1/2015Samuel Lai

CONTRAST NEPHROPATHIES

Understand the interaction between iodine, gadolinium and CKD

Know how to diagnose both contrast-induced nephropathy (CIN) and nephrogenic systemic fibrosis (NSF)

Know prevention options for CIN and NSF

OBJECTIVES

55 y/o female with CKD Stage IV (eGFR 15-29), DM II and HTN presents with new onset L sided paralysis. She is admitted to medicine after a CT Head Non-Contrast in the ED ruled out a hemorrhagic stroke

LABS: eGFR 20, Cr 2.3 (both at baseline)

Neurology consult recommends an MRI/MRA Head/Neck with and without contrast to rule out an ischemic stroke

What should you be concerned about?

CASE PRESENTATION

What is it? Thickening/hardening of skin, especially extremities and

trunk Dermal fibrosis with CD 34+ fibrocytes 2 to 18 months after gadolinium exposure

Clinical Findings Symmetrical, bilateral, indurated papules Possible erythema Lower legs and forearms, most commonly Systemic Symptoms

Fibrosis of lungs (ILD-like picture), myocardium, pericardium and pleura

Sclerodactyly, hyperpigmentation, epidermal atrophy Similar to scleroderma or scleromyxedema

NEPHROGENIC SYSTEMIC FIBROSIS

NSF PICTURES

NSF PICTURES

What causes it? Tissue deposition of gadolinium Activation of macrophages and fibroblasts Possible direct stimulation of bone marrow fibroblasts by

gadolinium

How do I diagnose it? Temporal relationship with gadolinium usage in CKD patient Punch biopsy of dermis Looking for CD34+ fibroblasts

NSF CONTINUED

Who should avoid gadolinium? Patients with eGFR < 30 mL/min, dialysis or AKI should

avoid gadolinium

What if I need to do use gadolinium anyway? Gadodiamide (Ominscan), Gadoversetamide (OptiMARK) and

Gadopentate (Magnevist) should be avoided Try Gadoteridol, Gadobutrol, Gadoterate Or ask your friendly radiologist!

If HD access present, would dialyze within hours and repeat in 24h

If no HD access? And eGFR < 15? Would initiate HD Otherwise, have a risk/benefit discussion about placing HD

access

NSF PREVENTION

You tell Neurology about the risk of NSF in this patient. The consult resident says, “Oh wow, you’re right! I forgot about that mini-lecture on the UCI website.”

“Let’s get a CTA of her head/neck in about one week to see if she had an ischemic stroke”

What should you be concerned about?

BACK TO OUR CASE

What is it? AKI induced within 24-48 hours after iodinated contrast

What causes it? Renal vasoconstriction Direct tubular cytotoxicity

How do you diagnose it? 60% patients oliguric with AKI symptoms (Hyper K and Ph,

Acidosis) FeNa generally < 1%, signaling pre-renal etiology UA = ATN picture (muddy brown casts, epithelial casts) Rule out other causes of AKI Consider renal biopsy (however, CIN generally resolves quickly)

CONTRAST INDUCED NEPHROPATHY

How do I prevent this? At Risk Pts: Cr > 1.5 mg/dL or eGFR < 60 mL/min

Utilize non-ionic, low or iso-osmolar agents (iopamidol) Ask your friendly radiologist!

Use minimal contrast and space out studies (> 48 hours)

Avoid nephrotoxic meds (NSAIDs) and hypovolemia

CIN CONTINUED

FLUIDS Saline vs. Bicarbonate vs. NAC (not well established)

Isotonic Saline 1 mL/kg for six to twelve hours prior and post procedure or 3 mL/kg one hour before and 1-1.5 ml/kg four to six after

Isotonic Bicarbonate (3 AMPs of bicarb into 850 mL of sterile water) 3 mL/kg one hour prior and 1 mL/kg six hours post procedure

N-acetylcysteine (controversial) 1200 mg PO BID the day before and day of procedure

CIN CONTINUED

How about hemodialysis/hemofi ltration? In patients with CKD Stage III to V, no benefit with

hemodialysis Also, no need to dialyze in patients who are HD-dependent

No studies support this

What do I do if my patient gets CIN? Supportive care, which is expected to resolve in 3-7 days

regardless of intervention

CIN CONTINUED

What should we do for our 55 y/o lady? If an ischemic stroke must be ruled out, need to discuss

with patient the risks/benefits of both studies

Remember: NSF: recommendation is post-gadolinium HD, requiring access CIN: recommendation is IV Fluids +/- NAC and supportive care

Initiate other risk-modifying treatments Lipid, Diabetes and HTN control

BACK TO THE CASE

NSF High-risk if eGFR < 30 mL/min, AKI or on dialysis Prevention = avoid types of gadolinium Along with post-gadolinium dialysis if access already

present Consider initiating HD if eGFR < 15 mL/min

CIN High risk if Cr > 1.5, eGFR < 60 mL/min or AKI Prevention = Fluids (Saline, Bicarbonate) and/or NAC Supportive care otherwise

SUMMARY