ZSFG Pearls 7/29: BUN, Schwannomas, pressors through PIVs

Thanks to Evie who presented a case of a 40W w/ h/o breast cancer, who came in with maroon stool and was found to have a pelvic schwannoma potentially with fistulization to small bowel.

Pearls from Dr. Cello:

  • On formed stool: If you see formed stool coated in blood, the lesion is likely coming from the sigmoid or distal to it as stool becomes fully formed in sigmoid
  • On BUN: It is virtually impossible for folks to have a normal BUN and be bleeding from an upper GI bleed.
  • On oral contrast: GIVE IT. It tastes like water, and Dr. Cello loves it.
    • You can see “entire sweep of duodenum,” jejunum, part of colon, pancreas with 500cc’s of oral contrast/Gastrografin. Oral contrast also distends the bowel and helps differentiate pancreas/retroperitoneal organs from everything else.
    • Wait 30mins after admin of Gastrografin (by 45mins, oral contrast gets to IC valve), then do IV contrast for info on perfusion.


A few words on Schwannomas:

  • They are benign neurogenic tumors originating in Schwann cells of the nerve sheath
  • Histologically (See slide below), typical schwannomas are composed of intermixed Antoni A (compact cellular regions, arranged in short bundles or interlacing fascicles; right side of slide) and Antoni B components (loose and hypocellular regions with more myxoid or edematous components; left side of slide)
  • Sporadic schwannomas affect patients of all ages, reaching a peak between 20 and 50, with no predilection to either sex or any race
  • Many schwannomas are discovered incidentally as solitary tumors on flexor surfaces in middle-aged people
  • They generally occur in the head and neck and extremities but rarely in the pelvis/RP
  • Retroperitoneal and pelvic schwannomas typically form large, well-circumscribed masses in the RP/pre-sacral area and frequently undergo cystic degeneration
  • With few exceptions, schwannomas do not transform to malignancy
  • On CT, schwannomas are hypodense to muscle, and they enhance with contrast
  • Treatment is usually focused most on pain control; the proportion of patients with symptoms and signs necessitating surgical removal is ~50%


We also discussed running pressors peripherally vs centrally:

  • 1 RCT (Richard et al. 2013, see below) involved patients who were randomized to either peripheral or central access in three French ICU’s
    • The study was analyzed by intention-to-treat, meaning if the pts in the peripheral group got central access, the complications were still assigned to the peripheral group
    • While the results listed less major complications with central rather than peripheral access, majority of the complications in the PIV group were actually the inability to insert a PIV
    • Additionally, the authors did not report details of the location of the catheters, the nature of the vasopressor, and the duration of infusion
    • 19 pts in the PIV group had a major complication of extravasation, requiring only observation and conservative management
  • 1 systematic review (Loubani 2015) found only observational reports of complications of pressors through PIVs
    • There were 204 local tissue injury events from vasopressor infusion from PIVs, but most (85.3%) of the complications occurred from PIVs distal to the antecubital or popliteal fossae and infusions running >4 hours (96.8%).
    • Only one event was identified where local tissue injury occurred with infusion of vasopressor via PIV from <1 hour, and it involved an infusion of phenylephrine of unspecified dose via left leg saphenous vein
    • This review was mainly from case reports and case series re: tissue injury or extravasation from vasopressor administration via peripheral IVs; further study is definitely warranted to clarify the safety of vasopressor administration via PIVs
    • Possible to conclude that in critically ill patients, with hemodynamic instability, vasopressor infusion through a proximal PIV (antecubital fossa or external jugular vein), for <4hours is unlikely to result in tissue injury and will reduce the time it takes to achieve hemodynamic stability



  • Richard et al. Central or Peripheral Catheters for Initial Venous Access of ICU Patients: A Randomized Controlled Trial. Crit Care Med. 2013 Sep;41(9):2108-15. doi: 10.1097/CCM.0b013e31828a42c5.
  • Loubani OM et al. A systematic review of extravasation and local tissue injury from administration of vasopressors through peripheral intravenous catheters and central venous catheters. J Crit Care 2015; 30 (3): 653.e9 – 653.e17. PMID: 25669592
  • Takaaki Nakashima, Daisuke Tsurumaru, Yusuke Nishimuta, Mitsutoshi Miyasaka, Akihiro Nishie, and Hiroshi Honda, “A Case of Pelvic Schwannoma Presenting Prominent Eggshell-Like Calcification,” Case Reports in Radiology, vol. 2013, Article ID 825078, 4 pages, 2013. doi:10.1155/2013/825078
  • http://www.emdocs.net/tag/vasopressors/



Evernote link: https://www.evernote.com/shard/s354/sh/6fe640b2-2e3d-4891-95f1-16a48c569fdd/ea2d4c5f950bb2ca1c8c7f3dd716edbc


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