Page 23 - Clinical Pearls in Cardiology

History and General Examination 11

of palpitations. It was found that a cardiac cause for
palpitation was more likely in the following scenarios:
• Male sex
• Those with previous history of heart disease
• Those with an irregular heart beat
• Duration of palpitation more than 5 minutes.
17. What is meant by edema?
Edema is defined as a condition where there is excess
amount of free fluid within the interstitial spaces. This
excess fluid produces a localized palpable swelling.
Edema does not become evident until the interstitial
fluid volume has been increased to about 2.5 to 3 liters.
The physiologic mechanisms that predispose to edema
formation are the following:
• Increased capillary filtration pressure
• Decreased capillary colloidal osmotic pressure
• Increased capillary permeability
• Obstruction of lymphatic flow.
When edema is due to generalized fluid retention,
its distribution is determined by gravity. In ambulant
patients, generalized edema is more obvious in the
dependent parts of the body, i.e. the legs (readily
demonstrated in the tissue space behind the medial
malleolus). In the recumbent posture, edema is most
prominent over the sacrum and lower back. Edema
due to impaired lymph flow is commonly referred to
as lymphedema. Chronic venous insufficiency is by
far the most common cause of edema in the general
population. Measurement of the day-to-day alterations
in body weight is the most reliable index of changes in
body water content.