DVT PoCUS: When?, Where?, How? and What to do next?

 

Dr. Kyle Traboulsee

EM Physician, PoCUS Fellow

Reviewed by Dr. David Lewis

Copyedited by Dr. Rawan Alrashed 

 


Background

Lower extremity deep vein thrombosis (DVT) is a common, and potentially life-threatening vascular condition, with an annual incidence of 1 per 1000 adults. If left untreated, it may progress to pulmonary embolism, which is associated with a higher mortality. Therefore, accurate and timely diagnosis and treatment are incredibly important. (1,2,3)

An initial approach to the diagnosis of DVT involves risk stratification, often with the clinical risk score “Well’s score”, in conjunction with D-dimer assays. Based on the associated pre-test probability of the above risk stratification, further imaging may be required.

Although the gold standard for the diagnosis of DVT has traditionally been contrast venography, Duplex ultrasonography has become the standard of care due (in large part) to its lack of radiation and intravenous contrast, as well as widespread availability. This elective scan evaluates from groin to ankle and can take upwards of 1 hour depending on the difficulty of the individual exam. Studies have shown that a simplified ultrasound technique, limited to proximal segments of the femoral and popliteal veins using compression alone has a high sensitivity and specificity for proximal DVT detection. (2,4)

Point of care ultrasound (POCUS) has been increasingly used by emergency room physicians to assess for proximal lower extremity DVTs, with studies finding comparable diagnostic accuracy to radiology or vascular lab-performed duplex ultrasonography for detection of proximal DVT. (2)

 

Anatomy

 

Figure 1: Veins of the lower extremity (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The venous anatomy of the lower limb is relatively simple. The most proximal vein of interest is the Common Femoral Vein (CFV), which gives off the great saphenous vein (a superficial branch). Distal to this, the Common Femoral Vein should bifurcate into the Deep Femoral Vein, and Femoral Vein.

 

       N.B: the Femoral Vein also known as the Superficial Femoral Vein, but because it is still considered a deep vein with respect to the diagnosis of deep vein thrombosis, it is usually referred to as simply the Femoral Vein.

 

As the femoral Vein travels distally, it enters the adductor canal, passing posterior to the knee, and becomes the popliteal vein. The popliteal vein gives rise to three deep veins at the level of the calf: the perineal vein, anterior tibial vein, and posterior tibial vein. (5)

 

DVT POCUS protocols

There are multiple POCUS protocols with respect to lower extremity DVT evaluation, ranging from a 2-point ultrasound scan to a whole leg protocol. The more commonly studied, and utilized, protocols in the emergency department are referred to as the 2-point compression study and 3-point compression study. (1,2,5)

(It should be noted that the “points” are regions being scanned, opposed to distinct, singular points).

 

Figure 2: DVT protocols (5)

 

 

2-point compression study

This study evaluates the:

  • common femoral vein
  • popliteal vein

The common femoral vein is evaluated from the inguinal ligament until it becomes the femoral vein, including the junction of the common femoral vein and greater saphenous vein (CFV-GSV). Ensure this scan includes at least 1-2cm above and below the CFV-GSV junction. (2)

The popliteal vein is assessed from the popliteal fossa until it trifurcates. (2)

 

3-point compression study

This technique evaluates the:

  • Common femoral vein
  • Femoral vein
  • Popliteal vein.

Like the “2-point” examination, the common femoral vein is evaluated from the inguinal ligament until it becomes the femoral vein (including the CFV-GSV junction). The femoral vein is then further evaluated at least 2 cm distal to the bifurcation of the femoral vein and deep femoral vein. Some variations on the 3-point protocol may suggest continued evaluation of the femoral vein distally as it transitions to the popliteal vein. (2,4,5)

 

PoCUS Technique (3-point compression technique)

The linear array is the probe of choice for this scan.

