Module 5: Acute Venous pathophysiology Flashcards
What is a D-Dimer Positive?
Blood test that detects a certain protein in the presence of some sort of blood clot.
DVT occurs in about how many Canadians each year?
200,000
Pulmonary embolism is the leading cause of what death associated with which demographic of patients?
Maternal women with child birth
A women’s risk of developing Venous thromboembolism (VTE) is how much greater if pregnant?
Six times
Pulmonary embolism causes more deaths annually in North America than what? 3
- Breast cancer
- AIDs
- Highway fatalities
Fetal Pulmonary embolism may be the most common preventative cause of ________ in ____________?
Hospital death in North America
Approximately how many patients are hospitalized each year for DVT in Canada each year?
60,000
What is the most common reason we scan extremity veins?
DVT
How much DVT is clinically diagnosed diagnose?
50%
What are some complications of DVT? 2
- Pulmonary embolism
- Chronic venous insufficiency (CVI)
How much pulmonary embolism originate in LE?
80%
If untreated what is the mortality rate of pulmonary embolism?
30%
Venous diseases can be what two things?
acute or chronic
Venous disease can effect what systems?
Both deep or superficial systems
The venous system can also be effected by what?
Non- venous pathologies
What are some underlying risk factors DVTs? 2
- Genetics
- Acquired - more common
What are some genetic factors for DVTs? 4
- Gender
- Race
- Antithrombin deficiency
- Fact V Leiden mutation
Acquired factors can be categorized into what system?
Virchow’s Triad
What is Virchow’s Triad?
- Stasis
- Injury
- Hypercoagulability
What is the most common factor for LE DVT?
Venous stasis
What are some reasons for Venous stasis? 5
- Immobility
- Congestive heart failure
- Obesity
- Pregnancy (vein compression L>R)
- Surgery (leg or hip example)
How would we get DVT from injuries?
Trauma to vessels, Like infection or HTN
What is the most common factor for UE DVT?
Central lines like peripherally inserted central catheter (PICC)
What is hypercoagulability?
The clotting ability of blood is increased
What are some reasons for Hypercoagulability? 4
- Pregnancy
- Cancer
- Estrogen intake (BCP, HRT)
- Genetic blood factors
What are some questions we ask for patient history for DVT? 5
- Previous DVT or family history
- Trauma?
- Surgery?
- Bed rest > 4 days
- Medications (BCP/HRT)
What is the difference between signs and symptoms?
Symptoms are patient recorded and signs are things we can see
Symptom could be something like pain, we can’t see pain
What are some common acute signs of onset for DVT? 5
- Pain
- Swelling (edema)
- Redness/ erythema
- Skin warm/ hot to touch
- Persistent pain (positive Homans sign)
What are some Symptoms of Pulmonary embolism? 4
- SOB
- Chest pain
- Hemoptysis
- Increased heart rate/ respiratory rate
C his
What are less common signs and symptoms for DVT? 6
- Ulceration (gaiter area, medical malleoulus) , shallow and round
- Discoloration in the gaiter area
- Varicose veins
- Pallor (phegmasia alba dolens) or getting white
- Cyanosis (phlegmasia cerulea dolens) or getting blue
- Positive D-timer test result
C pup VD
D-dimer test looks for what?
The presence of breakdown products of linked fibrin
D-dimers are very how sensitive to clots, and is it specific to DVTs?
Very sensitive 95%, but not specific to DVTs
For DVTs false positives occur due to what? 6
- Trauma
- Surgeries
- Pregnancy
- Malignancy
- Liver disease
- Kidney disease
PMS TLK
If there is a negative D-dimer test how likely is a DVT?
Unlikely
What is Well’s score?
Clinical assessment that estimates the DVT probabilities
What is the reported scores for Well’s score?
Low - 0
Intermediate - 1 or 2
High - 3
How is the Well’s score used for PE? 2
- Clinical assessment
- Positive criterion is a given number value
What is the PE well’s scoring system?
