2 April 2007

1. Agenesis of the Corpus Callosum
2. DMSA Scan
3. PKU and Fingernails
4. Persistent Fever
5. No Lead Shield for X-rays
6. Repeat "Newborn Screen"
7. Thrush, Face Rash
8. Cereal and Applesauce at 2 Months OK?
9. Disclaimer

• Read Questions & Answers in Another Column

Agenesis of the Corpus Callosum

Yesterday, when the pediatrician phoned us with his opinion of the ultrasound, he said, very bluntly I might add, that part of my son's brain might be missing. I questioned him a little more and found out that the portion that might be underdeveloped or missing is the corpus collosum. I guess this part of the brain is the fibres that connect the two hemispheres of the brain and this may be missing. We do have an appointment with a pediatric neurologist and we are endeavoring to speed this process up as the waiting list is quite long. Apparently, the next step is to get our son a cat scan. Furthermore, the pediatrician also said that there is some fluid on his brain and this may present other problems.

I realize that there are varying levels of this condition but, in your experience, what is the quality of life that can be expected for our son and what can we do to help? What are some of the obstacles that will be thrust in front of our son? How common is this disorder?

I realize that you are very busy, however, if you could please e-mail me at xxx@xxx.xxx I would be very grateful.

Thank you for your time.

-AB

Dear AB: I have no personal experience treating a patient with agenesis of the corpus callosum. My reading of the literature on the subject leads me to understand that while agenesis of the corpus callosum may be associated with your son's neurological symptoms, it alone is not responsible for his condition. Therefore, I cannot really suggest a course (prognosis) for your son on the basis of his having agenesis of the corpus callosum.

According to Goetz: Textbook of Clinical Neurology, 1st ed., Copyright © 1999 W. B. Saunders Company,

Agenesis of the corpus callosum can be found as an isolated malformation or in association with other malformations. A growing number of inborn errors of metabolism also include agenesis of the corpus callosum.

Isolated agenesis of the corpus callosum is sometimes discovered incidentally either on imaging studies that were obtained for other reasons, such as trauma, or at autopsy. In isolation, the abnormality clinically is largely silent and deficits may be discovered only on careful neuropsychological assessment. Findings resembling disconnection syndromes have been described in some patients; however, this is by no means a constant feature and in the majority of patients this characteristic cannot be demonstrated. Patients with agenesis of the corpus callosum have a higher incidence of seizures and mental retardation, partially reflecting the slightly higher incidence of neuronal migrational abnormalities also seen in these patients. It should be noted, however, that patients with mental retardation or seizures, or both, are also more likely to undergo CNS imaging, which skews the ascertainment of the clinicopathological correlations in agenesis of the corpus callosum.

Because it can be assumed that the clinical manifestations of agenesis of the corpus callosum most often depend on the associated CNS anomalies rather than on the lack of the corpus callosum itself, careful assessment for such associated malformations is mandatory. Although agenesis of the corpus callosum can be diagnosed on a CT scan ..., MRI is far superior in diagnosing associated structural abnormalities.

Sincerely,
Dr. Warren

My question is, can I skip the DMSA test? What are the risk?

Cheers!

-CS

Dear CS: With regard to imaging studies for evaluation of UTI (urinary tract infection), according to Behrman: Nelson Textbook of Pediatrics, Sixteenth Edition, Copyright © 2000 W. B. Saunders Company, "If vesicoureteral reflux is present, a DMSA scan often is performed to assess whether renal scarring is present. The DMSA is considered the most sensitive and accurate study for demonstrating scarring."

There is less radiation involved and less risk of an allergic reaction to DMSA than there is to a standard IVP (x-ray dye study of the kidneys and ureters) so it is a relatively safe test.

If you have not consulted a pediatric urologist, you should. Before proceeding with the test the urologist should explain to you what information he could find from the test and how that would alter his treatment plan. An understanding of this information will help you avoid agreeing to a test which is being done "just in case" or "just for the sake of completeness," but which will not alter your daughter's treatment.

Sincerely,
Dr. Warren

-R

Dear R: According to my texts, PKU can sometimes cause an eczematous rash, but there is no mention of any effects on the fingernails. Marks, dents, and irregularities on the fingernails may occur from any major illness or high fever. Occasionally, that may even result in cracking or peeling. Typically, each fingernail affected has the abnormality at the same level since the insult which affected the nail occurred at one point in time. The nails usually grow back normally.

As I have no experience treating PKU, I am reluctant to be the final authority regarding any question about PKU. If there is any question about the status of your daughter's PKU you should contact the doctor who is treating her.

Sincerely,
Dr. Warren

During the first week of the fever, the other symptoms that he had were diarrhea, fatigue, and reduced apetite. I took him in to the doctor for a step test, which was negative.

During the second week of the fever he complained of abdominal pain, he was holding himself more towards his back, so I took him back into the doctor, and they checked his urine, that came back normal. The other symptoms he had during this week were fatigue, reduced appetite, and no bowel movements.

