CBD 6: Thromboembolism Flashcards
Helen is a 32-year old woman who has presented with a 3-day history of pain on the left side of her chest. The pain is worse when she breathes in or coughs, and sharp at times. She feels short of breath, but is not sure if it is just due to pain. She has an occasional dry cough. She is normally fit and healthy and is on no medication other than Marvelon. She smokes 20 cigarettes/day and drinks 20-30 units of alcohol per week.
a) What is on your differential diagnosis so far? List four possibilities.
b) For each possible diagnosis, state one examination finding that would support this.
a) Pulmonary embolism
- symptoms/signs of current or prior DVT.
- Risk factors for VTE
b) Pneumothorax
- ipsilateral absent breath sounds, poor expansion and hyper-resonance to percussion, history of trauma or tall/thin etc.
c) Pneumonia
- fever, productive cough, crackles, dullness to percussion
d) Pericarditis
- fever, pericardial friction rub,
(in cardiac tamponade: Beck’s triad of hypotension, raised JVP and muffled HS)
e) Rib fracture
- localised tenderness, history of trauma,
possible flail chest (multiple fractures in multiple contiguous ribs resulting in free segment in chest wall and impaired ventilation)
You examine Helen, and find the following:
- Looks reasonably well
- No jaundice or pallor
- Temp: 37.3 C
- CVS: pulse 96 reg, BP 122/71, JVP not raised,
HS I + II + 0
- Resp: RR 20 (shallow), Air entry L=R, Breath sounds vesicular, no added sounds
- Abdo: NAD
- Limbs: NAD
- Neuro: Grossly normal
a) What critical observation has been omitted?
b) What are the most useful tests that can be done in the ED department? List four. For each test, state what information it may provide.
c) On ECG or Echo, there may be evidence in PE of…?
a) Oxygen sats
b) Tests:
- D-dimer: raised may indicate PE (note: if Wells’ score was > 4, she should go straight to CTPA)
- CXR: mainly to exclude alternatives, e.g. pneumothorax (loss of lung markings, radiolucency, mediastinal shift in pneumothorax), pneumonia. Note: CXR findings in PE - effusions, Hampton hump, Westermark sign
- ECG: mainly to exclude cardiac chest pain (ACS, pericarditis), PE changes (sinus tachy, S1Q3T3, RBBB, RAD, non-specific ST and T wave changes)
- ABG — hypoxia (but up to 20% of people with PE have a normal arterial oxygen pressure).
- Leg Doppler US: if suspicion of DVT
- Echo — for people with hypotension (clinically ‘massive’ pulmonary embolism), the absence of right heart failure excludes pulmonary embolism
c) Right heart strain/ failure (‘massive’ PE)
D-dimer test:
a) Is it specific or sensitive for DVT/PE?
b) What does this mean practically?
c) Also positive in what other conditions?
a) Sensitive, non-specific
b) Good at picking up those with a DVT/PE; poor at excluding those without DVT/PE (use PERC score for excluding PE)
c) DIC, recent surgery, or trauma, infection, liver or kidney disease, cancers, normal pregnancy, eclampsia
DVT:
a) Clinical features
b) Confusion with cellulitis
c) Other DDx
a) Pain/tenderness - along the line of the deep veins. Swelling - of the calf or thigh (usually unilateral, may be bilateral if iliac vein involvement). Pitting oedema. Distension of superficial veins. Warm skin. Erythema or cyanosis.
b) DVT may mimic cellulitis. Secondary cellulitis may develop with primary DVT. Primary cellulitis may be followed by a secondary DVT.
c) Thrombophlebitis, trauma, ruptured Baker’s cyst, lymphatic/venous obstruction, fluid overload (CCF, liver failure, nephrotic syndrome), vascultitis, compartment syndrome
PE:
a) 5 symptoms
b) 5 signs
a) Dyspnoea. Pleuritic chest pain, retrosternal chest pain. Cough and haemoptysis. Symptoms of DVT.
