A 70 yo male with new DKA???

Dr. Tang presents a 70 yo gentleman with PMH significant for SCLC with new onset DKA in the setting of atezolizumab (immune checkpoint inhibitor).

Teaching points:

1. What are the diagnostic criteria for DKA vs. HHS?

• Often, Beta-hydroxybutyrate is present in DKA; however the level does not correlate with the severity of DKA

• Acetone and Acetoacetate are other breakdown products of ketogenesis and are not as frequently measured

2. Management strategies for DKA:

• Correct hypovolemia and hyperosmolality

• Correct/replete potassium prior to starting insulin (IF K<3.3, need to replete K before starting insulin therapy).

• Give IV insulin to halt ketogenesis

3. Checkpoint inhibitor-induced Diabetes:

• These new immunotherapies target receptor:ligand pairs and modulate T-cell activity

• They are highly associated with development of autoimmune diseases

• Important to check A1C prior to and during treatment with immune checkpoint inhibitors

• Most common presentation with checkpoint-inhibitor-induced autoimmune diabetes presents with DKA

4. What are some potential paraneoplastic syndromes associated with SCLC?

• Hypercalcemia secondary to bony mets or tumor secretion of PTHrP, calcitriol or other cytokines --> anorexia, nausea, vomiting, constipation, lethargy, polyuria, polydipsia, dehydration

• SiADH secretion: frequently caused by SCLC and results in hyponatremia --> anorexia, nausea, vomiting, cerebral edema

• Neurologic syndromes: Lambert-Eaton myasthenic sydrome, cerebellar ataxia, sensory neuropathy, limbic encephalitis, encephalomyelitis, autonomic neuropathy, retinopathy, opsomyoclonus