How to diagnose and manage an adult patient with abnormal lambda and kappa light chain levels and severe concentric left ventricular hypertrophy?

Cardiac Amyloidosis: Urgent Diagnostic Workup Required

This patient with abnormal free light chains (kappa 94.8, lambda 62.1) and severe concentric LVH most likely has cardiac amyloidosis (AL type) and requires immediate hematologic evaluation including serum/urine immunofixation, bone marrow biopsy, and cardiac tissue diagnosis to confirm amyloid deposition and initiate life-saving chemotherapy.

Diagnostic Algorithm

Step 1: Recognize the Red Flag Pattern

• Severe concentric LVH with abnormal free light chains is cardiac amyloidosis until proven otherwise 1
• The combination of elevated free light chains (both kappa and lambda elevated, though kappa predominates here) with unexplained LVH strongly suggests AL amyloidosis rather than sarcomeric HCM 1
• Cardiac amyloidosis causes progressive increase in thickness of left AND right ventricular myocardium, interatrial septum, and AV valves 1

Step 2: Obtain Immediate Diagnostic Studies

Electrocardiogram - Look for specific patterns:

• Low QRS voltage despite increased LV wall thickness (found in up to 50% of AL amyloidosis patients) 1
• Measure the ratio between QRS voltages and LV wall thickness - discordantly low voltage relative to wall thickness strongly suggests amyloidosis over HCM 1
• Look for pseudo-infarct patterns (abnormal Q waves) 1

Echocardiography - Assess for amyloid-specific features:

• Biventricular wall thickening (not just LV) 1
• Interatrial septal thickening 1
• AV valve thickening 1
• Diastolic dysfunction with restrictive physiology 2
• "Granular sparkling" appearance of myocardium 1

Laboratory workup:

• Serum and urine immunofixation electrophoresis (IFE) - standard IFE may miss small clones, request high-resolution IFE if initial testing negative 3
• Serum free light chain quantification with kappa/lambda ratio 3
• NT-proBNP (markedly elevated in cardiac amyloidosis, often >5000-10,000 pg/mL) 4, 3
• Troponin 3

Step 3: Confirm Tissue Diagnosis

Abdominal fat pad aspiration (first-line, least invasive):

• Positive in many AL amyloidosis cases 3
• Congo Red staining for amyloid 2
• Immunofluorescence or immunoelectron microscopy for light chain typing (kappa vs lambda) 3

If fat pad negative, proceed to endomyocardial biopsy:

• Congo Red and Thioflavin T staining 2
• Critical: Immunofluorescence staining is mandatory - light microscopy alone will miss immunoglobulin deposition disease, which can appear normal on routine H&E staining 2
• Electron microscopy to confirm granular (not fibrillar) deposits 2
• Immunofluorescence will identify the specific light chain type (kappa vs lambda) 2

Bone marrow biopsy:

• Assess plasma cell percentage and clonality 3
• Immunofluorescence for light chain restriction 3
• Essential for confirming underlying plasma cell dyscrasia 2

Step 4: Exclude Other Causes of LVH

Rule out hypertensive heart disease:

• History of poorly controlled hypertension would suggest hypertensive LVH, but abnormal light chains make this diagnosis insufficient 1
• Hypertensive LVH typically shows concentric pattern but without the biventricular/biatrial involvement seen in amyloidosis 1

Rule out sarcomeric HCM:

• Family history of HCM or sudden cardiac death 1
• Asymmetric septal hypertrophy pattern (amyloidosis is typically symmetric/concentric) 1
• Systolic anterior motion and LVOT obstruction (suggests sarcomeric HCM, not amyloidosis) 1
• Normal free light chains (your patient has abnormal values) 1

Rule out other infiltrative diseases:

• Anderson-Fabry disease: angiokeratomas, neuropathic pain, corneal opacities 1
• TTR amyloidosis: carpal tunnel syndrome (especially bilateral in males), family history 1
• Glycogen storage diseases: pre-excitation on ECG, extreme LVH with very high voltage 1

Critical Management Pitfalls

Common Diagnostic Errors to Avoid:

1. Do not assume this is "just" hypertensive heart disease - the abnormal light chains demand full amyloid workup 1

2. Do not rely on standard immunofixation alone - small amyloidogenic clones are frequently missed; if clinical suspicion is high and standard IFE is negative, request high-resolution IFE and proceed to bone marrow biopsy 3

3. Do not perform endomyocardial biopsy without immunofluorescence - routine H&E staining may appear completely normal in immunoglobulin deposition disease; immunofluorescence is mandatory to detect light chain deposits 2

4. Do not delay hematology referral - cardiac AL amyloidosis has poor prognosis without treatment; median survival is 6 months if untreated with heart failure 1

5. Do not use ACE inhibitors empirically - patients with amyloidosis and renal involvement can develop rapid renal deterioration with ACE inhibitors due to low cardiac output state 4

Urgent Treatment Considerations

If AL amyloidosis is confirmed:

• Immediate hematology/oncology referral for chemotherapy (cyclophosphamide, bortezomib, dexamethasone is standard regimen) 3
• Consider autologous stem cell transplantation in eligible patients 3
• Monitor NT-proBNP as marker of cardiac response 3
• Diuretics for volume management (use cautiously - these patients are preload-dependent) 4
• Avoid digoxin (binds to amyloid fibrils causing toxicity) 1
• Avoid calcium channel blockers (negative inotropic effects poorly tolerated) 1

Prognosis markers:

• NT-proBNP >8500 pg/mL and troponin elevation indicate advanced cardiac involvement with poor prognosis 4, 3
• Achieving hematologic response (normalization of free light chains) improves cardiac outcomes 3