Low probability (<2)
Intermediate (2 to 6)
High (>6)
For thrombus formation where does it usually begin?
Soleal calf veins or the valve cusps due to stasis
What is thrombus formation?
- Red blood cells aggregate and cause fibrin formation and adheres to vessels walls
this induces further thrombosis which propagates along the vessel lumen
Acute stage of thrombus formation is within what time frame?
First 14 days after thrombus forms
What are other sites for thrombus? 5
- Muscular veins (gastrocnemius or soleal sinus)
- Valves sites
- Venous confluence
- Perforators
- Deep venous system or superficial system
Vm Vpd
What is the most common site for Calf vein DVT?
Soleal sinus
What is the current approaches to treatment for DVT? 2
- Surveillance with duplex US to check for propagation to larger veins
- Therapeutic anticoagulation for 6 weeks
Between a fem pop DVT and a calf DVT which is more serious? why?
Fem- pop DVT because of the higher risk of PE
For fem-pop DVTs what initial test is performed?
Duplex sonography initial test
What is the most common treatment for Fem-Pop DVT?
Anticoagulation therapy
Imaging the Iliac veins can be challenging and success is dependent on what?
Patients body habitus
For Iliac DVTs doppler signals can give what? ( Information given)
Indirect information
For iliac DVT we should compare what things and assess what?
We should compare bilateral CFV waveforms and assess the IVC
How do we confirm Iliac DVT?
Venography
What are UE DVTs a result of?
Central venous catheters
Besides Central venous catheters, what can UE DVT be a result of? 3
- Mediastinal lymphoma
- Previous radiation therapy
- Trauma or surgery to the area
When can an acute DVT be first seen?
First 14 days
Acute thrombus can look how?
Anechoic to hypoechoic and enlarges the vessel slightly
There will be incomplete compression of the lumen with the transducer
For a sub-acute DVT when would it present and what would it look like?
1 to 2 months old and can be slightly more echogenic and retracts in size
When the DVT is distal to where you scan the waveform can show what?
Reduced or absent augment
Collateralization is another sign of what?
DVT
Collaterals are what?
Accessory vessels that reroute flow around an obstruction.
Collaterals may occur rapidly in the presence of what?
DVT and may be readily seen
What are some Rare DVT conditions? 4
- May-Thurber syndrome
- Pages- Schreotter syndrome
- Phlegmasia Alba Dolens
- Phlegmasia cerulean dolens
What a some rare conditions of DVT?
- May- Thurner syndrome
- Page- Schroetter Syndrome
- Phlegmasia Alba Dolens
- Phlegmasia Cerulean Dolens
What is another name for May- Thurber Sydrome?
Iliac vein compression syndrome
What is May-Thurner syndrome?
Result of an anatomical variant of an overriding RT CIA compressing the LT CIV against the 5th Lumbar vertebra
Who is the most common demographic for May-Thurber syndrome?
Young females in their 20s to 40s
How does May-Thurner syndrome present like?
Left leg pain and swelling
What is the most common demographic for May-Thurner Syndrome?
Young females in their 20s and 40s
How do we diagnose May- Thurner Syndrome?
Venography with pressure measurements is the gold standard for diagnosis
What may we see during May-Thurner syndrome at the vein site in terms of flow pattern?
May see a narrowing with a jet at the site of the stenosis or a continuous flow pattern distal
What is another name for Paget- Schroetter Syndrome?
Spontaneous effort Thrombosis
Where is Paget-Schroetter syndrome most commonly seen?
Axillio- Subclavian thrombosis in ambulatory cancer free population
What demographic does Paget- Schroetter syndrome commonly affect?
Men, typically in their dominant arm
What can Paget-Schroetter syndrome be associated with?
Thoracic inlet abnormalities (cervical rib, muscle)
What is another name for Phlegmasia Alba Dolens?
Painful white inflammation
What is Phlegmasia alba dolens?
Massive occupation of the major deep venous system
Can the blood still drain with Phlegmasia Alba Dolens?
