Differentials
Pregnancy
SIGNS / SYMPTOMS
Amenorrhoea with breast tenderness, fatigue, nausea, and an enlarging abdomen may indicate pregnancy.
INVESTIGATIONS
Urine human chorionic gonadotrophin (hCG) level >25 IU/L (>25 mIU/mL) is considered positive for pregnancy.
Urine hCG level <5 IU/L (<5 mIU/mL) is considered negative for pregnancy.
Polycystic ovary syndrome
SIGNS / SYMPTOMS
Common features include hirsutism, acne, and scalp hair loss; irregular and infrequent periods (often <8 per year); weight gain; and infertility.
Sweating or oily skin may occur.
INVESTIGATIONS
Serum total and free testosterone elevated; serum dehydroepiandrosterone sulfate (DHEAS) elevated.
Symptoms typically begin at the time of puberty.
Hyperthyroidism
SIGNS / SYMPTOMS
Menstrual irregularity, hot flushes,[32] tachycardia, tremor, hair loss, anorexia, and weight loss.
INVESTIGATIONS
Thyroid-stimulating hormone levels may be suppressed (<0.01 IU/L [<0.01 mIU/mL]).
Hypothyroidism
SIGNS / SYMPTOMS
Heavy bleeding, infrequent or reduced menstrual bleeding/amenorrhoea. Other symptoms include fatigue, hair loss, dry skin, constipation, and weight gain.
INVESTIGATIONS
Thyroid-stimulating hormone levels may be elevated (>10 IU/L [>10 mIU/mL]).
Anorexia
SIGNS / SYMPTOMS
Patients with onset of anorexia later in life may also have amenorrhoea, vaginal dryness, and sleep disturbance but usually will also be underweight and may have electrolyte disturbance, anaemia, and bradycardia (or other cardiac arrhythmia). They do not experience hot flushes. It is normally possible to differentiate an eating disorder from premature menopause by taking a careful history of eating habits and measuring follicle-stimulating hormone (FSH).
INVESTIGATIONS
FSH levels will be low to normal (c.f., high in the menopause). There may be electrolyte disturbance, anaemia, and bradycardia in severe cases of anorexia nervosa.
Ovarian reserve tests (anti-Mullerian hormone, antral follicle count) are likely to be normal.
Adverse effects of medications such as tamoxifen, raloxifene, niacin, or nitrates
SIGNS / SYMPTOMS
Tamoxifen and raloxifene (selective oestrogen receptor modifiers) can cause hot flushes.
Niacin, prescribed to raise high-density lipoprotein cholesterol levels, can also cause hot flushes.
The medication history should include herbal and alternative preparations.
INVESTIGATIONS
Consider a trial of withholding the pertinent therapy to establish if the hot flushes are primarily medication-induced.
Consider non-hormonal treatments (e.g., clonidine, venlafaxine, gabapentin).
Carcinoid syndrome
SIGNS / SYMPTOMS
Symptoms of carcinoid syndrome include diarrhoea and flushes.
Other clinical features include wheeze, palpitations, telangiectasia, and abdominal pain.
INVESTIGATIONS
FBC, serum chromogranin A/B, and 24-hour urinary 5-hydroxyindoleacetic acid (5-HIAA) may be elevated.
Imaging studies to identify location of primary tumour.
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