Fontanel, bulging, vitamin

Acute poisoning with vitamin A produces symptoms such as drowsiness, sluggishness, irritability, an irresistible desire to sleep, severe headache, and papilledema. In some cases papilledema is the only symptom (SEDA-11, 333) (16,17). In young children, raised intracranial pressure with bulging of the fontanelle, papilledema, and diplopia have been observed (SED-8,799, 801) (SEDA-15, 411) (18). 

Acute toxicity is uncommon in adults. However, very large exposures to vitamin A have resulted in the development of increased intracranial pressure (symptoms described include headache, dizziness, vomiting, visual changes, and bulging fontanel in infants). 

A. Chronic vitamin A toxicity is characterized by dry, peeling skin and signs of increased intracranial pressure (headache, altered mental status, and blurred vision pseudotumor cerebri). Bulging fontanelles have been described in infants. Liver injury may cause jaundice and ascites. 

Arnrich, 1978). Marie and See (1954) have described the symptoms of acute vitamin poisoning in children, vomiting, drowsiness, and bulging of the fontanelle. Table 1 documents that adults tend to complain of severe headaches, vertigo, abdominal pain, vomiting. 

The adverse effects of vitamin A in so-called tolerable upper intake levels have been reviewed [1 ]. Chronic hypervitaminosis A is relatively rare. Its effects are varied and non-specific. In adults they include central nervous system effects, skin disorders, conjunctivitis, nausea, vomiting, teratogenicity, and hepatotoxicity. In infants and young children, skeletal and intracranial (e.g. transient bulging fontanelle) abnormalities can occur. There are conflicting data on the risks of bone fractures from high chronic dosing in industrialized countries. 

Baqui AH, De Francisco A, Arifeen SE, Siddique AK, Sack RB. Bulging fontanelle after supplementation with 25,000 lU of vitamin A in infancy using immunisation contacts. Acta Paediatr 1995 84(8) 863-6. 

---