 

 Femoral Veins

 

  1. Position the patient by raising the head of the stretcher 30 degrees and placing the patient in reverse Trendelenburg (if able). This allows distension of the lower limb veins. Slightly flex the knee and externally rotate the hip. (4,5)
  2. Place the probe along the inguinal ligament in the transverse plane midway between the pubic symphysis and anterior superior iliac spine and identify the common femoral vein (CFV). The common femoral artery and vein should be side by side, with the artery lateral to the vein.
  3. Ensure that you are at the most proximal part by sliding the probe proximally towards the abdomen until the CFV become in the far field obscured by bowel gases (most proximal point) then slide the probe distally and  Apply firm pressure with the probe until the vein collapses completely, or the artery begins to collapse without full collapse of the vein (which could indicate a DVT). (4,5)

 

Fig 3: Common femoral vein (5)

CFA: Common femoral artery
CFV: Common femoral Vein (5)

CFV compression (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

4. After that slowly slide the probe distally, stopping every centimeter (or every width of the probe head), to compress the vein, ensuring it flattens completely. The end point of the scan is 1-2 cm distal to the bifurcation of the common femoral vein into the deep femoral vein and femoral vein. (4,5)

a. Within the first 1-2 cm, the great saphenous vein will branch off from the common femoral vein, usually medially and near field. Monitor the compressibility of both the common femoral vein, as well as the first 1-2 cm of the great saphenous vein.

 

Fig. 4: Branching of great saphenous vein (5)

CFA: common femoral artery
CFV: common femoral vein
SV: Great Saphenous Vein (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

b. The common femoral vein should bifurcate into the deep femoral vein, and femoral vein 1-2 cm distal to the CFV-GSV junction.  Ensure compressibility is assessed at least 1-2 cm distal to the bifurcation if the common femoral vein. Consider continuing to scan distally until the femoral vein becomes the popliteal vein or are no longer able to assess.

 

Fig.5: Femoral vein (5)

FA: Femoral Artery
FV: Femoral Vein (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Popliteal vein

  1. If the posterior aspect of the knee (popliteal fossa) can be easily accessed in the patient’s current position (i.e., hip externally rotated, knee slightly flexed), no further positioning changes are needed. Other options include having the patient turn to a lateral decubitus position, with the leg of interest above the other, or, have the patient sit on the side of the stretcher, with their legs dangling. (4,5)
  2. Place the probe into the posterior crease of the knee (popliteal fossa), in a transverse plane and scan 2 cm above and below to locate the popliteal vein. If the structure is not immediately identified, slide the probe slightly medially and laterally to attempt to locate it. The vein should be near field, and directly over, the popliteal artery. Once located, assess compressibility of the vessel (4,5)

 

Fig. 6: Popliteal Vein (5)

PA: Popliteal Artery
PV: Popliteal Vein (5)

Popliteal Vein compression (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

Continue scanning distally (assessing compressibility along the way), until the popliteal vein trifurcates into the anterior tibial, posterior tibial, and peroneal vein. This marks the end of the examination. (4,5)

 

Fig.7: Popliteal Vein trifurcation (5)

PA: Popliteal artery
V: Popliteal Vein Trifurcation (5)

 

 

 

 

 

 

 

 

 

 

 

 

 

Doppler flow augmentation

If the veins are difficult to identify or compress, color doppler can be applied. With the probe held stationary over the vessel in question, gently squeeze the calf distal to the probe. This should augment blood flow into the vein of interest and appear (briefly) as a brighter signal. If there is no increase in blood flow seen, a DVT could be present. (3,5)

Of note, normal venous flow will also change with the respiratory cycle. As the intrabdominal pressure increases with inspiration, venous return from the lower extremities will decrease, while with expiration, flow increases. This can be appreciated with spectral doppler. (3)

 

Positive Scan

Failure to completely collapse the vein (with enough pressure to partially compress the adjacent artery), at any level, is highly suggestive for the presence of a clot.

Depending on the chronicity of the clot, it may appear echogenic enough to directly visualize under ultrasound, but this is not always the case. (3,4,5)

 

Direct clot visualization (5)

Non-compressible popliteal vein (own image)

Doppler flow around a DVT, popliteal vein (own image)

 

The Evidence

A meta-analysis published in 2019, looked at 16 articles utilizing either 2-point compression or 3-point compression and found comparable sensitivities and specificities for proximal DVT, with no statistically significant difference (1):

 

2-point compression technique

Sensitivity 91%

Specificity 98%

 

3-point compression technique

Sensitivity 90%

Specificity 95%

 

Although there was no statistically significant difference between tests, many clinicians still recommend performing the 3-point compression, to include visualization of the femoral vein.

