Hypothyroidism (Hashimoto’s)

Causes and Risk Factors

Hypothyroidism can develop for various reasons:

• Autoimmune thyroiditis (Hashimoto’s disease): The most common cause in iodine-sufficient regions.
• Iatrogenic causes: Following thyroid surgery or radioactive iodine therapy (when the thyroid gland is removed completely or almost completely).
• Medications: Certain drugs such as lithium, amiodarone, and interferon-alpha.
• Congenital hypothyroidism: Detected through newborn screening programs.
• Iodine deficiency or excess: Still prevalent in some regions.

Risk factors include female sex, age over 60, history of thyroid disease, thyroid surgery, or radiation exposure.

Clinical Manifestations

Symptoms typically develop slowly and may be difficult to recognize in the early stages. Common signs and symptoms include:

• Fatigue and weakness
• Weight gain despite decreased appetite
• Cold intolerance
• Constipation
• Dry skin and hair loss
• Menstrual irregularities
• Depression or mental slowing
• Bradycardia and hypotension in severe cases

In surgical patients, undiagnosed hypothyroidism can lead to delayed wound healing, increased sensitivity to anesthetic agents, and altered drug metabolism.

Diagnosis

Diagnosis is based on laboratory testing:

• TSH (Thyroid-Stimulating Hormone): Elevated in primary hypothyroidism.
• Free T4: Typically reduced.
• Anti-TPO antibodies: May be positive in autoimmune thyroiditis.

Subclinical hypothyroidism (elevated TSH with normal T4) should be monitored closely, especially in patients with cardiovascular risk or those scheduled for surgery.

Treatment and Management

The cornerstone of treatment is levothyroxine replacement therapy. Dosage is individualized based on age, weight, comorbidities, and TSH level.

• Follow-up: TSH levels should be monitored every 6–8 weeks during dose adjustment, and once stable, every 6–12 months.
• Special considerations: Dose adjustments may be required during pregnancy, illness, or significant weight changes.

Patient education is crucial—emphasizing the importance of regular medication use, awareness of interactions with substances like calcium or iron, and the need for routine follow-up.

Surgical Considerations

From a general surgery perspective, hypothyroidism poses specific challenges:

• Preoperative evaluation: Elective surgeries should be delayed until a euthyroid state is achieved.
• Anesthetic sensitivity: Patients may exhibit exaggerated responses to anesthetic agents.
• Postoperative recovery: Slowed metabolism can impair wound healing and prolong recovery.

Collaboration with endocrinology specialists can improve outcomes, particularly in complex or high-risk cases.

Conclusion

Hypothyroidism is a systemic but manageable condition. In surgical patients, early diagnosis and appropriate treatment significantly improve perioperative safety and long-term health. As part of a patient-centered approach, incorporating thyroid screening into routine evaluations—especially for individuals with nonspecific symptoms—enables timely diagnosis and better outcomes.