Embolism, Infarction, & Shock Flashcards
Describe an embolism
A detached intravascular solid/liquid/gaseous mass that occludes a blood vessel within circulation
Types of Emboli:
Thromboemboli
Air
Amniotic
Fat
Cholesterol
Pulmonary Thrombo-embolism:
Describe what Thrombo-embolisms are
Pulmonary emboli that start from deep venous thromboses, these fragmented thrombi are carried through larger veins & into the right side of the heart —> lungs
Pulmonary thrombo-embolism:
Describe a Saddle embolus
If the emboli occludes the main pulmonary artery & straddles the pulmonary artery bifurcation
Pulmonary thrombo-embolism:
Describe a Paradoxical embolism
A venous embolus that passes through an interatrial or interventricular defect to gain access to the systemic arterial circulation
Pulmonary thrombo-embolism:
Describe a Cor Pulmonale
When an emboli obstructs 60% or more of the pulmonary circulation these don’t normally cause hemorrhage or infarction this type of emboli can cause sudden death from right-sided heart failure or cardiovascular collapse
Systemic Thrombo-embolism:
Which conditions are most likely to give risk to systemic thrombo-emboli?
Most of these will arise form intracardiac mural thrombi and are associated with left ventricular thrombus because:
- Infarction
- Left atrial dilation
- Fibrillation
- Aortic aneurysms
- Atherosclerotic plaques
- Valvular vegetation
- Venous thrombi (aka paradoxical emboli)
Where do systemic thrombo-embolisms most commonly happen?
75% in the lower extremities & 10% in the brain
Describe a fat embolism
1.When fractures of long bones rupture vascular sinusoids causing fat and hematopoietic bone marrow to become an embolus and travel to the lung
2. Release of free fatty acids from the fat globules causes toxic injury to the endothelium
Describe the features/presentation of fat embolism syndrome
Patients will present with pulmonary insufficiency, neurological symptoms, anemia, & thrombocytopenia
It can happen 1-3 days after an injury and typically has sudden onset tachypnea, dyspnea, & tachycardia, irritability, restlessness (can progress to a delirium or coma)
Patient presents with petechial hemorrhages and hemorrhages in the white matter with evidence of injury by micro globules of fat
Patient likely suffered from a fat embolism syndrome
The following histo slide describes what type of embolus? What does the star highlight?
Bone marrow embolus within the pulmonary circulation
Star: Hemapoietic cells
Amniotic fluid embolism:
Describe the features of Amniotic fluid embolism
Arises as a complication of labor and the immediate postpartum period.
Features include:
- Sudden/severe dyspnea
- Cyanosis
- Shock
- Seizures
- Pulmonary edema & neurological impairment
If the patient survives they will still have pulmonary edema with disseminated intravascular coagulation
The histo slides describe what type of emboli?
Amniotic fluid emboli this happens when the amniotic fluid spills into mom’s circulation (from tears in placenta or uterine ruptures)
Squamous cells from fetal skin, lanugo hair, mucin, & fat from vernix caseosa can make their way into mom’s pulmonary circulation
Describe the features of an acute air embolism
Happens when gas bubbles in the circulation coalesce to form frothy masses that obstruct blood flow & cause ischemic injury
What are somethings that could cause an air embolism?
Barotrauma
Surgery
Dysfunctional one-way valve
Uncapped catheters
Bypass surgery
X-ray of a patient suggests the presence of which type of embolism?
Air embolism
Chest CT causes the following, what embolism is most likely? A & B
Air embolism (A)
Bilateral-pleural-based/wedge-shaped mass consolidations with central necrosis in lower lobes (B)
Decompression sickness:
Describe the features of Decompression sickness
Sudden changes in atmospheric pressure during ascent (i.e scuba diving).
Breathing in higher pressures causes nitrogen gas to dissolve in tissues and as the pressure reduces too fast the gas expands in tissues forming air emboli and ischemic injury (the bends)
Elbow/shoulder are most common in divers
How do you treat an air embolism?
A hyperbaric chamber to decompress the gas
Describe the features of Caisson disease (aka chronic air embolism)
This is a chronic form of decompression sickness (caisson disease) where recurrent/persistent gas emboli are in the bones and cause multifocal ischemic necrosis leading to osteonecrosis (6-60 months)
Which bones are most commonly effected by Caisson disease?
