Effective measures for secondary prevention of GSD type 1 include:[1]
Blood glucose (BG) monitoring
Prevent overtreatment
Growth tracking
Gastrointestinal or Nutritional recommendations
Hepatic and hepatic transplantation recommendations
Blood glucose (BG) monitoring
Initial diet prescription is established on the basis of frequent BG monitoring. Afterwards, BG monitoring is done randomly to avoid asymptomatic hypoglycemia.
Documentation of BG testing is done before each clinic visit to adjust diet, CS intake, and overnight gastric feedings (OGFs).
The following BG levels should be checked for 2–3 days before the clinic visit:
Before meals
Before cornstarch (CS) intake
Before and after exercise
If the cornstarch dose is changed, BG levels should be checked after 4 hours and then at hourly intervals to establish the duration of effectiveness. Effectiveness is measured by the duration of time for which the dose of CS will maintain the BG level >70 mg/dl.
Lactate meter
The lactate meter is a portable device to measure lactate concentration.[2]
Lactate concentrations are higher in patients with GSD type 1.
The lactate meter may act as a good supplement to glucose monitoring, particularly during times of illness to help prevent acute deterioration, to avoid hospitalization, or to alert the caregivers about emergencies.
Continuous blood glucose monitoring system
This is a method for monitoring and managing BG control in GSD patients.[3]
This system may also help detect asymptomatic hypoglycemia.
Prevent overtreatment
Parents should be educated to avoid overtreating patients.
Overtreatment may result in complications including increased glycogen storage and over time may lead to hyperinsulinemia and insulin resistance.[4]
Growth tracking
Growth should be tracked through parameters including:[1]
Height
Weight
Weight/height ratio
Body mass index
Head circumference
Changes in growth pattern is observed in poor metabolic control of GSD type 1.
Gastrointestinal or Nutritional recommendations
A metabolic dietician is an important member of the team. If not available, one should be consulted.
Maintaining blood glucose levels ≥70 mg/dl is important to achieve good metabolic control. Levels should e kept consistent to avoid hypoglycemia and fluctuations blood glucose levels.
In infants and children:
Avoid fasting for more than 3-4 hours.
Offer small, frequent feedings; avoid or limit sucrose, fructose, and galactose (a soy formula such as Prosobee may be used overnight).
Access via NG or G-tube placement is recommended for emergencies and/or for OGFs; caution with surgical G-tube placement should be taken in GSD 1b.
Monitor blood glucose before feeds.
Raw, uncooked cornstarch may be introduced between 6 and 12 months of age/
Continuous gastric feedings may be used overnight.
In adolescent and adults:
Avoid fasting for more than 5-6 hours with the use of raw, uncooked cornstarch and/or OGFs; it is important to not change the brand of cornstarch. If changed, then monitoring of BG levels after the change is necessary.
Plan for small, frequent meals (nutrient distribution:60-70% carbohydrates, 10-15% protein, <30% fat); avoid or limit sucrose, fructose, and galactose.
Regular blood glucose monitoring is needed, especially during periods of growth.
Multivitamins, calcium, and vitamin D are necessary because of the restricted nature of the diet.
Both overtreatment and undertreatment are harmful. Overtreatment can result in insulin resistance.
Good glucose control improves several of the metabolic sequelae of GSD 1.
Hepatic and hepatic transplantation recommendations
There should be monitoring for development of liver adenomas vias liver imaging especially after the onset of puberty.
Adenomas are often multiple. In some situations, there is regression of adenomas noted with good metabolic control./otehr genetic factors can play a role in hepatic adenoma development. There is a risk for adenoma HCC transformation, especially when there is a rapid increase in size or number of adenomas, routine laboratory testing to include hepatic profile (serum glutamic olalacetic transaminase, serum glutamic pyruvic transaminase, albumin, bilirubin) should be performed every 6 months. In the setting of consideration of an LT, laboratory testing that includes serum creatinine and international normalized ratio (prothrombin time/partial thromboplastin time) tests, in addition to hepatic profile, should be performed every 6 months.
α-Fetoprotein and chorionic embryonic antigen levels are often normal, even in the setting of HCC, and do not predict hepatocellular adenoma to malignancy transformation.
