Hypothyroidism Symptoms and Complications

Common Symptoms

• Fatigue and lethargy are common symptoms of hypothyroidism, affecting multiple body systems due to decreased metabolic rate and reduced thyroid hormone activity, as reported by the American Academy of Family Physicians 1, 2
• Weight gain and difficulty losing weight are symptoms of hypothyroidism, according to the American Academy of Family Physicians 2
• Intellectual slowness is a symptom of hypothyroidism, as noted by the American Academy of Family Physicians 1, 2
• Depression is a symptom of hypothyroidism, with a strength of evidence supported by the Journal for ImmunoTherapy of Cancer 3, 4
• Somnolence (excessive sleepiness) is a symptom of hypothyroidism, as reported by the American College of Cardiology 5, 6
• Hair loss is a symptom of hypothyroidism, according to the American Academy of Family Physicians 1, 2
• Myxedema (non-pitting edema/swelling) is a symptom of hypothyroidism, as noted by the American College of Cardiology and the American Academy of Family Physicians 2, 5
• Constipation is a symptom of hypothyroidism, as reported by the American Academy of Family Physicians 1, 2
• Bradycardia (slow heart rate) is a symptom of hypothyroidism, according to the American Heart Association, as published in Circulation 7
• Mild hypertension (often diastolic) is a symptom of hypothyroidism, as noted by the American Heart Association, as published in Circulation 7
• Narrowed pulse pressure is a symptom of hypothyroidism, as reported by the American Heart Association, as published in Circulation 7
• Pericardial effusions (in severe cases) are a symptom of hypothyroidism, according to the American Heart Association, as published in Circulation 7
• Muscle cramps are a symptom of hypothyroidism, as noted by the American Academy of Family Physicians 1, 2
• Muscle weakness is a symptom of hypothyroidism, with a strength of evidence supported by the Journal for ImmunoTherapy of Cancer 3, 4
• Heart failure is a complication of hypothyroidism, as reported by the American Heart Association, as published in Circulation 7
• Elevated thyroid-stimulating hormone (TSH) is a laboratory finding in hypothyroidism, as noted by the American Academy of Family Physicians 1
• Low free thyroxine (T4) is a laboratory finding in hypothyroidism, according to the American Academy of Family Physicians 1

Hypothyroidism Symptoms and Clinical Presentation

Dermatologic and Musculoskeletal Symptoms

• Coarse skin, periorbital puffiness, and proximal muscle weakness are common symptoms of hypothyroidism, affecting patients with decreased metabolic rate 8
• Delayed ankle reflex and slow movement are also associated with hypothyroidism, as a result of decreased metabolic rate 8
• Hoarseness is a voice change that can occur in patients with hypothyroidism, characterized by a low metabolic rate 8

Hypothyroidism and Peripheral Edema

Mechanism and Clinical Presentation

• The American Heart Association guidelines state that hypothyroidism causes specific hemodynamic changes, including bradycardia, that can contribute to fluid retention in patients with hypothyroidism 9
• The American College of Cardiology recommends considering hypothyroidism in the differential diagnosis of unexplained peripheral edema, as periorbital puffiness is a common early manifestation in patients with hypothyroidism 10
• Systemic vascular resistance increases by up to 50% in patients with hypothyroidism, contributing to fluid retention 9
• Mild diastolic hypertension with narrowed pulse pressure occurs in patients with hypothyroidism, leading to edema 9
• Pericardial effusions develop in severe cases of hypothyroidism, and the European Society of Cardiology guidelines state that therapy with thyroid hormone decreases pericardial effusion (Level of Evidence B, Indication I) 9, 11

Diagnostic Approach

• The American Heart Association recommends thyroid function testing, including measuring thyroid-stimulating hormone (TSH) and free thyroxine (T4), in all patients presenting with heart failure or cardiovascular symptoms, including unexplained edema 9
• The American College of Cardiology guidelines suggest measuring TSH and free T4 in all patients with unexplained edema, as elevated TSH with low or normal free T4 confirms the diagnosis of hypothyroidism 10
• Delayed ankle reflex, coarse and cold skin, slow movement, and periorbital puffiness are specific hypothyroid features that should be looked for in patients with unexplained edema 10

Treatment and Resolution

• The European Society of Cardiology guidelines state that therapy with thyroid hormone decreases pericardial effusion (Level of Evidence B, Indication I) and resolves edema in patients with hypothyroidism 11
• Thyroid hormone replacement therapy resolves the edema in hypothyroidism by decreasing the transcapillary escape rate of albumin, diurnal weight gain, and orthostatic fluid retention 11