Dear Doctor: Sometimes when I awake from a good sleep, one of my hands is asleep, and I have to shake or massage it back to normalcy. It's usually my thumb and the two fingers next to it. Is this normal?

Dear Reader: No, this is not normal. Your symptoms are typical of carpal tunnel syndrome, which occurs because of a compression of the median nerve at the wrist. The median nerve provides sensation to the thumb, index and middle fingers. It also supplies the muscles that control the thumb and the smaller muscles that control the index and middle fingers.

The median nerve is in real cramped quarters as it makes its way through the wrist. As you look at the palm surface of your hand and move your eyes toward your wrist you can see multiple tendons. The median nerve has to share room with nine of these tendons that are within the carpal tunnel. When there is inflammation in the wrist, or the tendons become inflamed, the median nerve gets compressed.

The first symptoms are often noted during sleep, when we have a tendency to flex the wrists, so that our hands curl. This flexion of the wrists causes greater compression of the median nerve, which leads to the sensation of tingling in the thumb and the index and middle fingers, as if your hands are falling asleep.

Carpal tunnel syndrome is very common and can be caused by repetitive work involving recurrent compression on the median nerve. Studies have been mixed as to the type of work that can cause this. One study showed that recurrent use of a computer mouse was associated with carpal tunnel syndrome, but there has been no consistent association with recurrent keyboard use.

Women are more likely to have carpal tunnel syndrome than are men. The rate is 5 percent in the general population, but women have rates ranging from 7 percent to 18 percent. One study, published in Environmental Research, for example, found a greater rate of carpal tunnel syndrome in female butchers and meat cutters.

Diabetes, rheumatoid arthritis and hypothyroidism are diseases that are associated with an increased risk of carpal tunnel syndrome.

As for a diagnosis, that can be done through a physical exam or through a nerve conduction study.

For starters, I would consult your doctor. If he or she diagnoses carpal tunnel syndrome, wearing a wrist brace at night would be the likely recommendation. Whether rigid or of a softer variety, wrist braces help because they don't allow the wrist to curl when you're sleeping. In addition, a physical therapist can teach stretches and range of motion exercises that can ease symptoms.

Finally, pay attention to signs of weakness in the hand. This would be noticed mostly in the use of the thumb, such as if you start dropping keys or begin having difficulty holding a cup. These signs suggest additional treatment, such as surgery, may be needed.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Sometimes I get a sudden hissing sound in my right ear that lasts for a few minutes and then slowly goes away. What is it, and is there anything I can do to make it stop?

Dear Reader: What you're experiencing is known as tinnitus, which is the medical term for a perceived sound that doesn't have an external source. Tinnitus is not a condition in and of itself, but is instead a symptom of some other underlying problem.

Exposure to noise is a major cause of tinnitus, as is hearing loss. Both can result in damage to the sensitive hair cells that line the cochlea. This is the portion of the inner ear that translates vibrations into nerve impulses, which are then sent to the brain to be interpreted as sound.

Blockage due to earwax buildup, as well as changes to the ear bones as we age, can contribute to tinnitus. Some medications, including certain antibiotics, cancer drugs, antidepressants and high doses of aspirin, are known to play a role in tinnitus.

Although the most common form of tinnitus involves a ringing in the ears, people with this condition may also hear the hissing you describe, as well as buzzing, clicking, humming, whistling or a roaring sound, like wind. In rare cases, patients with tinnitus have even reported hearing music.

Tinnitus can affect one or both ears. It ranges in volume from a low, background noise that is bearable and even forgettable, to sounds so loud and persistent that they interfere with daily life. In many cases, tinnitus is temporary. In severe cases, the phantom sounds never go away.

It is estimated that up to 45 million Americans -- that's 15 percent of the population -- report having some form of tinnitus on a regular basis. Like you, the vast majority of them have subjective tinnitus, which is sound that only the patient can hear. In objective tinnitus, which affects just 1 percent of the population, the sounds a patient hears are audible to others as well. The causes of objective tinnitus are most often internal conditions related to blood flow in vessels near the ear.

Men are more prone to tinnitus than women, and it becomes increasingly common as we age. Individuals who work in loud environments, such as factories and construction sites, are at increased risk. Recent studies suggest that earbuds, which sit so close to the delicate structures of the inner ear, may also put users at higher risk.

At this time, there is no single treatment for tinnitus. An examination by an ear specialist, known as an otolaryngologist, can pinpoint whether tinnitus is due to earwax buildup, medication or, more rarely, a blood vessel condition. These are often treatable. If not, your doctor can help you explore noise suppression techniques such as using a white noise machine, or masking devices that are worn in the ears.

Meanwhile, you can take steps to lessen the impact of tinnitus. Make sure your blood pressure is under control, avoid loud noises, which can set off a tinnitus episode, and -- this will improve your overall quality of life -- be sure to get enough rest.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: What can be done about interstitial cystitis, or bladder pain syndrome? I'm told there's no cause or cure, and that some doctors don't even believe it exists.

Dear Reader: Interstitial cystitis is a chronic condition of the bladder that's five times more common in women than men. Patients with interstitial cystitis have pain, pressure or bladder spasms, with symptoms worsening when the bladder is full and improving after voiding. The condition also causes an increase in urinary frequency and urgency. Because people with these symptoms need to use the bathroom frequently, the condition is extremely disruptive to their lives. Further, these symptoms disrupt sleep in 70 percent of patients, creating feelings of fatigue.

Now let's look at the cause: a disruption in the cellular lining of the bladder. This disruption allows urinary irritants, or chemicals, to penetrate through the lining of the bladder, affecting both the nerves and muscle of the bladder. The nerve irritation can send feedback to the central nerves of the spine. The spinal cord sends signals to the bladder and pelvis relaying pain information, perpetuating the pain in a back-and-forth cycle.

Doctors don't have a clear understanding of the inciting event that causes this inflammation. Interstitial cystitis may originate from a bladder infection, or from bladder irritants, such as caffeine, alcohol, spicy foods and citrus.

I've seen enough patients with this syndrome to know that interstitial cystitis, or as some call it, chronic bladder pain, is very much real. That said, other causes for the symptoms must be ruled out, requiring urine tests to check for infection or even directly visualizing the bladder with cystoscopy.

The first treatment step is to eliminate behaviors and foods/drinks that irritate the bladder, meaning stopping all consumption of caffeine, alcohol and tobacco. You can also consider the restriction of spicy foods and citrus. The second step would be to consider behavioral modification to decrease the frequency of urination. One study, published in the Journal of Urology, showed that diet and behavioral changes decreased symptoms in 45 percent of patients.

Physical therapy with a therapist who specializes in interstitial cystitis can relieve some of the pain in the pelvic region by working on tender areas and increasing muscle stability in the lower abdomen. A 2012 study published in the Journal of Urology showed a 59 percent decrease in symptoms compared to 26 percent who did general therapeutic massage.

Amitriptyline, a tricyclic antidepressant with multiple uses beyond depression, has potential as well. In a 2010 Journal of Urology study, the drug -- given at 50 milligrams -- was shown to decrease symptoms in 55 percent of patients with interstitial cystitis. The problem is that many patients cannot tolerate the side effects of this dose, so I would consider doses of 10 milligrams to 20 milligrams.

Pentosan polysulfate sodium, which seems to protect the lining of the bladder, may help as well, and the sedating antihistamine hydroxyzine can aid patients who have symptoms of pain and frequency of urination during the night.

While interstitial cystitis is not a well-understood disease, it is certainly a diagnosable condition.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)