Makindo Medical Notes

Glucagon may be ineffective to treat hypoglycaemia as glycogen cannot be mobilised

About

• They can be split into those affecting primarily muscle and those affecting the liver.
• See Von Gierke Diseaseentry

Aetiology

• Glycogen is a high molecular weight polymer of glucose residues. Both liver and muscle contain significant stores of glycogen.
• Glycogen is formed by glycogen synthase and broken down by glycogen phosphorylase.

Clinical

• They are nearly all autosomal recessive with deficiencies in enzymes important for glycogen storage or breakdown.
• Glycogen is stored in the liver so Hepatomegaly is common but NO SPLENOMEGALY
• Hypoglycaemia is seen - drowsiness, seizures etc..
• Failure to thrive and lactic acidosis and hypoglycaemia
• Most present in infancy to the paediatrician
• older children present with Hypotonia, muscle weakness and wasting

Complications long term

• Severe hypoglycaemia, cerebral oedema, coma and even death
• Hepatic tumour - adenoma and adenocarcinoma
• Glomerular hyperfiltration and glomerulosclerosis
• Brain damage, Severe anaemia
• Failure to thrive and Growth failure

Commoner forms

• 1 - von Gierke's (glucose-6-phosphatase deficiency)- Hepatomegaly, hypoglycaemia and lactic acidosis. High mortality though some survive.
• 2 - Pompe's disease - Heart failure and hypotonia. Death in infancy
• 5 - McArdle's disease - Muscle cramps, proximal wasting. Normal life expectancy.

Summary

Glycogen storage diseases (GSDs) are a group of inherited disorders characterized by abnormal glycogen metabolism, resulting in the accumulation of glycogen within cells. At least 15 types have been identified, with Types I-V being autosomal recessive. These diseases are diagnosed using the Periodic Acid–Schiff (PAS) stain to identify glycogen in tissues.

Mnemonic: "Vice President Can’t Accept Money" - Von Gierke, Pompe, Cori, Andersen, McArdle.