Other studies have quoted sensitivities ranging from 93% to as high as 100% (3).

It’s important to note that compression ultrasound alone is not accurate at picking up below-knee DVT. It is rare for below-knee DVT to progress to pulmonary embolism without first extending to an above-knee DVT. Therefore, although proximal DVT is of more clinical significance in the emergency department, a negative proximal PoCUS DVT scan should be followed by a repeat scan in 5-7 days to ensure a below-knee DVT was not missed. (3)

 

Pitfalls (false positives and negatives)

False negatives

  • Small, non-occlusive DVTs may near completely compress under applied probe pressure. Ensure complete vein occlusion when applying pressure during scan.
  • Excessive probe pressure. If enough pressure is applied to compress the adjacent artery, then a DVT may also be compressed.
  • A pelvic vein DVT may be missed either due to starting the scan to distally or being unable to compress the vein due to its location. Further imaging may be required if high clinical suspicion including venography, MRI, or extended ultrasound to include the iliac vessels and IVC (3,4).

 

False positives

  • Lymph nodes can appear as non-compressible vessels. If in doubt, rotating the probe in a longitudinal orientation will reveal the spherical nature of the lymph node.
  • Superficial thrombophlebitis. These non-compressible superficial veins may be mistaken for deep veins. The major difference is superficial veins should not accompany arteries.
  • Recanalized DVT. Old thrombi that have recanalized may not compress appropriately under probe pressure, but flow should be apparent on color doppler imaging. (3,4,5)

 

Approach to DVT Diagnosis/exclusion

One in three patients with untreated DVTs will progress to clinically significant pulmonary emboli, thus diagnosis and treatment of DVT is vitally important.

Although a positive scan is very helpful, a negative scan does not rule out a thrombus, specifically a below-knee DVT, which can propagate to an above-knee DVT, and eventually a PE given time.

Multiple diagnostic approaches have been described, incorporating the DVT PoCUS scan, well established risk stratification tools (Such as Well’s criteria), and repeat imaging. Below is one such approach, adapted from Mazzolai 2017. (5,6)

 

DVT diagnostic algorithm (5)

 

Bottom Line

DVT PoCUS is a (relatively) simple scan, that can be performed quickly and used to assess for proximal DVT. Its utility is well recognized, and it is considered one of the core ultrasound applications for emergency medicine physicians by the American College of Emergency Physicians.

When assessing for DVT, the PoCUS scan should be incorporated into a diagnostic algorithm along with other risk stratification tools, and due to its low sensitivity for below-knee DVT, repeat imaging in the context of a negative scan may be warranted.

 


References

  1. Lee, J. H., Lee, S. H., & Yun, S. J. (2019). Comparison of 2-point and 3-point point-of-care ultrasound techniques for deep vein thrombosis at the Emergency Department. Medicine, 98(22).
  2. Varrias, D., Palaiodimos, L., Balasubramanian, P., Barrera, C. A., Nauka, P., Melainis, A. A., Zamora, C., Zavras, P., Napolitano, M., Gulani, P., Ntaios, G., Faillace, R. T., & Galen, B. (2021). The use of point-of-care ultrasound (Pocus) in the diagnosis of deep vein thrombosis. Journal of Clinical Medicine, 10(17), 3903.
  3. Atkinson, P., Bowra, J., Harris, T., Jarman, B., & Lewis, D. (2019). Point-of-care ultrasound for Emergency Medicine and Resuscitation. Oxford University Press
  4. Socransky, S., & Wiss, R. (2016). Essentials of point-of-care ultrasound: The ede book. The EDE 2 Course, Inc.
  5. Dinh, V. (n.d.). DVT Ultrasound made easy: Step-by-step guide. POCUS 101. Retrieved November 26, 2021, from https://www.pocus101.com/dvt-ultrasound-made-easy-step-by-step-guide/.
  6. Mazzolai, L., Aboyans, V., Ageno, W., Agnelli, G., Alatri, A., Bauersachs, R., Brekelmans, M. P., Büller, H. R., Elias, A., Farge, D., Konstantinides, S., Palareti, G., Prandoni, P., Righini, M., Torbicki, A., Vlachopoulos, C., & Brodmann, M. (2017). Diagnosis and management of acute deep vein thrombosis: A joint consensus document from the European Society of cardiology working groups of aorta and peripheral vascular diseases and pulmonary circulation and right ventricular function. European Heart Journal, 39(47), 4208–4218.
  7. Deep vein thrombosis (DVT). ACEP Symbol. (n.d.). Retrieved November 29, 2021, from https://www.acep.org/sonoguide/basic/dvt/.

