A Deadly Product: Calcific Uremic Arteriolopathy
Misdiagnosed as Cellulitis
Kaumaka Shimatsu, MD, Shubha Ananthakrishnan MD, Ankur Sharma, MD
University of California, Davis Medical Center; Sacramento, CA
Hospital Course
course
Hospital
Learning
Objectives
Learning Objectives
•Calcific uremic arteriolopathy (CUA) is a
calcification of vessels in the dermis and
subcutaneous fat, leading to ischemia and tissue
necrosis
•Nephrology was consulted for routine dialysis on hospital day
2 and suggested the diagnosis of CUA
•Bone scan showed moderately intense increased uptake in the
medial left thigh consistent with CUA, biopsy (Figure 2) was
supportive of CUA
•CUA causes painful skin lesions that can mimic
cellulitis in dialysis patients with elevated
calcium-phosphate product and can result in high
mortality
• His dialysis was intensified and he was started on sodium
thiosulphate
•He developed new lesions on his right thigh, calf and left
ankle. His lesions enlarged, developed bullae, then ulcers.
•Clinicians in both outpatient and inpatient
settings should be highly suspicious of painful
skin lesions in these patients in order to make an
early diagnosis and initiate treatment of CUA
•His phosphorus level eventually normalized and his skin
lesions improved
Discussion
Case
Case Presentation
presentation
•71 yr old male with type 2 DM, Stage 5 CKD on
hemodialysis, systolic CHF, and history of PE,
previously on Coumadin presented to his PCP
with painful erythema over his left thigh
•He was diagnosed with cellulitis and treated with
one dose of IM ceftriaxone and started on a
course of keflex.
•He returned seven days later with extension of
the erythema, warmth & tenderness, now
doubled in size so he was admitted for
management of cellulitis after failed outpatient
treatment.
•He was afebrile and dermatologic exam was
notable for a 7”X8” exquisitely tender, indurated
plaque on an erythematous background over his
left medial thigh
•Labs showed no leukocytosis but were notable
for an elevated phosphorus of 9.5 mg/dL,
calcium of 9.4 mg/dL and PTH of 643 pg/mL.
•Lower extremity CT showed skin thickening and
subcutaneous edema extending to the
intermuscular fascia without subcutaneous
emphysema or abscess.
•He was admitted with a diagnosis of cellulitis
and was started on vancomycin and ceftriaxone
Figure 1. Nonulcerative calcific uremic arteriolopathy of the breast
demonstrating erythema with violaceous and reticulated skin.
Image obtained from Google images
• Prevalence: ~1% of CKD patients and 4.1% dialysis patients.
• Risk factors: hyperphosphatemia, elevated Ca2+ X PO4
product, calcium and vit D supplements, hypoalbuminemia,
female gender, warfarin use, obesity1
• Pathogenesis: vascular smooth muscle cells dedifferentiate
into "osteoblast"-like cells that produce bone matrix proteins2
• Lesions occur in vascular regions with thick adipose tissue like
breast, abdomen and thighs. They are exquisitely painful and
violaceous, forming plaques or nodules with skin mottling,
then bullae and ulcers, progressing to gangrene and sepsis.
• Six month mortality ~ 33% in plaques but > 80 % ulcers1
• Diagnosis is clinical, supported by bone scan. Tissue biopsy is
diagnostic but risks increased lesions and secondary infection1
• Management is supportive with intensified hemodialysis,
aggressive wound care and sodium thiosulfate (based on
success in case reports), duration usually 12 months
• Sodium thiosulfate may increase solubility of ca-phos deposits
• Prevention: goal Ca2+ × PO4 product < 55 mg2/dL2, PO4 < 5.5
mg/dL, Ca2+ < 9.6 mg/dL4
References
References
Figure 2. Biopsy showing subepidermal cleavage plane secondary to
ischemia, blood vessels filled with erythrocytes, and extravasated
erythrocytes suggestive of early thrombosis
1.
Fine A, Zacharias J. Calciphylaxis is usually non-ulcerating: risk factors, outcome and therapy. Kidney Int 2002; 61:2210.
2.
Rivet J, Lebbe C, Urena P, Cordoliani F, Martinez F, Baglin AC, et al: Cutaneous calcification in patients with end-stage
renal disease: a regulated process associated with in situ osteopontin expression. Arch Dermatol 2006; 142: 900-906.
3.
Goldsmith DJ: Calcifying panniculitis or ‘simple’ inflammation? Biopsy is better than a bone scan. Nephrol Dial
Transplant 1997; 12: 2463 – 2464
4.
Block GA, Port FK: Re-evaluation of the risks associated with hyperphosphatemia and hyperparathyroidism in dialysis
patients: recommendations for a change in management. Am J Kidney Dis 2000; 35: 1226 – 1237.
Authors would like to acknowledge Dr. Maxwell A. Fung, Pathology Dept, UCDMC for pathology images