Acta Pzdiatr Scand 68: 615-616, 1979
LETTER TO THE EDITOR
Sir, Although the mechanism proposed by Dr Katznelson (1) for the increased intracranial pressure observed in three infants with cystic fibrosis cannot be discounted, another explanation is possible. It has been reported previously (2) that a deficiency of vitamin A may predispose to development of increased intracranial pressure and bulging fontanelles in cystic fibrosis. In fact, we have observed a similar syndrome in infants who have been malnourished prior to the diagnosis of cystic fibrosis and who do not have severe respiratory distress. Dr Katznelson does not mention whether his three patients were treated with enzymes and/or vitamins during their hospital course. If so, this could account, perhaps, for the decrease in intracranial pressure noted. Finally, it is somewhat difficult to understand how such marked airway obstruction which produced increased intracranial pressure could occur with preservation of arterial blood gases. The relatively high Pa,, and appropriately lo’w Pace, in cases 1 and 2 leads one to believe that the airway obstruction could not have been excessive, at least in these two patients.
The Editor has asked Dr Katznelson to comment on this letter
I want to thank Dr Taussig for drawing attention to deficiency of vitamin A as yet another cause for increased intracranial pressure. Vitamin A and carotene blood levels were not determined in our cases and therefore obviously this possibility cannot be excluded, at least in two of the cases. Case 2 had a bulging fontanel at the age of one month. This is possibly too short a period in which to develop significant avitaminosis in our infant who had been perfectly normal nutritionally at birth. In the paper referred to by Dr Taussig (1) both infants had had overt clinical signs of vitamin A deficiency. None of our cases had had xeropthalmia. Dr Taussig’s suggestion that the improvement in the intracranial pressure in our cases was really the result of the “unknowing” associated administration of vitamin A and not to the improvement in the pulmonary status, as I proposed, fails to note the clinical observation that there had been a “rise and fall” in the bulge of the fontanel concomitantly with the increase and decrease of respiratory obstruction signs. This cycle occurred twice in Case 2 and three times in Case 3 and all in the Lynn M . Tuussig space of a few days. Had the first episode of Associate Professor of Pediatrics bulging fontanel been due to avitaminosis A Arizona Health Sciences Center and its alleviation the result of therapy, then Tucson, Arizona 85724 yet another mechanism must be marshalled to USA explain the subsequent episodes of recurring bulge of the fontanel. REFERENCES As to the question of the severity of airway I . Katznelson, D.: Increased intracranial pressure in obstruction, the clinical reversible picture of cystic fibrosis. Acfu Puediatr Scund, 67: 607, 1978. Severe tachypnea with poor air entry, clear 2. Keating, J. P . & Feigin, R. D.: Increased intracranial pressure associated with probable Vitamin A defi- lung fields on X-ray with overdistended lungs ciency in cystic fibrosis. Pediatrics, 46: 41, 1970. and small heart appear most suggestive of air-
616
Lettrr to the editor
way obstruction in C. F. In Case 3 the blood gas Ievels are in keeping with this. In Case 1 the Paco2 was only mildly low (Par(), 4.7 kPa). It is only in Case 2 that the Pat., was very low (PaCo2 3.1 kPa). This of course must have been the result of the hyperventilation, itself indicative of the degree of respiratory embarrassment and refers to the time of ad-
mission and not to the situation three days later when the fontanel bulged. It is not impossible that the may have been higher. D mKutznelson Dept. Of Pediatrics ‘‘A’’ The Chaim Sheba Medical Center
Tel-Hashomer Israel
LETTER TO THE EDITOR
Sir, Although the mechanism proposed by Dr Katznelson (1) for the increased intracranial pressure observed in three infants with cystic fibrosis cannot be discounted, another explanation is possible. It has been reported previously (2) that a deficiency of vitamin A may predispose to development of increased intracranial pressure and bulging fontanelles in cystic fibrosis. In fact, we have observed a similar syndrome in infants who have been malnourished prior to the diagnosis of cystic fibrosis and who do not have severe respiratory distress. Dr Katznelson does not mention whether his three patients were treated with enzymes and/or vitamins during their hospital course. If so, this could account, perhaps, for the decrease in intracranial pressure noted. Finally, it is somewhat difficult to understand how such marked airway obstruction which produced increased intracranial pressure could occur with preservation of arterial blood gases. The relatively high Pa,, and appropriately lo’w Pace, in cases 1 and 2 leads one to believe that the airway obstruction could not have been excessive, at least in these two patients.
The Editor has asked Dr Katznelson to comment on this letter
I want to thank Dr Taussig for drawing attention to deficiency of vitamin A as yet another cause for increased intracranial pressure. Vitamin A and carotene blood levels were not determined in our cases and therefore obviously this possibility cannot be excluded, at least in two of the cases. Case 2 had a bulging fontanel at the age of one month. This is possibly too short a period in which to develop significant avitaminosis in our infant who had been perfectly normal nutritionally at birth. In the paper referred to by Dr Taussig (1) both infants had had overt clinical signs of vitamin A deficiency. None of our cases had had xeropthalmia. Dr Taussig’s suggestion that the improvement in the intracranial pressure in our cases was really the result of the “unknowing” associated administration of vitamin A and not to the improvement in the pulmonary status, as I proposed, fails to note the clinical observation that there had been a “rise and fall” in the bulge of the fontanel concomitantly with the increase and decrease of respiratory obstruction signs. This cycle occurred twice in Case 2 and three times in Case 3 and all in the Lynn M . Tuussig space of a few days. Had the first episode of Associate Professor of Pediatrics bulging fontanel been due to avitaminosis A Arizona Health Sciences Center and its alleviation the result of therapy, then Tucson, Arizona 85724 yet another mechanism must be marshalled to USA explain the subsequent episodes of recurring bulge of the fontanel. REFERENCES As to the question of the severity of airway I . Katznelson, D.: Increased intracranial pressure in obstruction, the clinical reversible picture of cystic fibrosis. Acfu Puediatr Scund, 67: 607, 1978. Severe tachypnea with poor air entry, clear 2. Keating, J. P . & Feigin, R. D.: Increased intracranial pressure associated with probable Vitamin A defi- lung fields on X-ray with overdistended lungs ciency in cystic fibrosis. Pediatrics, 46: 41, 1970. and small heart appear most suggestive of air-
616
Lettrr to the editor
way obstruction in C. F. In Case 3 the blood gas Ievels are in keeping with this. In Case 1 the Paco2 was only mildly low (Par(), 4.7 kPa). It is only in Case 2 that the Pat., was very low (PaCo2 3.1 kPa). This of course must have been the result of the hyperventilation, itself indicative of the degree of respiratory embarrassment and refers to the time of ad-
mission and not to the situation three days later when the fontanel bulged. It is not impossible that the may have been higher. D mKutznelson Dept. Of Pediatrics ‘‘A’’ The Chaim Sheba Medical Center
Tel-Hashomer Israel
