26 December, 2012

RARE CAUSE OF ELEVATED FASTING BLOOD SUGAR!!

Dr. Michael Somogyi speculated that hypoglycemia during the late evening induced by insulin could cause a corrective hormone response that produces hyperglycemia in the early morning. This phenomenon was
named as Somogyi phenomenon. Patients with somoygi phenomenon have a higher fasting blood sugar levels. It is a common mistake that the patient increases night dose insulin to control the fasting values but
still lands up with higher fasting values!
The causes of Somogyi phenomenon include

  • Excess or ill-timed insulin
  • Missed meals or snacks
  • Inadvertent insulin administration.

Somogyi phenomenon is probably rare. It occurs in diabetes mellitus type 1 and is less common in diabetes mellitus type 2. If the cause is found out early and treated the prognosis for Somogyi phenomenon is
excellent, and there is no evidence of long-term sequelae.

WHY THIS HAPPENS??

The ability to suppress insulin release is an important physiologic response that people with type 1 Diabetes cannot carry out. Defense against hypoglycemia involves production of glucose from non-carbohydrate sources (gluconeogenesis and glycogenolysis) This mechanism is dependent on an intact glucose sensor system in the CNS, pancreas, and afferent nerves.

HORMONES WHICH HELP INCLUDE:

• The first to act and the most important hormone is Glucagon. Glucagon acts on the liver to stimulate glycogenolysis and gluconeogenesis
Epinephrine increases the delivery of substrates from the periphery, decreases insulin release, stimulates glucagon release, inhibits glucose utilization by several tissues, and stimulates a warning system with sweating, anxiety, and tachycardia.
Cortisol may aid in prolonged and severe cases of Somogyi phenomenon by blocking glucose use and stimulating hepatic glucose output
• Growth hormones are similar to those of cortisol

INVESTIGATIONS

Laboratory studies for identifying Somogyi phenomenon include fasting blood glucose, nocturnal blood glucose, HbA1c, and frequent glucose sampling. The fasting blood glucose level is expected to be inappropriately elevated due to hormonally induced rebound. A glucose reading in the middle of the night will disclose hypoglycemia as a result of insulin therapy. This will establish the diagnosis. Obtaining an HbA1C level may be helpful if it is within the reference range or low despite an elevated fasting glucose level. It supports the concept of a rebound fasting hyperglycemia in the face of normal glucose control. An elevated HbA1C does not rule out Somogyi phenomenon.

Frequent glucose monitoring may be necessary to confirm the diagnosis and look for other periods of hypoglycemia that may lead to rebound hyperglycemia. Frequent hypoglycemia is responsible for hypoglycemic unawareness, which may cause the typical symptoms of hypoglycemia to be missed.

Treatment & Management
Somogyi phenomenon should be suspected in patients presenting with atypical hyperglycemia in the early morning that resists treatment with increased insulin doses.

If nocturnal blood sugar is confirmatory or if suspicion is high, reduce evening or bedtime insulin. Clinical signs, including weight gain, normal daytime blood sugar levels, and relatively low HbA1c,
suggest over treatment.

We insist every patient to go for SMBG (self monitoring of blood glucose) and 7 point blood sugar charting. This will help identify somogyi phenomenon early and manage it efficiently. Controlling of fasting blood sugar is essential as there is evidence linking increased fasting blood sugar levels to microvascular complications.

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