Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
|
What are the basic, general possible pathogenesis pathways of metabolic disorders
|
Mutations blocking formation of biologically active proteins
Mutations effecting protein function Relationship between location of protein and site of pathology Relationship between molecular abnormality and resulting phenotype |
|
|
Approximately how many newborns presenting with a sepsis-like illness in the absence of any risk factors for infection have a metabolic defect
|
20%
|
|
|
What are some of the classifications of abnormal metabolites (or abnormal levels of normal metabolites) causing cellular poisoning
|
Small molecules: Aminoacidopathies and organic acidurias
Large molecules: Storage diseases |
|
|
List the categories of inborn errors of metabolism involving metabolites
|
Aminoacidopathies
Organic acidurias Storage diseases |
|
|
List the categories of inborn errors of metabolism involving energy deficiency
|
Mitochondrial defects
Fatty acid oxidation defects Congenital lactic acidemias |
|
|
List the categories of inborn errors of metabolism involving energy deficiency
|
Peroxisomal defects
|
|
|
How prevalent is PKU and which groups are most at risk
|
~1/10000 births
Most frequent in caucasians of northern european descent |
|
|
Describe the general progression for an untreated patient with PKU from birth
|
Affected babies appear normal at birth
Gradually develop irreversible sever mental retardation, pigment dilution, seizures, microcephaly |
|
|
Are there expected to be any abnormal metabolites in a patient with PKU
|
No, only normal metabolites at elevated levels
|
|
|
What is the therapy (long term) for a patient with PKU
|
Early onset therapy (within 1 month of birth)
Semi-synthetic diet Continuous therapy for life Restrict PHE intake to keep plasma levels in check over-restriction impairs growth |
|
|
What is the treatment for Urea Cycle Defects
|
Protein restriction, arginine supplementation and enhancement of ammonia excretion with drugs
|
|
|
Describe the liver enzymes that might be involved in a urea cycle defect
|
Five total, convert excess nitrogen from protein into urea
Four enzymes autosomal recessive OTC deficiency is X-linked recessive |
|
|
What are the clinical signs of a urea cycle defect
|
Protein intolerance with episodic vomiting, lethargy, coma
Possibly intracranial and/or pulmonary hemorrhage Cerebral edema |
|
|
What are the biochemical signs of a urea cycle defect
|
Severe hyperammonemia
Possible respiratory alkalosis Abnormal serum amino acids |
|
|
What is the initial treatment for OTC deficiency
|
Hemodialysis
Stop protein feeds High carbohydrate calorie diet Meds to shunt glycine & glutamate into different pathways |
|
|
Characteristics of galactosemia
|
Defect in carbohydrate metabolism
Autosomal recessive One of three proteins: GPUT, galactokinase, epimerase |
|
|
Describe classic galactosemia in a newborn given lactose during their first week
|
Vomiting and diarrhea
E coli sepsis Failure to thrive or weightloss Hepatomegaly, jaundice Kidney dysfunction Cataracting Increased ICP |
|
|
Untreated galactosemia results in? Delayed treatment?
|
Untreated = death
Delayed treatment = mental retardation, speech problems |
|
|
Lab abnormalities associated with galactosemia include
|
Galactosemia/galactosuria
Hypphosphatemia Hypokalemia Hypoglycemia |
|
|
Describe the pathogenesis of Fatty Acid Oxidation Defects
|
Can't make ketone bodies from fat (defect in mito. beta-ox)
Can't fuel brain during hypoglycemia |
|
|
What are the clinical signs of a fatty acid oxidation defect
|
Intolerance to fasting (Vomiting, Lethargy, Coma)
Can have SIDS Possible cardiomyopathy Abnormal tone Hepatomegaly |
|
|
What are the biochemical signs of a fatty acid oxidation defect
|
Metabolic acidosis
Hypoglycemia (with low ketosis) mild hyperammonemia Low free carnitine Abnormal liver transaminases |
|
|
Describe the pathogenesis of amino acid disorders
|
Excess AA precurors from block in metabolic pathway
|
|
|
Describe the biochemical signs of amino acid disorders
|
Normal pH
Normal ammonia Euglycemia Abnormal serum AAs |
|
|
Describe the clincal signs of amino acid disorders
|
Vomiting, lethargy, coma
Neonatal seizures Abnormal odor |
|
|
Describe the pathogenesis of organic acid defects
|
Defect in oxidation of AAs
|
|
|
Describe the clinical signs of organic acid defects
|
Present in newborn period with hyperammonemia (from secondary interference with urea cycle) and Severe metabolic acidosis
|
|
|
What is an important thing to remember for infants/children living with an organic acid disorder
|
Minor illnesses can precipitate metabolic decompensation (trigger life-threatening event)
|
|
|
MSUD falls under what category of metabolic disorders
|
Organic acid disorder
|
|
|
What is the evaluation/routine study for a patient with a suspected metabolic disorder (before referring to specialist)
|
CBC, serum electrolytes, serum glucose, urinalysis for ketones, arterial blood gas, liver transaminases, serum Ca++ & Mg+
|
|
|
General management for inborn errors of metabolism include
|
Avoiding offending precursor
Provide fluid and calories/prevent catabolism Remove toxic metabolites (dialysis, scavenger molecules) Water soluble megavitamin cocktail |
