Imaging Uganda/Africa

Glycogen storage disease

Introduction

Glycogen storage diseases (GSDs) are a group of inherited metabolic disorders characterized by abnormal glycogen metabolism. Hepatic involvement is prominent in types I (von Gierke disease), III (Cori disease), IV, VI, and IX. Ultrasound plays a key role in initial evaluation and monitoring of hepatic complications.

Ultrasound features

Characteristic sonographic findings in hepatic glycogen storage diseases:

hepatomegaly due to glycogenosis

1. Marked Hepatomegaly

  • Liver length >15 cm in midclavicular line
  • Homogeneous enlargement in early stages
  • Most prominent in types I and III
Increased liver echogenicity due to accumulation of glycogen

2. Increased Parenchymal Echogenicity

  • "Bright liver" appearance. Due to glycogen accumulation
  • Differentiate from steatosis by clinical contex

Diagnostic Pearls

  • Type I: Massive hepatomegaly + nephromegaly (kidneys also store glycogen)
  • Type III: Hepatomegaly + muscle weakness (combined hepatic/muscular form)
  • Liver texture often remains homogeneous until late stages

Disease-Specific Findings

GSD Type Enzyme Deficiency Key Ultrasound Features
Type I (von Gierke) Glucose-6-phosphatase Massive hepatomegaly, nephromegaly, hepatic adenomas (after puberty)
Type III (Cori) Glycogen debranching enzyme Hepatomegaly, may develop cirrhosis in adulthood
Type IV Branching enzyme Cirrhosis with heterogeneous echotexture (progressive)
Type VI/IX Liver phosphorylase/kinase Mild hepatomegaly, often improves with age

Hepatic Adenomas in GSD-I

Develop in 22-75% of GSD-I patients by 2nd-3rd decade:

  • Appear as well-circumscribed hypoechoic masses
  • Multiple lesions common (adenomatosis)
  • Surveillance recommended every 6-12 months
  • Risk of malignant transformation (hepatocellular carcinoma)

Monitoring and Complications

1. Adenoma Surveillance

  • Baseline ultrasound at puberty in GSD-I
  • Monitor for size increase (>5 cm higher risk)
  • Contrast-enhanced US/CT/MRI for characterization

2. Progression to Cirrhosis

  • Most common in GSD types III and IV
  • Look for nodular surface, coarse echotexture
  • Portal hypertension signs may develop

Ultrasound Protocol for GSD Monitoring

  • Measure liver span in midclavicular line
  • Document parenchymal echogenicity (compare to kidney)
  • Screen for focal lesions (adenomas)
  • Assess for signs of portal hypertension if cirrhotic
  • Include kidney evaluation in GSD-I
.