Urea Cycle Disorders Flashcards Preview

DEMS 3 > Urea Cycle Disorders > Flashcards

Flashcards in Urea Cycle Disorders Deck (12)
Loading flashcards...
1
Q
OTC Deficiency (genetics/severity)
Ornithine Transcarbamylase
A

X-LINKED
Most common urea cycle disorder
Severe (males without enzyme often die as newborns)
15% of female carriers have clinical symptoms

2
Q

OTC defic Labs/diagnx

A

Serum aa: low citrulline, high glutamine

Urine: elevated orotic acid (organic)

3
Q

CPS1 defic (severity)

A

Carbomylphosphate Synthatase 1

SEVERE

4
Q

Genetics of Urea Cycle defic

A

All are AR

except OTC that is X-linked

5
Q

Plasma NH3 in Urea Cycle Defic

A

> 150 umol/L WITH A NORMAL ANION GAP AND NORMAL GLUCOSE

and mutations on molecular analysis

6
Q

Citrullemia Type 1/ASS1 Defic

A

Argininosuccinate SYNTHETASE 1
SEVERE but still able to incorporate SOME nitrogen into urea cycle intermediates
HIGH CITRULLINE

7
Q

Argininosuccinic Aciduria/ASL Defic

other sx

A

Argininosuccinate LYASE
Chronic hepatomegaly, trichorrhexis nodosa (node like appearance of fragile hair)
High citrulline
Enlarged hepatocytes (my progress to fibrosis)
Poss AST/ALT elevations

8
Q

NAGS defic

A

N-acetyl glutamate synthetase

Resmbles CPS1 defic as defic is in enzyme that yeidls CPS1 cofactor

9
Q

ARG defic, ORT-1 defic, Citrin defic PRES

A

Milder
Hyperammonemia sx triggered by stress/ilness
Can develop:
progressive spasticity, tremor, ataxia, choreoathetosis

10
Q

Pres for all but the milders

A

Depends on enzyme, partial defic can present like milders
Normal at birth but can develop hyperammonemia within first few days of life
Cerebral edema, lethargy, early HYPERventilation
Hypothermia, seizurues, vomiting, psychoses, HYPOventilation as cerebral edema progresses

11
Q

Acute Hyperammonemia Treatment

A

Dialysis and hemofiltration
Ammonia scavenging drugs (Na benzoate, Na phenylacetate)
Limit dietary protein
IV fluids and cardiac pressors (but avoid overhydration)
Arginine/citrulline as appropriate

12
Q

Chronic Hyperammonemia Treatment

A

Limit dietary protein
Supplement certain aa
LIVER TRANSPLANT for server neonatal pres or recurrent episodes after max medical tx
Genetic counseling