 

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Superficial can also be Deep – Superficial Thrombophlebitis

Superficial Thrombophlebitis – an approach to diagnosis and management

Resident Clinical Pearl (RCP) May 2020

Dr. Devon Webster – PGY2 FMEM Dalhousie University, Saint John NB

Reviewed by Dr. David Lewis

 


Case

Claude Virchow is a 59-year-old gentleman who presents to your emergency department complaining of pain to his medial right leg. 2 days ago, he bumped his knee and since then, has developed a hard, rope-like, tender swelling along the inside of his knee. On exam, you see the following image and he winces as you palpate along the indurated cord.

Figure 1 Source

In the next bed over, is a 39-year-old man presents with similar induration along his antecubital fossa bilaterally. He has a history of IVDU and was seen a week prior for the same problem. He is back as the indurated areas seem to be extending and his pain is worsening despite abstinence from injection and adherence to conservative measures. There are no signs of infection.

What are your recommendations?


 

What is superficial thrombophlebitis?

  • Thrombus formation in a superficial vein with associated inflammation of the vessel wall.
  • Typically involves the lower extremities with greater saphenous vein involvement in 60-80% of cases
  • Less commonly, affects the superficial veins of the upper extremities, neck (external jugular) or causes ‘Mondor’s syndrome,’ a superficial thrombophlebitis of the anterior chest wall.

 

Why does it matter?

  • In patients with superficial venous thrombosis (ST) >5cm in length, approximately 20% have a concomitant DVT and 4% have a PE
  • Some patients with ST may be candidates for anticoagulation

 

Anatomy review:

  • Lower extremity:
    • Superficial venous system: primarily comprised of the greater and lesser saphenous veins (aka long and short saphenous veins)
    • Deep venous system: anterior tibial, peroneal and femoral veins.
    • The saphenofemoral junction (SFJ) forms the connection between the deep and superficial systems.
  • Upper extremity:
    • Superficial: digital, metacarpal, cephalic, basilic and median veins
    • Deep: radial, ulnar, brachial, axillary, subclavian veins

Figure 2 Source


 

Figure 3 Source


 

Risk Factors:

  • The same as VTE! E.g. malignancy, trauma, hormone therapy, etc.
  • Varicose veins account for up to 90% of cases of lower limb ST and risk factors for varicose veins (e.g. lack of physical activity, venous stasis) increase the risk of ST.
  • Risk factors suggesting concomitant DVT when ST is also present: age >60, male sex, bilateral ST, presence of systemic infection, absence of varicose veins.
  • Mondor’s: often associated with breast reconstruction

 

History & Physical:

  • The patient may describe a painful, erythematous, swollen, hard vein that is tender to touch.
  • Inquire about symptoms and looks for signs suggestive of DVT, PE or secondary infection.
  • Low grade fever may be present in uncomplicated ST but higher fevers and erythema extending beyond the borders of the vein suggest suppurative ST.
  • Ask about risk factors as per VTE though may be idiopathic.
  • Note that a D-Dimer is not a helpful tool for distinguishing ST from DVT

 

Which patients with superficial thrombophlebitis require ultrasonography?  

  • Lower limb:
    • US recommended for MOST patients
    • If clinical picture is not obvious
    • If suspected concomitant DVT
    • ST is above the knee, especially if above mid-thigh
    • ST is in the upper calf near perforating veins in the popliteal fossa
  • Upper limbs:
    • Patients with ST of veins approaching the deep venous system (basilic, cephalic veins) that do not respond to conservative measures or have progression of their symptoms should undergo duplex US to evaluate for clot extension.
  • Mondor’s (anterior chest): US rarely required

 

Key points on ultrasound report:

  • For lower extremities, assess proximity to the saphenofemoral junction (SFJ) and the length of the ST. Specifically determine if ST is >5cm in length or if <3cm proximity to the SFJ.
  • Rule out DVT
  • Rule out other causes of pain (e.g. popliteal cyst, muscle mass)

