Approach to hypoglycemia: Clinical sciences

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Introduction0:00–0:28

Hypoglycemia is defined as a blood sugar below 55 milligrams per deciliter that occurs in the presence of symptoms, but some individuals can become symptomatic at levels like 70.
Some important causes of hypoglycemia include medication-induced and alcohol-induced hypoglycemia, as well as endogenous hyperinsulinism and non-insulin-mediated hypoglycemia.Now, if you suspect hypoglycemia, you should first perform an ABCDE assessment to determine if your patient is unstable or stable.

Unstable patient0:28–2:20

If the patient is unstable, stabilize the airway, breathing, and circulation. Next, obtain a fingerstick glucose level, while obtaining IV access to give IV glucose immediately.
In addition, begin continuous vital sign monitoring, such as blood pressure, heart rate, and pulse oximetry; and if needed, provide supplemental oxygen.Here’s a high-yield fact to keep in mind!
Most individuals don’t develop symptoms until their blood glucose level falls below 55 milligrams per deciliter. However, some patients may become symptomatic when their blood glucose falls below 70 milligrams per deciliter; while other patients with diabetes may experience impaired hypoglycemia awareness and experience symptoms only when their glucose falls severely low, which puts them at higher risk for life-threatening consequences.
Because this range is highly variable, there’s no glucose value that defines hypoglycemia, so always correlate your patient’s symptoms with lab results.
Hypoglycemia is often observed in the setting of critical conditions, such as renal failure, liver failure, and sepsis. Renal failure leads to reduced clearance of insulin, while liver failure decreases gluconeogenesis, both causing hypoglycemia.
Sepsis triggers cytokine release, which increases glucose utilization and also inhibits gluconeogenesis. So, it’s important to treat the underlying condition to normalize your patient’s blood glucose.
Lastly, keep in mind that nocturnal hypoglycemia warrants assessment of the basal insulin dose.Now that we're done with unstable patients, let’s go back to the ABCDE assessment and discuss the stable ones.

Stable patient2:20–7:09

If your patient is stable, first obtain a focused history and physical examination, obtain a fingerstick glucose and order labs to confirm the blood glucose levels.
Your patient may report fatigue, confusion, lightheadedness, hunger, tremor, and, in severe cases, even seizures. They might have a known history of diabetes requiring treatment with insulin or oral hypoglycemic medications, or recent alcohol overuse.
Additionally, physical exam might reveal tachycardia, diaphoresis, or pallor, while fingerstick glucose and laboratory findings will typically show a blood glucose below 55 to 70 milligrams per deciliter.Ok, so with your patient’s history, physical exam findings, and low blood glucose level, you can diagnose hypoglycemia, but not necessarily a hypoglycemic disorder.
To diagnose a hypoglycemic disorder, your patient must meet the Whipple triad criteria, which includes the presence of hypoglycemic symptoms, a blood glucose below 55 to 70 milligrams per deciliter, and relief of symptoms after ingesting glucose.
Since you have already identified symptoms and hypoglycemia, give your patient either oral or IV glucose and assess their response.
If the patient’s symptoms aren’t relieved with glucose, the Whipple triad is not present, and there’s no hypoglycemic disorder.
On the other hand, if giving glucose relieves the symptoms, the Whipple triad is present, so you can diagnose a hypoglycemic disorder.
Here’s a clinical pearl to keep in mind! If your patient no longer has symptoms, order a supervised fast to induce hypoglycemia and perform a diagnostic workup.
This is a reliable method to evaluate for a hypoglycemic disorder that occurs in food-deprived conditions. Ok, now that you’ve diagnosed a hypoglycemic disorder, review your patient’s medications.
Your patient may report taking a glucose-lowering medication, such as insulin, or oral hypoglycemic medications like sulfonylureas.
Other medications that may cause hypoglycemia include ACE inhibitors, indomethacin, and β-blockers, especially in the setting of impaired renal or hepatic function.
So, if your patient is taking any of these, diagnose medication-induced hypoglycemia. Here’s a clinical pearl to keep in mind!
Hypoglycemia can occur if insulin is given by accidental dosing error, self-administration, or even maliciously to an unsuspecting patient.
These causes may not be obvious and can look like endogenous hyperinsulinism. So, if your patient presents with hypoglycemia and no clear cause, order an insulin C-peptide level which is elevated in endogenous hyperinsulinism.
On the other hand, exogenous insulin administration will reveal a low C-peptide level. Now, if your patient took an oral hypoglycemic medication, endogenous insulin levels will be high and the C-peptide will also be elevated, but you’ll see levels of the medication in your patient’s blood.
Ok, now that we’ve reviewed what to do if your patient is taking glucose-lowering medications, let’s focus on what to do if they are not.
In this case, you should consider excessive alcohol use. Next, revisit the history and physical, and order a serum alcohol level.
If there is a history of recent alcohol use with signs of intoxication on physical exam, and if the serum alcohol is measurable, diagnose alcohol-induced hypoglycemia.
However, if there’s no history of recent alcohol overuse, no signs of intoxication, and if the serum alcohol is not measurable, your patient’s hypoglycemia is not alcohol-induced.
At this point, you should consider endogenous hyperinsulinism, so order plasma glucose, insulin, C-peptide, proinsulin, and beta-hydroxybutyrate.
Also, check the plasma glucose response to a 1 mg dose of IV glucagon. Use these lab values to assess the criteria of endogenous hyperinsulinism.
Criteria are met when you find plasma glucose below 55 milligrams per deciliter; an insulin level of 3 microunits per milliliter or greater; C-peptide 0.6 nanograms per milliliter or greater; and proinsulin of 5 picomoles per liter or greater.
Also, beta-hydroxybutyrate should be 2.7 or less; and plasma glucose should rise at least 25 milligrams per deciliter after administration of IV glucagon.
If the patient meets these criteria, diagnose endogenous hyperinsulinism and order insulin antibodies. If insulin antibodies are positive, diagnose insulin autoimmune hypoglycemia.

