Toni and Dave Flashcards
What is an urticarial rash?
AKA hives. A raised, red itchy rash, usually as the result of an allergic reaction.
What is atopy?
The genetic tendency to develop allergic diseases. It is usually related to a heightened response to allergens, especially food and airborne allergens. AD.
describe the pathophys of anaphylaxis
IL4 causes B cells to change from making IgM IgE. IgE binds to mast cells and basophils. Release of histamine.
Histamine binds to H1 receptors which is coupled to the Gaq/11 pathway activates PLC and increases intracellular Ca2+ levels, causing bronchoconstriction and increased vascular permeability.
Histamine also binds to H2 receptors, which is Gas coupled. It is highly expressed in B cells, T cells, dendritic cells, gastricparietal cells, SMCs and brain and cardia tissues. Activation causes airway mucus production, vascular permeability and secretion of gastric acid. It also causes the relaxation of SM in blood vessels accounting for the vasodilation.
difference between food allergy and intolerance
A food allergy causes an immune reaction that affects numerous body organs and causes a range of symptoms.
An intolerance has fewer symptoms and is often limited to digestive problems. Bofy’s inability to process the food- lack enzyme.
tests for allergy
Skin prick test- drop of liquid with allergen onto forearm, skin under drop is gently pricked. If you are allergic, then an itchy red bump will appear within 15 minutes.
Blood tests- either instead of or alongside the skin prick test. Analysis for antibodies specific to an allergen.
Patch tests- used to investigate contact dermatitis. Small amount of suspected allergen is added to special metal discs which are taped to the skin for 48 hours and monitored for a reaction.
Elimination diet- avoid eating a certain food to see if it makes a difference to the symptoms, a few weeks later you might be asked to eat the food again to check for a reaction.
Challenge testing- eat food you suspect to be allergic food in increasing amounts to look for a reaction.
mechanism of pyrexia
Immune system secretes pyrogens, which inhibit heat-sensing neurons and excite cold-sensing ones. This tricks the hypothalamus into thinking the body is cold, which leads it to raise body temperature.
IL6, TNFa are endogenous pyrogens.
Act on preoptic nucleus on hypothalamus.
Excessive high temp denatures proteins= coag cascade initiated= DIC.
distinguish between food poisoning and food-borne infection
Foodborne infection is an infection caused by eating food contaminated with live organisms or their toxins. It can also include allergic reactions and other conditions where the food acts as the carrier of an allergen. Food poisoning is a form of food borne infection and is caused by the ingestion of preformed toxins e.g. heavy metals.
how does campylobacter cause the symptoms seen in food poisoning?
o Penetrates the GI mucus by using its high motility and spiral shape. It binds to gut enterocytes and induces symptoms by releasing toxins, mainly enterotoxin and cytotoxins.
how does salmonella cause the symptoms seen in food poisoning?
o Induces its own phagocytosis into cells, penetrate epithelial cells in the intestinal wall. Has Salmonella Pathogenicity Islands which encode for secretory systems and multi-channel proteins that allow the bacteria’s effectors to enter the cell cytoplasm. The effectors then activate signaling that causes reconstruction of the actin cytoskeleton of the host cell allowing the bacteria to enter and cause its effects.
how does listeria cause the symptoms seen in food poisoning?
Release of virulence factors e.g. internalin, listeriolysin O, phospholipases allows it to enter cells. Spreads by a process involving actin polymerization. Corsses intestinal wall at Peyer/s patches to invade the mesenteric lymph nodes and blood. Main target is liver, where the bacteria divides in hepatocytes.
how does E. Coli cause the symptoms seen in food poisoning?
Releases toxins such as heat-labile enterotoxin, cytolysin and shiga toxin, which cause symptoms
What steps should the GP/HCP do to investigate and report a suspected outbreak?
o Health protection regulations (2010) say that HCPs have the legal obligation to report suspected outbreaks to the Proper Officer.
o This regulation also requires laboratory testing of samples to identify the causative agent- should then notify PHE.
o HCPs should give info about the area and environment involved, characteristics of the suspected outbreak, person directly affected by outbreak and the population at risk.
o This data is then inputted into HP zone which allows for surveillance and case management throughout England- allows us to view a summary of all current activity, run queries and extract timely and comprehensive info on incidents and outbreaks.
Importance of reporting of communicable disease in terms of outbreak and management control (CCDC)?
o The protection of the community against infectious disease and other dangers to health
o The prevention of the spread of infectious disease
o The provision of assistance to any other person who exercises functions in relation to above
symptoms in adults of dehydration
feeling thirsty, dark and strong smelling urine, feeling dizzy or light-headed, fatigue, dry mucous membranes and eyes, decreased urinary frequency, muscle cramps, headache, dry, cool skin, fainting, tachycardia, tachypnoea, confusion.
symptoms of dehydration in children
dry mouth and tongue, no tears when crying, dry nappies for over 3 hours, sunken eyes and cheeks, sunken fontanelle, drowsy, lack of energy and irritability.