 

Treatment:

  • General measures:
    • Non-pharmacologic
      • Elevate extremity
      • Apply continuous, moist heat x72 hrs
      • Remove any offending solution or catheter
      • Encourage early mobility
    • Pharmacologic
      • Tylenol, NSAIDs
      • Topical NSAIDs
      • Do not give antibiotics unless signs of infection.
  • Upper extremity ST
    • Anticoagulation?
      • Limited data to guide management!
      • Some experts would suggest consideration of anticoagulation for patients with ST that are at risk for DVT (e.g. ST in veins in close proximity to deep veins).
      • May consider anticoagulation for pts with persistent symptoms despite conservative mgmt. (e.g. ongoing excessive pain and swelling) as anticoagulation is effective in alleviating symptoms, especially if ST precipitated by malignancy.
      • However, when considering treatment, important to note that PE from upper extremity ST is rare!

 

  • Mondor’s (chest well) ST
    • Self-limited. Conservative management.

 

  • Lower limb ST (see algorithm below):
    • ST within 3 cm of saphenofemoral junction: therapeutic dose of anticoagulation for 3 months
      • g.: rivaroxaban 15mg PO BID x3 weeks, followed by 20 mg OD, warfarin, full dose LMWH
    • ST >/5cm in length but >3 cm from saphenofemoral junction: prophylactic doses of anticoagulation
      • g.: rivaroxaban 10mg PO OD, dalteparin 5,000U SC q24hrs
    • ST <5cm, >3 cm from saphenofemoral junction but with severe symptoms or risk factors for extension: prophylactic doses of anticoagulant for up to 45 days
    • ST <5cm, >3cm from saphenofemoral junction, no severe symptoms or risk factors: conservative treatment

Figure 4 Approach to lower limb superficial thrombophlebitis. Source: Thrombosis Canada

 


 

Disposition & Prognosis:

  • Patients with extensive or recurrent ST should be referred to a specialist
  • Isolated lower limb uncomplicated ST not affecting the great or small saphenous veins and no risk factors for DVT: organize repeat clinical examination in 7-10 days to assess for resolution or progression. If symptoms or exam worsens, order ultrasound.
  • Resolution of ST may take up to 2-6 weeks.

 

Bottom Lines:

  • Superficial thrombophlebitis may be associated with DVT in up to 20% of cases and PE in up to 4%.
  • Ultrasound should be organized for most patients with lower limb ST and for some patients with upper extremity ST (progressive symptoms and concern for extension to deep venous system)
  • Patients with lower limb ST within 3 cm of the saphenofemoral junction should be treated with full dose anticoagulants. Those with ST >5 cm in length but farther from the SFJ, with severe symptoms or at high risk for clot extension should be treated with lower doses of anticoagulant.
  • Consider anticoagulants for patients with upper extremity ST with severe persistent symptoms not responding to conservative measures to alleviate their discomfort.
  • Patients with uncomplicated lower limb ST should have follow up organized within 7-10 days.

 

References:

  1. Chopra, V. Uptodate. Catheter-related upper extremity venous thrombosis [internet]. 2019 Nov 14. Available from: https://www.uptodate.com/contents/catheter-related-upper-extremity-venous-thrombosis?search=Catheter%20related%20upper%20extremity%20venous%20thrombosis&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
  2. Scovell, S. Uptodate. Phlebitis and thrombosis of the superficial lower extremity veins [internet]. 2019 Oct 3. Available from: https://www.uptodate.com/contents/phlebitis-and-thrombosis-of-the-superficial-lower-extremity-veins?search=Phlebitis%20and%20thrombosis%20of%20the%20superficial%20lower%20extremity%20veins&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
  3. Thrombosis Canada. Superficial Thrombophlebitis, Superficial Vein Thrombosis [internet]. 2019 Mar 25. Available from: https://thrombosiscanada.ca/clinicalguides/?search=superficial%20thrombophlebitis#
  4. Thrombosis Canada. Deep Vein Thrombosis (DVT): Treatment [internet]. 2016 May 19. Available from: http://thrombosiscanada.ca/wp-content/uploads/2016/05/3_Deep-Vein-Thrombosis-Treatment-2016May19-FINAL.pdf
  5. Mustonen, P. EBM Guidelines. Superficial venous thrombophlebitis [internet]. 2020 Mar 16. Available from: https://www.ebm-guidelines.com/ebmg/ltk.free?p_artikkeli=ebm00920
  6. Venes, D. Taber’s Medical Dictionary. Phlebitis [Internet]. Available from: https://www.tabers.com/tabersonline/view/Tabers-Dictionary/749144/all/phlebitis.
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EM Reflections – November 2019