The head/shaft of the humerus
Lower end of the femur
Tibial head
Cholesterol crystal embolism (blue toe/purple toe syndrome):
Describe the features of Cholesterol crystal embolism
Severe atherosclerosis of larger arteries (aorta) can cause ulcerative atherosclerotic plaque
Patients tend to complain about pain in their legs, butt, lower back, & restless legs
Cholesterol crystal embolism typically happens in patients with what condition?
Usually in patients with advanced atherosclerosis of the abdominal aorta because the cholesterol crystals micro-embolize in the lower extremities
Cholesterol embolism:
Describe Livedo reticularis.
This makes a mottled, purplish discoloration of the skin with reticulated cyanotic areas surrounding central cores (fishnet pattern) because of spasms/obstructions of perpendicular arterioles and pooling blood in surrounding venous plexuses
Cholesterol embolism:
Describe what a biopsy of areas with livedo reticularis will show?
Occlusions of arterioles by multinucleated foreign-body giant cells and fibrosis surrounding biconvex/needle-shaped clefts that correspond to cholesterol crystal micro emboli
Describe what a fat embolism is?
The release of fat globules from bone marrow when it’s fractured causing Petechial hemorrhages, pulmonary insufficiency, neurological impairment, anemia, & thrombocytopenia usually 1-3 days after the injury
Describe what an Amniotic fluid embolism is?
a complication of labor that happens immediately in the post-partum period as Sudden and severe dyspnea, cyanosis, shock/seizures, pulmonary edema, & neurological impairments,
Caisson disease
Livedo reticularis & cholesterol embolism
Anatomy of vascular supply:
How does blood supply effect an organs resistance to thromboembolism?
Organs with dual artery blood supply are more resistant to thrombo-embolism infarct (i.e lungs and spleen)
Slowly developing occlusions are less likely to cause _________ because they provide time to develop ____________ of perfusion
infarction because they allow time to develop alternate pathways
Which tissue is more vulnerable to hypoxia? neurons or skeletal muscle
neurons
Anterior compartment syndrome
this is caused by arterial hemorrhage into a compartment (in any extremities) where the increased pressure in the closed space pinches off blood flow to that area
Usually from crushing injuries (blocks venous outflow)
Describe the features of testicular torsion
The spermatic cord twists cutting off blood supply to the epididymis and testis (bell-clapper deformity)
Sudden onset of pain and swelling in testes, asymmetrical scrotum and a high-riding testicle
Must do surgery within 6hrs!
What’s the differential diagnostic criteria between testicular torsion and ependymitis?
Positive Phern’s sign (pain is better when testes are elevated) = epididymitis
Negative Prehn’s sign (pain is worse when testes are elevated) = testicular torsion
Describe the features of ovarian torsion
- Sudden onset of extreme lower abdominal pain radiating to the back, side, and thigh &
- Nausea/vomiting
- Mild fever
- Tachycardia
What condition puts a patient at higher risk of developing intestinal hemorrhagic infarction and why
Diabetics because they’re more prone to atherosclerosis which can occlude the mesenteric artery
A pulmonary embolism will result in what type of infarct?
A red infarct because organs like the lung and spleen have dual artery supply making them more resistant to thromboembolisms
Wedge shaped, pale infarcts that impact organs with a single arterial supply
White infarcts
How do you differentiate ischemic or hemorrhagic occlusions and what are the treatment options for each?
Use a CT scan if it’s ischemic use thrombolytics if it’s hemorrhagic palliative care :(
What embolism has neutrophils?
Septic embolism
Describe the features of the following type of embolism?
A septic embolism, that happens when microbes seed necrotic tissue or infected valve vegetation embolizes this is the only emboli that has neutrophils!
Myocardial infarction can lead to what type of Shock?
Cardiogenic shock
Ventricular rupture can lead to what type of Shock
Cardiogenic shock
Arrythmia can lead to what type of Shock?
Cardiogenic shock
Cardiac tamponade can lead to what type of Shock?
Cardiogenic shock
Describe the features of hypovolemic shock
- Low cardiac output
- Less left ventricular diastolic pressure
- Usually from excessive fluid or sodium loss
- Decreased PCWP but a normal ejection fraction
- More peripheral vascular resistance (RAAS)
- dECREASED VENOUS
Pulmonary embolism can lead to what type of Shock?
