78 y/o male with remote history of GI bleeding and IVC filter placement for treatment of previous DVT/PE presents with acute right leg swelling. Doppler notes recurrent DVT. What is the treatment?

Reevaluate the initial contraindication to anticoagulation and purpose for IVC filter placement, in this case GI bleeding, and determine whether the contraindication still exists or can be mitigated.   If the patient can be anticoagulated, he should be.  An IVC filter should not be viewed as an equivalent substitute to anticoagulation in the setting of acute VTE and is certainly not an “insurance policy” against subsequent PE.  Small thrombi are capable of passing through patent filters or through collaterals around obstructed filters; furthermore, direct thrombus extension can occur through the filter itself.


Source

Greer, J.  Wintrobe's Clinical Hematology.  12 ed.  2008.

Fedullo, P.  "Inferior vena cava filters"  Up to Date.  Jan 2012.

Nanda, S.  "Inferior Vena Cava Anomalies - A Common Cause of DVT and PE Commonly Not Diagnosed"  American Journal of the Medical Sciences.   May 2008.

How low can you go: Assuming intravascular volume is maintained and cardiovascular status is not impaired, oxygen delivery will be adeuate until the hematocrit falls below what percent?

10 percent.

At rest, oxygen delivery is normally four times oxygen consumption. There is an enormous reserve.


Source

Kleinman, S. "Massive blood transfusion" Up to Date. 2011 Jan.

Warfarin Failure: What are the treatment options if a patient develops a DVT while on warfarin?

If INR is subtherapeutic, less than 2.0, this is not a true warfarin failure.  Reinstitute heparin or LMWH until INR in target range.

If INR is therapeutic,  consider the following options 

• aim for a higher target INR, 3.0 - 4.0 
• switch to LMWH
• switch to Fondaparinux
• place an IVC filter, although this could serve as a nidus for subsequent thrombosis in the long run

Source

Cleveland Clinic Foundation Intensive Review of Internal Medicine.  2009.

At what hemoglobin concentration is a blood transfusion indicated in a hemodynamically stable, non-hemorrhaging patient?

Hgb < 7 g/dL

or < 8 g/dL if > 65 y/o or with history of cardiovascular or respiratory disease


Source

Kleinman, S. and May, A. "Indications for red cell transfusion in the adult"  Up to Date.  Sept 2010.

INR "too high to be measured". Patient on warfarin for a-fib and presently asymptomatic with no active bleeding or other bleeding risk factors. Treatment?

Hold warfarin.

Vitamin K 5 - 10 mg PO.

Monitor INR closely.

If INR were 5 - 9 (measurable, but high), omit 1 - 2 doses and resume warfarin at lower dose; OR omit 1 dose and give 1 - 2 mg of vitamin K PO before resuming lower dose.


Source

Winshall, J. and Lederman, R.  Tarascon Internal Medicine and Critical Care Pocketbook. 4th ed.

Which steroid is best for treating elevated intracranial pressure secondary to brain cancer/mets? Why?

Dexamethasone. It is the most lipid soluble of all the steroids and hence can cross the blood-brain barrier.


Source

Halfdanarson, T. et al. "Oncologic Emergencies: Diagnosis and Treatment" Mayo Clin Proc. 2006 June (LLSA Readings 2009)

What are the mechanims by which a cancer can compress the spinal cord?

1. Cancer metastasizes to a vertebral body which subsequently erodes and encroaches on the spinal cord (most common mechanism).
2. A cancer occupying the paraspinous space may enter the spinal canal through the intervertebral foramen and subsequently cause cord compression.
   
3. Cancer occurs directly at the spinal cord or meninges.
   

Source

Halfdanarson, T. et al. "Oncologic Emergencies: Diagnosis and Treatment" Mayo Clin Proc. 2006 June (LLSA Readings 2009)

A rare but don't-want-to-miss cause of pediatric extremity pain: acute lymphoblastic leukemia. What are some clinical clues?