Thanks to Dr Paul Page for leading the discussions this month

Edited by Dr David Lewis 


Discussion Topics

  1. Popliteal Artery Thrombus

    • Closed loop communication is key to avoid possible poor outcomes with follow up
    • Relying on other specialties to arrange follow up with ED patients can result in error. Direct contact with specialty to arrange urgent follow up is the best approach
    • Also make sure patient is aware of plan
  1. Vertebral Artery Dissection / Thrombus

    • A thorough neurological exam and documentation is essential for vertigo presentation
    • Can’t walk, Can’t go home
  2. Elderly Delirium / Dementia with Sepsis

    • Majority of delirious patients are quiet and withdrawn, not hyperactive
    • For patients with dementia , get baseline functioning from family if possible

Popliteal Artery Thrombus

The full differential diagnosis should be considered in possible cases of DVT including Baker’s cyst, cellulitis, lymphedema, chronic venous insufficiency, superficial thrombophlebitis, popliteal venous or arterial aneurysm, peripheral vascular disease, enlarged lymph nodes compressing the veins, heterotopic ossification, hematoma, and muscle tears.

 

Ultrasound for Lower Extremity Deep Venous Thrombosis
Multidisciplinary Recommendations From the Society of Radiologists in Ultrasound Consensus Conference

It’s Not All Deep Vein Thrombosis: Sonography of the Painful Lower Extremity With Multimodality Correlation

 

Consultations and Referals

One of the most common ways for doctors to collaborate is through referral and consultation. Poor communication between referring physicians and consultants can lead to disruptions in care, delayed diagnoses, unnecessary testing, iatrogenic complications, and frustrated physicians and patients. Improving the referral-consultation process is one of the most effective ways of providing safer care and reducing the risk of medical-legal difficulties.

  • What is the question I want answered?
  • Who has the specialized knowledge and skill to answer it?
  • How urgent is the clinical situation?
  • Do I need advice from the consultant or would a transfer of care to the consultant be more appropriate in the specific circumstances?
  • Have all the appropriate steps been taken to this point?
  • Has the patient consented to the referral?

CMPA Guidance on Referrals

 

 


Vertebral Artery Dissection / Thrombus

See these SJRHEM Reflections post on the same subject:

EM Reflections – March 2017

EM Reflections – May 2019

 

and this post on the HINTS exam:

HINTS exam in Acute Vestibular Syndrome

 

 

 

 


Elderly Delirium / Dementia with Sepsis

The fluctuating presentation of delirium makes it difficult to recognize but we should be attentive to certain hallmarks, including alterations in attention and awareness and acute changes in cognition.  These can be associated with hallucinations or other perceptual disturbances.  Collateral information and family input can be critical in detecting changes from baseline function and cognition.  The more acute temporal course of delirium is important to distinguish from underlying dementia, which is itself one of the most important risk factors for delirium.  The most common presentation, the hypoactive form, is a quiet, subdued, withdrawn state.

The Seriousness of Deliriousness: Delirium in the ED

 

See this SJRHEM Rounds

ED Rounds – Delirium in the ED

 

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EM Reflections – May 2017

Thanks to Dr Paul Page for his summary

Edited by Dr David Lewis

 

Top tips from this month’s rounds:

  1. DVT – Anticoagulation Bridging… when is it needed?
  2. Anticoagulated elderly patient with minor trauma. Can we rely on a recent INR?
  3. Abdominal pain in an elderly patient. Does a nonspecific exam and normal vitals exclude serious illness?

 


DVT – Anticoagulation Bridging… when is it needed?

Consider the type of anticoagulation best suited for your patient. Remember warfarin needs bridging until therapeutic INR is achieved.  Ensure that patients discharged after hours have a robust plan for follow up and enough supply until follow up occurs.

