Metabolic Medicine Flashcards
Which condition is associated with sweaty feet odour?
Isovalaeric Acidaemia
What is the investigation of choice for isovalaeric academia?
Urine organic acids showing elevated C5 acylcarnitine
Which condition is associated with a sweet smell to ear wax/ urine?
Maple syrup urine disease
How is MSUD diagnosed?
Detection of L-alloisoleucine
What is the management of MSUD?
Leucine, isoleucine and valine
Which condition is associated with a musty smell?
PKU
What are the symptoms of PKU?
Fair hair
Blue eyes
Eczema
Photophobia
Microcephaly
Intellectual disability
Epilepsy
What is the pathophysiology of PKU?
A deficiency in phenylalanine hydroxyalase causes elevated levels of phenylalanine
Low tyrosine levels also lead to low dopamine and epinephrine levels
How is PKU diagnosed?
Plasma amino acids
Elevated phenylalanine levels
How is PKU managed?
Commence low protein diet
Phenylalanine free medical formula - should be mostly breast fed as this is naturally low in phenylalanine (e.g. XP Analog LCP)
Avoid aspartame’s
What are the features of homocystinuria?
Tall stature
Intellectual disability
Ectopia lentísimo (downward dislocation of the lens)
Osteoporosis
Recurrent thrombosis
What is the pathophysiology of homocystinuria?
Due to a deficiency of cystathionine beta-synthase
How is homocysteine diagnosed?
Elevated methionine
Elevated homocysteine levels
How is homocysteine diagnosed?
High dose pyridoxine
What differentiates homocystinuria from marfan syndrome?
Autosomal recessive
IQ down
Lens dislocation down
What differentiates Marfan syndrome from homocystinuria?
Autosomal dominant
IQ up
Lens dislocation up
What condition is associated with black urine?
Alkaptonuria
How is alkaptonuria diagnosed?
Homogentisic acid in urine
Features include failure to thrive, hepatomegaly, renal tubular acidosis (Fanconi syndrome) and radiographic fraying of rickets?
Tyrosinaemia type 1
aka hepatorenal tyrosinaemia
How is tyrosinaemia diagnosed?
Elevated plasma and urine succinylacetone levels
What are the key findings of urea cycle disorders?
Very high ammonia (>1000)
Respiratory alkalosis
What are the laboratory findings in MCAD?
Hypoketotic hypoglycaemia
Hyperammonaemia
Elevated C6, C8 and C10 carnitine esters on plasma acylcarnitine profile
Which condition can present with cataracts and hypoglycaemia?
Galactosaemia
What are the features of galacetosaemia?
Cataracts
Hypoglycaemia
Vitreous haemorrhage
Jaundice
Hepatosplenomegaly
Which condition presents with positive urine reducing substances?
Galacetosaemia
What is a the possible complications of galactosaemia?
E. coli sepsis
Ovarian failure
Amenorrhoea
What are the features of Pompe disease?
Muscle wasting
Cardiomegaly
Macroglossia
What is the pathophysiology of McArdle Disease?
Deficiency of muscle phosphorylase which is required in the conversion of glycogen to glucose
Hence a lack of glucose in the muscle causes pain or cramps on exercising
What are the features of McArdle disease?
Exercise induced cramps/ exercise intolerance
Can cause rhabdomyolysis
Elevated CK levels at rest
Which condition should be considered in infants who are given juice/ fruit for the first time?
Fructose 1, 6 diphosphate deficiency
What are the features of mucopolysaccharidoses?
Initially appear normal however with the accumulation of mucopolysaccharides the patient develops:
Coarse facial features
Organomegaly
Bony deformities
Developmental regression
Sensory loss (hearing and vision)
What do the eyes appear like in Hurler Syndrome (MPS type 1)?
Cloudy corneas
What do the eyes appear like in Hunter Syndrome (MPS type 2)?
No cloudy cornea
Remember Hunters have sharp vision therefore no clouding of the cornea
What is the pathophysiology of Gaucher disease?
Due a deficiency of glucocereborsidase enzyme which leads to deposition of glucocerebroside in cells of the macrophage-monocyte system
This causes deposition in the spleen causing enlarged spleen and thrombocytopenia
What are the features of Gaucher Disease?
Enlarged spleen - very significant
Bone pain
Hyperpigmentation
Thrombocytopenia
Anaemia
What is the pathophysiology of Niemann-Pick disease?
Lipid storage disorder due to a deficiency of acid sphingomyelinase enzyme
What are the features of type A Niemann Pick disease?
Common in Ashkenazi jews
Hepatosplenomegaly
Progressive loss of motor skills
Cherry-red spot
Which condition presents with episodic pain in the hands and feet, anihidrosus and corneal opacities?
Fabry Disease
What is the pathophysiology of Fabry disease?
Deficient activity of lysosomal enzyme alpha galactosidase
What diagnosis would seizures to auditory stimuli and cherry red spots point you in the direction of?
Tay-Sachs disease
Which condition is associated with self mutilating behaviours (biting fingers and lips)?
Lesch-Nyhan disease
How is the anion gap calculated?
(Na + K+) - (Cl + HCO3-)
Normal anion gap is 8-12
When a patient is lacking small intestine - how should they be fed?
Perenteral nutrition