During this third week of fever, I have taken him back a third time, and they have finally taken blood, they tell me that all him blood work came back normal, his white count is 7.6. He is now more active, and his apetite is better, and he is having normal bowel movements, but he is still running the low-grade fever.

They tell me that he most likely had one virus on top of another, on top of another, and do not seem to be concerned. I am not satisfied with these answers, should they be looking for something else?

Should I bring him in again, or should I just ignore the fevers? Please let me know your thoughts, I am going out of my mind.

Thank you.

-Desperate in Minnesota

Dear Desperate: The first issue in addressing your concerns is the definition of fever. To some extent it depends how you're taking the temperature and how accurate your readings are. The normal temperature of 98.6 F (37 C) is an average normal and not the full range. A rectal temperature taken with a mercury glass thermometer which is below 100 F is not considered a fever. In much of the literature the upper limit of normal is considered to be 38 C (100.4 F). In my experience, after an illness minor elevations of the temperature may persist. I cannot tell you how long and I'm not sure if the matter has been studied since most people don't take temperatures when a child is no longer ill.

I cannot comment on your son's blood work since you only told me his white count and I don't know what other tests were done. Aside from looking at the white count to see if it helps distinguish between viral and bacterial infection blood tests can also check for mononucleosis, Lyme disease, and a variety of inflammatory (rheumatic) diseases. Same lack of comment regarding his urine test since I don't know if he had a urine culture or just a urinalysis. A culture is required to rule out infection.

Since your son had abdominal pain and diarrhea as prominent symptoms during his illness he may have had dysentery caused by salmonella, shigella, or campylobacter. These illnesses can be prolonged and the diarrhea may be followed by constipation or tenesmus (a frequent urge to have a stool, often without success or passage of only a small mucousy stool). A stool culture would be necessary to test for these infections. Antibiotic treatment is not always useful and, especially after recovery, not warranted.

Since you are able to pinpoint a beginning and end to your son's symptoms of illness and he appears to be getting better, it may not be necessary to pursue further evaluation of his fever at this time. On the other hand, if he continues to feel ill, persistent fever, even low grade fever, does require a thorough evaluation.

Sincerely,
Dr. Warren

My question: Is it accepted practise not to place a lead apron over a child's internal organs? i would appreciate a detailed response. I was surprized and very concerned about this "oversight." Thank you in advance for your information.

Sincerely,
-TT

Dear TT: Radiation effects are cumulative over a lifetime with the largest risk being damage to germ cells (reproductive tissue) so that, whenever possible, the genitals should be shielded for all x-rays. However, the dose of radiation from a single x-ray is so small as to carry virtually no risk. Therefore, it is acceptable practice not to shield the genitals if the shield will obscure the view of what is being examined as would be the case when x-raying the pelvis or the hip sockets.

Sincerely,
Dr. Warren

-BC

Dear BC: The newborn screening tests are used to test for a variety of metabolic diseases and blood diseases. If a newborn were sick and had a transfusion prior to testing, that could make the test results invalid. Since the test is meant to be run on newborns, if there is no fetal hemoglobin found, the presumption is that the baby had a transfusion which invalidates the test results, and therefore a repeat specimen is requested. However, since your son is already 6 months old, that would be an invalid conclusion. The testing program is probably not set up to accommodate testing 6 month olds. Your doctor should contact them before repeating the test to clarify the situation.

Sincerely,
Dr. Warren

Thank you for your help.

-MP

Dear MP: Without seeing the corners of your daughter's mouth I can't be sure whether or not it's related to the thrush. The Nystatin only works by being applied to the thrush. It is not absorbed by the body like some medications. When it is put into the mouth it mixes into the saliva and coats the membranes in the mouth and throat. If your baby has thrush in the corners of her mouth you would have to apply the Nystatin directly to those spots with a swab.

1½ year olds often have their hands in their mouth. The constant exposure to moisture may cause a rash on the face and sores in the corners of the mouth. This may respond to a thin layer of Vaseline on the cheeks and a dab of Vaseline lip balm in the corners of the mouth to protect the skin from moisture. Unfortunately, I cannot diagnose rashes by e-mail, so I can't be certain about the best course of action. Many people refer to a variety of bumpy rashes as hives. If your child really has hives, that would be an allergic reaction to something.

If in doubt, for any persistent problem, see your doctor.

Sincerely,
Dr. Warren

-M

Dear M: Please read my article, Feeding Your Infant for complete information about feeding infants. It won't hurt your baby to feed solids at this young age, but the American Academy of Pediatrics does not recommend introduction of any solids until at least 4 months of age. Adding cereal to a bottle increases the carbohydrate content of the feeding and makes the feeding thicker, but it does not make the feeding more nutritious or satisfying. In fact, increasing the amount of carbohydrate in the feeding lowers the protein content. Formula is food. If your baby spits up several hours after a feeding, you will see that the protein has curdled and become solid in the stomach. Six ounces of formula every 3 hours is perfectly reasonable for a 2 month old. I would not offer the baby cereal or fruit, or put cereal in the bottle.

Sincerely,
Dr. Warren

If your questions haven't been answered here, perhaps you would like to

ask Dr. Warren a question?!?