Endocrine · Year 2 · from Endocrine

Case 2: Severe Hypoglycemia in a Patient with Type 1 Diabetes

Patient Demographics

• Age: 34 years
• Sex: Female
• Occupation: Registered nurse (works night shifts)

Chief Complaint

"My husband found me unresponsive this morning."

History of Present Illness

A 34-year-old woman with type 1 diabetes for 20 years is brought to the emergency department by her husband, who found her unresponsive in bed at 7 AM. She appeared pale and diaphoretic, and he was unable to wake her despite shaking. He administered intranasal glucagon which he had been taught to use, and she gradually became responsive over 15-20 minutes. By the time of ED arrival, she is alert but confused about the morning's events. She recalls going to bed at 11 PM after her usual evening insulin dose but does not remember waking up. Her husband reports she has had several "low blood sugar episodes" over the past few months, including one where she became confused during a family dinner. She admits she often does not feel her low blood sugars coming on anymore.

Medical History

• Type 1 diabetes x 20 years
• Hypothyroidism
• Recurrent hypoglycemia (several episodes in past 3 months)
• Prior severe hypoglycemia requiring paramedic assistance 6 months ago

Current Diabetes Regimen

• Insulin glargine 22 units at bedtime (basal)
• Insulin lispro per sliding scale and carb counting (bolus)
• Estimates total daily dose ~45 units
• Self-monitoring blood glucose 3-4 times daily
• Does not use continuous glucose monitoring

Physical Examination (In ED)

• Vital Signs: BP 128/78 mmHg, HR 88 bpm, Glucose (POC): 142 mg/dL (after glucagon)
• General: Alert, oriented x 3, mild residual confusion
• Cardiovascular: Regular rhythm, no murmurs
• Neurologic: Intact, mild tremor resolving
• Skin: Diaphoresis resolved

Workup

• Laboratory Studies:
• Glucose (venous): 138 mg/dL (after glucagon)
• HbA1c: 6.4% (below typical target - suggests frequent lows)
• C-peptide: <0.1 ng/mL (confirms type 1, no endogenous insulin)
• BMP: Normal
• TSH: 2.1 mIU/L (on levothyroxine)
• Patient's Glucose Log Review:
• Multiple readings <70 mg/dL over past month
• Several readings <54 mg/dL
• No symptoms documented with many low readings

Diagnosis

Severe hypoglycemia (Level 3) with hypoglycemia unawareness in type 1 diabetes

Hypoglycemia Classification

Contributing Factors

1. Hypoglycemia unawareness: Loss of autonomic warning symptoms from recurrent hypoglycemia
2. HbA1c 6.4%: Below target, indicating frequent hypoglycemia
3. Shift work: Irregular eating and sleeping patterns
4. Fixed basal insulin dose: May be excessive for her overnight needs
5. No CGM: Lacks real-time glucose monitoring and predictive alerts

Treatment

ACUTE MANAGEMENT (Already provided):

• Intranasal glucagon by husband (appropriate)
• Now euglycemic - oral carbohydrates to prevent recurrence

HYPOGLYCEMIA UNAWARENESS REVERSAL:

1. Strict hypoglycemia avoidance for 2-3 weeks:

• Raise glycemic targets temporarily
• Target fasting glucose 100-150 mg/dL
• Avoid ALL hypoglycemia
• Autonomic awareness often returns after 2-3 weeks without lows

INSULIN REGIMEN ADJUSTMENTS:

1. Reduce basal insulin: Decrease glargine from 22 to 18 units
2. Review bolus dosing: Consider reducing insulin-to-carb ratio
3. Consider insulin pump: Allows variable basal rates (lower overnight)

CONTINUOUS GLUCOSE MONITORING (CGM) - Essential:

1. Recommend CGM with alerts: (e.g., Dexcom G6, Libre 2)
2. Benefits:

• Real-time glucose readings every 5 minutes
• Predictive low glucose alerts (warns before hypoglycemia occurs)
• Patterns identification
• Time in range metrics

1. Set low alert at 80 mg/dL (higher threshold given unawareness)

CONSIDER HYBRID CLOSED-LOOP SYSTEM:

• Insulin pump + CGM integration
• Automatic basal adjustment based on glucose trends
• Suspend insulin delivery when glucose dropping
• Shown to reduce hypoglycemia significantly

PATIENT AND FAMILY EDUCATION:

1. Glucagon availability: Prescription for nasal glucagon (Baqsimi) or ready-to-inject (Gvoke)
2. Husband education: Reinforce glucagon administration technique
3. Rule of 15: 15g fast-acting carbs, wait 15 minutes, recheck
4. Driving safety: Do not drive if glucose <80 mg/dL or feeling "off"
5. Medical alert bracelet

ADJUSTED GLYCEMIC TARGETS:

• HbA1c goal: 7.0-7.5% (slightly higher to reduce hypoglycemia risk)
• Time in range goal: >70% (70-180 mg/dL)
• Time below range (<70): <4%
• Time below 54 mg/dL: <1%

Clinical Pearl

Hypoglycemia unawareness occurs in ~25% of patients with type 1 diabetes and significantly increases the risk of severe hypoglycemia. It results from repeated hypoglycemic episodes that blunt the counter-regulatory hormone response and autonomic symptoms. The good news is that strict hypoglycemia avoidance for 2-3 weeks can often restore awareness. A HbA1c below target (especially <6.5%) in a patient with type 1 diabetes should raise suspicion for frequent hypoglycemia. Continuous glucose monitoring with predictive alerts is transformative for these patients, warning of impending lows before they occur. Hybrid closed-loop systems further reduce hypoglycemia by automatically adjusting insulin delivery. All patients with type 1 diabetes and their close contacts should have glucagon readily available and know how to use it.

Clinical Image

Insulin delivery devices used in diabetes management. Proper insulin technique and timing are critical to avoiding hypoglycemia, particularly in patients with type 1 diabetes.

Image Source: Wikimedia Commons - "Insulin syringe and pen" License: CC BY-SA 4.0 URL: https://commons.wikimedia.org/wiki/File:Insulin_syringe_and_pen.jpg

All cases for this lecture as Markdown