Dizziness or syncope.
b) Tachycardic, tachypnoeic, hypoxic, hypotension and shock, signs of RHF (raised JVP, tricuspid regurgitation), pleural rub
The medical SHO is studying for his MRCP and says he wonders if she has thrombophilia.
a) What is thrombophilia?
b) Hereditary causes
c) Acquired causes
a) Predisposition to thromboembolism
b) Hereditary: Factor V Leiden mutation, and deficiencies of antithrombin, protein C and protein S
c) Acquired: APLS, acquired antithrombin deficiency (pregnancy, liver failure), cancer, myeloproliferative disorders
Wells’ score for PE (2-level)
a) PE likely: cut-off and further management
b) PE unlikely: cut-off and further management
c) What score is used to exclude PE in low-risk patients?
a) >4 points (PE likely):
- Immediate CTPA
- Give LMWH in the interim if delay in CTPA is likely
b) 4 or less (PE unlikely):
- arrange a D-dimer test
- D-dimer positive = manage as for likely PE (Wells > 4)
- D-dimer negative = consider alternative diagnosis
c) Pulmonary embolism rule-out criteria (PERC): if any criteria are positive, PE cannot be ruled out.
PE differentials.
a) Resp
b) CV
c) MSK
d) GI
e) Other causes of collapse
f) Chest wall tenderness occurs in what % of PEs?
a) Pneumothorax, pneumonia, acute exacerbation of chronic lung disease.
b) ACS, acute heart failure, dissecting or rupturing aortic aneurysm, pericarditis.
c) Musculoskeletal chest pain. Note that chest pain with chest wall palpation occurs in up to 20% of people with confirmed PE.
d) GORD, oesophageal spasm,
e) Any cause for collapse such as vasovagal syncope, orthostatic hypotension, arrhythmias, seizures, CVA
f) 20% (note: tenderness does NOT mean MSK)
CTPA.
a) What patients should not undergo CTPA?
b) What alternative is there?
c) What finding is diagnostic for a PE on CTPA?
d) Name some findings on plain CXR suggestive of PE
a) Severe renal impairment (due to contrast)
b) V/Q scan
c) Filling defect
d) Pleural effusions, Hampton hump, Westermark sign
Wells’ score for DVT.
a) Useful in what settings?
b) Low-risk: cutoff and further management
c) Moderate risk: cutoff and further management
d) High risk: cutoff and further management
e) If US leg positive for DVT, management?
a) Outpatient and ED (not inpatient)
b) 0 or less: D-dimer test (positive: US leg, negative: no further action)
c) 1-2: high-sensitivity D-dimer (positive: US leg, negative: no further action)
d) 3 or more: USS leg (D-dimer also to risk stratify)
e) Anticoagulation (regardless of D-dimer and Wells’ score)
Risk factors for VTE.
- Mnemonic: THROMBOSIS
Travel History of VTE, hypercoaguable Recreational drugs Old (>60) Malignancy Broken bones Oral contraceptives/obstetrics/HRT Surgery/smoking Immobilization Sickness (CHF/MI, IBD, nephrotic syndrome, vasculitis)
PE management:
a) A - E
b) Haemodynamically stable
c) Haemodynamically unstable
d) Who is LMWH/fondaparinux not suitable in?
e) Target INR
a) Oxygen 100%. Obtain IV access, monitor closely, start baseline investigations. Fluids as necessary. Analgesia PRN (e.g, morphine)
b) Anticoagulation: LMWH/fondaparinux for 5 days or until INR is above 2.0 for 24 hours (whichever is longest). In most, warfarin/NOAC is commenced within 24 hours and continued for 3 months (longer in unprovoked PE)
c) Thrombolysis or surgical embolectomy
d) Renal failure - give unfractionated heparin (UH) instead
e) 2.0 - 3.0 (in mechanical heart valves, 2.5 - 3.5)
Virchow’s triad for thrombosis.
Hypercoagulability
Blood stasis
Endothelial injury
Compartment syndrome.
a) Most common sites affected
b) Causes
c) Presentation
d) Treatment
a) Forearm, lower limb, gluteals, abdomen
b) Trauma, tight plaster cast compression, infection, crush injury, burns, muscle hypertrophy (e.g. body builders, athletes), iatrogenic (IM injections)
c) Pain, pain, pain (increasing, despite immobilisation), sensory deficit, tenderness, pain increase on passive movement, later: acute ischaemic limb features
d) Urgent decompression: remove any precipitants (e.g. plaster casts, splints or dressings) and perform open fasciotomy if necessary
