HOW DO pH INDICATORS WORK? pH indicators detect the presence of H+ and OH-. They do this by reacting with H+ and OH-: they are themselves. weak acids and bases. If an indicator is a weak acid and is coloured and its conjugate base has a different. colour, deprotonation causes a colour change.
Have varicose veins, which are a common cause of superficial thrombophlebitis. Have a pacemaker or have a thin, flexible tube (catheter) in a central vein, for treatment of a medical condition, which may irritate the blood vessel wall and decrease blood flow. Are pregnant or have just given birth.
For external hemorrhoids, bothersome protrusions and difficulties keeping the anal area clean. External hemorrhoids may also cause intermittent swelling, irritation, and mild discomfort, especially after a period of diarrhea or constipation. For thrombosis of an external hemorrhoid, a painful bulge or firm lump suddenly appears at the rim of the anus. The lump may have a blue or purple tint.