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CARDIOLOGY > Deep venous thrombosis > Flashcards

Deep venous thrombosis Flashcards

1
Q

Differential diagnosis

A

Ruptured Baker’s cyst
Cellulitis
Lymphadenopathy

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2
Q

Gold standard test

A

Venography

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3
Q

D- dimers

A

A negative test rules out DVT,but a positive test does not diagnose DVT.D-dimers is a breakdown product of fibrin and can be released by many things including MI,malignancy,pregnancy,inflammation,stroke,infarct,trauma and is often raised post operatively

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4
Q

Treatment

Whats the aim ?

A

To prevent embolism

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5
Q

Treatment

A

LMWH - This is usually started as soon as the diagnosis is made,and is normally continued for a minimum of 5 days.It is usually stopped when the INR is in the target range (2-3)

Warfarin- also started at the same time as heparin ,but warfarin actually increases coagulability in the first few days of use ; hence the use of heparin initially.Warfarin is continued for :
6 months if it is the first DVT
3 months if it is the first DVT and occured post operatively
Indefinitely if it is a recurrent DVT or if there is a genetic clotting disorder , or if there are other large risk factors

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6
Q

Coagulation investigations

A

1) Bleeding time : tested by pricking the finger.Normal values : 1-7 mins
2) Coagulation time : unreliable ,blood sample and test how long it takes for a clot to form.3-15 mins
3) Prothrombin time (PT) :This is dependent on the factors produced in the liver.Heparin is monitored by APPT,Warfarin is monitored by INR

4)INR-the nternal normalised ratio.This test inly looks at the extrinsic clotting pathway.You can use it to look at liver function , warfarin dose and vitamin K status Normal values:0.9-1.3.When someone is on warfarin therapy , the target usually between 2-4 but may vary for individuals.

APPT

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7
Q

ECG Mnemonic

A

S1Q3T3

S1 - increased S waves in lead I
Q3 - increaseed Q waves in lead III
T3 - inverted T waves in lead III

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8
Q

Prevention

A
  1. Stop the pill 4 weeks before a planned operation
  2. Mobilise early after the operation
  3. Heparin - 5000u/12hrs may be given pre-operatively as may enoxaparin(20mg/24hrs) or dalteparin - these are LMWH’s and are likely to cause less bleeding and do not need to monitoring - so in this situation are better than heparin for most patients
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9
Q

The two major consequences o DVT

A
  • pulmonary embolism (PE) (also termed venous
    thromboembolism)
  • postphlebitic syndrome
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10
Q

Treatment

In patients with proximal DVT,

A

elevation o the a ected extremity above the level o the heart helps reduce edema and tenderness, and anticoagulation prevents extension o the thrombus and PE. Initial anticoagulation typically consists o subcutaneous low molecular weight
heparin (LMWH). Intravenous un ractionated heparin is a cost-e ective alternative that has
been used success ully or this purpose or many years, but LMWH is more convenient to
administer. War arin, an oral anticoagulant, is then prescribed or long-term management
and is continued or several months, depending on the underlying cause o DVT. Newer oral
anticoagulants, such as the actor Xa inhibitors rivaroxaban and apixaban (see Chapter 17),
allow a broader range o options or acute and long-term treatment o DVT. Catheter-based
thrombolysis may be use ul or selected patients with ilio emoral deep vein thrombosis

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11
Q

Treatment o patients with calf DVT

i.e., thrombus con ned to below the knee

A

is more controversial because pulmonary emboli rom that site are uncommon. Some experts advocate
serial noninvasive monitoring to determine i the thrombus propagates into proximal veins,
whereas others treat such thrombosis with heparin (un ractionated or low molecular weight)
followed by warfarin for 3 to 6 months.

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12
Q

Prophylaxis against DVT

A

is appropriate in clinical situations in which the risk o developing the condition is high, such as during bed rest ollowing surgery. Prophylactic measures
may include subcutaneous un ractionated heparin, LMWH, low-dose oral war arin, or one o
the newer oral anticoagulants, as well as compression stockings, and/ or intermittent external
pneumatic compression o the legs to prevent venous stasis

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13
Q

Initial management of varicose veins is

A

conservative, with periodic leg elevation and compression stockings; severe symptomatic varicose veins can be treated with sclerotherapy,
radio requency or laser ablation, or surgical ligation and removal.

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14
Q

Definition

A

A deep-vein thrombosis (DVT) is a blood clot that forms within the deep veins,usually of the leg,but can occur in the veins of the arms and the mesenteric and cerebral veins
According to Virchow’s diagram ->main pathophysiological mechanisms->
1.Damage to the vessel wall
2.Blood flow turbulence
3.Hypercoagulability

DVT is commonest in the lower limb below the knee and starts at low-flow sites , such as the soleal sinuses,behind venous valve pockets

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15
Q

The blood clot or part of it can break free called

A

embolism and become lodged in the blood vessels of the lung,causing pulmonary embolism

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16
Q

clots are firm and are mostly made up of

A
  • fibrin and red blood cells.On autopsy , the majority are attached to venous walls.
  • within 72 hours,an estimated 50% of intraoperative calf DVTs resolve on their own.
  • About 1 to 6 of these extend into the proximal veins of the leg,causing venous obstruction and damage to affected valves
  • A subset of proximal DVT becomes mobile and progresses to pulmonary embolism (PE),a potentially fatal condition
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17
Q

Clinical presentation

A

Medical history !!

