An Unlikely Cause of Hypokalemia

Management of small cell lung cancer complicated with paraneoplastic Cushing's syndrome: a systematic literature review

Paraneoplastic Cushing's syndrome (PCS) is a rare, but clinically important feature of small cell lung cancer (SCLC) that is associated with even worse prognosis. To identify key considerations in comprehensive management of SCLC patients complicated with PCS, we conducted a systematic review of relevant reports on PubMed and Web of Science, focusing on SCLC with PCS cases. The systematic review analyzed 61 reports published between 1985 and 2022 with a total of 157 SCLC patients included. Out of the 157 patients, 132 (84.1%) patients across 58 (95.1%) reports were diagnosed with ectopic Cushing's syndrome. The immunohistochemical (IHC) staining for adrenocorticotropic hormone (ACTH) was performed on 30 (19.1%) patients across 22 (36.1%) reports and demonstrated encouraging performance. For treatment, chemotherapy and ketoconazole were utilized in 50 (81.97%) and 24 (39.34%) reports, respectively. Regarding cause of death, infection and cancer were equally frequent, each being recorded in 17 (27.87%) reports. To conclude, the majority of PCS cases in SCLC patients were caused by ectopic hormone secretion. In order to make a differential diagnosis, it is recommended to utilize IHC staining for a specific hormone such as ACTH or corticotropin-releasing hormone. In the comprehensive treatment of SCLC with PCS patients, effective management of hypercortisolism and potent safeguarding against infection play two crucial roles. Ultimately, further confirmations are required regarding the specificity and accuracy of IHC staining technique as well as the efficacy and safety of immunotherapy in the treatment of SCLC with PCS patients.

Correlation of serum electrolytes with serial miRNA in advanced stage non-small cell lung cancer (NSCLC) in Indonesia

Objective

This study aims to evaluate the correlation between electrolytes and serial miRNAs from our previous study. We want to prove that there is the molecular basis that underlying electrolytes disturbances as the predictive indicator to the outcome in NSCLC patients.

Results

There were positive correlation between potassium level with miR-34 (p  = 0.008, r  = 0.366), miR-148 (p  = 0.004, r  = 0.394) and miR-155 (p  = 0.031, r  = 0.300).

Refractory hypokalaemia and hypertension with metabolic alkalosis: an acute presentation of Cushing's disease secondary to a pituitary macroadenoma

A 68-year-old woman presented with right arm cellulitis, not responsive to oral antibiotics. Intravenous antibiotics were commenced, and an ultrasound scan confirmed a collection that was surgically drained. She developed refractory hypokalaemia with normal magnesium, no gastrointestinal losses and no iatrogenic cause. She was hypertensive, hyperglycaemic, alkalotic, clinically obese with proximal myopathy and skin bruising. These clinical findings and refractory hypokalaemic hypertension with metabolic alkalosis raised a suspicion of Cushing's syndrome (CS). 24-hour urinary free cortisol (24 hours) was grossly raised on two occasions. The adrenocorticotropic hormone (ACTH) was significantly raised at 154 ng/L, confirming ACTH-dependant CS. A CT scan of the thorax, abdomen and pelvis excluded an ectopic source of hypercortisolaemia. MRI pituitary revealed an invasive macroadenoma. Treatment with endoscopic debulking resulted in the resolution of hypokalaemia and metabolic alkalosis with significant improvement in hyperglycaemia and hypertension.

Association of hypokalemia with cortisol and ACTH levels in Cushing's disease

Hypokalemia is a common feature in patients with Cushing's syndrome (CS). Whether the occurrence of hypokalemia is associated with cortisol and adrenocorticotropic hormone (ACTH) levels is still unclear. Approximately 80% of cases of endogenous CS are due to Cushing's disease (CD). The purpose of this study was to determine the association of hypokalemia with cortisol and ACTH levels in patients with CD. The retrospective study included 195 patients with CD referred to our medical center from January 2011 to December 2017. The results show that 25.64% (50/195) of the patients had hypokalemia. The 24-h urinary free cortisol (UFC) and plasma cortisol levels were significantly higher in patients with hypokalemia than those with normokalemia (P < 0.05). Plasma ACTH levels were similar between the patients with hypokalemia and normokalemia (P > 0.05). Cortisol levels were negatively correlated with plasma potassium levels (08:00: r = -0.344 (P < 0.01), 00:00: r = -0.435 (P < 0.01); 24-h UFC: r = -0.281 (P < 0.05)). There was no significant correlation between the plasma ACTH and potassium (08:00: r = -0.093 (P > 0.05), 00:00: r = -0.184 (P > 0.050)). Our current data suggest that cortisol level, instead of ACTH level, is correlated with plasma potassium level. A high cortisol level may be the principal cause of hypokalemia.

A Case of Hypokalemia Possibly Induced by Nafcillin

(1) Background: The use of intravenous antibiotics for severe infections is a common practice, either as inpatient or outpatient treatment. In the case of methicillin-susceptible Staphylococcus aureus (MSSA), nafcillin is a commonly prescribed intravenous antibiotic, given its known efficacy to treat infections related to this organism effectively. However, it is not without side effects. (2) Methods: We present an interesting case of persistent hypokalemia in a patient after he was started on nafcillin infusion for an MSSA infection, which eventually resolved with the completion of the treatment. (3) Results: Hypokalemia is a known side effect of nafcillin infusion, and it is believed to be mainly due to its antibiotic effect as a non-absorbable ion in the distal tubule and/or intracellular redistribution due to volume depletion. (4) Conclusions: A review of the available literature revealed that hypokalemia is a known side effect of nafcillin infusion; however, if present, it is usually mild, and only a few cases of severe hypokalemia have been reported. Usually, hypokalemia resolves when the nafcillin infusion is stopped; however, in certain cases, when this is not possible, oral potassium replacement can be used while the patient is receiving nafcillin. Clinicians should be aware of this rare, but possible, complication when using nafcillin.

Hypertension and severe hypokalaemia associated with ectopic ACTH production

Ectopic adrenocorticotropic hormone (ACTH) secretion represents 5%-10% of cases of Cushing's syndrome (CS), and approximately 50%-60% of these arise from neuroendocrine lung tumours, including small-cell lung cancer (SCLC). We report a 42-year-old man admitted with hypertension, metabolic alkalosis and severe hypokalaemia. On physical examination, centripetal obesity with 'moon face' and 'buffalo's hump' were identified, and wheezing on left lung was heard. A markedly elevated serum cortisol, ACTH and urine free cortisol production supported the diagnosis of CS. Chest CT showed a left hilar mass with metastasis to the liver, adrenal glands and lymph nodes. Bronchoscopy identified bronchial infiltration by SCLC. Treatment with metyrapone and chemotherapy was started. Despite initial improvement, progressive clinical deterioration occurred, culminating in death 1 year after diagnosis. Ectopic ACTH secretion is uncommon but should be suspected in patients with severe hypokalaemia, hypertension and metabolic alkalosis, especially in the context of lung cancer.