A Case of Cushing Syndrome Diagnosed by Recurrent Pathologic Fractures in a Young Woman
Sacrum of the 28 year old female patient were fractured while moving an object seven months before visiting a hospital so she received conservative treatment. Two months before visiting the hospital, thoracic vertebra radiography was performed since she claimed lower back pain. Compression fractures were diagnosed on 12th thoracic vertebra and then she visited orthopedics in our hospital. A dual energy X-ray absorptiometry (DXA) of lumbar spine and femur revealed relatively low BMD for her age and she was referred to endocrinology department for further investigation. There was no medication history of taking calcium, vitamin D supplement, and oriental medicine etc. Menarche was began when she was 13 years old but menstruation was stopped one year before the hospital visit; but there was no unusual finding in obstetrics examination so she was still being monitored. There was no alcohol drinking and smoking history, family history of osteoporosis and fractures, and other unusual findings.\nAt the time of her visiting, she complained severe back to pain and had 154.4 cm of height, 45.2 kg of body weight, 19 kg/m2 of body mass index (BMI), 130/100 mmHg of blood pressure, 87 times/minute of pulse, 18 times/minute of breathing, and 36.9℃ of body temperature. Moon face was not clearly shown but mild edema on the face and truncal obesity. The upper and bottom limbs were relatively thin and skin became thin as well. Purple spots were exhibited.\nA blood test, leukocyte, hemoglobin, platelets were 7,630 mm3 (neutrophils 84.7%, lymphocyte 8.7%, eosinocyte 0.3%), 13.4 g/dL, 169,000/µL. Fasting glucose, albumin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and creatinine were 112 mg/dL, 4.1 g/dL, 19 IU/L, 27 IU/L, 409 IU/L, and 0.8 mg/dL, respectively. Total calcium and phosphate were 9.1 mg/dL and 2.7 mg/dL, respectively, and albumin/globulin ratio was not reversed. In addition, serum intact parathyroid hormone, osteocalcin, C-telopeptide, and concentration of plasma 25-hydroxy vitamin D were 36.43 pg/mL (normal range: 13-54), 5 ng/mL (normal range: 4-20), 0.83 ng/mL (normal range: < 0.573), and 33.18 ng/mL, respectively. Thyroid function tests resulted in free T4 1.3 ng/dL, thyroid stimulating hormone (TSH) 0.43 mIU/L, and T3 57.2 ng/dL, indicating a normal range.\nA compression fracture were observed at 12th thoracic vertebra in spine x-ray () and Z-score of lumbar vertebrae (L1-4) and femoral neck were -2.9 and -2.1 on DXA, respectively, representing below the expected range for age ().\nWhile being hospitalized, the patient put on brace for conservative treatment with regards to the vertebral compression fracture. As the patient claimed chest pain during the treatment, plain radiography was performed. In the result, fractures were exhibited at right 7th and 10th ribs. Cushing's syndrome was considered due to repetitive pathologic fractures, low BMD regarding age, and the gross findings. Then, free cortisol in urine and 17-hydroxycorticosteroid were tested and then resulted 1,062 µg/day and 17.3 mg/day (normal range: 3-15), respectively, indicating cortisol excess. In order to confirm the diagnosis, a low-dose dexamethasone suppression test was carried out. As a result, we confirmed diagnosis of Cushing's syndrome because basal cortisol was 29.34 µg/dL and cortisol on 3rd day was 28.40 µg/dL indicating that it was not suppressed. Since adrenocorticotrophic hormone was relatively low (10.26 pg/mL), abdomen computed tomography (CT) was performed without a high-dose dexamethasone suppression test considering Cushing's syndrome caused by adrenal adenoma. A 2.7 × 2.4 sized adenoma was observed on left adrenal gland (), so that the patient received laparoscopic left adreanalectomy and was given 30 mg of hydrocortisone a day after the operation. However, after 2 months, the patient visited the hospital again due to severe pain on the lower back again and new compression fractures were taken place at 6th, 8th, 9th, and 11th thoracic vertebrae and 2th and 3rd lumbar vertebrae. Then, 750 mg of calcium citrate and 10 µg of cholecalciferol were given once a day and 20 µg of 1-34 parathyroid hormone (teriparatide) was injected once a day for 6 months total. In DXA performed 11 months after the treatment, BMD of lumbar vertebrae (L1-4) and femoral neck were increased by 4.5%, 1.9%, and 5.5%, respectively. Serum alkaline phosphatase, intact parathyroid hormone, osteocalcin, and concentration of blood 25-hydroxyl vitamin D were 304 IU/L, 28.57 pg/mL (normal range: 13-54), 16.1 ng/mL (normal range: 4-20), and 21.5 ng/mL, respectively. Currently, hydrocortisone was reduced to 10 mg a day; the patient is still being monitored without further fracture occurrences.