pocketziggy

It’s Been Over One Year…

pocketziggy — Sun, 31 Jul 2011 13:47:20 +0000

…since pocketziggy’s last post, but for a good reason. Preparing for Anatomic and Clinical Pathology board examinations has taken a toll on pocketziggy’s professional and personal life. Many apologies to our readers for the paucity of updates. However, let the mile marker read that pocketziggy has passed both the Anatomic and Clinical board examinations with flying colors (credential below). The posts will flow [more] freely from now on…

Filed under: Uncategorized

The Hageman Factor

pocketziggy — Mon, 08 Feb 2010 15:57:51 +0000

Aside from the New Orleans Saints winning Super Bowl XLIV, not much happened over the week-end, so here’s a mini-lesson. Contrary to the general rule of thumb that derangements involving clotting factors at “higher” levels in the clotting cascade cause a greater effect on coagulation, a deficiency in Factor XII (Hageman factor) does not result in hemorrhage or increased risk of hemorrahge. This zymogen activates to the serine protease Factor XIIa and is responsible for activating Factor XI and prekallikrein in the intrinsic coagulation pathway.

Filed under: Clinical Pathology Tagged: coagulation

Recombinant Factor VIIa

pocketziggy — Fri, 29 Jan 2010 16:03:34 +0000

I must say that intra-operative use of NovoSeven®RT has saved a few patients on my watch. The licensed indications include treatment of episodic bleeding in patients with congenital Factor VII deficiency, acquired hemophilia, or hemophilia A or B patients with Factor VIII or Factor IX inhibitors, as well as prevention of bleeding during surgical or invasive procedures involving these mentioned patient types. Dosage amount and frequency is variable based upon patient type and application. Please download the package insert below in .pdf format and note that this document, in its most current form, as well as those for several other product lines, is also freely available at Novo Nordisk for download.

NovoSeven®RT package insert as of 01/29/2010:
NovoSeven®RT

I would really like to hear of your experiences with this product, positive or negative.

Filed under: Clinical Pathology Tagged: blood bank, coagulation

Albumin Replacement

pocketziggy — Thu, 14 Jan 2010 22:35:01 +0000

A weary pathology resident was called one evening and was requested to calculate the dose of 25% human albumin for a 100 kilogram patient with ascites scheduled for a therapeutic tap. Her advice was to dose 1 gram of 25% albumin per kilogram body weight to support plasma oncotic pressure and avoid hypovolemic shock secondary to paracentesis. Since the 25% albumin is stocked in 50 mL bottles, eight bottles were released at 12.5 grams albumin per bottle. Typically, 5% albumin, which is oncotically equivalent volume for volume with plasma, is utilized primarily for volume expansion roughly equal to the amount infused, whereas hyperoncotic 25% albumin is typically utilized to correct oncotic deficits. Please download the package inserts below in .pdf format and note that these documents, in their most current form, as well as those for several other product lines, are also freely available at Talecris Biotherapeutics for download.

Plasbumin® package inserts as of 01/14/2010:
Plasbumin®-5
Plasbumin®-25

Please note that Plasbumin®-5 and Plasbumin®-25 are registered trademarks of Talecris Biotherapeutics, a provider of human albumin products and their package inserts, among many other things.

Posted in Clinical Pathology Tagged: blood bank

Hexosaminidase Testing

pocketziggy — Wed, 13 Jan 2010 17:22:12 +0000

Hexosaminidase heterodimeric isozyme A, along with cofactor GM2 Activator Protein, catalyzes the degradation of GM2 gangliosides, and is composed of subunits encoded by the HEXA and HEXB genes. Mutations involving HEXA are the main cause of Tay-Sachs disease. At my facility, we do not test in-house for this isozyme fraction, or for total hexosaminidase. The test is available as a send-out using whole blood or serum. Other hexosaminidase isozymes (B, S, and the cytosolic C and D) are not tested for routinely. Only hexosaminidase C, which is actually the bifunctional protein NCOAT encoded by MGEA5, posesses a known physiologic function, being linked to diabetes mellitus Type 2. By the way, mutations in both HEXA and HEXB result in deficiencies in both hexosaminidase A and B, clinically Sandhoff disease, a lipid storage otherwise disorder indistinguishable from Tay-Sachs disease. Make no mistake, though. Sandhoff is not the same entity as the Tay-Sachs AB variant. And while I am rambling on about Tay-Sachs variants, if the total hexosaminidase and hexosaminidase A tests are negative in the face of clinical Tay-Sachs disease, a second-order hexosaminidase A MUGS test is available as a send-out that identifies the presence of an alpha chain site defect responsible for the rare B1 variant of the disease. And that’s all I have to say about that.