Abdominal ultrasound is reasonable in the pediatric population. Abdominal imaging should be performed at baseline and every 12-24 months.
Abdominal computed tomography/magnetic resonance imaging with contrast should be performed in older patients or patients within the pediatric age group once adenoma is detected on ultrasound and are to be repeated every 6 - 12 months or earlier based on laboratory and clinical findings.
Percutaneous ethanol injections, radiofrequency ablation, and partial liver resection are treatment options for liver adenomas (especially if an increase in size, number, or bleeding is noted). A high suspicion of HCC is needed because no reliable biomarker is currently available for HCA-to-HCC transformation. A sudden increase in size or number, or an increase in vascularity of adenomas, is concerning for nHCC transformation.
Monitoring of the patient's MELD score is critical because it is used to assess the extent of liver disease and for ranking for LT. The latter should be performed at centers with experience in ranking GSD 1 severity.
Nephrology recommendations
Diagnostic studies should be performed at routine visits to follow renal manifestations of GSD type 1, including:
Renal ultrasound to assess kidney size and growth, nephrolithiasis, or nephrocalcinosis
Urinalysis for hematuria and proteinuria
Quantification by spot samples of urinary microalbumin/creatinine excretion, citrate, and calcium/creatinine excretion
Measurement of serum electrolytes, calcium, and phosphate; blood urea nitrogen and serum creatinine with calculation of estimated GFR.
Consider initiating an ACE inhibitor or ARB with evidence of hyperfiltration (sustained estimated GFR >140ml/min/1.73 m2).
Initiate an ACE inhibitor or ARB for persistent microablbuminuria (>30ug albummin/mg creatinine).
Initiate an ACE inhibitor or ARB for frank proteinuria (>0.2 mg protein/mg creatinine).
Initiate citrate supplementation for hypocitraturia, use of potassium citrate in patients with good renal function, accompanied by careful monitoring of electrolytes. Use of extreme caution in the setting of renal failure.
Consider a thiazide diuretic for hypercalciuria.
Maintain normal blood pressure for age.
Hematology recommendations
Evaluation of anemia should include nutritional causes, adenomas, enterocolitis, menorrhagia in females, and occult blood loss. Evaluations should include complete cell count with manual differential, serum, total iron-binding capacity, and reticulocytes counts.
In GSD type 1a, if anemia is severe, evaluation for hepatic adenomas should be performed.
In GSD type 1b, if anemia is severe, evaluation for GSD enterocolitis should be performed.
If iron deficiency anemia is documented, iron supplementation (oral or i.v.) as needed and optimization of metabolic control are recommended. Consider iron deficiency anemia if iron levels donot improve.
Neutropenic patients with GSD type 1b should e treated with G-CSF, particularly if there is already a history and pattern of fever, infections, or enterocolitis.
The lowest effective G-CSF dose should be used to avoid worsening of splenomegaly, hypersplenism, hepatomegaly, and bone pain. G-CSF should be administered subcutaneously starting at 0.5 -1.0 µg per kilogram per day given daily or every other day. The G-CSF dose should be increased stepwise at approximately 2-week intervals until the target ANC of more than 500 to upto 1.0 x 109/L is reached. This dose then should be maintaied, adjusting for subsequent increases in the patient's weight with growth and development.
Blood count with manual differential should be monitored several times per year. Bone marrow examinations are not recommended unless therre is an unexpected change in the patient's other blood counts.
↑ 1.01.1Kishnani, Priya S.; Austin, Stephanie L.; Abdenur, Jose E.; Arn, Pamela; Bali, Deeksha S.; Boney, Anne; Chung, Wendy K.; Dagli, Aditi I.; Dale, David; Koeberl, Dwight; Somers, Michael J.; Burns Wechsler, Stephanie; Weinstein, David A.; Wolfsdorf, Joseph I.; Watson, Michael S. (2014). "Diagnosis and management of glycogen storage disease type I: a practice guideline of the American College of Medical Genetics and Genomics". Genetics in Medicine. doi:10.1038/gim.2014.128. ISSN1098-3600.