Dehydration, certain medications, heart problems, untreated diabetes, and nervous system disorders can all cause low diastolic blood pressure
. Hypothyroidism, hyperthyroidism, Addisons’ disease, hypoglycemia
, VitB12 and folate deficiency can all cause hypotension. The other reason is bleeding somewhere in the body, like a bleeding peptic or duodenal ulcer. Hence get a stool examination done for occult blood. The other causes of bleeding gut is IBS, ulcerative colitis and Crohn’s disease.