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When in doubt, think like a doctor

Consider the following medical dilemmas, all brought to my attention in the past week:

A newborn baby has her blood sent for routine screening for genetic problems, like all babies in Massachusetts. Her adrenal hormone level comes back abnormal. Should her parents worry she has a genetic disease?

A 6-month-old healthy boy sees his doctor for a routine checkup. The doctor notices an ear infection and recommends antibiotics. But the boy's father is dubious; should he give the medication?

My 1-year-old niece was born with mild torticollis, or twisted neck. Her pediatrician recommended physical therapy, which had limited success. Now, a plastic surgeon wants to cut a spastic muscle on the baby's neck, which he promises will improve the problem. My sister-in-law is torn: Should she permit the surgery?

Many parents rightly trust their doctors' judgment. From time to time, however, they feel uncomfortable with a medical decision and are left feeling confused and powerless.

To take charge of such situations, parents should take a page from doctors who use ''clinical trials" as the basis of modern medicine. Doctors use systematic methods to compare medical choices, and parents can become better advocates for their children by understanding these techniques.

The first thing parents need to understand is that a diagnosis is often uncertain -- in the first case, a hormone problem. Second, consider what happens if nothing is done about the problem; for example, what happens to 6-month-olds with ear infections who don't get any treatment? Third, ask, what happens to children who get a proposed therapy like surgery for torticollis compared with those who don't?

Contrary to popular belief, many medical tests aren't definitive; they only suggest probabilities. For example, testing a newborn's blood for the adrenal hormone appears like a great idea at first glance: it's 100 percent effective at catching the 1 child in 10,000 with the hormone deficiency.But this excellent test also identifies many children who don't have the condition; thus only 1 out of 20 children who test positive actually have it. The positive test makes it more likely, but doesn't give an absolute answer. So, for uncommon problems (like some genetic syndromes, and even prostate and breast cancer), a screening test is often wrong, even when positive.

This isn't just confined to fancy tests. Consider ear checks at routine infant physicals. Ear infections are hard to diagnose, and studies show that pediatricians often don't agree whether a given ear is infected. Thus, more likely than not, a child without obvious symptoms who is diagnosed with an ear infection doesn't have one.

Anyone getting a screening test must be willing to undergo more confirmatory procedures as simple as a blood test, or as invasive as major surgery -- or learn to live with some uncertainty.

In 1999, for example, Pediatrics reported that 1 in 4 children getting surgery for appendicitis has a normal appendix. That doesn't mean surgeons are fools. It means appendicitis is hard to diagnose, and many surgeons think it better to err on the side of caution. A parent might agree, but then again, might not.

Doctors rarely say something like, ''Based on the information we have now, there's a 15 percent chance Bobby has an ear infection, but we could do a needle puncture of the eardrum to be more confident," even though that's the truth. In today's litigious climate, doctors often pursue the most conservative course, even if it means doing lots of tests and giving potentially unnecessary medicine.

Once the diagnosis is made, parents should then ask about the ''natural history," or what happens to affected patients who are left untreated. It's important to ask for specific probabilities.

For example, although 7 in 10 ear infections get better without treatment, one reason to treat is to avoid complications such as very rare ear bone infections. More than 99 percent of newborns with fevers over 100.3 degrees are fine, but one in a few hundred can have meningitis. Some doctors think untreated torticollis causes crossed-eyes and head deformities, but the chances are unknown.

Once parents are confident of their child's diagnosis and aware of the possible outcomes, they can then decide whether they are OK with the risk of doing nothing versus doing something.

Ideally, a parent would peek into two hypothetical futures, where one's child was given or not given a treatment, and see which way is better. Since that's impossible, we rely on ''placebo-controlled" studies, in which one group of kids is treated and another isn't.

Now comes another shock: Many treatments don't transform a sick child into a healthy one. About 8 in 10 kids given antibiotics for ear infections improve in two days, but so do 7 of 10 kids given nothing. About 7 in 10 with attention deficit disorder improve with Ritalin, but so do about 2 in 10 who are untreated. Penicillin doesn't cure strep throat any faster than a placebo; it just prevents an uncommon side effect called rheumatic heart disease. About 4 in 1,000 kids who get their tonsils removed get throat infections yearly, the same number as those who still have their tonsils.

Unfortunately, no studies exist for many therapies. No one, for example, has compared whether torticollis surgery for mild cases is better than no surgery.

Groups aimed at adults, such as the American Heart Association, have taken a lead in helping sort through confusing data. From treating high blood pressure to placing artificial heart valves, the heart association explicitly grades both the quality of supporting medical data, and the strength of their support.

There's nothing comparable for most childhood diseases, but when parents hear that little voice of doubt about a proposed medical plan, they should start asking savvy questions. Considering what data there is empowers parents to thoughtfully agree or disagree with their doctors' recommendations.

Dr. Darshak Sanghavi, a clinical fellow at Children's Hospital and Harvard Medical School, can be reached at  

Copyright 2005 The New York Times Company