Pregnancy presenting as hyperthyroidism with negative urine pregnancy test

Area of Science:

• Endocrinology
• Gynecology
• Obstetrics

Background:

• Hyperthyroidism symptoms like tachycardia and exophthalmos can mimic other conditions.
• Lactating mothers may present with unusual symptoms requiring thorough investigation.
• Hydatidiform mole, a complication of pregnancy, can lead to hormonal imbalances.

Observation:

• A 22-year-old lactating mother presented with symptoms of uneasiness, palpitation, tachycardia, and exophthalmos.
• She had an abdominal lump but a negative urine pregnancy test.
• Thyroid profile indicated hyperthyroidism, and ultrasonography revealed a hydatidiform mole.

Findings:

• A low beta-human chorionic gonadotropin (β-hCG) level was observed, which paradoxically increased after suction and evacuation.
• The 'high-dose hook effect' was identified as the cause of the erroneous low β-hCG readings.
• Thyroid function and symptoms resolved spontaneously one week after mole evacuation.

Implications:

• The high-dose hook effect can cause misinterpretation of β-hCG levels in cases of hydatidiform mole.
• Accurate interpretation of β-hCG is crucial for managing hydatidiform mole and associated conditions.
• Prompt diagnosis and management of hydatidiform mole can lead to complete resolution of secondary hyperthyroidism.