Module #5-Path: furncale and carbuncle Flashcards
Gram Positive Bacteria are considered an exotoxin, what are the gram positive bacteria?
Staphylococci
Streptococci
Corynebacteria Diptherae
Actinomyces Israelii
What is the pathogenesis for gram positive exotoxins?
Superantigens
Give an example of a gram positive bacteria exotoxin infection
Toxic Shock Syndrome: intravaginal tampon if left too long leads to growth of staph aureus —- leads to release of exotoxin in circulation — leads to conjunctivitis and vomiting
Gram negative bacteria are considered an endotoxin, what are the gram negative bacteria?
N. meningitides N. Gonorrhoea Salmonella Typhi Klebisella, E. coil, Pseudomonas (bronchopneumonia) Bartonella Henslae
What is the pathogenesis for gram negative endotoxin
Possess a lipopolysaccharide wall (LPS). Bacteria lysis leads to large amounts of LPS in blood — this binds with lipopolysaccharide binding protein (LBP) forming an LPS-LBP complex — LPS-LBP is picked by macrophages that release TNF – damage of endothelium —– PMNs bind onto damaged epithelium —-release IL-1 procoagulant factor —DIC
What is the importance of infectious diseases?
Major problem in spite of improved living conditions, vaccinations, antibiotics
More than 10 million deaths/yr in developing countries
New and fatal infections ares still being recognized
What are some barriers to bacterial invasion?
Skin-Keratin Layer
IgA in mucosa, mucus in gut, lungs
Ciliary movement in bronchial passages
Normal Commensals
What are the steps in the diagnosis of infectious disease?
Clinical features: hx, PE
Knowledge of epidemiology: common infections in the geographic area
Isolate the organism: pus, bl, tissue, fluids
Ab response: demonstrate rising titers
Biopsy
Therapeutic response
What are key cells seen in bacterial, viral and fungus infections?
Bacterial: polymorphonuclear Leukocytes
Virus: Macrophages, lymphocytes
Fungus: mixed PMN + lymphocytes + Macrophages + Giant Cells
Bodies response to infection differs depending on the organism. What is the difference between a local and a systemic infection ?
Local: inflammation at the site of infection
Systemic: Response to infection
mediated through cytokines, fever/headache/leukocytosis, increased metabolic rate and memory cells for the future
How can infections spread through the body?
Lymphatics: Lymphadenitis (local and distant)
Venous (regional veins, thoracic duct) – reach vena cava and R heart —- right sided valve = endocarditis
Reach the lung and pulmonary artery and produce lung abscess
Through pulmonary veins – L sided heart (mitral, aortic valve) = endocarditis
Distant abscess: brain, kidney, spleen, brain
What is bacteremia?
Spread of bacteria in blood
–bacteria destroyed by immune system = no symptoms
What is septicemia?
Bacteria in blood multiply
- -usually accompanied by fever, chills = serious condition
- -can set up distant foci of spread in other tissues = septicemic abscess
What are the steps in a bacterial infection?
Enter the body: ingestion, inhalation, and inoculation
Multiply locally
Spread: lymphatics, blood (plasma, RBC, leukocytes), nerves
Tissue planes, BMs, pleura, pericardium, peritoneum, meninges
What are the types of tissues responses (to damage)?
Acute inflammation: bacterial Lymph Mononuclear: Virus Granulomatous: TB Mixed acute/chronic:Fungus Eosinophils: parasites Fibrosis: Schistosoma Necrosis: Clostridia (Gas gangrene) Pseudomembrane: diphtheria, Clostridium difficile
What is an example of a gram + enterotoxin and exofoliatintoxins?
Enterotoxin: food poisoning
Exofoliatintoxin: Scaled skin Syndrome
What is folliculitis?
Inflammation/Infection of 1+ hair follicle w/o accessory glands
What is a furuncle (boil)?
Single infected hair follicle + accessory gland
accumulation of pus/dead tissue
What is a carbuncle?
Collection of several furuncles
numerous pus filled w/PMNs, macrophages, necrotic cells
skin — abscess — lymphatics —- venous and other organs
Where is a carbuncle normally found?
Nape of the neck
Carbuncle is typically found in what kind of patients?
Diabetic patients because patients do not heal properly (due to decreased blood flow and polyneuropathy) and they have a lot of glucose that the bacteria is going to feed on
What two bacteria are the most common in a furuncle and carbuncle?
Staph Aureus
Strep Pyogenes
What is the pathogenesis for a furuncle and carbuncle?
Direct damage via enzymes (streptokinase and hyaluronidase)
How does a patient present with a furuncle and carbuncle?
Cardinal signs of inflammation and pus
Diagnosis for carbuncle or furuncle?
History and physical; no biopsy
What would you see on histology for a furuncle or carbuncle?
Liquefactive necrosis or pus with PMNs, macrophages and necrotic cells
What is the healing course for a furuncle or carbuncle?
Most likely outcome is fibrosis because the infection gets down to the dermis (so you will see a scar)
Impetigo is a superficial bacterial skin infection, caused by what two types of bacteria?
Staph. Aureus
Strep Pyogenes
What is the classic sign you see on physical examination on these patients?
Honey colored scabs formed dried serum on an erythematous base
What is the course of impetigo?
Begins as a small pustule that ruptures and leaves an erosion
What patients are most likely going to present with impetigo?
Children, esp kids in daycare and rubbing their face with dirty hands
spread via fomites (aka inanimate objects) from child to child from one side of the cheek to the next
most common on face near mouth and nose
A patent with impetigo, it will resolve with no scar, why?
Because the bacteria only affects the epidermis
What type of hypersensitivity is impetigo?
Type III - immune complex mediated
What is a complication patients can get with Strep Pyogenes in impetigo?
Post streptococcal glomerulonephritis (because this is a type III hypersensitivity) —- look for hematuria, proteinuria, polyuria, oliguria, HTN and periorbital edema
this is called NEPHRITIC SYNDROME (2-3 weeks)
What additional symptoms can patients have with impetigo?
fever and signs of acute inflammation