Cardiogenic Shock
Fluid loss (hemorrhage, vomiting, diarrhea, burns etc) can lead to what type of Shock?
Hypovolemic shock
Overwhelming microbial infections (fungi/bacteria) can lead to what type of Shock?
Shock via systemic inflammation (septic shock)
Superantigens (TSS) can lead to what type of Shock?
Shock via systemic inflammation (septic shock)
Trauma/burns/pancreatitis can lead to what type of Shock?
Shock via systemic inflammation (septic shock)
What are some of the features of Septic shock
Cytokine cascades (inflammation)
Peripheral vasodilation/blood pools (warm)
Disseminated intravascular coagulation
Describe the features of Cardiogenic shock?
- Systemic hypoperfusion causing low cardiac out put (cold),
- High PCWP
- Increased peripheral vascular resistance
- Lactic acidosis
- Decreased left ventricular filling
- Lactic acidosis
How does left sided heart failure lead to cardiogenic shock ?
Lower cardiac output means higher EDV which causes more PCWP causing pulmonary edema and cardiogenic shock
Occlusion of what artery most commonly leads to Ventricular fibrillations
Occlusion of the LADA causes an anterior septal infarct blocking blood supply to the Purkinje fibers causing ventricular fibrillation
Describe the properties of IL-1
- It’s secreted by macrophages
- Acts as an endogenous pyrogen (fever, edema, adhesion/diapedesis)
- Hemopoietic growth factor
Describe the properties of IL-2
- Secreted by Tcells
- Stimulates the proliferation/differentiation of Tcells
Describe the properties of IL3
- Secreted by activated Tcells
- Hemopoietic growth factor
Describe the properties of IL-4
- Secreted by TH2 (CD4) & Mast cells
- Promotes differentiation of helper T-cells to TH2 to activate B & T cells to class switch (IgE–>IgG)
Describe the properties of IL5
- Secreted by TH2 & Mast cells
- It stimulates the growth and differentiation of eosinophils & Bcells to class switch (IgA)
Describe the properties of IL-6
- Secreted by macrophages/monocytes
- It promotes fever and stimulates the liver to make acute phase reactants (hepcidin, CRP etc)
- It also inhibits hematopoiesis (new RBC formation)
Describe the properties of IL-7
- Secreted by adventitial reticular cells
- They help differentiate pluripotent stem cells into progenitor B & T cells
- Also helps maturation of NK cells & lymphocytes
Describe the properties of IL-8
- Secreted by macrophages, endothelial cells, leukocytes, & skeletal muscle cells
- Chemotaxis & degranulation
Describe the properties of IL-10
- Secreted by TH2, T-regulatory cells, & macrophages
- It’s an anti-inflammatory that inhibits macrophages, dendritic cells, & MHCII cells
Describe the properties of IL-11
- Secreted by stromal cells of bone marrow
- increases platelet count and differentiation of CRP, Hepcidin, & ESR
Describe the properties of IL-12
- Secreted by macrophages
- It activated NK cells & promotes the differentiation of naive T-cells
Describe the properties of IL-13
- Secreted by TH2 cells, B-cells, CD8 cells, Alveolar macrophages, Mast cells, & Basophils
- Increases the expression of VCAM-1 & stimulates IgE production via B-cells
Describe the properties of IL-17
- Secreted by TH17 cells & CD8 cells
- It stimulates the production of IL’s 1, 6, 8, 12, 18, & INF-y (all proinflammatory)
- It also recruits neutrophil to inflammation
Describe the properties of IL-24
- Secreted by Tcells & monocytes
- Suppresses tumors
Describe the properties of IL-28, 29
- Secreted by dendritic cells
- They promote antiviral immunity
Describe the properties of IL-32
- Secreted by monocytes, macrophages, & NK cells
- It induces TNF-a, IL-8/6 (Proinflammatory)
- It also induces apoptosis
Describe the features of septic shock
Sepsis that comes from s. aureus, s. cocci, e.coli, pseudomonas, & candida
- Cytokine storm via TNF & IL-1
- Patient initially has a high WBC count but then it drops (false positive) because the marginal pool)