Hypothyroidism

History Taking

Chief Complaint

• Complaints of fatigue or increased need for sleep

• Unexplained weight gain

• Feeling cold when others do not

History of Presenting Complaint

• Long-standing lethargy and tiredness that has been gradually worsening

• Complaints of dry skin and hair

• Voice changes, possibly hoarseness

• Sensation of a lump or fullness in the neck

• Memory problems or depression

System Review

• Gastrointestinal: Constipation, decreased appetite

• Cardiovascular: Slower heart rate, high cholesterol levels

• Neuropsychiatric: Mood swings, depression, difficulty concentrating

• Musculoskeletal: Muscle weakness, joint or muscle pain

• Dermatological: Dry, cold, pale skin, hair loss

• Reproductive: Menstrual irregularities, decreased libido

Past Medical History

• Previous diagnosis of other autoimmune diseases, such as Type 1 diabetes or vitiligo

• History of neck radiation therapy for cancer treatment

Past Surgical History

• Thyroid surgery or radioiodine treatment for hyperthyroidism

Drug History

• Recent initiation of medication known to affect thyroid function (like amiodarone or lithium)

• Lack of response or suboptimal response to treatment for depression

Family History

• Close relatives with autoimmune thyroid diseases or other autoimmune diseases

• Family history of thyroid disease or thyroid surgery

Personal History

• Difficulty in performance at work or school due to cognitive changes

• Changes in physical activity due to fatigue and weakness

Social History

• Diet: Inadequate intake of iodine-rich foods

• Any recent significant stressors

• Smoking: This is relevant because tobacco use can influence the risk of autoimmune thyroid disease.

OBG History

• Postpartum thyroiditis

• Menstrual irregularities, usually menorrhagia

Physical Examination

General Examination

• Pallor, which might suggest anemia often seen in hypothyroidism

• Puffy face, specifically around the eyes, and coarse facial features

• Dry, rough, and cool skin to touch

• Slow movements and speech

• Swelling in the lower legs

Examination of Hands and Arms

• Cold and dry hands

• Slow relaxation phase of deep tendon reflexes, particularly in the Achilles tendon

Examination of Mouth

• Macroglossia (large tongue)

• Hoarse voice

Examination of Neck

• Enlarged thyroid gland or thyroid surgery scar

• Slow return phase of the reflex after testing with a tendon hammer (delayed relaxation phase)

Cardiac Examination

• Bradycardia (low heart rate)

• Pericardial effusion may lead to muffled heart sounds

Respiratory Examination

• Generally, the respiratory examination is normal unless a goiter is large enough to compress the trachea.

Neurological Examination

• Delayed relaxation phase of deep tendon reflexes

• Cerebellar ataxia or peripheral neuropathy in severe or long-standing cases

Additional Examination if required

• Cognitive assessment might show slowed processing speed or poor short-term memory

• Measurement of weight and body mass index due to possible weight gain

• Checking ankle reflexes can be useful in hypothyroidism; the relaxation phase is characteristically slow.

Investigations

Laboratory Investigations

• Thyroid function tests: To check levels of Thyroid Stimulating Hormone (TSH) and free thyroxine (FT4). High TSH and low FT4 indicates primary hypothyroidism.

• Anti-thyroid peroxidase (anti-TPO) antibodies: These are usually elevated in autoimmune thyroid diseases like Hashimoto's thyroiditis.

• Full Blood Count (FBC): Hypothyroidism can sometimes cause normocytic normochromic anemia.

• Lipid profile: Hypothyroidism often causes an increase in cholesterol levels.

• Creatinine Kinase (CK): May be elevated due to muscle breakdown in severe hypothyroidism.

Imaging Investigations

• Thyroid ultrasound: To assess for goitre or thyroid nodules, and to check the overall structure of the thyroid gland.

• Thyroid nuclear medicine scan: If nodules are detected, to differentiate between 'hot' (hyperfunctioning) and 'cold' (hypofunctioning or non-functioning) nodules.

Invasive Investigations

• Fine-needle aspiration (FNA) cytology: This would only be required if a suspicious nodule was found on ultrasound to rule out malignancy.

Other Tests

• ECG: Hypothyroidism can cause bradycardia and other ECG changes.

• Psychometric tests: If there's suspicion of cognitive impairment due to hypothyroidism.

• Prolactin levels: Hyperprolactinemia can occur in hypothyroidism as TRH (thyrotropin-releasing hormone) also stimulates prolactin release.

• Glucose test: To rule out associated diabetes as autoimmune diseases can co-exist.

Management

General Management

• Lifestyle advice: Regular exercise and a balanced diet to help manage weight.

• Regular follow-up: To monitor symptom progress and adjust treatment as necessary.

Medical Management

• Levothyroxine: Start on a low dose, adjust based on TSH and FT4 levels, aim to keep TSH in the normal range.

• Monitor thyroid function: Regular blood tests (TSH, FT4) to guide levothyroxine dose adjustment.

• Treatment of associated conditions: Such as high cholesterol or depression.

Surgical Management

• Thyroid surgery: Rarely needed unless goitre is large and causing compression symptoms or if malignancy is suspected.

Other

• Psychological support: For patients dealing with changes in mood and cognition.

• Education: Help patients understand the nature of the disease, the importance of compliance with medication, and the need for regular follow-ups.

• Referral to endocrinologist: Complex cases may require specialist input, such as those with cardiac disease or pregnant women.

• Regular bone density scans: In post-menopausal women, as long-term levothyroxine can increase the risk of osteoporosis.