Paraneoplastic Syndromes

Paraneoplastic Syndromes – Justin Lo

Hypercalcemia of malignancy

Background

  • Caused by PTHrP production, osteolytic lesions, and/or rarely exogenous Vit D
  • PTHrP Breast cancer, NSCLC (squamous)
  • Osteolysis Multiple Myeloma, Breast Cancer;
  • Exogenous Vit D Lymphoma

 

Evaluation

  • Correct [Ca+2] for hypoalbuminemia: add 0.8 x (4.0 – albumin)
  • Send basic hyperCa+2 work-up – PTH, Vit D, etc (see hypercalcemia section)
  • PTHrP is called “Parathyroid Hormone-related Peptide-ARUP” in Epic

 

Management

  • First-line: IVF without calcium such as Normosol goal urinary output of 150-200 mL/hr
    • Strict I/Os; Cautious IV fluids if pt w/cardiac or renal dysfunction
    • Add Furosemide if hypervolemic (do not empirically start)
  • Second-line: Zoledronic acid 4mg IV (takes 24-48 hours to see effect)
  • AMS or severe hypercalcemia (>14mg/dL): calcitonin 4 IU/kg (req. attending approval) 
  • Monitor creatinine, calcium and potassium
  • Begin treatment for underlying malignancy ASAP

 

 

SIADH

Background

  • Euvolemic hypotonic hyponatremia with urine sodium >20 and typically urine Osm >100
  • Associated with: SCLC (most common), head/neck cancers, breast cancer
  • See "Nephrology" for additional information

 

Management

  • Free water restriction to 800mL/day
  • Refractory: salt supplementation (e.g. salt tabs) +/- loop diuretic

 

 

Carcinoid Syndrome

Background

  • Episodic flushing, diarrhea, wheezing/SOB due to secretion of histamine & serotonin
  • Most common: Neuroendocrine tumors – GI (often with mets to liver and lung)

 

Evaluation

  • Urine: UR 5-HIAA (ARUP)
  • Imaging to identify tumor(s) (CT chest/abdomen/pelvis)

 

Management

  • Short-term treatment: subQ or IV octreotide (see UpToDate for dosing)
  • Antidiarrheals (Imodium, Lomotil, etc.) to slow transit
  • Long-term treatment: depot (IM) forms of octreotide and lanreotide

 

 

Autoimmune encephalitis, encephalomyelitis, and myelitis

Background

  • Encephalopathy (limbic or brainstem), +/- myelitis (limb ataxia, sensory deficits)
  • Associated with small cell lung cancer and checkpoint inhibitor therapy

 

Evaluation

  • LP: make sure to order CSF oligoclonal bands & CSF IgG index
  • “Paraneoplastic AutoAb Eval-MAYO” (add "CSF" to the front of the order name if for LP)
  • NMDA-R can be ordered as a standalone test 
  • CT head
  • EEG if concern for subclinical seizures

 

Management: Consult Neurology, for possible immunosuppressive therapy (steroids, IVIG)

 

 

Lambert-Eaton myasthenic syndrome (LEMS)

Background

  • Muscle weakness due to autoantibody against calcium channels resulting in ACh release
  • Associated with SCLC (most common) & lymphoma

 

Presentation: Proximal muscle weakness, diminished DTRs

 

Evaluation

  • Nerve conduction studies: EMG w/ NCV
  • Serum “Paraneoplastic AutoAb Eval-MAYO”

 

Management: Consult Neurology