In “Nate’s method”… what is the diagnosis?

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Nate Hellman, the founder of this blog, was a personal friend. We trained together as MGH Renal Fellows. It has been three years since his passing. I often wonder how much he would have achieved by now. For sure, he would be on staff at Mass General and on faculty at Harvard Medical School. He would be well immersed in setting up his independent research career. He would be the caring doctor we all knew him to be. And most certainly, he would be writing this blog. Those of us who knew him personally, know that Nate had the ability to write and release his brilliant thoughts to the world with little worry or inhibition, one of many traits I always admired in him. I think it came from his wonderful ability to laugh at himself and remain honest and real, no matter what. I have decided to start blogging, in an effort to remind myself, all of us here at MGH and all of you out there of “Nate’s method.” At least, I intend to try…
Here is the unknown case that was presented to me at the MGH Renal Grand Rounds this past Tuesday. One of our Renal Fellows, Dr. Jie Cui, presented the case, and will be blogging on her own thoughts on PAN soon (I have inside information here!):
HPI: 41 yo M with no PMH was admitted with acute onset pain radiating to his R groin, 10/10, sharp and persistent. In the ER, he was found to have BP 188/116, mildly elevated Cr to 1.3, and elevated LDH 520. His CT showed bilateral renal infarcts and renal artery clot.
Home Medication: None
Physical Exam: Vital Signs: T 98 HR 76 BP 120/90 GEN: Well appearing man in NAD HEENT: MMM, oropharynx clear; PERRL. Cards: NSR, RRR, normal S1, S2, no murmur/gallops/rubs Chest: CTA B/L, no wheezing/rales/rhonchi Abd: Soft/ND, + BS, RLQ (+) tenderness, no rebound/guarding, no bruits Back: no CVA tenderness Ext: normal tone, no edema, 5/5 muscle strength, no joint tenderness or deformities Skin: no rash Results: NA 135, K 3.7, CL 101, CO2 23, BUN 10, CRE 1.42, EGFR 55, GLU 80
CA 8.8, MG 2.3, TBILI 0.5, TP 6.9, ALB 3.5, GLOB 3.4, LDH 363 CRP 11.8
FE 33, TIBC 194, TIBC 161
WBC 9.84, RBC 3.98, HGB 12.7, HCT 36.1, MCV 90.7, MCH 31.9, MCHC 35.2, PLT 226
PT 14.5, PT-INR 1.1, PTT 59.0, Hypercoagulable work up (-) antiphospholipid antibodies (-), homocysteine (-)
ANA (-), ANCA (-), C3, C4 normal, Cryo (-),hepatitis (-), HIV (-), Urine protein/cr: 0.12, 24 hour urine creatinine clearance: 54ml/min Urine sediment: 1-2 WBC, 1-2 normal RBCs, no casts. All Cultures were negative.
CT abdomen and pelvis: 1. Bilateral renal artery clot 2. There is a focal, geographic area of decreased perfusion involving the upper pole of the right kidney. 3. A focal area of cortical volume loss and decreased enhancement in the left kidney is also noted, suggestive of scarring.
Questions for the discussant: 1. What is the differential diagnosis? 2. What diagnostic procedure would you perform? We discussed the following differential: The differential of acute flank pain is: Renal calculus – but no evidence on CT Pyelonephritis – but cultures were negative Other abdominal pathology as source of the pain – pancreatitis, cholecystitis – but no evidence on CT Renal Infarct – yes, there is evidence for this on CT This brings us to the differential for renal infarct: Thromboembolic – from heart or aorta – but echocardiogram, including transesophageal echo with bubble study were negative, also cultures remained negative at all times In situ thrombosis – no clear evidence for this Renal artery occlusion from aortic dissection – no evidence for this on CT Spontaneous or iatrogenic renal artery dissection – no evidence for this on CT Fibromuscular dysplasia – no evidence for this based on history (no h/o HTN for example) Segmental arterial mediolysis – possible, but again not supported by the CT Complication of anti-phospholopid syndrome – but entire hypercoagulability panel was negative Cocaine use – this could easily be the cause of this bilateral renal artery thrombosis, the patient continued to deny cocaine use, but this was strongly suspected, urine tox studies were apparently negative, but timing may have been the issue there…Polyarteritis nodosa – interesting and also likely, the patient is HBV negative, but could be “idiopathic” PAN. Given the above differential, a renal angiogram was performed which was read as consistent with medium vessel vasculitis, suggestive of PAN. The patient was treated with steroids and cytoxan and is presently doing well, with creatinine stable in the 1.4 range and no new symptoms. Still, we were left a bit dissatisfied with this outcome, as the diagnosis of PAN is not consistent with bilateral renal artery clot, which was clearly seen on CT in this patient. I am still worried about cocaine use or another etiology… Please comment and let us know your thoughts!


  1. Hi Jamie!
    Good to hear from you!
    Both the bilateral nature and the large vessels involved do not fit great, but the angiogram of the mesenteric arteries was a bit more telling…

  2. Ptt is sl. long. You state hypercoag w/u was negative. I assume this included a drvvt?

  3. Hi Anna- great to see you posting on here. Is it the bilateral nature of the clots that you feel is not consistent with PAN? Or the fact that the clots appear to be in the main renal arteries (large vessels)?

  4. Yes, there were findings consistent with PAN ("beads on a string") in the mesenteric arteries as well.

  5. Was there any other areas consistent with PAN on the arteriography? Did IR shoot of the other arteries in the abdomen (i.e, celiac, SMA, IMA)?

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