What are the key considerations in managing multiple myeloma (MM) in the Intensive Care Unit (ICU)?

Managing Multiple Myeloma in the ICU: Critical Monitoring and Interventions

When managing multiple myeloma patients in the ICU, immediately assess and aggressively treat the life-threatening complications: renal failure, hypercalcemia, hyperviscosity, infections, spinal cord compression, and tumor lysis syndrome, while initiating bortezomib-based therapy for patients with renal dysfunction. 1

Immediate Life-Threatening Complications to Assess

Renal Failure (Present in ~19% at diagnosis)

• Check serum creatinine, urine protein electrophoresis, and serum free light chains immediately 2, 3
• Initiate aggressive hydration (2-3 liters/day) to maintain urine output >100 mL/hour 1, 3
• Start bortezomib-based therapy immediately—this is the treatment of choice for myeloma-associated renal failure 1, 4
• Consider plasmapheresis for symptomatic hyperviscosity or severe renal dysfunction, though institutional practices vary 1
• Avoid nephrotoxic agents including NSAIDs, IV contrast, and aminoglycosides 3
• Initiate renal replacement therapy if severe uremia, hyperkalemia, or volume overload develops 3

Hypercalcemia (Calcium >11 mg/dL)

• Administer aggressive IV hydration with normal saline (200-300 mL/hour initially) 1
• Give zoledronic acid 4 mg IV (preferred bisphosphonate for hypercalcemia) 1
• Add calcitonin 4-8 IU/kg SC/IM every 6-12 hours for rapid effect 1
• Administer corticosteroids (dexamethasone 40 mg daily) which treat both hypercalcemia and myeloma 1
• Monitor for polyuria, dehydration, and declining GFR 1

Spinal Cord Compression (Medical Emergency)

• Obtain urgent MRI of entire spine if any neurological symptoms, back pain, or weakness 1
• Start high-dose dexamethasone 40 mg IV immediately 1
• Consult radiation oncology emergently—deliver 20-30 Gy in 5-10 fractions for impending cord compression 1
• Do not delay systemic therapy for radiation—these can be given concurrently 1
• Consider surgical decompression if neurological deterioration despite radiation 1

Hyperviscosity Syndrome

• Assess for visual changes, bleeding, altered mental status, or headache 5, 6
• Check serum viscosity if IgM or IgA myeloma with symptoms 5
• Initiate plasmapheresis immediately as adjunctive therapy for symptomatic hyperviscosity 1
• Begin systemic chemotherapy concurrently to reduce paraprotein production 1

Infections (Leading cause of death in MM)

• Obtain blood cultures, urinalysis, and chest imaging immediately for any fever or suspected infection 1
• Start broad-spectrum antibiotics immediately—do not wait for culture results 1
• Common pathogens include H. influenzae, S. pneumoniae, Gram-negative bacilli, and viruses (influenza, herpes zoster) 1
• Check for neutropenia (common with chemotherapy) and consider G-CSF if severe 1
• Initiate prophylaxis: acyclovir/valacyclovir for herpes zoster (especially with bortezomib), consider antibacterial prophylaxis for first 2-3 months of lenalidomide/pomalidomide therapy 1

Tumor Lysis Syndrome

• Monitor closely in patients with high tumor burden starting chemotherapy 4
• Check potassium, phosphate, calcium, uric acid, LDH, and creatinine every 6-8 hours initially 4
• Administer aggressive IV hydration (3 liters/day) 4
• Give allopurinol 300 mg daily or rasburicase for severe hyperuricemia 4

Hematologic Complications Requiring Monitoring

Severe Anemia (Hemoglobin <10 g/dL in ~73% at diagnosis)

• Transfuse packed red blood cells (leukocyte-reduced) for symptomatic anemia or hemoglobin <7-8 g/dL 1, 7, 2
• Target hemoglobin around 12 g/dL (avoid >14 g/dL due to thrombotic risk) 1
• Check B12, folate, iron studies, and endogenous erythropoietin levels 1, 7
• Consider erythropoietin-stimulating agents if hemoglobin <10 g/dL with symptomatic anemia, especially with renal failure 1, 7

Thrombocytopenia and Neutropenia

• Monitor complete blood counts at least every 2-3 days in ICU setting 4
• Platelet transfusion for counts <10,000/μL or <50,000/μL with bleeding 4
• Dose-reduce or hold chemotherapy for severe cytopenias per protocol 4

Venous Thromboembolism (Highest risk first 6 months)

• Initiate VTE prophylaxis in all patients unless contraindicated 1
• Use full-dose anticoagulation (LMWH or warfarin) for high-risk patients receiving IMiDs (lenalidomide/thalidomide) with additional risk factors 1
• Use aspirin 100 mg daily for lower-risk patients on IMiDs 1
• Risk factors include: high-dose dexamethasone, doxorubicin, immobility, prior VTE, concurrent erythropoietin 1

Cardiovascular and Pulmonary Monitoring

Cardiac Toxicity

• Monitor closely for worsening heart failure or new cardiac dysfunction, especially with bortezomib 4
• Obtain baseline ECG and consider serial troponins if cardiac symptoms 4
• Use caution with bortezomib in patients with existing heart disease 4

Hypotension

• Monitor blood pressure closely, especially with bortezomib therapy 4
• Use extreme caution in patients on antihypertensives, with history of syncope, or dehydration 4
• Hold antihypertensives if orthostatic hypotension develops 4

Acute Respiratory Syndromes

• Monitor for new dyspnea, cough, or hypoxia—acute respiratory distress can occur with bortezomib 4
• Consider interrupting bortezomib if new pulmonary symptoms develop 4
• Obtain chest imaging and consider infectious vs. drug-induced etiology 4

Neurological Complications

Peripheral Neuropathy (Common with bortezomib, thalidomide)

• Assess for paresthesias, neuropathic pain, or motor weakness daily 1, 4
• Dose-reduce bortezomib (1.3→1.0→0.7 mg/m²) or switch to weekly dosing if neuropathy develops 1, 4
• Consider subcutaneous rather than IV bortezomib to reduce neuropathy risk 1

Posterior Reversible Encephalopathy Syndrome (PRES)

• Obtain urgent brain MRI for new visual changes, seizures, headache, or altered mental status 1, 4
• Discontinue bortezomib immediately if PRES suspected 1, 4

Gastrointestinal Complications

• Anticipate nausea, vomiting, diarrhea, and constipation with chemotherapy 4
• Provide scheduled antiemetics and antidiarrheals prophylactically 4
• Maintain aggressive fluid replacement for severe diarrhea 4

Hepatic Monitoring

• Check liver function tests (AST, ALT, bilirubin) at baseline and regularly during treatment 4
• Reduce bortezomib starting dose for moderate-to-severe hepatic impairment 4
• Interrupt therapy if hepatotoxicity develops to assess reversibility 4

Critical Pitfall to Avoid

Never delay initiation of systemic myeloma therapy while addressing complications—bortezomib-based regimens can be started concurrently with supportive measures and are essential for disease control, which is the most effective way to reverse complications like renal failure and anemia. 1, 7 The exception is ensuring adequate hydration before starting therapy in patients with renal dysfunction to prevent tumor lysis syndrome. 4