Outpatient Management of Anticoagulation Therapy – American Family Physician 2013

 

For Warfarin therapy in DVT, Thrombosis Canada recommends:

Full-dose low molecular weight heparin (LMWH) overlapping with warfarin for at least 5 days and until the INR is at least 2.0 for at least 2 days.

 

Bridging is not required when prescribing a Direct Oral Anticoagulant (DOAC) e.g Apixaban or Rivaroxaban.

 

Thrombosis Canada tool to support decision making for Anticoagulation therapy in DVT

Management of DVT:

General measures:
Unless compression ultrasound (CUS) is rapidly available, patients with moderate-to-high suspicion of DVT (except those with a high risk of bleeding) should start anticoagulant therapy before the diagnosis is confirmed.  Imaging confirmation should be obtained as soon as possible.
Outpatient management is preferred over hospital-based treatment unless there is an additional indication for hospitalization.
Initial treatment should have an immediate anticoagulant effect. Therefore, warfarin monotherapy is not appropriate initially.

Treatment Regimens:

Depending on the clinical presentation, one of following regimens should be used for the initial 3 months:

  • Full-dose low molecular weight heparin (LMWH) overlapping with warfarin for at least 5 days and until the INR is at least 2.0 for at least 2 days.
  • Full-dose IV heparin overlapping with warfarin for at least 5 days and until the INR is at least 2.0 for at least 2 days.
  • Apixaban 10 mg PO BID for 1 week before reducing dose to 5 mg PO BID.
  • Rivaroxaban 15 mg PO BID for 3 weeks before reducing dose to 20 mg PO once daily.
  • Full-dose SC LMWH or IV heparin for at least 5-10 days before switching to dabigatran 150 mg PO BID or to edoxaban 60 mg PO once daily.
  • Full-dose LMWH alone without switching to an oral anticoagulant.
  • Full-dose LMWH for the 1st month or so before switching to a DOAC or warfarin.

 


Anticoagulated elderly patient with minor trauma. Can we rely on a recent INR?

 

Elderly patients on warfarin presenting with minor trauma are commonly seen in the ED.  Many will have been on warfarin for a prolonged period and will have stable INRs. However we can not rely on a previous INR level when assessing the current presentation. Consider the following rational:

  • Why did the patient fall?
  • Do they have a concomitant illness?
  • Are they compliant with their medication?
  • Have they been prescribed or are you considering prescribing new medication that may interact with warfarin?

Clinically Significant Drug Interactions

Anticoagulated patients frequently re-attend the ED with complications of bleeding after discharge following minor injury e.g enlarging hematoma, blood soaked dressings, missed internal bleeding, mobility failure. Consider whether admission for observation may be more appropriate than discharge in this group of patients. For those discharge ensure that they have close support and clear advice on when to return.

Practical tips for warfarin dosing and monitoring – Cleveland Clinic Journal

 

See this recent Medical Student Pearl on Reversal of Anticoagulation in the ED

Reversal of Anticoagulation in the Emergency Department

 


 

Abdominal pain in an elderly patient. Does a nonspecific exam and normal vitals exclude serious illness?

Elderly patients presenting to the ED with acute abdominal pain should be considered extremely high risk. Published series have reported mortality rates approaching 10% (https://www.ncbi.nlm.nih.gov/pubmed/7091511)

Presentations can be delayed, physical exam can be innocuous, lab results can be misleading. The risk of serious pathology is much greater and the outcome of delayed diagnosis can be significant.

Abdominal emergencies in the geriatric patient – Int J Emerg Med. 2014; 7: 43.

 

 

An excellent post from ALIEM – 10 Tips for Approaching Abdominal Pain in the Elderly

After seeing your fifth young patient of the day with chronic pelvic pain, constipation, and irritable bowel syndrome, it is easy to be lulled into the mindset that abdominal pain is nothing to worry about. Not so with the elderly. These 10 tips will help focus your approach to atraumatic abdominal pain in older adults and explain why presentations are frequently subtle and diagnoses challenging.

 

Erect CXR – Abdominal Series – Free air under diaphragm in perforated bowel

 

Bottom Line –

Elderly patients with abdominal pain are at a much greater risk of serious pathology and require an extremely thorough assessment before (if ever) discharging with a rule-out diagnosis e.g constipation, gastro, abdo pain NYD etc.

 

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