Keith Roach, MD, syndicated columnist

DEAR DR. ROACH: I am 76 years old, and I have had an essential tremor for over six years. It has progressively gotten stronger, mainly in my hands. I have been reading about an MR-guided focused ultrasound and was wondering if you considered this safe. This involves creating a small lesion in the thalamus, which concerns me. — S.F.

ANSWER: An essential tremor, formerly called a benign familial tremor, is common (in 5% of adults over 60) and highly variable, with most people getting affected in their hands and arms but also their heads or voices. An ET can make it very difficult to write and eat. Alcohol can temporarily make the tremor better but is never a good long-term treatment.

Medications such as propranolol or primidone are the usual first-line treatment. If they are unsatisfactory, I refer my patients to a movement-disorder neurologist to confirm the diagnosis and consider alternative treatments. When medications are inadequate, surgical treatments, including deep-brain stimulation and MR-guided focused ultrasound, can be considered.

I have had patients go through MR-guided focused ultrasound, and my experience has generally been favorable with my patients being happy with the results. You are quite right that this technique causes a “lesion” in the brain. Multiple ultrasound beams converge on a precise point in the thalamus (a very deep structure in the brain that is responsible for the coordination of movement), heating up this part of the brain and destroying it.

This does cause the loss of brain cells, and side effects of gait instability or numbness are common, although they tend to improve over time. I don’t recommend this therapy lightly and always make sure that my patient has had a good trial of multiple other treatments before considering this irreversible treatment.

DEAR DR ROACH: I have a cold. I use two brands of nasal spray for congestion, but both say not to use them for more than three days as they may cause “rebound” congestion. Can I alternate them for six days or three days each? One is oxymetazoline, and the other is phenylephrine. — A.M.H.

ANSWER: Nice try, but both of these drugs work the same way. (Afrin is one brand name for oxymetazoline, and phenylephrine is sold as Neo-Synephrine, among other names.) They constrict the blood vessels of the nose, stimulating receptors in the blood vessels called alpha-1 and alpha-2. This lets people breathe easier by reducing swelling. I find these particularly effective in people who are going on airplanes, where swelling in the nasal passages and sinuses can cause painful pressure imbalances.

Unfortunately, the body’s response to decongestants like these is to adjust the receptors so that the medication stops being as effective after a few days, even as few as three days. People who continue to use them find that they just aren’t effective and often increase their use, which makes them even less effective. If a person tries to stop at this point, they can have terrible nasal symptoms. This cycle is called rhinitis medicamentosa and can only be broken when the person stops the medicine.

Other medicines, like nasal steroids, can help with the misery that people feel while their receptors return to normal. Still, the best way of dealing with it is to never get it in the first place, which is why manufacturers recommend (and I completely agree) limiting any of these to no more than three days.