  • Pain (50% of pts)
  • Redness
  • Swelling (70% of patients) - ANKLE
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18
Q

Physical examination

A
  • Limb edema may be unilateral or bilateral if the thrombus is extending to pelvic veins
  • Red and hot skin,with dilated veins
  • Tenderness
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19
Q

DVT Physical exam

A

Special attention should be directed to :

  • The vascular system
  • Extremities (e.g looking for signs of superficial or DVT)
  • Chest
  • Heart
  • Abdominal organs
  • Skin ( e.g skin necrosis,livedo reticularis )
20
Q

Probability of the patient having a DVT is as follows :

A 
0     = low probability
1-2   = moderate propability
>= 3 = high propability

An updated version simplifies the scoring process into 2 categories :
< 2 points = DVT unlikely
>=2 points = DVT likely

21
Q

Inestigations

A

Following investigations are done:

  • D-dimers(very sensitive but not very specific )
  • Coagulation profile
  • Proximal leg ultrasound,which when positive ,indicates that the patient should be treated as having a DVT
22
Q

D-dimers testing

A

is a simple blood test of fibrin degradation.D-dimers levels are increased by any condition that produces fibrin,one of the primary components of deep vein thrombi.The negative likelihood ratio is higher than 99%
The test is best used to rule out DVT in outpatients with a low probability of proximal DVT

23
Q

Ultrasonography

A

identifies thrombi by directly visualizing the venous lining and by demonstarting abnormal vein compressibility or , with doppler flow studies , impaired venous flow.The test is > 90% sensitive and > 95 % specific for femoral and popliteal vein thrombosis but is less accurate for iliac or calf vein thrombosis

24
Q

D-Dimers

A

is a byproduct of fibrinolysis;elevated levels suggest recent presence and lysis of the thrombi.D-Dimers assay vary in sensitivity and specificity;however , most are sensitive and not specific.Only the most accurate tests should be used.For example ,a highly sensitive test is enzyme-linked immunodorbent assay (ELISA),which has a sensitivity of about 95%

25
Q

D-Dimer

if pretest probability of DVT is low

A

DVT can be safely excluded in pts with a normal D-dimer level on a sensitive test.Thus, a negative D-dimer test can identify patients who have a low propability of DVT and dot require ultrasonography.However , a positive test result is nonspecific because levels can be elevated by other conditions (e.g liver disease,trauma,pregnancy,positive rheumatoid factor,inflammation,recent surgery,cancer) , further testing is necessary

26
Q

D-Dimers if pretest propability is moderate high

A

D-dimer testing can be done at the same time as duplex ultrasonography.A positive ultrasound result confirms the diagnosis regardless of the D-dimer level.If ultrasonography doesn’t reveal evidence of DVT , a normal D-dimer level helps exclude DVT.Patients with an elevated D-dimer should have repeat ultrasonography in a few days or additional imaging , such as venography,depending on clinical suspicion , nography,depending on clinical suspicion

27
Q

Venography

A

Contrast venography was the definitive test for the diagnosis of DVT but has been largely replaced by ultrasonography which is noninvasive , more readily available , and almost equally accurate for detecting DV.
Venography may be indicated when ultrasonography results are normal but pretest suspicion for DVT is high.The complication rate is 2%, mostly because of contrast agent allergy

28
Q

Water - excitation radiofrequency pulse ;

A

provide simultaneous views of thrombi in deep veins and subsegmental pulmonary arteries ( for diagnosis of pulmonary embolism)

29
Q

Differential diagnosis

A
  • Pyomyositis
  • Fibula shaft fracture
  • Cellulitis
  • Ruptured Baker’s cyst
  • Neurogenic leg pain
  • Hematoma
  • Rupture of Achilles Tendon
  • Soleus muscle strain
  • Acute psoterior compartment syndrome
  • Calf muscle cramps
30
Q

Primary prevention

A

A combination of mechanical + pharmacological measures can be used to prevent DVT.Mechanical prophylaxis involves the use of graduated compression stockings,intermittent pneumatic compression and venous foot pumps to improve blood flow in the deep veins of the leg

31
Q

Common agents for pharmacological prophylaxis include

A
  • warfarin

- subcutaneous unfractionated heparin ( UFH) and low molecular weight heparins (LMWH)

32
Q

cornerstone of treatment

A

Anticoagulation
NICE guidelines only recommend treating proximal DVT ( not distal ) and those with pulmonary emboli.In each patient, the risks of anticoagulation need to be weighed against the benefits

