A patient with newly diagnosed diabetes has a hemoglobin (Hb) A1c of 12.2% and glucose 350 mg/dL, despite increasing insulin (glargine [Lantus]) to 25 units. The patient has a history of cirrhosis. All labs are normal, including magnesium and phosphorus. What else can I do to lower blood sugar? — Cyndi Phung, NP, Philadelphia
This patient may be “under-insulinized.” The recommended starting dose for basal insulin for type 2 diabetes is 0.2 units/kg. A patient weighing 100 kg would need a minimal starting dose of 20 units of glargine daily, with titration of dose upward by 10% every three days to obtain a goal fasting glucose of 130-180mg/dL. Once you reach a total basal dose of more than 0.5 units/kg daily, consider adding mealtime insulin (Clinical Diabetes. 2009;27:72-76; available at clinical.diabetesjournals.org/content/27/2/72.full, accessed July 15, 2012).
As evidenced by the HbA1c, this patient may also be experiencing glucose toxicity, which happens when blood glucose levels are very high. Insulin secretion by the pancreas is blunted in this state, along with abnormally high glucagon levels (that drive more glucose production by the liver) and subsequent worsening insulin resistance. Insulin resistance will also worsen if the patient is severely obese and insulin-resistant with a poor diet.
The history of cirrhosis brings up an interesting point. Patients with severe cirrhosis and liver dysfunction can sometimes develop “liver diabetes,” which is usually manifested clinically as mild glucose intolerance, not the out-of-control diabetes described above. Individuals with cirrhosis can have decreased hepatic glycogen stores and thus may be at higher risk for hypoglycemia, so insulin titration should be performed slowly and accompanied by frequent home glucose monitoring (Clinical Diabetes. 2004;22:42-44, accessed August 2, 2012).—Kathy Pereira, MSN, FNP-BC, assistant professor, co-coordinator, family nurse practitioner program, Duke University School of Nursing, Durham, N.C. (166-2)
These are letters from practitioners around the country who want to share their clinical problems and successes, observations and pearls with their colleagues. We invite you to participate. If you have a clinical question, submit it here.