Yes through the collaterals
Can blood still drain in Phlegmasia Alba Dolen?
Yes through the Collaterals
What does Phlegmasia Alba Dolens look like?
Extensive edema with a white discolouration
What does Phlegmasia Alba Dolen progress to?
Cerulea Dolens
What is another name for Phlegmasia Cerulea Dolens?
Painful blue inflammation
What is Phlegmasia Cerulea Dolens?
Occlusion of the major deep venous system
What is Phlegmasia Cerulea Doleans?
Occlusion of the major deep venous system and the collaterals
What does Phlegmasia Cerulea Dolens result in?
Reduced arterial flow
What does Phlegmasia Cerulea Dolens present with?
Massive thigh and calf swelling with a blue discolouration.
In Phlegmasia Cerulea Dolens what happens if we leave it untreated?
Venous gangrene and massive tissue death
Would Phlegmasia Cerulea Dolens be an emergency?
It would we a surgical emergency
Would Phlegmasia Cerulea Dolens be a emergency?
A surgical emergency
Treatments for DVTs can be grouped into how many categories?
Three
What are the three categories for DVT treatment?
- Prevention (control of the risk factors)
- Medical
- Surgical
How can we prevent a DVT? 4
- Control the risk factors
- Limit long period of inactivity
- Wear support hose elevating legs
- Blood tests to test for hypercoagulability states and blood factors remember Virchow’s triad
What are some medical treatments for DVT? 2
- Anticoagulation therapy
- Thrombolytic agent
How long will someone be on anticoagulation therapy for medical treatment?
3-6 months
If a clot is recurrent how long will the a person be on anticoagulation therapy?
Life
What does Anticoagulation therapy do?
Prevent clot propagation
Does anticoagulation therapy dissolve the thrombus?
Nope
What happens during the thrombolytic treatment for DVT?
Streptokinase may be injected to dissolve the thrombus
When is thrombolytic agents used for DVT?
Used when the symptoms are severe
What can Thrombolytic Agents lead to?
Major bleeding episodes
What are some surgical treatments for DVTs? 3
- Venous thrombectomy
- Bypass grafting
- Balloon Venoplasty and stunting
When do we do a venous thrombectomy?
Patient with impending limb loss (Phlegmasia Cerulea dolens) if a thrombolytic agent does not work.
What is bypass grafting?
Caval Occulsion
When would we use balloon venoplasty and stenting? 2
- Chronic iliofemoral DVT
- May-Thurner Syndrome
What is an IVC filter?
An option for patient who cannot be anticoaguated
What is superficial thrombophlebitis?
As a painful superficial cord and inflammation in the veins
For a superficial thrombophlebitis what can ultrasound do?
Determine the extent of thrombus
Approximately how much of the superficial thrombosis has a concurrent DVT or PE?
25%
Anticoaguation therapy is indicated if the thrombus is at what level?
5cm more in length or is 3 cm of the SFJ.
the same consideration is given to the SSV and popliteal anastomosis
What is the treatment for thrombophlebitis? 4
- Apply heat to site
- Compression stockings
- Non- steroidal anti-inflammatory meds
- Low molecular weight heparin for 45 days
What are some corrective tests for venous thromboembolic disease (VTE)? 4
- Venography
- CT
- Nuclear medicine
- MRI
A Venography is what?
A X-ray taken of the leg where contrast media is injected to outline the veins
For Venography the contrast is injected where?
Into a large vein in the foot/ankle
Venography is a very invasive test and has been largely replaced by what?
Ultrasound
Some patients are contraindicated for what procedures?
Venography contrast
What is CTs used for in terms of DVTs?
Pulmonary angiogram or CTPA
CT is the standard test for what?
Pulmonary embolism
CTs also require what to be injected?
Contrast to be injected into the patient
What kind of nuclear medicine test used for DVTs?
Ventilation perfusion (V/Q) scan
What is the process of the Ventilation-perfusion (V/Q) scan?
