Adrenal Insufficiency and Bronchopulmonary Dysplasia in Low Birth

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					Aggett P, et al. Arch Dis Child 1980;55:547-550.                        deficiencyor possiblya medical condition that interfered with
Bilinski DL, et al. Arch DermatoI1987;123:1221-1224.
                                                                       zinc absorption or utilization? Moreover,there is no discus-
Buehning LJ, Goltz RW. JAm AcadDermatoI1993;28:499-501.
Heinen F, et al. Eur J Pediatr 1995;154:71-75.                         sion about the mother's nutritional status duringpregnancy.
                                                                       Speculation that the marginal zinc status of the mother may
Editor's comment: Zinc deficiencyis rare without a predis-             have contributed to the baby's congenital abnormalities is
posing disease such as acrodermatitisenteropathica. How-               appropriate. In animal models,zinc deficiency during ges-
ever,it must be consideredin the premature infant who may              tation has resulted in teratogenic fetal abnormalities,includ-
have less than normal zinc absorption. This particularcase             ing neural tube defects. Epidemiologic data also link
was complicatedby prematurityand maternalzinc deficiency.              maternal zinc deficiency and CNS malformations in the fe-
He respondedreally wellto therapy. Interestingly, authors
                                                     the                tus. Women with acrodermatitisenteropathica have a high
point out that if zinc oxidepaste is usedfor diaperrash,the zinc       incidence of spontaneous abortions and fetal alterations,
may be absorbed transcutaneously       from theanogenitalarea.         including skeletal abnormalities and anencephaly.
                                                                          Zinc needs of growing infants may be best met by breast
                                            Judith G. Ha", MD          milk even when there is intestinal malabsorption. However,
                                                                       low-birth-weight infants may be at risk for zinc deficiency
2nd Editor's comment: Zinc deficiencyin premature,breast-              and for these infants, the quality of the breast milk must be
fed infantshas been previouslydescribedin the literature. It is        considered. Zinc content of human milk normally falls as
not apparent whythe authorsstate that thiscase is an example           lactation progresses. Thus, banked human milk may con-
of a "distinctform of zinc deficiencysyndrome." The infant de-         tain less zinc than the mother's own milk and should be ana-
scribed received markedlyinadequatezinc intake from day 4              lyzed and supplemented with breast milk fortifier before use
through 21 of life by being treated parenterally without zinc          in feeding premature infants. Providing parenteral nutrition
supplementation.Thezinc content of thebreastmilk also was              to a premature infant without zinc supplementation is inap-
poor: <50% of the usual zinc contentof human milk. No infor-           propriate medical care. Current recommendations call for
mation waspresentedregardingthe amount of breast milk that             400 mg/kg/d of zinc in total parenteral nutrition solutions.
the baby was receiving. Since the infant was failing to thrive,        Poor nutrition during gestation will have a great impact on
energy requirements theinfant may not have been metsec-
                       of                                               the health of the baby, and knowledge of the mother's nutri-
ondary to inadequatebreast milk feedings.                              tional health will assist in treating the infant appropriately.
   No information was given to explain why the mother was
zinc deficient. Did she have a genetic disposition to zinc                                                         Fima Lifshitz, MO




Adrenal Insufficiency and BronchopulmonaryDysplasia in Low Birth Weight Infants
The causes of bronchopulmonary dysplasia are not clear,                reactions can be excessive and damage repair progresses
 but it has been associated with injuries due to mechanical            very slowly.
ventilation. However, chronic lung disease and bronchopul-                 Some studies done in animal models have shown that in
monary dysplasia can develop in small premature infants                the first few hours of life the response to adrenocorticotro-
 who show little initial respiratory distress and who have never       pic hormone (ACTH) may be absent (Guillet et al; and Walker
needed respiratory assistance.                                          et al). Studies in humans show that in the first hours of life
     Glucocorticoids produced by the adrenal glands play an im-        some low-birth-weight neonates may also lack the appropriate
 portant role in the resolution of inflammation and the response       response mediated by the hypothalamic-pituitary-adrenal
to stress. The trigger for the release of glucocorticoids from         axis. This has been called the neonatal stress "nonrespon-
the adrenal glands is the hypothalamic-pituitary-adrenal axis.         sive" or "hyporesponsive" period. During this period the ad-
 If this axis is functioning normally, inflammatory reactions          renal gland shows a diminished or absent response to ACTH.
are easily resolved and the damage repaired. However, if               This nonresponsiveness is thought to resolve within the first
the axis is not functioning properly, impaired inflammatory            week of life.
                                                                           A recent study by Watterberg and Scott suggested that
                                                                        some premature infants may not recover from the neonatal
                                                                        stress nonresponsive period as fast as expected and are
                                                                       thus predisposed to greater damage from inflammatory re-
                                                                       actions. In order to confirm this, they tested the cortisol re-
                                                                       sponse to ACTH by measuring blood cortisol secretion levels
                                                                       in a population of very-iow-birth-weight infants.
                                                                           At the end of the first week of life, the infants who had
                                                                       higher blood cortisol levels recovered without broncho-
                                                                       pulmonary dysplasia while the infants with lower cortisol lev-
                                                                       els eventually developed bronchopulmonary dysplasia and