• fever
• lymphadenopathy
• testicular enlargement
• mediastinal mass
• peripheral blood abnormalities: anemia and/or thrombocytopenia

Source

Horton, T. MD and Steuber, P. MD "Overview of the presentation and classification of acute lymphoblastic leukemia in children" Up to Date. 5 Feb 2008.

What's the optimal route to administer vitamin K for correcting excess anticoagulation after warfarin: PO, SC, IM or IV?

Depends on the situation.

The advantage of the IV route is that it reverses the INR the most quickly, however this route is associated with rare anaphylactic reactions. Despite this potential side effect, the American College of Chest Physicians recommends the IV route for treatment of serious or life-threatening bleeding secondary to use of vitamin K antagonists such as warfarin, where the advantage of quick reversal outweighs the risk. The risk can be mitigated by administering the medication slowly, not to exceed 1 mg/min.

The IM route is not recommended given potential for hematoma formation.

Given a 24 hour time frame to take effect, the PO route is more efficacious at reversing the INR than SC; and just as good as IV.

Bottom line: Use IV for super quick reversal; if stat reversal is not indicated, go with PO. Onset of action: oral = 6-10 hours, IV = 1-2 hours. Peak effect: oral = 24-48 hours, IV = 12-14 hours.

Source

Valentine, K. MD PhD and Hull, R. MBBS, MSc. "Correcting excess anticoagulation after warfarin" Up to Date. 14 August 2008.

Vitamin k1 (phytonadione): Drug information. Lexi-Comp

What are the indications and contraindications to platelet transfusion?

Alright, here's the case ... 46 y/o female s/p ventral hernia repair 1 week ago presents with swelling and slight discomfort below incision site that developed over the past several days. CT notes an underlying 2 x 2 cm fluid collection, likely hematoma. Labs notable for platelet count of 53,000; coags are normal. Is a platelet transfusion indicated?

Depends. If the hematoma is getting bigger suggesting ongoing bleeding then definitely; if not, one could probably do without and follow the patient closely.

Indications for platelet transfusion:

• active bleeding and platelets less than 100,000
  
• anticipated invasive procedure with potential for bleeding and platelets less than 50,000
  
• prophylaxis if platelets less than 10,000 or less than 20,000 with risk of bleeding secondary to dysfunctional platelets (uremia, aspirin)
  

Relative contraindications for platelet transfusion:

• TTP/HUS, HELLP, HIT. Primary treatment for a consumptive coagulopathy is to treat the underlying problem, not to transfuse platelets as they simply will be broken down and consumed. However, if the patient has marked thrombocytopenia, less than 20,000, or moderate thrombocytopenia, less than 50,000, and serious bleeding then platelet transfusion should be considered.

Source

Sabatine, M. MD. Pocket Medicine: The Massachusets General Hospital Handbook of Internal Medicine, 3rd ed. 2008.

Winshall, J. MD and Robert, L. MD. Tarascon Internal Medicine and Critical Care Pocketbook, 4th ed. 2007.

Should patients diagnosed with venous thromboembolism and history of brain cancer be treated with anticoagulation or IVC filter placement?

Depends. Anticoagulation can cause bleeding but IVC filters have their own inherent problems including filter thrombosis, postphlebitic syndrome and recurrent DVT/PE.

• For patients with brain tumors at increased risk of hemorrhage (ie metastases from melanoma, choriocarcinoma, thyroid carcinoma and renal cell carcinoma) an IVC filter is recommended.


• For brain tumors at decreased risk of hemorrhage, anticoagulate for 3 - 6 months, with exception of malignant glioma for which longer term anticoagulation is recommended. While LMWH is more costly, it is preferred over warfarin given decreased interaction with other drugs, convenience of not having to monitor the level of anticoagulation on a regular basis, and greater efficacy at reducing risk of recurrent thromboembolism without increasing risk of bleeding.

Source

Wen, P. MD and Hart, R. MD. "Anticoagulant and antiplatelet therapy in patients with brain tumors." Up to Date. 14 August 2008.

American Society of Clinical Oncology Guideline: Recommendations for Venous Thromboembolism Prophylaxis and Treatment in Patients with Cancer. 2007 Dec 1. J Clin Oncol 25: 5490-5505.