Is there such a condition known as labile hypertension and if there is what causes it?

Yes.: Labile, the opposite of stable, means your BP is not elevated at all times, rather rises in response to situations or different conditions, such as "white coat hypertension". Previously thought to be less serious, it is now treated as aggressively as full time hypertension. It can be caused by surges of adrenaline, which can be caused by low blood sugar. Get tested for Insulin resistance.

Labile HTN cause: Every one's blood pressure is labile i.e. it varies with every heart beat. Labile HTN is the condition in which sometimes the BP is above some definition of high, say 140 systolic and sometimes below it. We generally do not treat HTN unless the average is 140 or more. If less than 140 we do not treat. Important to get many accurate BPs to make Dx of HTN. I recommend home device accurate on you.