Middle back pain: Back pain in the middle back area. See detailed information below for a list of 31 causes of Middle back pain, Symptom Checker, Assessment Questionnaire, including diseases and drug side effect causes. Â» Review Causes of Middle back pain: Causes | Symptom Checker Â» | Assessment Questionnaire Â» Causes of Middle back pain:
Valvular Heart Disease. Disorders of certain heart valves can also lead to left atrial enlargement. The mitral valve separates the left atrium from the left ventricle. If the mitral valve becomes narrow -- a condition known as mitral stenosis -- blood accumulates in the left atrium and causes enlargement.
A: Flooded or fluid-filled lungs, or pulmonary edema, occurs when air sacs in the lungs fill with fluid, according to the Mayo Clinic. Causes of pulmonary edema include a weakened left ventricle in the heart, trauma, drowning, high altitude and reactions to drugs or toxins.