Disorders of Carbohydrate Metabolism Flashcards
Lactose intolerance
- Lactase hydrolyzes lactose to glucose and galactose
- Deficiency of lactase
- lactose accumulates in the gut.
- Irritant diarrhea and flatulence
- congenital or acquired.
- Acquired lactose intolerance when there is a sudden
change to a milk based diet. - Curd treatment, because lactobacilli contains lactase.
Carrier protein defective in glucose-galactose malabsorption
SGluT-1
Carrier protein defective in congenital renal glycosuria
SGluT-2
A newborn baby had severe abdominal distension, severe abdominal pain, and diarrhea after being fed breast milk. Urine analysis revealed the presence of
reducing sugar. What is the possible defect? What is the confirmatory diagnostic test? How can it be treated?
- Lactose intolerance
- Symptoms due to undigested lactose causing its fermentation
- Lactose excreted in urine giving positive Benedicts test
- Confirmed by stool acidity test (lactic acid)
- Lactose free/soy milk, lactase tablets
Type 1 glycogen storage disease
Von Gierke’s
- Glucose 6 phosphotase
- Glucose 6 P accumulated, sent to HMP producing more ribose and purine nucl.
1. Fasting hypoglycemia that does not respond to adrenaline
2. Hyperlipidemia
3. Lactic acidosis, ketosis
4. Hyperuricemia
5. Liver enlargement and cirrhosis due to glycogen deposits
6. Children die early
Rx: little food at frequent intervals
Type 2 glycogen storage disease
Pompe's - a 1,4 glucosidase 1. Accumulation of glycogen in lysosomes of heart, liver, muscle 2. Infantile form: Death before 2 yrs Juvenile: Myopathy Adult: Muscular dystrophy
Type 3 glycogen storage disease
Cori’s
- a 1,6 glucosidase
- symptoms disappear at puberty
1. Branched dextrin accumulates
2. Fasting hypoglycemia
3. Hepatomegaly
4. Myopathy
Type 4 glycogen storage disease
Anderson’s
- branching enzyme
- glycogen with few branches
- liver failure may be due to immune rxn against abnormal glycogen
1. Hepatosplenomegaly
2. Cirrhosis
3. Cardiac, liver failure before 5yo
Type 5 glycogen storage disease
McArdle’s
- muscle glycogen phosphorylase
1. Exercise intolerance
2. Accumulation of glycogen in muscles
3. Myoglobinuria
Type 6 glycogen storage disease
Her’s
- Liver glycogen phosphorylase
1. Mild hypoglycemia
2. hepatomegaly
3. hyperlipidemia
4. ketosis
Type 7 glycogen storage disease
Tarui’s
- phosphofructokinase of muscle and RBC
1. Exercise intolerance
2. Haemolytic anaemia
G6PD deficiency
- X linked recessive
- only manifested on administration of antimalarial drug (primaquine), sulpha drugs or fava beans
- primaquine stimulates peroxide formation inside RBC
- as NADPH is low, this leads to lysis
- drug-induced haemolytic anaemia
- inc. met-Hb in circulation
- offers resistance to plasmodium infection
Bridges Good syndrome
Chronic Granulomatous Disease
- defect in NADPH oxidase system
- increased risk for infections like pneumonia, skin abcesses, osteomyelitis
Essential pentosuria
- one of Garrod’s tetrad
- inborn error
- absence of xylitol dehydrogenase/xylulose reductase
- L xylulose excreted in urine - positive Benedict
- Barbiturates, aminopyrine inc. xylulosuria
A 2-year-old child presented with liver enlargement. On investigation, Blood sugar–50 mg%, Uric acid–10 mg%, lactic acid–15 mg% and ketone bodies were present. Plasma cholesterol–300 mg%. What is the likely diagnosis? What is the biochemical basis of the disorder and its treatment?
Von Gierkes Hypoglycemia Hyperlactitemia Metabolic acidosis Hyperlipidemia Hyperuricemia Rx: maintain normoglycemia