Understanding Diagnosis

Preemie with IV 
Overview of diagnosis

Obtaining a diagnosis is the first step in treatment. Diagnosis is an attempt to find out exactly what is wrong with a premature baby so that appropriate steps can be taken to solve the problem and help the baby to get better.

Diagnosis is sometimes simple. For example, if a premature baby has a yellowish tint to the skin, he almost certainly has jaundice. The appropriate treatment, phototherapy, can begin right away. This diagnosis can often be made just by looking at the baby, although jaundice should be confirmed through blood tests as well.

At other times, diagnosis is not so easy. A sign or symptom may be the same for several different conditions. For example, while an abnormally high breathing rate suggests that there may be a breathing problem, rapid breathing may be a symptom caused by a problem with another part of the body. An increased heart rate could be caused by something mild that may resolve itself, or by something more serious that will require intervention.

When the signs and symptoms are non-specific and do not point directly to one condition, doctors make what is called a differential diagnosis. This is a list of different possible conditions that the baby may have, based on his symptoms.

Sherlock Holmes, when faced with a difficult and confusing case, would eliminate the impossible; whatever was left, no matter how improbable, must be the answer. At times, diagnosis of an illness or condition can require a similar process. When symptoms suggest several possibilities, doctors will eliminate some of the possibilities with further tests until there is only one possibility left.

Treatment without a confirmed diagnosis

Eliminating possibilities to confirm a diagnosis may take some time. In such cases, treatment may begin before a definitive diagnosis is made. For example, if doctors suspect that a premature baby has an infection, it is likely that the baby will be given antibiotics even before the infection is confirmed with blood tests. This is because treating an infection is easier and more effective when begun early and, even if blood tests come back negative for infection, the antibiotics will do little harm. The risks of not treating a possible infection, which can rapidly deteriorate, outweigh the risks of prescribing an antibiotic to a premature baby who, it may turn out later, does not have an infection.

Treatment also has a role to play in diagnosis. Sometimes doctors may make what is sometime called a provisional, or tentative diagnosis, where a condition is suspected but not yet confirmed, and begin treatment for the suspected condition. If the baby gets better as a result of the treatment, this can help confirm the diagnosis. Conversely, if the baby does not respond to treatment, it is likely that either the provisional diagnosis or the treatment was wrong. For example, if a premature baby is given antibiotics because infection is suspected but the antibiotics do not make the baby better, then it is unlikely that the baby has an infection and the baby’s symptoms must be from some other cause. Although this process can be frustrating, a possibility has been eliminated, which means that doctors are one step closer to a definitive diagnosis.

Diagnosis can be further complicated by the fact that a premature baby may have more than one condition, may have a complex condition, or may have a very rare condition, perhaps with overlapping or even conflicting symptoms. In these cases, it may take even longer to make the correct diagnosis.

How this section is organized

In the diagnosis section of this site, individual conditions are addressed on individual pages. Additionally, individual types of diagnostic procedures, such as X-rays and blood tests, are also addressed on individual pages. There are also discussions about other issues surrounding diagnosis, including consent, the process by which a parent understands and approves of the treatment given to their premature baby.

Jonathan Hellmann, MBBCh, MHSc,  FCP(SA), FRCPC

10/31/2009


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