Summary

Doege–Potter syndromeis a paraneoplastic syndrome characterized by nonislet cell tumor hypoglycemia due to a solitary fibrous tumor, which produces insulin-like growth factor II. In this report, we present the case of a 67-year-old male with recurrent and refractory hypoglycemia due to DPS successfully treated with imatinib. He initially presented with neuroglycopenic symptoms and dyspnea secondary to a giant tumor in the left hemithorax, which was totally resected. During follow-up, 7 years later, he presented with thoracoabdominal tumor recurrence associated with severe hypoglycemia and underwent subtotal tumor resection, with a subsequent improvement of symptoms. The following year, he had a recurrence of his intra-abdominal tumor, which was unresectable, associated with severe hypoglycemia refractory to dextrose infusion and corticosteroids, thus receiving imatinib with a favorable response. The clinical presentation, diagnostic approach, progression of the disease, and response to treatment with imatinib in the management of a patient with large, recurrent, and unresectable mesenchymal tumors with insulin-like growth factor-2 secretion causing hypoglycemiahighlight the importance of this case report.

Learning points

• Doege–Potter syndrome (DPS) is a rare cause of tumoral hypoglycemia of non-pancreatic origin.

• Some malignant or benignant neoplasms have ectopic secretion of insulin-like growth factor-2.

• Total surgical removal is the principal treatment in patients with DPS.

• Tyrosine kinase inhibitors management in DPS may contribute to improved tumor control in patients with unresectable tumors and severe hypoglycemia.

Summary

Postoperative (PO) complications after transsphenoidal surgery (TSS) are rare when performed in pituitary referral centers. Partial hypopituitarism is more frequent and somewhat expected. Meningitis, cerebrospinal fluid leaks, and visual deficits are unusual. Cerebrovascular complications, including cerebral vasospasm are rare, usually under-appreciated and not mentioned to the patient prior to the surgery. This is a report of a 51-year-old male with a non-functioning pituitary macroadenoma presenting with partial hypopituitarism and visual field loss. The patient was submitted to an uneventful TSS. On the first PO day, he developed a left palpebral ptosis with unequal pupils and impaired consciousness (12 points on Glasgow Coma Scale). CT scan revealed a perimesencephalic subarachnoid hemorrhage (SAH) grade 1 according to the modified Fisher scale. High-dose dexamethasone (16 mg/day) was initiated and the patient became more alert (Glasgow 14). On the fifth PO day, due to progression of the neurological deficits (left III, IV, and VI cranial nerves palsy, ataxia, dysdiadochokinesia, right dysmetria, and dysarthria), a magnetic resonance angiography was obtained and revealed a recent mesencephalic infarct without evident vasospasm. Nevertheless, nimodipine 60 mg 4/4 h was initiated. No improvement was seen after 3 days of treatment. The patient was discharged and put on rehabilitation, returning to normal gait and balance after 7 months. This, therefore, is a case of an unexpected mesencephalic infarct probably due to vasospasm induced by minor SAH. Although exceptionally rare, informing the patient about this event prior to TSS is important due to its significant neurological impact. More data are needed considering preventive treatment with nimodipine as soon as SAH is detected after TSS and whether it would improve neurological outcomes.

Learning points

• Whenever neurological deficits arise after transsphenoidal surgery (TSS), systemic infection, meningitis, electrolyte imbalance, and evident hemorrhage must be promptly investigated.

• Although rare, cerebral vasospasm (CVS) after TSS is associated with high morbidity and high mortality rates.

• Vigilance for vasospasm is necessary for patients undergoing TSS for pituitary adenoma, especially those with significant suprasellar extension.

• Informing this event to the patient prior to TSS is essential due to its significant morbidity and mortality.

• Post-TSS subarachnoid hemorrhage and hemiparesis may be important clues indicating CVS and infarction.

• There is limited evidence in the literature regarding post-TSS CVS surveillance and treatment strategies which could have an impact on clinical decisions.

Summary

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) induce osmotic diuresis by inhibiting the proximal renal tubular reabsorption of the filtered glucose load, which in turn can occasionally lead to severe dehydration and hypotension amidst other adverse effects. We present a case of a 49-year-old man with type 2 diabetes mellitus (T2D) on canagliflozin, a SGLT2i. The patient was brought to the emergency room following a motor vehicle accident. He was confused and had an altered mental status. His blood alcohol and urine toxicology screens were negative. Initial investigations revealed that he had severe hyponatremia with euglycemic ketoacidosis. The adverse condition was reversed with close monitoring and timely management, and the patient was eventually discharged. This is the first report to suggest hyponatremia as a potentially serious adverse effect following SGLT2i therapy. Its impact on the renal tubule handling of sodium and water is not yet well characterized. While further studies are warranted to understand better the pathophysiological mechanisms associated with SGLT2i-induced adverse effects, timely dose reduction or perhaps even its temporary discontinuation may be recommended to prevent complications.

Learning points

• Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are usually well-tolerated, but some serious adverse effects have been documented.

• Our case report suggests hyponatremia as a potential, rare side effect of SGLT2i and makes physicians aware of the occurrence of such life-threatening but preventable complications.

• Timely and close monitoring of the patient, with temporary discontinuation of this drug, may be recommended towards effective management.

• Studies demonstrating a comprehensive understanding of SGLT2i-related electrolyte derangements are warranted.

Learning points:

• When a toxic ingestion is suspected, direct visualization of the patient’s pills is advised in order to rule out the possibility of patient- or pharmacist-related medication errors.

• Though sending a specimen for determination of the plasma metformin concentration is important when a metformin-treated patient with diabetes presents with lactic acidosis, complex relationships exist between metformin accumulation, hyperlactatemia and acidosis, and the drug may not always be the precipitating factor.

• Intermittent hemodialysis is recommended as the first-line treatment for metformin-associated lactic acidosis (MALA).

• An investigational delayed-release form of metformin with reduced systemic absorption may carry a lower risk for MALA in patients with renal insufficiency, in whom metformin therapy may presently be contraindicated.

Learning points

• High TSH levels, as described in RTH syndrome, are known to be associated with an increased risk of developing thyroid nodules, with subsequent growth and malignancy.

• The exact role of TR β mutants in thyroid carcinogenesis is still undefined.

• We report the first case of multiple Hürthle cell adenomas associated with RTH.