Medial Arterial Calcification and AL Amyloidosis
No, medial arterial (Mönckeberg) calcification of the foot is not associated with AL (light-chain) amyloidosis. Mönckeberg sclerosis occurs predominantly in patients with diabetes mellitus, chronic kidney disease, advanced age, and following sympathetic denervation—not in AL amyloidosis. 1, 2
Established Causes of Mönckeberg Calcification
The evidence clearly identifies specific populations at risk for medial arterial calcification:
Diabetes mellitus with peripheral neuropathy: Medial calcification is frequently seen in diabetic patients with severe neuropathy, where it can interfere with ankle-brachial index (ABI) measurements by producing falsely elevated readings (ABI >1.40). 1
Chronic kidney disease: Medial calcification develops in most patients as they transition to significant CKD, representing accelerated atherosclerosis with osteoblastic transformation of vascular smooth muscle cells. 3
Sympathetic denervation: In a study of 60 patients (19 diabetic, 41 non-diabetic) examined 6-8 years after lumbar sympathectomy, 92% developed medial calcification—occurring regardless of diabetes status. After unilateral sympathectomy, calcification occurred on the operated side in 88% versus only 18% on the contralateral side. 4
Advanced age: Medial calcification occurs commonly in aged individuals as part of the natural aging process. 5
AL Amyloidosis: Distinct Vascular Pathology
AL amyloidosis causes a completely different pattern of vascular involvement:
Amyloid protein deposits in coronary vessel walls: The amyloid deposits occur in the media and adventitia of coronary arteries and veins, potentially causing cardiac ischemia—but this is protein deposition, not calcium phosphate precipitation. 1
No association with medial calcification: None of the comprehensive guidelines on AL amyloidosis diagnosis 6, treatment 7, or clinical manifestations 8 mention medial arterial calcification as a feature of the disease.
Clinical Distinction and Diagnostic Implications
When evaluating a patient with medial calcification on foot radiographs:
First, assess for diabetes and neuropathy: Peripheral neuropathy associated with diabetes is the most common cause of medial wall calcification (Mönckeberg sclerosis), which produces rigid arteries and elevated ABI readings. 1
Second, evaluate renal function: Check for chronic kidney disease, as CKD is strongly associated with accelerated medial calcification through phosphorus-mediated osteoblastic transformation of vascular smooth muscle cells. 3
Do not pursue AL amyloidosis workup based on calcification alone: The presence of medial calcification should not trigger evaluation for AL amyloidosis unless the patient has other cardinal features such as restrictive cardiomyopathy, nephrotic-range proteinuria, peripheral neuropathy with autonomic features, or macroglossia. 6
Radiographic Differentiation
Medial calcification has characteristic radiographic features that distinguish it from intimal atherosclerotic calcification:
Regular and diffuse pattern: Medial calcification appears as regular, linear "railroad track" calcification along arterial walls, correctly identified in 92% of cases by radiographic criteria. 9
No physiologic stenosis: Unlike intimal calcific atherosclerosis, medial calcification does not necessarily cause arterial stenosis or reduced blood flow, though it does increase arterial stiffness. 1, 9
Common Pitfall to Avoid
Do not confuse the renal manifestations of AL amyloidosis with the renal disease that causes medial calcification. While AL amyloidosis causes nephrotic syndrome with proteinuria in approximately 70% of patients 8, this is due to amyloid deposition in glomeruli—not the chronic kidney disease that drives medial calcification through mineral metabolism derangements. 3