DEAR DR. DONOHUE: I was responsible for my friend’s wedding reception. Halfway through it, I fainted. The room was hot, and I was stressed out. I was rushed to the ER and discharged within an hour. They told me to see my doctor, and I did. My doctor, who is a fuddy-duddy, says I had neurocardiogenic syncope and that I need a tilt-table test. What is this, and what is that test? Is it necessary? I feel fine. – T.T.

ANSWER: “Neurocardiogenic syncope” is the medical term for a common faint. It used to be called “vasovagal syncope.” Both terms invest it with an ominous ring, but the common faint is not a usual sign of any medical disaster, present or future.

When people stand in one place for a long time, exercise in hot environments, are under emotional stress or are in great pain, blood can pool in the lower half of the body. That takes a significant amount of blood out of circulation. To compensate, the heart should speed up. However, sometimes a series of inappropriate reflexes occurs that slows the heart and further lowers blood pressure already lowered by the deficit of circulating blood. The brain doesn’t get enough blood. People become lightheaded. They sweat. Their vision blurs. They slump to the ground in a faint. That saves the day. Falling to the ground overcomes the force of gravity that keeps blood pooled in the legs. Blood returns to circulation, pressure rises, and people wake from their faint.

Your doctor wants to be sure you don’t have any serious conditions that cause fainting — heart-rhythm problems, heart-valve problems or seizures. Be grateful you have a fuddy-duddy doctor. Such doctors seldom make big mistakes.

The tilt-table test is a way to see if your nervous system is prone to developing reflexes that bring on faints. The patient is strapped to a table that is vertically rotated 60 degrees. The sudden change will induce a faint in people susceptible to neurocardiogenic syncope.

DEAR DR. DONOHUE: I was diagnosed with liver cirrhosis one year ago. A CT scan and blood work revealed this.

Recently I had an ultrasound done, and it showed I have a normal liver, and my blood tests have come back great.

I have two questions: Could I have not had cirrhosis? Can cirrhosis be confirmed only with a liver biopsy? – A.N.

ANSWER: The definition of cirrhosis is irreversible injury to the liver with extensive fibrosis. “Fibrosis” is the equivalent of saying “lots of scar tissue.” “Irreversible” in the definition implies that the condition does not go away. However, if cirrhosis is confined to a small area of liver or if the fibrosis is scanty, then the liver can recover.

CT scans and ultrasounds produce pictures of the liver that show features characteristic of cirrhosis. Neither is a definitive test. A biopsy yields irrefutable evidence. However, a biopsy is not necessary in all instances when the diagnosis of cirrhosis is made. Scans and ultrasounds together with lab tests and the signs and symptoms of cirrhosis provide enough proof that a biopsy is often not needed.

I don’t know how to explain your good luck. Maybe the first diagnosis was in error. Maybe your liver recovered from a mild degree of cirrhosis. Whatever the case, be glad.

DEAR DR. DONOHUE: My doctor says I have the heart of an athlete. My cholesterol is good. I do not exercise. I smoke three to four packs of cigarettes a day. I consume a lot a caffeine and have poor nutritional habits. I am overweight. Why am I so healthy? I am 47. – S.T.

ANSWER: I don’t want to burst your bubble, but I can pretty well guarantee that you will not remain healthy. You can’t rely on a few tests at a relatively young age to assure you that you will not meet with a medical catastrophe even a short time down the road. Luck has been on your side. It won’t stay there.

DEAR DR. DONOHUE: I am 62 and have suffered from bipolar disorder for 20 years. Lithium changed my life. I no longer have the cycles of depression and mania that I used to have. A recent blood test showed I have some kidney impairment, and my family doctor thinks I should stop lithium. I am afraid I will relapse if I do. What would you do? – F.K.

ANSWER: I would ask your family doctor and your psychiatrist to talk to each other.

Lithium has been around for many, many years and, for the most part, has been a boon to those with bipolar disorder, keeping them on an even keel.

It can, in a few people, affect kidney function. I would have to know the exact numbers on your kidney tests before I could make any definite statements about continuing or discontinuing its use. If the numbers are only slightly elevated, a case can be made to continue with it.

On the other hand, if the tests show a marked deterioration of kidney function, then the lithium has to be stopped. Other medicines can be substituted.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.