No abstract

Background: Gestational trophoblastic disease (GTD) represents a group of tumours caused by abnormal proliferation of trophoblastic cells, including molar pregnancy. Elevated β-hCG levels are an established marker for the presence of the disease and useful for monitoring. Due to the shared structural homology of β-hCG and TSH, hyperthyroidism can occur. Clinical Cases: We present two patients with GTD associated with hyperthyroidisim. Case 1, a 20 year old female (G1P0) presented to the emergency department complaining of vaginal bleeding associated with abdominal pain. She was estimated to be 13 weeks. Laboratory evaluation were β-hCG 648 324 IU/L, TSH 0.06 (0.35 - 4.94 mIU/L, free T4 23.2 (9.0 - 19.0 pmol/L, Hb 8.0 (11.6 - 16.4 g/dL). Ultrasound revealed molar pregnancy. She underwent uterine evacuation, thereafter complicated with thyroid storm (Burch Wartofsky score = 45). Post- operative vitals were BP 192/112, pulse rate 120 bpm and temperature 360C. She was managed in high care on labetolol, carbimazole, lugol’s iodine and hydrocortisone. She was subsequently referred to Medical Oncology for further management. Histology sample obtained in theatre confirmed complete molar pregnancy. Her staging CT scan indicated the presence of small lung nodules, suggesting metastatic disease. The patient’s FIGO/WHO score was III: 2. At the time of preparing this study, she had already received 7 weeks of methotrexate intramuscularly and still had detectable β-hCG levels. Case 2 was a 31 year old female presented similarly. This was her second pregnancy (G2P1), 12 weeks by dates. Her vitals were BP 141/74, pulse rate 110 bpm and temperature 36oC. The Ultrasound revealed larger for gestational age uterus with cystic structures in utero. Her quantitative β-hCG was significantly elevated (> 1 500 000 IU/L) she was thyrotoxic [TSH (<0.1 (0.34 - 4.94 mIU/L) free T4 (47.2 (9.0 - 19.0 pmol/L)], however did not develop thyroid storm (Burch Wartofsky score = 20). This patient also underwent uterine evacuation and did well post operatively. She was treated for her thyrotoxicosis with carbimazole, propranolol and thiamine. Further management was by Medical Oncology. Histological examination was in keeping with a partial mole. Her staging CT scan showed no metastasis, and had a FIGO/WHO score of 1: 4 due to her pre-treatment hCG of >1.5 million IU/L. She received 7 cycles of intramuscular methotrexate from which she achieved and maintained suppressed β-hCG levels (<1 IU/L). Conclusions: This study has demonstrated that the β-hCG levels may not always correlate with disease severity and prognosis. When comparing the two patients Case 1 had lower levels of β-hCG and of free T4 than Case 2, however was clinically more unwell, developed thyroid storm and had metastatic disease. Case 2 had hCG levels almost double those of Case 1, wsa stable and her levels decreased much quicker reaching undetectable levels