NEW YORK - A detailed history, complete physical examination and judicious use of the laboratory are key to diagnosing and determining the proper treatment of children with respiratory infections, Leonard R. Krilov, MD, aid here at the 13th Annual Infectious Disease in Children Symposium.
"One agent can cause multiple clinical syndromes, and a respiratory infection can be located in different regions of the respiratory tree. I can give you a textbook list of bacteria, fungi, protozoan and viruses that can all cause the same syndrome, but the interesting part of clinical medicine is how do you sort this out?" he asked.
Krilov, the chief of pediatric infectious diseases at Winthrop University Hospital in Mineola, N.Y., presented an overview of patient evaluation, illustrated by specific case examples.
Age can be critical to diagnosis and treatment. Pneumonia in a 1-month-old, for example, is treated differently than pneumonia in a 10-year-old, Krilov said.
When the patient presents with symptoms is important. What time of the year is it? Seasonality may have an effect on a differential diagnosis. Colder seasons are peak times for most respiratory syndromes, but some can occur throughout the year.
Gathering information about duration and severity of symptoms will help dictate a clinical approach to treating the disease. Equally important is understanding the environment the patient has experienced recently. Questions about travel and animal exposure may be the obvious ones to ask, but physicians should also ask about family members, friends and neighbors who may expose the patient to the causal agent.
Krilov used the case of a 14-month-old boy to illustrate this point. The child presented with a fever of 102.2° F, increased restlessness and distress following three days of a congested nose and decreased activity. Physical exam suggest bacterial pneumonia.
Further history, however, revealed that the child's maternal grandfather lived with the family and experienced a 15 lb. weight loss and a worsening smoker's cough over the previous three months. A chest X-ray showed the grandfather has classic cavitary re-activated tuberculosis. The more detailed history pointed physicians to the idea that the child could likely have acquired primary tuberculosis.
"History is the key. Primary tuberculosis may look like any other pneumonia," Krilov said, adding that laboratory tests are needed to confirm the diagnosis and to identify the patient's organism to begin treatment.
As shown in the previous case, history, physical examination and laboratory results work in concert. There are two aspects of a physical exam for patients with respiratory infections. The first is an overall assessment of the severity of the illness.
"This will affect both how quickly you act and the way you approach the patient. It may also affect your differential diagnosis," Krilov said.
Physicians should examine vital signs, the degree of cyanosis, evidence of retractions and a non-specific sense of toxicity. It is important to assess hydration status, particularly for younger patients, he added.
The second aspect of the exam should focus on the chest. This will address the issues of focality and diffuse disease. Changes in egophony or decreased tactile fremitus may provide clues about the extent of disease in an older child.
Physicians should also note extrapulmonary physical changes, such as rashes or joint disease.
Three-Pronged Approach to Patient Evaluation
following is the three-pronged approach to diagnosing and
evaluating the patient.
"In the ambulatory setting, there are frequent times when the laboratory is not even used. Even in the more severely ill patient where you are addressing issues of lower tract respiratory infection, the laboratory is not frequently that helpful," Krilov said.
"When you do order tests for a patient with significant respiratory disease, what are you going to look at?" he asked.
A complete blood count, white blood count and differential may offer non-specific information about the nature of the infection. In younger children, a blood culture may identify the etiologic agent in cases of suspected bacterial sources.
Viral studies can help physicians reach a specific diagnosis and avoid toxic or non-specific therapies. Chest x-rays are frequently used and can help determine diffuseness or focality of disease.
Sputum analysis can be useful, but almost impossible to obtain in younger children unless they are intubated and a tracheal specimen can be taken.
"It is critical in my mind that if you are going to analyze sputum, you include a Gram's stain to assess the nature of the inflammatory response as well as predominant organism," Krilov said.
When physicians are concerned about lower respiratory tract disease and involvement, measuring the patient's oxygenation can be valuable.
"Information from history and physical and laboratory presentation can really guide the approach to respiratory infection," Krilov said.
He offered the following case as an example. A 2-month-old infant presents with a one-week history of cough and runny nose. When admitted, weakness and lethargy increase and he has increased respiratory distress with diffuse rales and rhonchi notes. The x-ray shows diffuse, bilateral disease. Diffuse pneumonia is the diagnosis.
Treatment depends on what caused the disease. A brief history reveals the infant is breast-fed and more detailed questions reveal the mother had mastitis and stopped breast-feeding several days before her son became ill.
Putting all of the information together, in context, helps the physician diagnose staphylococcal pneumonia. The X-ray does show pathopneumonic pneumatoceles in the right lower lobe, which supports the diagnosis.
"It is important if you are concerned about bacterial pneumonia in the young infant with diffuse disease to consider Staphylococcus aureus. Your routine antibiotic therapy may not include specific anti-staphylococcal coverage otherwise, and children need prolonged IV therapy to affect a cure," Krilov explained.
For more information:
- Krilov LR. Approach to the child with respiratory infection. Presented at the 13th Annual Infectious Diseases in Children Symposium. Nov. 18-19, 2000. New York.
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