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.

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.

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.

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

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.

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

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.

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

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

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.

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

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.

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.

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.

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/78076
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