From the Guidelines
Hypothyroidism presents in several main forms, including subclinical and overt manifestations, with the most common presentations being fatigue, cold intolerance, weight gain, dry skin, hair loss, constipation, and bradycardia, as noted in studies such as 1 and 2. The main forms of presentation of hypothyroidism can be categorized into:
- Subclinical hypothyroidism, which is often asymptomatic and characterized by elevated TSH levels with normal T4 levels, as defined in 1
- Overt hypothyroidism, which is defined biochemically by an elevated TSH level and a low T4 level, and may present with symptoms such as fatigue, feeling cold, weight gain, hair loss, and constipation, as described in 1
- Congenital hypothyroidism, which presents in infants with poor feeding, prolonged jaundice, large fontanelles, and developmental delays if not treated promptly
- Hashimoto's thyroiditis, an autoimmune condition that is the most common cause of hypothyroidism in developed countries and may initially present with transient hyperthyroidism before progressing to hypothyroid symptoms ### Key Presentations Some key presentations of hypothyroidism include:
- Fatigue and cold intolerance
- Weight gain and dry skin
- Hair loss and constipation
- Bradycardia and cognitive impairment
- Depression and menstrual irregularities in women
- Muscle cramps and myxedema, characterized by facial puffiness, peripheral edema, and thickened skin ### Laboratory Findings Laboratory findings typically show:
- Elevated TSH and low free thyroxine (T4) levels in overt hypothyroidism
- Elevated TSH with normal T4 levels in subclinical hypothyroidism, as noted in 2 ### Treatment Treatment typically involves levothyroxine replacement therapy, with dosing individualized based on patient age, weight, and severity of the condition, starting at 1.6 mcg/kg/day for most adults and adjusted based on TSH levels measured every 6-8 weeks until stabilized, as recommended in 2. The management of hypothyroidism should be guided by the severity of symptoms and TSH levels, with treatment aimed at normalizing TSH levels and alleviating symptoms, as outlined in 2.
From the FDA Drug Label
Thyroid hormone drugs are indicated: As replacement or supplemental therapy in patients with hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis This category includes cretinism, myxedema and ordinary hypothyroidism in patients of any age (pediatric patients, adults, the elderly), or state (including pregnancy); primary hypothyroidism resulting from functional deficiency, primary atrophy, partial or total absence of thyroid gland, or the effects of surgery, radiation, or drugs, with or without the presence of goiter; and secondary (pituitary) or tertiary (hypothalamic) hypothyroidism The main forms of presentation of hypothyroidism include:
- Cretinism
- Myxedema
- Ordinary hypothyroidism
- Primary hypothyroidism
- Secondary (pituitary) hypothyroidism
- Tertiary (hypothalamic) hypothyroidism 3
From the Research
Main Forms of Presentation of Hypothyroidism
The main forms of presentation of hypothyroidism can vary widely, ranging from asymptomatic to life-threatening cases. Some of the most common symptoms include:
- Fatigue and lethargy 4, 5, 6, 7
- Weight gain 4, 5, 6, 7
- Cold intolerance 4, 5, 6, 7
- Constipation 4, 5, 6
- Dry skin 4, 5, 6
- Voice changes 4, 5
Clinical Presentation
The clinical presentation of hypothyroidism can differ with age and sex, among other factors 4. In some cases, the symptoms may be non-specific and overlap with other conditions, making diagnosis more challenging 6.
Severity of Symptoms
The severity of symptoms can range from minimal to life-threatening, with myxedema coma being a rare but severe complication of untreated hypothyroidism 5, 7.
Diagnosis and Treatment
Diagnosis is typically made on biochemical grounds through serum thyroid function tests 7, and treatment usually involves lifelong hormone replacement therapy with synthetic thyroid hormone replacement medication, such as levothyroxine 5, 6, 7.