Clinical Medicine A Textbook of Clinical Methods and Laboratory Investigations Clinical Medicine A Textbook of Clinical Methods and Laboratory Investigations JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD New Delhi • Panama City • London • Philadelphia (USA) Editor-in-Chief KV Krishna Das BSc MBBS FRCP(E) FAMS DTM and H(Edin) Consultant Physician and Hematologist, Ex-Director and Professor Department of Medicine, Trivandrum Medical College Thiruvananthapuram, Kerala, India Editors Mathew Thomas MD Professor and Head, Department of Medicine, Dr Somervell Memorial CSI Medical College and Hospital, Karakonam, Thiruvananthapuram, Kerala, India PK Sasidharan MD Professor and Head, Department of Medicine, Government Medical College Kozhikode, Kerala, India S Aswini Kumar MD Professor, Department of Medicine, Trivandrum Medical College, Thiruvananthapuram, Kerala, India R Kasi Visweswaran MD DM(Nephrology) Ex-Professor, Department of Nephrology, Nephrologist, Ananthapuri Hospital and Research Institute Thiruvananthapuram, Kerala, India C Sudheendra Ghosh MD(Med) MD(Resp) Dip NB MPH(USA) Joint DME, Trivandrum Medical College, Thiruvananthapuram, Kerala, India KR Vinaya Kumar MD DM Professor and Head, Department of Gastroenterology, Trivandrum Medical College Thiruvananthapuram, Kerala, India Fourth Edition ® Headquarters Jaypee Brothers Medical Publishers (P) Ltd. 4838/24, Ansari Road, Daryaganj New Delhi 110 002, India Phone: +91-11-43574357 Fax: +91-11-43574314 Email: