This Study Aim is to Compare the Effect of Oral Methyl Prednisolone on Different Radiological Patterns of Hypersensitivity Pneumonitis as it Was Found That Not All Patients Get Satisfying Therapeutic Effect After Taking Corticosteroids.

The Aim of This Work is to Compare the Effect of Oral Methyl Prednisolone on Different Radiological Patterns of Hypersensitivity Pneumonitis and to Evaluate the Patient's Clinical and Functional Status After Taking the Required Dose of Methyl Prednisolone. Not All Hypersensitivity Pneumonitis Patients get the Same Therapeutic Effect after taking Corticosteroid so by Comparing the Effect of Methyl Prednisolone on Patients With Different Radiological Pattern we Will be Able to Select the Patient Who Really Need to Take Corticosteroid and Who Don't so we Will Protect the Patient Who Doesn't Need to Take Oral Corticosteroids From Its Numerous Side Effects All Patients Will Undergo the Following Assessment Before and After Taking 0.5 mg/kg/Day of Methyl Prednisolone for 8 Weeks : High Resolution CT (HRCT) of Chest , Chest X-ray , Spirometry, 6 Minute Walk Test to Evaluate the Patient's Functional Status and Oximetry to Measure Percentage of Oxygen in Blood

hypersensitivity Pneumonitis patients will be divided in two groups : non- fibrotic hypersensitivity Pneumonitis patients ( nfHP) and fibrotic hypersensitivity Pneumonitis patients ( fHP), based on HRCT findings. All patients will undergo the following assessment at the beginning of the study: High resolution CT (HRCT) of chest , Spirometry to assess forced expiratory volume in 1 second (FEV1), Forced vital capacity (FVC) and FEV1 to FVC ratio , 6minute walk test , Oximetry to measure percentage of oxygen in blood. Then all patients took methyl prednisolone 0.5mg/kg /day orally for 8 weeks . During the treatment period Pulmonary spirometry will be done every 2 weeks and 6 minute walk test will be done every 4 weeks as follow up At the end of the treatment period all these assessments will be repeated to compared the patients functional and clinical statues before and after taking methylprednisolone.