DEAR DR. ROACH: I hope you can answer some questions about myelodysplastic syndrome. What does it do to your body? Is there a known cause or cure? What is the prognosis? — P.B. ANSWER: The myelodysplastic syndromes are a group of similar diseases, specific types of blood cancers, that prevent your bone marrow from working properly. They also can transform into acute leukemia. These are uncommon cancers, with perhaps 30,000 cases per year in the U.S. The specific myelodysplastic syndromes are now categorized by appearance, genetic abnormalities of the cells, and condition of the bone marrow.
MDS may arise from damage to DNA, such as from radiation or other toxic exposures. However, many cases have no known cause, and it’s likely that these are spontaneous mutations in the bone marrow cells.
Because MDS is a group of related diseases, the treatment and prognosis vary among the different subtypes. However, supporting the bone marrow with transfusions of red blood cells and platelets often is necessary. Medications to stimulate both red and white blood cell production can be used. A few people will be recommended for bone marrow (stem cell) transplant, but the decision to consider this treatment must be made cautiously, as many people who get MDS will not benefit from this treatment due to age or other medical conditions.
The prognosis depends on the age of the person affected and their specific MDS. A person younger than 60 with a low-risk MDS has a median survival (based on data published in 1997) of about 12 years. However, high-risk MDS has a much worse outcome: Half of people succumb within six months. Advances in treatment since these data were published have improved these results, but not as much as hoped.
DEAR DR. ROACH: My 89-year-old mother suffers from “fluttering” in her heart. She saw an expert in cardiac arrhythmias, who diagnosed her with tachy-brady syndrome” and “sick sinus syndrome.” A nurse also said she has PVCs. She is taking metoprolol, but still has episodes of fluttering. What are these conditions? Are there other medications she could take to correct this heart condition? —M.D.P.
ANSWER: Tachy-brady syndrome (from the Greek roots for “fast” and “slow”) and sick sinus syndrome are the same thing. The “sinus” in “sick sinus syndrome” refers to the sino-atrial node of the heart, which is the heart’s natural pacemaker. It is where every beat normally starts. This part of the heart can become diseased, and the heart can beat both too quickly (tachycardia) and, at other times, too slowly (bradycardia). Sick sinus syndrome can come from many different conditions and, rarely, from medications.
Medications are sometimes used for sick sinus syndrome. Beta blockers, like the metoprolol your mother is taking, are given to slow down the tachycardic component of sick sinus, but it can make the bradycardia worse. Most often, the treatment for sick sinus syndrome is a permanent pacemaker. Not everyone needs it, but I’m sure your mother’s cardiologist is monitoring her and will recommend a pacemaker if needed. If one is necessary, 89 years old is not too old to put in a pacemaker.
PVCs are very common and do not usually indicate disease in the heart, although they are more common in people with heart disease, especially poor blood flow to the heart. Premature ventricular contractions themselves seldom need treatment.