Posted in Clinical Pathology Tagged: chemistry, rare disease

Transfusion Site Pain

pocketziggy — Sun, 10 Jan 2010 00:41:19 +0000

Pain at the transfusion site, when not associated with acute hemolytic transfusion reactions, is most commonly due to the release of bradykinin from venule endothelium, and it is also possibly potassium-related. Bradykinin is formed from the cleavage of high molecular weight kininogen (HMWK) by kallikrein in the kinin-kallikrein system, and is among a few other things a potent vasodilator and alterer of capillary permeability via its interactions with prostacyclin, nitric oxide and endothelium-derived hyperploarization factor (EDHF), which hyperpolarizes vascular smooth muscle to the point of relaxation. Bradykinin concentration is increased with the administration of ACE inhibitor medications, which prevent its degradation by ACE (a kininase enzyme); therefore, note should be taken of those ACE inhibitors with the shortest half-lives, if discontinuation of the drug class is contra-indicated: captopril (Capoten) has a half-life of 1.9 hours, while ramipril (Altace) has a half-life of 2-4 hours.

Posted in Clinical Pathology Tagged: blood bank

Happy Feet!

pocketziggy — Thu, 07 Jan 2010 00:04:55 +0000

Big news for us today! After review, pocketziggy has been added to the Medpedia News & Analysis – Medical Specialties channel at the Medpedia Project website. This means that you can read our posts directly from within the cozy comfiness that is The Medpedia Project, as well as right here on the blog. While you’re visiting us at Medpedia, please consider joining by creating an account.

Posted in Uncategorized

Asparaginase

pocketziggy — Thu, 10 Dec 2009 18:11:59 +0000

A 14 year old female with Trisomy 21 and a new diagnosis of Pre-B ALL is undergoing induction using a modified COG protocol, and is receiving asparaginase (Elspar) to deprive the leukemic cells of essential circulating asparagine. Asparaginase has several known adverse effects, including decreased synthesis of several coagulation and anticoagulation factors, including fibrinogen, antithrombin III and in some cases, proteins C and S.

Posted in Anatomic Pathology, Clinical Pathology Tagged: hematology, oncology

Protamine sulfate and LMWH

pocketziggy — Thu, 08 Oct 2009 17:46:04 +0000

Got a call from an intern covering our local Veteran’s Hospital regarding a male inpatient who had thoracentesis performed earlier in the day and now was bleeding into his thoracic cavity. He is on prophylactic enoxaparin and, per on-call Heme/Onc, should be receiving FFP, not protamine sulfate. Trust me, this is more history than we usually get. So this morning at Rounds we scratched our heads and wondered silently to ourselves, Hmm… is anticoagulation secondary to LMWH as reversible with protamine sulfate as is anticoagulation secondary to unfractionated heparin?

It turns out that reversal is achieved with protamine sulfate, but according to Hirsch et al., unlike its efficacy with unfractionated heparin, protamine does not completely abolish the anti-Xa activity of LMW heparins. However, for patients who experience bleeding while receiving LMW heparin, protamine sulfate (1 mg/100 anti-Xa units of LMW heparin) may reduce clinical bleeding, presumably by neutralizing the higher molecular weight fractions of heparin within the product, which are thought to be most responsible for this complication. Smaller doses are needed if the LMW heparin was injected more than 8 hours before the event requiring neutralization. Chest 2008; 133:141S.

It also turns out on-call Heme/Onc did recommend reversal with protamine sulfate (nothin’ but LOVE and RESPECT), but for many likely reasons, that information was relayed incorrectly.

Posted in Clinical Pathology

What Is Normal, Anyway?

pocketziggy — Sat, 25 Jul 2009 20:07:33 +0000

Once upon a midnight dreary, there was a pathology resident on call who was faced with evaluating a neonate for the purpose of providing FFP for a “high” INR without current bleeding. I thought a post with a couple of pre-Vitamin K normal coagulation study values and ranges would therefore be a worthy edition. Taken from a recent lecture I attended from Jed Gorlin, MD regarding current Pediatric Transfusion Guidelines.

INR (range)
- premature 3.0 (1.5-5.0)
- neonate 1.7 (0.9-2.7)
- adult 1.1 (0.8-1.2)

aPTT (range)
- premature 105 (76-128)
- neonate 44 (35-52)
- adult 33 (25-39)

Factor IX (range)
- premature 12.3 (5-24)
- neonate 32 (15-50)
- adult 105 (70-142)

That is all, but more from this lecture will be posted at a later date.

Posted in Clinical Pathology Tagged: blood bank, coagulation