33
Q

Anticoagulants

A
  • All patients with DVT are given anticoagulant. Typically, patients are initially given an injectable heparin and in fractionated or low molecular weight for 5 to 7 days, followed by longer term treatment with an oral drug.
  • For patients who are start warfarin, warfarin is started within 24 to 48 hours after the start of the injectable heparin.
  • For patients were to start an oral factor aXa inhibitor (edoxaban) or dabigatran etexilate,the oral agent is started on the day after the 5 or 7 days of injectable heparin is completed.
  • The reason for this different approach is that when starting warfarin, it takes about five days to attend a therapeutic affect; hence ,They need to overlap with rapidly acting heparin for 5 to 7 days.
  • On the other hand, oral factor Xa inhibitors and dabigatran attain a therapeutic effect within 2 to 3 hours of intake and there is no need to overlap these drugs with an injectable heparin
  • Select patients may continue treatment with a LMWH rather than switching to an oral drug for example patients with extensive iliofemoral DVT or selected patients with cancer.
  • Alternatively, anticoagulation may be initiated with selected direct oral and Koglin (rivaroxaban or Apixaban) without forgiving and injectable heparin.
34
Q

Low risk

A

Ambulatory patient without additional VTE risk factors
Ambulatory patient with expected LOS <= 2 days , or same day / minor surgery
Only a few patients !
Ambulation and education

35
Q

Moderate risk

A

All other patients. Most patients (not LOW or HIGH age category)
LMWH or UFH 5000 units SQ

36
Q

High-risk

A

Elective major lower extremity arthroplasty
Hip, pelvic, or severe lower extremity fractures
Acute spinal cord injury with paresis
Multiple major trauma
Abdominal or pelvic surgery for a cancer
LMWH or Arixtra or Coumadin

37
Q

Low

A 
Age > 50 yo
Myeloproliferative disorder 
Dehydration 
CHF
 active malignancy 
hormonal replacement 
moderate to major surgery
38
Q

Moderate

A 
Prior history of VTE 
impaired mobility 
inflammatory bowel disease 
active rheumatic  disease 
sickle-cell disease 
Oestrogen-based contraceptives 
central venous catheter
39
Q

High

A 
Acute  or chronic lung disease
Obesity
Known thrombophilic state
Varicose veins/chronic stasis 
Recent postpartum with immobility
Nephrotic syndrome
Myocardial infarction
40
Q

Secondary prevention

A

Early mobilisation
In conjunction with anticoagulation, bedrest is commonly prescribed in the immediate days following the diagnosis of LE DVT. This practice is applied with the intent of preventing clot dislodgement and the incidence of PE
- According to a systemic review, only ambulation is associated with your incidences of new PE and increased mortality. As such, early mobilisation is instrumental for the prevention of DVT sick well
- Graduated compression stockings
- To prevent DVT recurrence, the application of graduated compression stockings is recommended beginning within one month of diagnosis of proximal DVT and continuing for a minimum of one year after diagnosis.

41
Q

Associated illnesses that are a consequence of VTE events

A

Chronic thromboembolic pulmonary hypertension (main pulmonary artery pressure greater than 25 million American write the persist six months after BE, 2- 4 percentage of patients after PE)

What’s the robotic syndrome (calf swelling and skin pigmentation; venous ulceration in severe cases
up to 43% of patients develop PTS within 2 years

42
Q

Prognosis for DVT

A

Without a takeaway treatment, lower extremity DVT has a 3% of risk of Fadel BE, that you dropped extremity DVT is very rare. Recovery during the tea is Lois for patients with transient risk factors (e.g., surgery, drama, temporary immobility) and greatest for patients with persistent risk factors (e.g., cancer), ideal perfect DVT, or in complete resolution of past DVT (residual thrombus)

A normal d-dimer level of day and after warfarin is stopped may help predict a relatively low risk of DVT or PE recurrence. Risk of venous insufficiency is difficult to predict.
Risk factors for postphlebitic syndrome include proximal thrombosis ,recurrent ipsilateral DVT, and body mass index (BMI) >= 22 kg/m2

43
Q

DVT clot removal

A

When the patient has large thrombus in proximal vein and the only solution is to remove his clot from vein
Dissolving and/or mechanical removal restores the flow
decreases risk of clot
allows venous valves to return to normal function
can decrease long-term anticoagulation

44
Q

Thrombolytic (fibrinolytics) drugs

A

Thrombolytic drugs, which include alteplase, panic the place, and streptokinase, lies clothes and maybe more effective than anticoagulation alone in selected patients, but the risk of bleeding is higher than with heparin. Consequently, thrombolytics soon be considered only in highly selected patients with DVT. Patient who may benefit from thrombolytics include those lesson 60 years with extensive iliofemoral DVT who have evolving or existing link Iskagna (e.g. phlegmasia cerulea dolens) and do not have risk factors for bleeding

45
Q

Surgery

A

Surgery. Is rarely needed. Thrombectomy, fasciotomy, or both are mandatory for phlegmasia Alba Dolans or phlegmasia cerulea Dolens unresponsive to thrombolytics to try to prevent limb threatening gangrene

CARDIOLOGY (19 decks)

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