OVERVIEW

What is insulin resistance in Type B insulin resistance syndrome?

Type B insulin resistance syndrome is a rare disease that can be difficult to understand at first. To comprehend this condition, it's essential to first grasp what insulin resistance means.

In this era of widespread diabetes, most people are familiar with insulin—a crucial substance in the human body that regulates blood sugar levels.

Simply put, insulin resistance means that the efficiency of insulin in the body has declined.

To illustrate, if one unit of insulin could previously perform the task of lowering blood sugar, now it can't. Multiple units of insulin are required to achieve what one unit used to accomplish. This is insulin resistance.

The mechanisms behind insulin resistance are complex; some are understood, while others remain unclear.

What is Type B insulin resistance syndrome?

Type B insulin resistance syndrome is a form of insulin resistance, also known as "autoimmune insulin receptor disease."

For insulin to lower blood sugar, it must bind to insulin receptors. If insulin is likened to a key, the insulin receptor is the keyhole. When insulin binds to its receptor, it triggers a series of subsequent "mechanisms," leading to a reduction in blood sugar.

If a substance called "insulin receptor antibodies" appears in the body and occupies the insulin receptor keyhole first, it creates a situation where insulin has fewer keyholes to bind to. As a result, its blood sugar-lowering effect is significantly weakened, manifesting as severe insulin resistance. This is Type B insulin resistance syndrome.

Type B insulin resistance is difficult to cure. Treatment mainly focuses on managing high and low blood sugar levels. Immunosuppressants may also be used for immunomodulatory therapy, but there is currently no standardized treatment protocol.

Type B insulin resistance syndrome is often accompanied by—or may even precede—other autoimmune diseases, most commonly systemic lupus erythematosus and Sjögren's syndrome.

If Type B insulin resistance syndrome exists, is there a Type A insulin resistance syndrome?

If there's a Type B, there must be a Type A. If the insulin receptor gene is defective, the keyhole becomes misshapen and no longer matches the insulin "key." This also severely impairs blood sugar control, leading to severe insulin resistance. This is Type A insulin resistance syndrome.

Is Type B insulin resistance syndrome common?

Type B insulin resistance syndrome is extremely rare, with fewer than 100 cases reported worldwide.

SYMPTOMS

What are the common manifestations of Type B Insulin Resistance Syndrome?

• Abnormal blood sugar: Typical manifestations often include the "three excesses and one deficiency" symptoms of diabetes, namely polydipsia, polyuria, polyphagia, and weight loss. Different patients may exhibit varying blood sugar abnormalities, such as:

  • Persistent hyperglycemia without hypoglycemia;

  • Persistent hypoglycemia without hyperglycemia, which may occur as fasting or postprandial hypoglycemia;

  • Initial hyperglycemia followed by hypoglycemia, intermittent hypoglycemia, or occasional hypoglycemia;

  • Initial hypoglycemia followed by hyperglycemia.

  • Hypoglycemia in patients can be severe, even leading to hypoglycemic coma.

• Acanthosis nigricans: Certain areas of the skin exhibit thickened, velvety hyperpigmented patches (appearing noticeably darker and rougher than surrounding skin, often mistaken for inadequate washing). This is a common characteristic of severe insulin resistance, frequently seen in the armpits, groin, and neck, and may also affect the perioral and periorbital regions. In some cases, acanthosis nigricans can extensively involve the trunk, buttocks, and mucocutaneous junctions, such as the lips and perineum.

• Manifestations of associated autoimmune diseases: Such as systemic lupus erythematosus, Sjögren's syndrome, and other corresponding symptoms (refer to the respective disease entries).

• Polycystic ovary syndrome-related manifestations: Female patients of reproductive age may exhibit symptoms related to polycystic ovary syndrome, such as irregular menstruation, amenorrhea, hirsutism, acne, and infertility.

What severe consequences can Type B Insulin Resistance Syndrome cause?

Type B Insulin Resistance Syndrome primarily leads to abnormal blood sugar levels. Persistent hyperglycemia can trigger diabetic ketoacidosis, while severe, prolonged hypoglycemia may be fatal.

CAUSES

What is the cause of Type B insulin resistance syndrome?

The presence of insulin receptor antibodies in the body is the cause of Type B insulin resistance syndrome. For details, see "What is Type B insulin resistance syndrome?" in the "Introduction" section.

