What are the symptoms of hypothyroidism?

Symptoms of Hypothyroidism

Hypothyroidism presents with a wide range of symptoms primarily due to decreased metabolic rate, including fatigue, weight gain, cold intolerance, constipation, hair loss, and cognitive issues. 1, 2

Common Symptoms

General Symptoms

• Fatigue and lethargy are among the most prevalent symptoms (68%-83% of patients), resulting from decreased metabolic rate 1, 2
• Weight gain and difficulty losing weight due to decreased fat-burning rate 1, 3
• Increased sensitivity to cold (cold intolerance) from decreased heat production 3, 4
• Somnolence (excessive sleepiness) 1

Dermatologic Symptoms

• Dry, coarse skin and periorbital puffiness 1, 3
• Hair loss 1, 5
• Myxedema (non-pitting edema/swelling) in more severe cases 1

Neurological and Cognitive Symptoms

• Intellectual slowness and cognitive issues (45%-48% of patients) 1, 2
• Memory loss and difficulty concentrating 2
• Depression 1

Cardiovascular Symptoms

• Bradycardia (slow heart rate) 1
• Mild hypertension (often diastolic) 1
• Narrowed pulse pressure 1
• Pericardial effusions in severe cases 1

Musculoskeletal Symptoms

• Muscle cramps and weakness 1
• Delayed ankle reflex and slow movement 1
• Proximal muscle weakness 1

Gastrointestinal Symptoms

• Constipation 5, 1, 3

Voice Changes

• Hoarseness 1

Reproductive Symptoms

• Menstrual irregularities (approximately 23% of women), including oligomenorrhea and menorrhagia 2
• Disrupted ovulation and infertility 2
• Increased risk of miscarriage 2, 4

Laboratory Findings

• Elevated thyroid-stimulating hormone (TSH) 1, 2
• Low free thyroxine (T4) 1, 2

Important Clinical Considerations

Symptom Variability

• Symptoms can range from none to life-threatening 6, 4
• Presentation may differ based on age, sex, and other factors 6
• Symptoms are often nonspecific and can overlap with other conditions, making diagnosis challenging in some cases 3, 7

Potential Complications if Untreated

• Heart failure 1, 2, 3
• Myxedema coma - a life-threatening condition characterized by hypothermia, hypotension, and altered mental status with mortality rates up to 30% 2, 3
• Insulin resistance and hyperglycemia in patients with diabetes 2
• Increased risk for cardiovascular events 2, 7

Diagnostic Approach

• Diagnosis is primarily biochemical rather than symptom-based 2, 4
• Overt primary hypothyroidism is defined by high TSH and low free T4 2
• Targeted testing is recommended for high-risk patients rather than general screening 2