What are the initial symptoms of hypothyroidism?

Initial Symptoms of Hypothyroidism

The initial symptoms of hypothyroidism typically include fatigue, weight gain, hair loss, cold intolerance, constipation, and depression, which should prompt clinical suspicion and appropriate laboratory testing. 1

Common Early Symptoms

Hypothyroidism presents with a constellation of symptoms that develop gradually as thyroid hormone levels decline:

Physical Symptoms

• Fatigue and weakness
• Unexplained weight gain
• Cold intolerance
• Hair loss
• Dry skin (xeroderma)
• Constipation
• Voice changes (hoarseness)
• Muscle cramps

Psychological/Cognitive Symptoms

• Depression
• Mental slowness
• Reduced concentration

Symptom Progression

The presentation of hypothyroidism follows a typical pattern:

1. Early/Initial Stage: Subtle, nonspecific symptoms that are often attributed to other conditions:

   • Fatigue that doesn't improve with rest
   • Mild weight gain despite unchanged diet
   • Feeling colder than others in the same environment
   • Mild constipation

2. Progressive Stage: As thyroid hormone deficiency worsens, additional symptoms emerge:

   • More pronounced weight gain
   • Intellectual slowness
   • Insomnia
   • Voice changes
   • More severe constipation 1

Special Considerations

Women's Health

Women experience a higher prevalence of hypothyroidism (4-10%), with symptoms sometimes manifesting as:

• Irregular menstrual cycles
• Fertility issues 2

Subclinical Hypothyroidism

Many patients have subclinical hypothyroidism, defined as elevated TSH with normal free T4 levels, which may present with minimal or no symptoms despite laboratory abnormalities 1

Diagnostic Approach

When hypothyroidism is suspected based on symptoms:

1. Laboratory Testing: The recommended initial test is measurement of thyroid-stimulating hormone (TSH), with reflex testing of free thyroxine (T4) 1, 3

2. Diagnostic Criteria:

   • Overt hypothyroidism: Elevated TSH with low free T4
   • Subclinical hypothyroidism: Elevated TSH with normal free T4 4

Clinical Pitfalls to Avoid

• Overlooking subtle symptoms: The insidious onset of hypothyroidism means early symptoms may be attributed to aging, stress, or other conditions
• Focusing only on classic symptoms: Not all patients present with the full spectrum of symptoms
• Ignoring demographic risk factors: Women and older adults have higher prevalence 3
• Relying solely on symptoms for diagnosis: Laboratory confirmation is essential, as symptoms alone are nonspecific 2

When to Suspect Hypothyroidism

Consider hypothyroidism in patients presenting with:

• Multiple vague complaints including fatigue, weight gain, and cold intolerance
• New onset or worsening depression, especially in women
• Unexplained hyperlipidemia
• Bradycardia with other suggestive symptoms 2

Remember that symptoms can vary widely in presentation and severity, making laboratory testing essential for confirming the diagnosis in suspected cases.