PE and lung nodules Flashcards
PE definition
- obstruction of pulmonary arteries or one of its branches
- usually thrombus travels from elsewhere in body
causes of PE
- thrombus (VTE)- most common
- tumor
- fat
- air
- other substances
classification of PE
- acute- si/sx immediately
- subacute- presents over days or weeks
- chronic
possible locations for PE
- saddle
- segmental
- subsegmental- difficult to pick up on CTA
saddle PE
- massive PE in main pulmonary arteries
- very likely to cause hemodynamic instability
risk factors for PE
- post op- especially ortho surgery
- sedentary state
- malignancy
- hx of VTE
- pregnancy
- OCP
- obesity
- heavy cigarette smoking
- inherited hypercoag disorders
ortho surgeries that are highest risk of PE
- THR
- TKR
- hip fx surgery
- pelvic fx
- multiple fx from severe trauma
when can an embolism cause a stroke rather than PE
- if pt has PFO or ASD
- allows the embolus to skip the lungs
symptoms of PE
- sudden onset SOB
- pleuritic chest pain
- heart palpitations/ tachycardia
- DVT
- hypoxia
- tachypnea
- consider risk factors
hemodynamically unstable pts from PE
- most likely to die from PE
- most likely to get fibrinolytic therapy
- hypotension < 90 for > 15 min
- severe RB failure -> death from shock
- elevated troponin from right heart strain
- death occurs within first 2 hours
- risk of death stays elevated for 72 hours
diagnosis of PE
- use wells criteria
- D dimer for low probability pts
- CXR- usually negative
- chest CTA with contrast- gold standard
- V/Q scan when pt cannot get CTA
- venous US- look for loss of vein compressability
- EKG
- echo- right heart strain
PERC- pt does NOT need D dimer if all of the following are negative:
- age < 50
- HR < 100
- oxygen > 95
- no hemoptysis
- no estrogen use
- no prior DVT or PE
- unilateral leg swelling
- no sx or trauma requiring hospitalization in last 4 weeks
EKG features of PE
- sinus tachycardia
- S1 Q3 T3
- RV strain- T wave inversion in R and anterior precordial leads
- complete or incomplete RBBB
- nonspecific St or T wave changes
treatment options for PE
- risk stratify to determine if primary or secondary tx
- primary- thrombolysis, reserved for high risk pts
- secondary- anticoag or IVC filter
anticoag tx for PE
- stabilizes clot but doesnt dissolve clot
- started immediately
- LMWH injection -> warfarin bridge
- fondaparinux injection -> warfarin bridge
- unfractionated heparin as continuous infusion -> warfarin bridge
- Xa inhibitors
- dabigatran
considerations for anticoag tx
- pt compliance
- cost
- most C/I if CrCl < 30
- if reversal agent needed
- malignancy- use LMWH
- pregnancy- use LMWH
provoked clots
- post op
- trauma
- estrogen exposure
- usually low rate of recurrence
- anticoag tx for 3-6 mo
unprovoked clots
- idiopathic
- long haul air travel
- some hypercoag conditions- anticardiolipid ab
- indefinite anticoag tx
IVC filters
- active bleeding precludes anticoagulation
- recurrent VTE despite anticoag tx
- high risk pts that are not candidates for fibrinolysis
complications of IVC filters
- caval thrombosis
- bilateral leg swelling
- doubled DVT rate
VTE prophylaxis
- heparin or LMWH at lower doses in hospitalized pts
- used in high risk ortho pts- usually LMWH or Xa inhibitors
- ASA not recommended as sole agent
PE prognosis
- recurrence rate depends on adequate anticoag tx
- depends on if its provoked or unprovoked
- PH is long term sequelae
- death- untreated mortality rate is 30%
- most deaths occur in first week following dx
pulmonary nodule
- lesion that is within and surrounded by pulmonary parenchyma
- aka coin lesion
- < 3 cm in size
- not assoc with atelectasis or LAD
pulmonary mass
- > 3 cm in size
dx of pulmonary nodules
- CXR- can miss small nodules
- CT
- PET
- MRI
chest CT for pulmonary nodules
- more sensitive than CXR for small nodules
- usually get CT if there is abnormal CXR finding
- higher radiation and more expensive
- standard slices- 3.5-5 mm
- high res slices- 1 mm
soft tissue windows in CT
- look for LAD, vessels, and soft tissue
- usually done with contrast
lung tissue windows
- used to det what is embedded within lung tissue i.e. nodules
- usually no contrast
when is CT C/I
- IV contrast allergies
- renal insufficiency
- pregnancy
- cant accommodate pts > 400 lbs
PET
- uses FDG contrast
- very sensitive, less specific
- can be used for staging and monitoring tx of cancer
- very expensive, not always covered by insurance
- cant differentiate between inflammation and malignancy
what is SUV
- standardized uptake value in PET scan
- tells you how “hot” a lesion is
- SUV > 3 is beyond physiologic uptake
what malignancies tend to have false negative PET scans
- adenocarcinomas in situ
- carcinoid tumors
chest MRI
- used to assess tumor size, extent, and invasion into adjacent structures
- good to determine tissue plants- fat, muscle, bone, vessel
- no radiation
- limited use for solitary pulm nodules no adjacent to other structures
when are chest MRI C/I
- metal implants or pacemakers
when is PET not useful
- if nodule is < 8-10 mm
- too small to be detected on PET
size of nodules
- usually the larger the size the more likely to be malignant
- > 20 mm has 75% chance of malignancy
- 8-20 mm has 15% chance of malignancy
nodule borders
- malignant lesions have irregular or spiculated* borders
- benign usually smooth and discrete
- metastatic lesions can have smooth and discrete borders but tend to be diffuse
nodule calcification
- usu seen in granulomatous disease and hamartomas (both benign)
- osteosarcomas and chrondrosarcomas tend to have pulmonary calcifications
nodule growth
- malignant lesions are slow growing, increase in size over 4-6 mo
- benign lesions grow rapidly- usually infectious or inflammatory
air bronchogram
- collapsed lung around an airway
benign causes of nodules
- infections- 80%
- inflammatory- 10%
- hemartmoas- 10%
hemartoma
- bengin nodule
- comprised of cartilage, fat and muscle
- “popcorn” calcifications