Wei Qiang1, Sucai Song1,2, Tianjun Chen3, Zhe Wang4, Jun Feng5, Jiaojiao Zhang6, Hui Guo7. 1. Department of Endocrinology and Metabolism, The First Affiliated Hospital of Xi'an Jiaotong University, No.277 West Yanta Road, 710061, Xi'an, People's Republic of China. 2. Department of Endocrinology, The First Affiliated Hospital of Zhengzhou University, 450052, Zhengzhou, People's Republic of China. 3. Department of Respiratory and Critical Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, 710061, Xi'an, People's Republic of China. 4. Department of Thoracic Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 710061, Xi'an, People's Republic of China. 5. Department of Vascular Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, 710061, Xi'an, People's Republic of China. 6. Department of Pathology, The First Affiliated Hospital of Xi'an Jiaotong University, 710061, Xi'an, People's Republic of China. 7. Department of Endocrinology and Metabolism, The First Affiliated Hospital of Xi'an Jiaotong University, No.277 West Yanta Road, 710061, Xi'an, People's Republic of China. guohui002420@163.com.
Abstract
BACKGROUND: Manifestations of hypokalaemia in ectopic adrenocorticotropic hormonesyndrome(EAS) vary from mild muscle weakness to life-threatening arrhythmia. Herein, we present a rare case of EAS with concomitant rhabdomyolysis(RM) as a result of intractable hypokalaemia. CASE PRESENTATION: A 64-year-old man was admitted for limb weakness and facial hyperpigmentation for 2 weeks. Lab tests revealed intractable hypokalaemia (lowest at 1.8 mmol/L) and metabolic alkalosis. The diagnosis of RM was based on a creatine kinase(CK)level of 5 times the upper limit. The elevated CK and myohemoglobin (Mb) levels returned to within the normal range after the alleviation of hypokalaemia. The patient was diagnosed with ACTH-dependent Cushing's syndrome (CS) based on unsuppressed serum cortisol after a low-dose dexamethasone suppression test(LDDST) and remarkably elevated ACTH levels. The diagnosis of EAS was made based on the results of a high-dose dexamethasone suppression test(HDDST) and bilateral inferior petrosal sinus sampling(BIPSS). Multiple lymph nodes in the left supraclavicular fossa, right root of neck, mediastinum and bilateral hili of the lung were found with abnormal uptake of 68Ga-DOTA-NOC. Mediastinoscopic lymph node biopsy was performed. The pathological diagnosis was small-cell and large-cell neuroendocrine carcinoma with positive ACTH staining. The patient was prescribed mifepristone and received one cycle of chemotherapy. The patient could not tolerate subsequent chemotherapy and died of dyscrasia. CONCLUSIONS: RM is a rare complication of EAS with insidious onset and atypical clinical manifestations. Serum potassium levels should be vigilantly monitored to avoid RM in EAS.
BACKGROUND: Manifestations of hypokalaemia in ectopic adrenocorticotropic hormonesyndrome(EAS) vary from mild muscle weakness to life-threatening arrhythmia. Herein, we present a rare case of EAS with concomitant rhabdomyolysis(RM) as a result of intractable hypokalaemia. CASE PRESENTATION: A 64-year-old man was admitted for limb weakness and facial hyperpigmentation for 2 weeks. Lab tests revealed intractable hypokalaemia (lowest at 1.8 mmol/L) and metabolic alkalosis. The diagnosis of RM was based on a creatine kinase(CK)level of 5 times the upper limit. The elevated CK and myohemoglobin (Mb) levels returned to within the normal range after the alleviation of hypokalaemia. The patient was diagnosed with ACTH-dependent Cushing's syndrome (CS) based on unsuppressed serum cortisol after a low-dose dexamethasone suppression test(LDDST) and remarkably elevated ACTH levels. The diagnosis of EAS was made based on the results of a high-dose dexamethasone suppression test(HDDST) and bilateral inferior petrosal sinus sampling(BIPSS). Multiple lymph nodes in the left supraclavicular fossa, right root of neck, mediastinum and bilateral hili of the lung were found with abnormal uptake of 68Ga-DOTA-NOC. Mediastinoscopic lymph node biopsy was performed. The pathological diagnosis was small-cell and large-cell neuroendocrine carcinoma with positive ACTH staining. The patient was prescribed mifepristone and received one cycle of chemotherapy. The patient could not tolerate subsequent chemotherapy and died of dyscrasia. CONCLUSIONS: RM is a rare complication of EAS with insidious onset and atypical clinical manifestations. Serum potassium levels should be vigilantly monitored to avoid RM in EAS.