Pediatric emergency medicine trisk 2427 2427

Phosphoenolpyruvate carboxylase deficiency
Pyruvate carboxylase deficiency
Pyruvate dehydrogenase complex deficiency
Succinate dehydrogenase deficiency
Peroxisomal disorders
Adrenomyeloneuropathy
Adrenoleukodystrophy in neonatal, adult
Catalase deficiency
Glutaric acidemia type III
Leber hereditary optic neuropathy
Refsum disease infantile, adult
Rhizomelic chondrodysplasia punctata
Wolfram syndrome
Zellweger syndrome
Congenital disorders of glycosylation
Disorders of metal transport
Disorders of heme metabolism
Disorders of nucleic acid metabolism
Disorders of cholesterol synthesis
Disorders of bile acid synthesis
Disorders of neurotransmitter metabolism
Laboratory Findings. In the patient with potentially life-threatening symptoms, evaluation for possible
IEM should be initiated immediately.
The initial laboratory evaluation of a patient with suspected IEM includes electrolytes, glucose, venous
blood gas, CBC, ammonia, lactate, blood urea nitrogen (BUN), creatinine, liver tests (aspartate
transaminase [AST] and alanine transaminase [ALT], prothrombin time [PT], partial thromboplastin time
[PTT]), uric acid and urinalysis. If possible, the initial evaluation should also include samples for
specialized testing including plasma amino acids, urine organic acids, and acylcarnitine profile ( Table
95.4 ). In addition to these studies, patients with history or physical examination suggestive of myopathy
should have lactate dehydrogenase, aldolase, creatinine phosphokinase, and urine myoglobin measured as
part of their initial screen.

If a metabolic disease is suspected, consultation with an IEM specialist should be considered to guide
further laboratory evaluation and assist with the appropriate collection and processing of specimens.
Blood should be collected and sent for plasma amino acids and acylcarnitine profile, while urine should
be collected for potential analysis of organic acids, acylglycine, and/or orotic acid ( Table 95.5 ).
Additional blood and urine for possible further testing should be obtained and stored. Cerebrospinal fluid
(CSF), if obtained, should be collected at the same time as plasma and immediately frozen and stored for
possible further testing for neurometabolic disorders, most commonly nonketotic hyperglycinemia,
disorders of serine biosynthesis, and/or neurotransmitter disorders. Measurement of lactate and pyruvate
are important components of the ED evaluation but may be difficult to interpret, particularly in the patient
with hypoxia, poor perfusion, seizure, and/or sepsis. Laboratory abnormalities are often transient,
particularly if fluids and/or glucose are administered; therefore, normal values do not rule out an IEM. It
is critical to obtain pretreatment specimens, if possible. If pretreatment specimens were not obtained, as is
often the case because many IEMs are first suspected based on results of routine laboratory studies,