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"ITP: How much treatment is enough?" (April) was informative, but did not mention pulse dexamethasone therapy for chronic idiopathic thrombocytopenic purpura (Adams DM et al: J Pediatr 1996; 128:281). For the last two years I have treated an adolescent with this therapy with good efficacy and minimal side effects. It seems preferable to splenectomy.
Joseph T. Malak, MD
The author replies: I am very pleased that Dr. Malak's patient is responding nicely to pulse dexamethasone therapy. Unfortunately, others have not experienced such success. Despite the initial positive results, more recent experiences with pulse dexamethasone therapy have been less favorable. Side effects are substantial, and no more than 20% to 30% of patients respond. This response is not clearly greater than the intermediate to long-term response rate of untreated patients with refractory chronic ITP. At present, therefore, few pediatric hematologists are using pulse dexamethasone therapy for children with persistent ITP.
"When earaches and sore throats are more than a pain in the neck" (March) was very interesting and thorough, and the mnemonics were clever. After correctly pointing out at the beginning of the article that day care, school-age siblings, and exposure to tobacco smoke are risk factors for recurrent infection, however, the authors leave these factors out of Table 3, which lists causes of recurrent infection.
Passive smoking is a well-described risk factor for many pediatric infections and is much more common than some of the rare illnesses that the authors did list (Aligne CA et al: Arch Pediatr Adolesc Med 1997;151:648). When considering causes of recurrent infections, especially potentially preventable causes, it is important to remember environmental tobacco smoke exposure.
C. Andrew Aligne, MD
The author replies: Dr. Aligne's letter highlights an important risk factor for recurrent upper respiratory tract infections: environmental tobacco smoke exposure. Since it is such a significant modifiable risk factor, we included it in the first paragraph of our article. The mnemonic in Table 3 was constructed to give the practitioner a list of disease states that might present with recurrent infections of various types.
"Strabismus: Getting it straight" (February) was of great interest to me because about one year ago, my 5-month-old daughter's subtle strabismus was found to be due to advanced retinoblastoma. Because of this personal experience, I would like to emphasize a few points about retinoblastoma that I did not appreciate previously.
I knew that a white reflex should raise immediate concern about retinoblastoma. I did not know, however, that retinoblastoma is not always white. When the tumor arises in the internal layers of the retina, it grows into the vitreous and produces the usual textbook picture of retinoblastoma. If it arises in the external layers of the retina, the tumor growth causes retinal detachment and the tumor remains covered by the retina. An ophthalmologist examining the dilated eye would still see the tumor, but a pediatrician might miss it since a red reflex, perhaps an irregular one, could still be present. This is what happened with my daughter. Even the pediatric ophthalmologist described only an "opacity behind the left lens" before dilating the eye. Only dilation revealed the true extent of disease and the totally detached retina. Some observers advocate dilation at well-baby exams. We should at least darken the room when we check for a red reflex, to maximize natural dilation.
As the authors mentioned, parents might report strabismus that is not present during the office exam. The same is true for leukocoria, or any irregular light reflection. It is so important to listen to parents' descriptions, especially if they don't match your exam. I have talked with many families of children with retinoblastoma, which they often describe as a "catch-me-if-you-can disease." Many parents report seeing abnormalities at home, but because the eyes appear normal in the office diagnosis is delayed. Often, the abnormalities are apparent only under certain lighting conditions. We, for example, sometimes caught a fleeting glimpse of a reddish glow from my daughter's pupil, but no one else ever saw it and her office exam was normal. Although my daughter had true strabismus between the ages of 3 and 5 months, she sometimes went for days with her eyes generally well aligned, tracking perfectly.
My daughter has done very well. Her left eye was enucleated shortly after diagnosis. Her right eye contained three small tumors that have been treated successfully with laser and cryotherapy. She has not required chemotherapy or radiation. Her central vision is perfect, and she has only some "blind spots" in her peripheral visual field at the sites of the retinal scars.
Barbara LaDine, MD
The author replies: I would like to thank Dr. LaDine for her poignant letter. I have a few comments to add to her observations:
A "white reflex" (leukocoria) is not the only abnormality to look for during the red reflex test. As Dr. LaDine correctly points out, a retinoblastoma can remain covered by the retina and fail to produce a white reflex. A darker area in the red reflex may also represent pathology, such as a cataract. Significant refractive errors can also be detected by noting an abnormal red reflex. Finally, asymmetric red reflexes could also signal an amblyogenic process.
Retinoblastoma may not be present at birth, but can develop later. This is also true for childhood cataracts. The red reflex test should be incorporated into all well-baby visits during the first few years of life.
A small retinoblastoma in the peripheral retina may not cause any change in the red reflex initially. Any infant born to a family with a history of retinoblastoma deserves a dilated retinal examination by a pediatric ophthalmologist at birth and additional follow-up dilated examinations at an interval to be determined by the examining ophthalmologist.
Strabismus can signal significant intraocular pathology, which in rare cases can be life-threatening. Prompt evaluation by a specialist avoids delay in diagnosis and treatment.
Darron A. Bacal, MD
Julia McMillan. Letters. Contemporary Pediatrics 2000;7:21.