Endogenous hyperinsulinism7:09–8:32

However, if they are negative, suspect an insulinoma and order imaging, which could include a CT, MRI, or ultrasound. If imaging reveals a small hypervascular pancreatic lesion, like in this CT scan, this confirms the diagnosis of insulinoma, which is commonly seen in association with multiple endocrine neoplasia syndrome, or MEN syndrome for short.
Here’s a clinical pearl to keep in mind! Gastric bypass patients who had the Roux-en-Y procedure are at an increased risk of hypoglycemia for two reasons.
First, endogenous insulin secretion is elevated after surgery. For some patients with persistent hyperglycemia, this increase in endogenous insulin is an additional benefit.
But for others, it can cause dangerously low levels of glucose. Second, since this procedure is associated with a shorter food transit time, nutrient absorption is reduced, resulting in lower postprandial glucose levels.
These factors combined create the potential for endogenous insulin to be elevated out of proportion to the postprandial blood glucose, causing postprandial hypoglycemia.Now let’s go back and discuss patients who do not meet the criteria for endogenous hyperinsulinism.

Non-insulin-mediated hypoglycemia8:32–9:03

In this case, you should consider non-insulin-mediated hypoglycemia and order insulin receptor antibodies, which act as receptor agonists.
This means that they mimic the action of insulin, eventually causing hypoglycemia despite low insulin levels. If they’re positive, diagnose insulin receptor autoimmune hypoglycemia; but, if negative, consider growth hormone or cortisol deficiency.Alright, as a quick recap… When approaching a patient with hypoglycemia, first perform an ABCDE assessment to determine if they’re unstable or stable.

Review9:03–9:54

If unstable, proceed with acute management, obtain fingerstick glucose levels, and give IV glucose. If your patient is stable, obtain history and physical examination, fingerstick glucose and labs to confirm hypoglycemia.
Then, to diagnose a hypoglycemic disorder, your patient must meet the Whipple triad criteria, which includes the presence of hypoglycemic symptoms, a blood glucose below 55 to 70, and symptom relief after ingesting glucose.
Lastly, look for and address the underlying cause of hypoglycemia, which can be medication-induced, alcohol-induced, due to endogenous hyperinsulinism,
Approach to hypoglycemia: Video, Steps, and Uses | Osmosis