Patho & Pathophis Shock 2 Flashcards
What is Distributive shock characherised as
Loss of vessel tone
Enlarged vascular compartment
Displaced vascular volume from heart/central circulation
What are the 2 main causes of distributive shock
Decreased sympathetic control
Excessive vasodilatory substances released
How is Distributive shock described
Blood volume stays the SAME. Vasculature expands until normal volume doesn’t fill circulatory system
What happen in Distributive shock
In distributive shock the vessels stay in vasodilation causing more plasma to leak out of the vessel into the interstitial space, therefore leading to decreased blood volume
What are the 3 subsets of Distributive shock
Neurogenic
Anaphylactic
Septic
What causes Neurogenic shock
Parasympathetic overstimulation and sympathetic under stimulation
What can cause neurogenic shock
Injury to spinal cord or medulla
Hypoxia
Lack of glucose to CNS
CNS depressing drugs
General anaesthesia
In addition to loss of autonomic processes there is also a loss of thermoregulation due to the inability to sweat
What is the progression of Neurogenic shock
What defines anaphylaxis
Anaphylaxis is severe, life threating, systemic hypersensitivity reaction resulting in decreased blood pressure, airway obstruction and severe hypoxia
Mostly caused by a type 1 hypersensitivity
What are some common causes of anaphylaxis
Foods
Insect venom
Latex
Meds
Immunotherapy
Define an Antigen
Something that stimulates an immune response
Define an Allergen
An antigen that causes an allergy
Define Hypersensitivity
Abnormal & excessive response of activated immune system causing injury & damage to host tissues
Define an Allergy
A type 1 hypersensitivity reaction
Define an Antibody
A family of defensive proteins the body makes when stimulated by an antigen. These are produces by B lymphocytes and plasma B cells
Immune response
What are hypersensitivity Disorders
Collective term for immune response disorders
What is a type 1 Hypersensitivity disorder
Classic allergic response IgE-mediated.
They develop rapidly on exposure to antigen
Sensation stage of initial allergen exposure
What are essential in producing type 1 hypersensitivity reactions
Mast cells & Basophils
Anaphylactic reaction subsequent exposure
What happen in mast cell degranulation
As the antibodies attach to the mast cell they release a bunch of different mediators which have a inflammatory response
What is the action of Histamine
This causes an increase in nitric oxide production which is a strong vasodilator it also causes smooth muscle in the bronchioles to constrict, while causing vascular smooth muscle to relax. This increases permeability of the vessels resulting in more oedema in the pulmonary system and reduced preload to the heart affecting MAP
How many distinct phases does anaphylactics have
2
A primary - which commences 5-30 mins post allergen exposure & subsides within 60mins. This is mediated by the key mediator HISTAMINE
In the primary stage it causes vasodilation, vascular leakage, smooth muscle contraction (in the broncus)
The secondary phase typically occurs 2-8 hrs after resolution can last several days.
The main cause are eosinophils (type of white blood cell) residing in connective tissue underneath respiratory, gut, urogenital epithelium
It releases toxic proteins & free radicals
It causes intense infiltration of tissues with eosinophils & other acute chronic inflammatory cells & tissue destruction
What are Atopic Reactions
Local hypersensitivity reactions usually occur when offending allergen is confined to particular exposure site.
People prone to atopy often develop reactions to more than one environmental allergen causing yearly symptoms.
Some symptoms are
Urticarial -skin rash
Allergic rhinitis - inflammation and irritation of mucus in the nose
Atopic dermatitis - eczema
Bronchial asthma
What is Atopy
Atopy is the predisposition for people to develop allergic reactions when coming into contact with an allergen. People are more likely to have Atopy when there is a family history
Summary of Anaphylaxis
What is sepsis
It is a systemic reaction to a pathogen
What are the first 2 steps of sepsis
The pathogen attaches to the toll-like receptors on white blood cells. From this it causes the activation of plasma derived inflammatory mediators and cell derived inflammatory mediators
What is included in the plasma derived inflammatory mediators
The complement system
Coagulation factors
The kinin system
What is included in the complement system
This includes a number of proteins that induce vascular permeability and vasodilation. This results in heat and redness, it also causes antigens and antibodies to bind for the immune response
What is included in the coagulation factors
These are plasma proteins, in particular thrombin stimulates realse of CELL derived mediators for the cascade of inflammation to continue, Causes inappropriate clotting
What is included in the Kinin system
This is part of the plasma protein family leading to the activation of the inflammatory response including vasodilation, blood coagulation & pain
What is included in the cell derived inflammatory mediators
Histamine
Proinflammatory cytokines
Leukocytes
Prostoglandins
Where is Histamine produced
It is produced in the basophils and mast cells, it increases permeability so fluid leaks out into surrounding tissue
What are Proinflammatory cytokines
These are cell signaling proteins. Their net effects are fever, vasodilation, hypotension, oedema, elevated white blood count
What is the role of Leukocytes (white blood cells)
These adhere to adhesion cells and leave the circulatory system to extravascular tissue
What do Prostaglandins do
This cause inflammation, can trigger clotting cascade and innate organ failure
What are some symptoms that patients may be complaining of in sepsis
Sore limbs
Headache
low Temp
What are the late stages of sepsis
Depressed myocardial function
Leucopoenic -
Thrombocytopenia -
Thrombi
Pulmonary congestion
DIC - Disseminated intravascular coagulation
What triggers depressed myocardial function
You eventually become acidotic which leads to cellular oedema therefore causing less venus return to the heart and less cardiac output. The pathogen is also toxic to cardiac cells
What is Leucopoenia
This is the bodies ability to make new white blood cells. Becuase the body has been fighting the infection for so long it can not longer make as many
What does thrombi mean
Thrombi is the wide spreading clotting factors that is going on in the body
What causes pulmonary congestion
Pulmonary congestion is caused by the wide spread clotting factors occurring in the body, the pulmonary tissue is especially susceptible to inflammation and impairment
What is DIC
Disseminated intravascular coagulation. This is wide spread coagulation that can cause damage to the microvasculature which can cause organ dysfunction. This is also where strong anticoagulants are released therefore increasing bleeding
What is a indication of DIC
Bruising on their skin (blotches all over the skin)
This is because of the increased bleeding going on
What are some signs of MODS
Multiple organ dysfunction is serve pulmonary impairment with fluid building up in the lungs making gas exchange non effective.
another sign is VT or VF because of the heart being affected
Summary of sepsis
Is temperature a guide to sepsis?
No high temp is the FIRST response on the infection. Dont use it as a hallmark for diagnosis
