īedtime BG levels may predict nocturnal hypoglycemia, thus, bedtime self-monitoring of BG (SMBG) is the simplest way for patients to predict and take measures to prevent nocturnal hypoglycemia. Young children are particularly susceptible to severe and prolonged episodes of nocturnal hypoglycemia. Although rare, permanent brain damage has been suspected to result from severe recurrent hypoglycemia however, a recent meta-analysis concluded otherwise. Įxperimentally induced asymptomatic nocturnal hypoglycemia augments hypoglycemia unawareness, decreasing the threshold of BG that produces neuroglycopenic symptoms, counterregulatory hormone responses, and cognitive impairment during subsequent hypoglycemic episodes.
Although disturbed sleep secondary to nocturnal hypoglycemia also affects vitality and mood, its impact on neuropsychologic performance is less clear. Coma, seizures, serious injuries such as fractures, joint dislocations, cardiac arrhythmia, or death, although rare, have been reported. Mild or moderate hypoglycemic episodes that progress without intervention have the potential to result in more serious sequelae. Stimuli for self-treatment are absent, thus, waking during an episode to ingest a snack is unlikely. Nocturnal hypoglycemia is more worrisome than daytime hypoglycemia because sympathoadrenal responses to hypoglycemia, subjective symptoms that provide warning, and cognitive function are suppressed during sleep. In addition to the reduced insulin and counterregulatory responses in T1DM and T2DM patients, diminished physiologic defenses during sleep, behavioral factors, and limitations of therapy used for diabetes management contribute to nocturnal hypoglycemia ( Nocturnal hypoglycemia episodes average 86 minutes in duration, but hypoglycemia unawareness and frequent severe daytime hypoglycemia may lead to prolonged nighttime hypoglycemic episodes. Patients with diabetes may have a reduced tendency to be awakened by hypoglycemia, mediated by reduced plasma epinephrine, cortisol, and pancreatic polypeptide responses. Ĭlinical features of nocturnal hypoglycemia include vivid dreams or nightmares, poor sleep quality or restlessness during sleep, morning headache, chronic fatigue, mood changes, increased muscle tone, night sweats, convulsions, and enuresis in children. Ingestion of alcohol in the evening may increase the risk for nocturnal hypoglycemia.
Patients with T2DM treated with long-acting sulfonylureas, insulin, or insulin combined with oral antidiabetes drugs (OADs) are also susceptible. Incidence rates vary from 12% to 56% however, because 49% to 100% of episodes occur without symptoms, the actual incidence may be much higher.
During the Diabetes Control and Complications Trial (DCCT), 43% of all hypoglycemic episodes and 55% of severe episodes reported occurred during sleep. Nocturnal hypoglycemia is common, especially in patients with T1DM. An episode of abnormally low BG (typically ≤ 63 mg/dL ) occurring at nighttime during sleep is a useful working definition. CGMS isĪ useful tool to diagnose asymptomatic nocturnal hypoglycemia.Cyclic diurnal variations in BG occur normally, making it difficult to precisely define nocturnal hypoglycemia. Values ≤100 to 150 mg/dL, and predominately in the early part of the night. Conclusions: Nocturnal hypoglycemia is frequent, of long duration, associated with bedtime glucose The incidence of nocturnal hypoglycemia was similarįor patients using insulin pump and injection therapy, and there was no correlationīetween hemoglobin A1c and incidence or duration of hypoglycemia. Mg/dL vs 84.5 minutes for >100 mg/dL, P = NS), and no bedtime glucose value between 110 and 300 mg/dL decreased the incidence There was no difference in hypoglycemia duration (86.4 minutes for glucose ≤100 Increase (46% vs 26%, P =.01) with a value of ≤150 mg/dL most episodes occurred between 9 PM and 1 AM. There was a 2-fold increase (45% vs 22%, P =.015) in the incidence of hypoglycemia with a bedtime glucose ≤100 mg/dL and a 1.7-fold Results: A glucose value of ≤40 mg/dL occurred on 27% of nights and ≤50 mg/dL on 35% of nights.
Data were analyzed for glucose ≤40 or ≤50 mg/dL, comparing bedtimeīlood glucose levels of ≤100 or >100 mg/dL and ≤150 or >150 mg/dL. Study design: Patients (n = 47, 18 boys, mean age 11.8 ± 4.6 years) with type 1 diabetes used CGMSįor 167 nights. Objective: To use the Continuous Glucose Monitoring System (CGMS, MiniMed, Sylmar, Calif) toĭetermine if bedtime blood glucose levels were associated with the occurrence of nocturnal