEN. CONT..

9. PRODUCTIVE COUGH DISCOMFORT IN CHEST DYSPNEA FEVER FATIGUE WEIGHT LOSS CHIEF COMPLAINTS

10. SKIN COLOUR: A CHARACTERISTIC RED SPOTS IN CHEEKS IS SEEN INSPECTION : ASSYMETRICAL MOVEMENT IS SEEN PALPATION : REDUCED TACTILE FERMITIUS IS SEEN PERCUSION : RESONANT TO DIFFUSELY HYPERRESONANT ASCULTATION : CRACLES SOUND IS HEARD EXAMINATION

11. DIAGNOSIS DEPENDS ON ESTABLISHING HISTORY OF EXPOSURE TO AN OFFENDING ANTIGEN THAT CORRELATES WITH RESPIRATORY AND SYSTEMIC SYMPTOMS. A CAREFUL OCCUPATIONAL AND HOME HISTORY MUST BE TAKEN. IF NEEDED CLINICIAN SHOULD VISIT THE WORK AND HOME ENVIRONMENT. SPECIFIC ENQUIRIES MUST BE MADE ON GEOGRAPHIC AND SOCIAL ENVIRONMENT. DIAGNOSIS

12. INSTRUMENTAL DIAGNOSIS: CHEST IMAGING PULMONARY FUNCTION TEST BRONCHOSCOPY LUNG BIOPSY LAB DIAGNOSIS: BLOOD TEST INSTUMENTAL AND LAB DIAGNOSIS

13. THE MAINSTRAY OF TREATMENT FOR HP IS ANTIGEN AVOIDANCE ONCE THE POTENTIAL ANTIGEN AND LOCATION IS IDENTIFIED EFFORTS SHOULD BE MADE TO MODIFY THE ENVIRONMENT TO MINIMIZE THE PATIENT EXPOSURE. THIS MAY BE ACCOMPLISHED WITH MESAURES SUCH AS REMOVAL OF BIRDS AND MOULDS AND IMPROVED VENTILLATION ACUTE HP IS SELF LIMITING DISEASE AND HENCE NO PHARMACOLOGICAL THERAPY IS NEEDED. IN SUB ACUTE AND CHRONIC PHARMACOLOGICAL THERAPY IS NEEDED WITH ADMINISTRATION OF GLUCOCORTICOIDS. TREATMENT

14. PROGNOSIS IS GOOD IF THE DISEASE AND ITS CAUSATIVE AGENT IS IDENTIFIED EARLY HENCE FURTHER EXPOSURE CAN BE AVOIDED. ESTABLISHING LUNG SCARRING,HOWEVER WILL NOT RESOLVE AND THESE PATIENTS MAY PROGRESS WITH LUNG FAILURE. PROGNOSIS

15. PROPHYLAXIS INVOLVES IDENTIFYING THE ALLERGIC SUBSTENCES IN THE ENVIRONMENT AND PREVENTING ITS EXPOSURE TO THE HYPERSENSITIZED PEOPLE CAN BE THE MEASURE TO PREVENT THE DISEASE. PROPHYLAXIS

16. HARRISON’S BOOK OF INTERNAL MEDICINE VOL 2 PGS1142-1147 http://medlineplus.gov/ency/article/000109.htm http://www.ncbi.nlm.nih.gov/pubmed/7807612 REFERENCE