Ventilation part involves inhaling a radioactive gas to demonstrate the presence of a Pulmonary embolism
What does a V/Q scan show?
Parts of the lung that are getting oxygen
What should the perfusion look like for a V/Q scan?
We should look at blood flow to the lung to see if there is diminished flow from clots
What is the probability of V/Q scans reporting P/E?
High/ moderate/ low probability
What is a isotope Venography?
A nuclear medicine test where a radioisotope is injected to evaluate peripheral and pulmonary veins
What does the Isotope Venography tag?
The thrombus
How often is isotope Venography used?
Infrequently
With such vague symptoms, there are many differentials to consider when you scan, name a couple. 9
- Bakers cysts
- Hematoma
- Edema
- Lymphedema
- Infection
- Abscess
- Cellulitis
- Tumours
- Popliteal A aneurysm
What is a bakers cyst?
Dilation of bursa in the Posteromedial knee
What is bakers cysts common with?
Degenerative joint disease and rheumatoid arthritis
The Baker cysts can extend into what?
Muscle planes, and become hemorrhagic or rupture
Baker cysts can cause what? 3 (s/s)
- Pain
- Tenderness
- Swelling
How might a bakers cyst look?
Tear drop shape and may not be visible with the knee extending
If we see a bakers cysts what should we do?
Measure in three planes and interrogate with colour doppler
What causes hematomas?
Results of trauma, anticoaguation therapy or vigorous exercise
What is the sonographic appearance dependent of for hematomas?
Dependent on age of occurrence
Where should we scan for hematomas?
Where it hurts or where there is a palpable lump
If we see a hematoma how should we note it for the rad?
Measure in three planes and interrogate with colour doppler
What causes soft tissue edema occur?
Increased venous pressures
What are some examples of things that may cause soft tissue edema? 5
- Heart failure
- Fluid overload
- DVT
- Venous obstruction
- Presents as leg swelling
What is this?
Soft tissue edema
If CHF is the cause then the edema is what will we see in terms of edema? Why?
- Bilateral edema
- Increased hydrostatic pressure
For edemas the patient can present with what? 2
- Dyspnea
- Possible negative D-dimer
If we see an edema what can we do?
Use ultrasound to rule out DVT
What does the waveform of edemas look?
Can be pulsatile
What is a lymphedema? What is it due to? 4
obstruction of lymph drainage due to
1. Malignancy
2. Trauma
3. Surgery
Where are lymphedemas common?
In the calf and upper extremity
2/3 of lymphedema cases are what? (unilateral or bilateral)
Unilateral
What does lymphedema’s demonstrate?
Pitting edema
What is the appearance of lymphedema’s?
Milky appearance
What does an infection- abscess and cellulitis a result of?
Bacterial infection
What is a abscess?
Enclosed collection of pus
What is cellulitis?
Diffuse collection of fluid within the subcutaneous tissue
What may infections cause? 4 (s/s)
- Swelling
- Erythema
- Pain
- Tenderness
Ultrasound infections to do what?
Confirm that the venous system is patent
What is adenopathy?
Enlarged lymph nodes that can be mistaken for thrombosed veins
Adenopathy may cause what to the legs? 2
- Limb swelling
- Compression of veins
What does a benign lymph node look like?
- Ovoid
- Wider then tall
- Hypoechoic hilum
- Less than 1 cm
What does a malignant lymph node look like? 4
- Rounded shape
- Taller than wide
- Increased Colour flow
- Lose normal architecture
What are some examples of tumours? 2
- Benign (Lipoma)
- Malignant (Sarcoma, Lymphoma)
Tumours are usually solid but may have areas of what?
Necrosis
As a sonographer what should we do if we see a tumour?
Interrogate with colour and Doppler
What does popliteal aneurysm present with? 4
- Lump or pain behind the knee
- Dilated arterial wall
- Colour flow if patent
- Higher risk with AAA
What is this an example of?
Popliteal Aneurysm