Hypertension, meralgia paresthetica, BUN

DEAR DR. DONOHUE: I have hypertension that is treated with two different blood pressure medicines. Generally, the systolic pressure remains in the 115-to-135 region, and the diastolic pressure in the 75-to-85 region. Recently I have had three nosebleeds, the first at about 4 a.m., and the other two between 7:30 a.m. and 8:30 a.m. I checked my blood pressure at 2 a.m., before the third bleed, and it was 188/87. I concluded that my nosebleeds were caused by high nighttime blood pressure. I now take my medicine at 10 p.m. The blood pressure elevation continues, but it's not as high as before. Why does it rise so high at night? -- C.S.

ANSWER: Blood pressure doesn't stay at one level throughout the day and night. It has a 24-hour rhythm. It dips to its lowest point in the first few hours of sleep and reaches its highest point in the early-morning hours, between 6 a.m. and 9 a.m. The surge occurs in the transition from sleep to wakefulness. For those who like an explanation for everything, it's the body's way of preparing itself to meet the oncoming day. Your blood pressure peak at 2 a.m. isn't far from the high-point time. High blood pressure in itself doesn't often cause a nosebleed. It can make a nosebleed last longer and bleed heavier, but it doesn't usually start one. A dry nasal lining is more often the cause. A slight touch to the nose can cause the dry lining to slough off and start bleeding. A little dab of Vaseline can keep the lining from drying. If you want an accurate record of what your blood pressure is throughout the day and night, you can obtain it by wearing an ambulatory blood pressure monitor. It's an automated unit that records blood pressure every 15 to 30 minutes for 24 hours. You learn exactly when your blood pressure spikes and how long it stays elevated.

DEAR DR. DONOHUE: I have recently been diagnosed with meralgia paresthetica. I understand it has to do with the lateral femoral cutaneous nerve. I have had one shot to numb this nerve but got no relief. Now the doctor wants to do another shot. When do I say no to more shots? Is there some other kind of treatment for it? -- S.

ANSWER: Meralgia paresthetica comes from compression of the nerve you named. It serves the upper thigh area, the area covered by a pants pocket or by a cowboy's holster. Compression causes nerve irritation and pain in the area of the nerve's distribution. What causes the compression? For some, it's fat tissue, and weight reduction takes care of the problem for them. Tight garments, like skin-tight jeans, are another cause. The solution is wearing something less constricting. Even a tight seat belt can bring on the problem. For many, a definite cause cannot be found. It just happens. Injecting the area with a pain-numbing drug can often deaden pain. Quite often, a cortisone medicine is mixed with the numbing agent to reduce nerve inflammation. Three injections are generally the limit. After three, if there is no relief, further injections are unlikely to work. If pain isn't relieved and if no identifying cause can be found and removed, then surgery on the nerve is an option. Rarely is that necessary.

DEAR DR. DONOHUE: Will you explain the BUN test? Mine came back as high -- 23, with normal being 7 to 18. My doctor hasn't said anything about it. Does that mean that a 23 isn't so bad, or did they file the results without reading them? -- S.C.

ANSWER: "BUN" stands for "blood urea nitrogen," a waste product of body metabolism. In many labs, the normal range is 10 to 20 mg/dL (3.6 to 7.1 mmol/L). BUN is a rough estimate of how well the kidneys work. If they aren't filtering waste products well, BUN rises. Your value of 23 is not alarming. The kidneys aren't in really bad shape until BUN hits 50. Look on your lab slip. Is creatinine listed? It's a more accurate test of kidney function. If it's normal, then you can forget your BUN number. 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.