So why do insulin receptor antibodies appear in the body? It may be related to immune system dysfunction. As a result, Type B insulin resistance syndrome is often accompanied by other autoimmune diseases, such as systemic lupus erythematosus and Sjögren's syndrome, which are also associated with immune system dysfunction.

Who is commonly affected by Type B insulin resistance syndrome?

Type B insulin resistance syndrome most frequently occurs in individuals aged 40–60, with a higher prevalence in women. The male-to-female ratio is 2:1. It has been reported more often in African American women.

Is Type B insulin resistance syndrome contagious?

No.

Is Type B insulin resistance syndrome hereditary?

No.

DIAGNOSIS

How is Type B Insulin Resistance Syndrome diagnosed?

When diagnosing Type B Insulin Resistance Syndrome, doctors primarily rely on manifestations of severe insulin resistance, such as hyperglycemia, hypoglycemia, and acanthosis nigricans.

During blood sugar reduction, if the required insulin dosage is unexpectedly high, or blood tests reveal elevated insulin (and C-peptide) levels, it suggests severe insulin resistance.

A history of autoimmune diseases or hematologic malignancies, such as systemic lupus erythematosus, autoimmune thyroid disease, or Hodgkin's lymphoma, serves as an important clue for Type B Insulin Resistance.

A positive insulin receptor antibody test supports the diagnosis of Type B Insulin Resistance Syndrome.

What tests are needed for Type B Insulin Resistance Syndrome?

• Blood glucose: May present as hyperglycemia or hypoglycemia.

• Insulin and C-peptide: Significantly elevated levels indicate insulin resistance.

• Autoantibodies: Such as antinuclear antibodies, to assess the presence of other autoimmune diseases.

• Insulin receptor antibodies: A positive result supports the diagnosis of Type B Insulin Resistance Syndrome. However, few hospitals can perform this test.

• Others: Thyroid function, cortisol, and sex hormones to evaluate other endocrine disorders; liver and kidney function, lipid profile for a comprehensive health assessment.

TREATMENT

Which department should I visit for Type B insulin resistance syndrome?

Endocrinology.

Can Type B insulin resistance syndrome resolve on its own?

No.

How is Type B insulin resistance syndrome treated?

Treatment for Type B insulin resistance syndrome mainly includes managing hyperglycemia, hypoglycemia, and immunomodulatory therapy.

• Hyperglycemia treatment: The goal is to control blood sugar at lower or near-normal levels. Insulin is typically used, often in high doses (1.5–2.0 units/kg or more). Combining insulin with metformin or thiazolidinediones (e.g., pioglitazone) can improve insulin resistance and reduce insulin dosage.

• Hypoglycemia treatment: The quickest and most effective method is glucose supplementation. Mild cases may consume sugary foods (preferably glucose tablets or glucose water), while severe cases require intravenous glucose. If glucose alone fails to raise blood sugar quickly, glucocorticoids may be used.

• Immunomodulatory therapy: Options include glucocorticoids, plasmapheresis, cyclophosphamide, cyclosporine, azathioprine, mycophenolate mofetil, and rituximab. Treatment is largely empirical, emphasizing early and adequate intervention, but standardized protocols are lacking.

Does Type B insulin resistance syndrome require hospitalization?

Hospitalization is necessary if the condition is unstable.

Can Type B insulin resistance syndrome be cured?

No, it cannot be cured.

DIET & LIFESTYLE

What should patients with Type B insulin resistance syndrome pay attention to in daily life?

Patients with Type B insulin resistance syndrome should primarily be vigilant about hypoglycemia, as its occurrence can often be fatal.

Symptoms of hypoglycemia include noticeable hunger, palpitations, trembling hands, dizziness, anxiety, cold sweats, etc.; severe cases may involve abnormal behavior or coma.

What dietary precautions should patients with Type B insulin resistance syndrome take?

• For patients with hyperglycemia, they can follow dietary principles for diabetes.

• For patients prone to hypoglycemia, they should carry sugar-containing foods or beverages, such as candies, fruit juice, or crackers, and consume them promptly if hypoglycemia occurs.

PREVENTION

Can Type B Insulin Resistance Syndrome Be Prevented?

Currently, there are no effective measures to prevent the occurrence of Type B insulin resistance syndrome.