Etiologies for Restrictive Cardiomyopathy
                                             

Idiopathic
Endomyocardial fibrosis, Loeffler eosinophilic endomyocardial fibrosis

Secondary restrictive cardiomyopathy
Infiltrative-Hemochromatosis, Amyloidosis (most common cause of RCM in the USA), Sarcoidosis
Other: Radiation induced, Anthracyclines (eg: Doxorubicin), Malignancy, Glycogen storage diseases, Systemic sclerosis

Etiologies for Constrictive Pericarditis

Idiopathic, viral pericarditis, Tb (most common worldwide), connective tissue disorders, uremia, neoplasms, drugs (eg:Procainamide/Hydralazine)

Restrictive Cardiomyopathy vs. Constrictive Pericarditis

Amyloidosis-remember that it is a systemic disease!

• RENAL (# 1 MC): proteinuria (usually nephrotic range)
• CV (#2 MC): cardiomyopathy (restrictive), arrhythmias, angina, low voltage on EKG with pseudo-infarct pattern
• GI: Hepatosplenomegaly, gastroparesis
• NEURO: Peripheral/autonomic neuropathy, median nerve compression (carpal tunnel), orthostatic hypotension
• MSK: pseudo hypertrophy of muscles, macroglossia with lateral scalloping, amyloid arthropathy (thickening of synovial membrane)
• HEMATOLOGIC: Decreased Factor X activity (increased risk of bleeding)
• PULM: Tracheobronchial infiltration most common, pleural effusion, rare to have Pulm. HTN
• SKIN: easy bruising (ecchymosis), periorbital ecchymosis (“Racoon Eyes”) that is worse with Valsalva maneuvers, nail dystrophy, Alopecia,

  
  Making the diagnosis

• Start with fad pad biopsy due to low risk of bleeding but if negative, may need to biopsy affected organs to make diagnosis. Stain with Congo Red stain and look for Apple-Green birefringence under polarized light to make diagnosis
• Most common cause of Amyloid in the USA is AL Amyloid-clonal expansion of plasma cells in the bone marrow that secrete a clonal Ig Lambda chain that deposits as amyloid fibrils into tissues, can occur with or without multiple myeloma, including with non-Hodgkins lymphoma and Waldensrom’s macroglobulinemia 
• Check immunofixation and free light chain assay (SPEP/UPEP can be falsely negative)