                                                                   3                                  Vol.              1995
                                                                                                    GGH 11. No.4-December
remained dependent on oxygen supplementation. Watterberg                Editor's comment: These observationscould have impor-
and Scott concluded that the infants in the latter group may not       tant ramificationsforpreventive therapyin premature infants.
be able to secrete an adequate amount of cortisol in response          Bronchopulmonarydysplasia is a very crippling disorder and
to stress and thus inflammation goes unchecked and renders             its prevention would cel1ainly be welcome. The observa-
them susceptible to long-term lung injuries.                            tions need to be confirmed. An appropriate method of
                                                                       screening and trial of therapy could then lead to prevention
Guillet C, et al. Endocrinology 1980;106:991-994.                      of this dreaded complication of prematurity.
Walker CD, et al. Endocrinology 1986;118:1445-1451.
Watterberg KL, Scott SM. Pediatrics 1995;95:120-125.                                                                   JudithG. Hall,MD



Reduced Growth Honnone Secretion With Maintained Periodicity Following Cranial
Irradiation in Children With Acute Lymphoblastic Leukaemia
Lannering et al obtained growth hormone (GH) determina-                24 hours was withinthe normal rangefor both boys and girls.
tions every 20 minutes for 24 hours in a group of 34 children          Beforepubertya broad range of cyclesper 24 hourswas seen;
with acute lymphoblastic leukemia (ALL) who had received               thesesynchronized                                    1
                                                                                            during pubertyto approximately every 3
cranial irradiation with 18to 24 Gy. These children (12 boys           to 4 hours. Lowerpeakamplitudes    were observedinlhe irradi-
and 22 girls) had been diagnosed 4 to 10 years previously;             ated children. There was no correlationbetweentime from di-
their mean age at diagnosiswas 3.9 years. Fourteen(5 boys              agnosisand GH secretionor the maximalGH level duringthe
and 9 girls) were prepubertal at the time of the study (using          24-hourperiod. There were no obvious influencesof the time
Tanner staging). Heightwas expressedas standarddeviation               of diagnosison GH secretion. Children who were still prepu-
scores (SOS)in comparison with Swedish reference values                bertalat the time ofthe studyhad lostan average of 0.2 SOS.
for healthy children. A control group of 208 children was              Childrenwho had enteredpuberty lostan average of 1.0SOS.
utilized. The GH profiles were analyzed using the Pulsar                  The authorsstate that their resultsindicatenot only that cra-
pulse detection program and Fourier time-series analysis.                              in
                                                                       nial irradiation the range of20 to 24 Gy altersGH secretion
   The estimated GH secretion rate in all irradiatedALL chil-          (as determinedby Moell et ai, 1988), but also that irradiation
drenwas belowthe median ofthat of controlsfor pubertal  stage          with 18 Gy both beforeand duringpuberty reducesGH secre-
and sex. The difference betweenpatients and controls was               tion. Specifically,therewas lowerpulseamplitudein the irradi-
                   in
more pronounced latepubertythan beforepuberty.GH secre-                ated patients,            a            GH
                                                                                      suggesting physiologic insufficiency.Height
                  by
tion as expressed the areaunderthecurvewasalsoreduced       in         of the childrenat a meanfollow-upage of 7 yearsfell withinthe
irradiatedchildren. However,the number of GH peaksover                  normalrange for the Swedishpopulation. Final heightswere
                                                                        not reachedin a majorityofpatients. The authorsfurtherstate
                                                                       thatthe impairment   observedin growth issmall beforepuberty.
                                                                                              is
                                                                       The recommendation madethatALL patientsshouldbe stud-
                                                                       ied repeatedlyas adults to evaluate the effects of decreased
                                                                       GH secretionon organsotherthan the growthplate.

                                                                       Lannering   B, et al. Clin Endocrinol   1995;42:153-159.

                                                                       Editor's comment: More and more information regarding
                                                                       the effects of cranial irradiation on pituitary function is be-
                                                                       coming known. Although most pediatric endocrinologists
                                                                       recognize that irradiation with 24 Gy could be expected to
                                                                       be associated with pituitary dysfunction,it is not generally
                                                                       felt that lower dosages will be detrimental. However, few
                                                                       investigatorshave performed the carefultype of analysis that
                                                                       Lannering and coworkers presented. Their data suggest
                                                                       that there are indeed significant reductions in GH secretion
                                                                       with smaller doses of radiation that may not be clinically ob-
                                                                       servable (no obvious reduction in stature) until puberty, and
                                                                       that there is little difference between the effects of 18 and
                                                                       24 Gy. It will be interesting to review final heights in the
                                                                       patients reported in this study. One may then be able to
                                                                       better counsel families whose children have received even
                                                                       modest doses of cranial irradiation.

                                                                                                                           L.     MD
                                                                                                                    William Clarke,


GGHVol. 11. No.4-December 1995                                     4