Metabolic Medicine Flashcards
Anion gap calculation and normal value
[Na + K] - [Cl + HCO3]
Normal 10-16
Type I GSD
deficiency of glucose-6-phosphate
presentation of Type 1 GSD
hepatomegaly (2y to glycogen storage)
cherubic facies
hypoglycaemic symps in the neonatal period
Rx Type 1 GSD
regular feeds through the day and continuous feed overnight
Type V GSD
McArdle’s disease
Muscle cramps/pain/fatigue during brief intense exercise
Dark coloured urine (myoglobin)
presentation of MCADD
can present with an intercurrent illness or following a prolonged period of fasting
hypoketotic hypoglycaemia
Rx MCADD
avoidance of prolonged fasting
additional supplementation of glucose during intercurrent illness §
what are apolipoproteins
proteins that bind with lipids (trigs & cholesterol) to form lipoproteins»_space; enables transport of lipids around the body
Apolipoprotein CII deficiency
impaired clearance of chylomicrons (lipoproteins that mainly transport trigs)
- xanthomas
- incr risk of CVS disease and pancreatitis
inheritance of apolipoprotein B deficiency
AD
consequence of apoliprotein B deficiency
raised LDL cholesterol in the blood
are trigs normal or raised in apolipoprotein B deficiency
normal
inheritance of galactosaemia
AR
what is deficient in galactosaemia
the enzyme galactose-1-uridyl transferase
consequence of galactosaemia
cannot convert galactose to glucsoe
presentation galactosaemia
vomiting
diarrhoea
faltering growth
jaundice
cataracts **
e.coli UTI **
Rx galactosaemia
lactose and galactose free diet > soya based feed (Casein-hydrolysate formula)
inheritance of GLUT-1 deficiency
AD - mutation in SLC2A1 gene
what is the role of GLUT-1
the primary transport protein that allows glucose to cross the BBB
presentation GLUT-1 deficiency
aberrant gaze saccades
refractroy seizures
spasticity
ataxia
dystonia
triggers > exercise/stress/weather changes
Ix GLUT-1 deficiency
LP - low CSF plasma glucose & low lactate
Genetic testing
Rx GLUT1 deficiency
ketogenic diet - high fat, avoid carbs
What is important perioperatively (fluid wise) for patietns with GLUT-1 deficiency
avoid dextrose in fluids as this will provoke crisis
what is kearn’s sayre syndrome
mitochondrial disorder
-progressive ophthalmoplegia
- ptosis
- cardiac conduction abnormalities
what is niemann-pick type c disorder
a lysosomal storage disorder
mutation in NPC disorder
NP1 mutation (95%) on long arm of chromosome 18
or
NP2 mutation on long arm of chromosome 14
consequence of NPC disorder
inability to transport cholesterol and fatty acids, leading to accumulation in tissue incl brain
presentation of NPC disorder
huge variety, can present perinatally if severe or not be discovered until adulthood
perinatal
- ascites / cholestasis / hepatomegaly
infancy
- hepatosplenomegaly / delayed psychomotor development / vertical supranuclear gaze palsy ** / sensorineural hearing loss
eye movement disorder in NPC
vertical supranuclear gaze palsy
what are mucopolysaccaridoses (MPS)
a group of lysosomal enzyme deficiency disorders, usually involved in the breakdown of glycosaminoglycans
pathophysiology of MPS
mutation in the IDUA gene»_space; failure to breakdown glycosaminoglycans»_space; accumulation and multi organ disease
characteristic features of MPS
coarse facies
macroglossia
micrognathia
cardiomyopathy
presentation of MPS type 1 (hurler syndrome)
corneal clouding
inheritance of MPS
Type 1, 3, 4 and 5 AR
Type 2 X-linked
presentation of MPS type 2 (hunter syndrome)
similar to hurler’s syndrome but no corneal clouding
presentation of MPS type 3 (sanfillipo syndrome)
major development and intellectual delay
Ix for MPS
urine glycosaminoglycans - will be raised
what causes non-ketotic hyperglycinaemia
a defect in the glycine cleavage system»_space; glycine encephalopathy
presentation of non-ketotic hyperglycinaemia
seizures in utero ‘rhythmic fetal movements’
soon after birth - profound apnoeas/lethargy/myoclonic seizures/refractory status
inheritance of PKU
AR
deficiency in PKU
phenylalanine hydroxylase (converts phenylalanine to tyrosine)
presentation PKU
2y to raised phenylalanine levels
- microcephaly
- seizures
- LD
- eczema
- fair skin & eyes
- dysmorphic features
Rx PKU
low protein diet (Reduce intake of phenylalanine)
tyrosine supplementation
enzyme deficient in maple syrup urine disease (MSUD)
alpha-keto-acid dehydrogenase
inheritance of homocystinuria
AR
problem in homocystinuria
disorder of conversion of methionine to cysteine»_space; consequent accumulation of homocysteine
