Dr.KevinMarnu USMLE

04/30/2026

USMLE 🇺🇸 STEP1- “Which Antibody Is Associated With an Increased Risk for Poor Renal Outcome?”..

A 58-year old patient with a history of mixed connective tissue disease presents to the dermatology clinic complaining of firm, indurated skin affecting the forearms and puffy fingers. The patient complains of the fingers turning white and blue in the cold with associated skin pain. A skin biopsy from the edge of a hyperpigmented plaque on the lateral forearm showed thickened collagen bundles within the reticular dermis and a perivascular and interstitial mononuclear cell infiltrate. The autoimmune panel was positive for ANA, U-1-RNP, and topoisomerase 1 antibodies.

Based on the history, clinical image, and biopsy results, which antibody is associated with an increased risk for poor renal outcome?

[A]. Centromere
[B]. Double-Stranded DNA 🧬(DsDNA)
[C]. Topoisomerase I (Scl-70)
[D]. RNA Polymerase III (RNA Pol III)

02/18/2026

02/12/2026

02/08/2026

01/19/2026

U$MLE 🇺🇸 $TEP 2CK :
THE CAUSE OF THIS PATIENT’S SADDLE NOSE 👃 DEFORMITY & KIDNEY MASS ?

Q : A 39 year old woman 👵 presents at the emergency with epistaxis, tracheal stenosis, and hypertension. She reports a 22-Ib weight loss over the past 4 months.
On physical examination she is noted to have a nasal bridge tenderness and a saddle nose 👃 deformity.
Urinalysis shows traces of proteinuria only, with no red blood 🩸 cells. Blood 🩸 work reveals a normal creatinine level, and positive C-ANCA. An abnormality on the abdominal CT prompts a renal biopsy, with the abnormal renal pathology as shown in the image below.

What Is the primary treatment for this condition?

[A] Chemotherapy
[B] Levofloxacin and Percutaneous drainage
[C] Radical Nepthrectomy
[D] Corticosteroids and Cyclophosphamide
[E] Immunoglobulins

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