Acute neonatal presentation

The clinical syndrome of acute neonatal hyper-ammonemic encephalopathy described in the case report represents the classical presentation of a patient with a urea cycle disorder (UCD). It is important to note that this neonatal course represents only the most common and severe presentation of a UCD. This holds true for all the diseases listed in Table 18-1, with the exceptions of arginase (ARG-1) deficiency, which results in progressive spasticity of the lower limbs, and of the mitochondrial membrane transporters citrin and ornithine transporter 1 (ORNT-1). Deficiency of citrin results in adult-onset encephalopathy deficiency of... 

A second, cytosolic CPS activity (CPSII) occurs in mammals as part of the CAD trifunctional protein that catalyzes the first three steps of pyrimidine synthesis (CPSII, asparate tran-scarbamoylase, and dihydroorotase). The activities of these three enzymes—CPSII, aspartate transcarbamoylase, and dihydroorotase—result in the production of orotic acid from ammonium, bicarbonate, and ATP. CPSII has no role in ureagenesis, but orotic aciduria results from hepatocellular accumulation of carbamyl phosphate and helps distinguish CPSI deficiency from other UCDs. Defects in CPSI classically present with neonatal acute hyperammonemic encephalopathy. The plasma citrulline and urine orotic acid concentrations are both low. A definitive diagnosis can be established by enzyme assay of biopsied liver tissue or by mutation analysis. 

The liver has a limited number of ways of responding to injury. Acute injury to the liver may be asymptomatic, but often presents as jaundice. The two major acute liver diseases are acute hepatitis and cholestasis. Chronic liver injury generally takes the clinical form of chronic hepatitis its long-term complications include cirrhosis and HCC. The discussion of liver disease wiU focus mainly on these patterns, and a few diseases that differ from this general pattern. Because the types of disease seen in neonates differ significantly from this model, diseases of infancy are discussed separately in Chapter 31. 

This chapter addresses the problems of acute respiratory distress syndromes in neonates, children, and adults. Abbreviations are used throughout the text, and a glossary for physiology, diseases, and drugs is presented in Table 28-1. Descriptions of ventilator-related terms are provided in Tables 28-2 and 28-3. Because the physiology of neonatal respiratory distress syndrome (RDS) and acute respiratory distress syndrome (ARDS) has some differences, these diseases will be discussed separately. 

The clinical presentation of acute hematogenous osteomyelitis is summarized in Table 116-3. Although neonatal hematogenous... 

B. Neonatal drug withdrawal may occur In infants with chronic prenatal exposure to illicit or therapeutic drugs. The onset is usually within 72 hours of birth, but a postnatal onset as late as 14 days has been reported. Signs usually commence in the nursery, and infants are not discharged until clinically stable. However, with early discharge from nurseries becoming the norm, an infant in withdrawal may first present to an emergency department or acute care clinic. The presentation may be as mild as colic or severe as withdrawal seizures or profound diarrhea. 

Carty HM (2002) Paediatric emergencies non-traumatic abdominal emergencies. Eur Radiol 12 2835-2848 Ceres L, Alonso I, Lopez P et al (1990) Ultrasound study of acute appendicitis in children with emphasis upon the diagnosis of retrocecal appendicitis. Pediatr Radiol 20 258-261 Chao HC, Kong MS, Chen JY et al (2000) Sonographic features related to volvulus in neonatal intestinal malrotation. J Ultrasound Med 19 371-376 Chinn DH, Millar El, Piper N (1987) Hemorrhagic cholecystitis. Sonographic and clinical presentation. J Ultrasound Med 6 313-317... 

Individual inborn errors of metabolism are very rare, but as a group, they represent a quite common cause of acute deterioration in newborns. In the first days to weeks of life, neonate with inborn errors of metabolism and metabolic intoxication may be asymptomatic or present with symptoms similar to the more common manifestation of disorders of early infancy, including generalized... 

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