Infections Flashcards
Folliculitis
isolated infection of the hair follicle only
furuncle
infection of hair follicle and sebaceous gland
Carbuncle
infection of hair follicle and many sebaceous gland, seen in diabetes
cellulitis
inflammation of the subcutaneous tissues in skin.
infected hair follicle is most commonly infected by
S. aureus, also some skin bacteria and fungi
symptoms of furuncle
warm and painful, possible malaise and fever
spread of a furuncle
through path of least resistance in blood or lymph.
Impetigo is
a non specific epidermal alternation and superficial dermal inflammation
course of impetigo
starts as a macule and becomes a larger postule, postule ruptures and results in erosion and dry crusted honey colored serum
spread of impetigo.
from veins to heart, can cause endocarditis, to lungs can cause lung abscess to left heart can cause endocarditis, to other organs and body, can cause sepsis and ascess
impetigo is aquired through
direct contact with skin
impetigo is caused by
S. aureus and S. pyogenes and is primarily found in children.
damage is impetigo is a form of
direct injury.
CSF in Bacterial Meningitis
cloudy, low glucose, high protein with neutrophils and you will be able to isolate the orgnanism
CSF in Fungal Meningiits
clear, glucose and proteins are normal, you can isolate the organism, can be acute or chronic. You have neutrophils AND lymphocytes in CSF.
CSF in Viral Meningitis
clear less inflammtory response, usually lymphocytes if anything. can image the firuse, proteins are normal, glucose can be depleted
CSF for Tuberculosis in the meninges
usually chronic, use acid fast stain, low in glucose and high in proteins, will form a cob web lesion.
Waterhouse Friderichsen Syndrome
must have Bilateral adrenal hemorages, DIC, and be infected with Neisseria meningtidesa gram negative diplococci.
WF syndrome causes
sepsis
DIC complications
systemic activation of coagulation that results in formation of thrombi thorughout the microcirculation, consumption of platelets and coagulation factors. (consumptive coagulopathy. fibrinolysis is activated. leads to uncontrolled beleding. Fever, hypotension, Purpura, Echymossis, Schock.
Neisseria miningitis is transmitted by
respiratory water droplets.
Bronchopenumonia (lobular
has a patchy appearance, affects the bronchioles and spreads to the surrounding alveoli . It infects the lung parenchyma and sits in the bronchioles where it spreads. Destruction of bronchioles and alveoli by nutrophils. this leads to scar formation. . caused most often by S. Aureus. can also be caused by Kelbsiella, E. Coli, Psuedomonas.
consolidation
area of lung tissue filled with fluid.
Bronchopneumonia signs and symptoms.
productive cough, fever shaking, chills, dyspnea, tachypnea, chest paind during breaths.
X-ray for bronchopneumonia will show
splotches of hyper dense areas
Lobar pneumonia,
caused by infections with multiple microorganisms and chronic infections like streptococcus pneumoniae (higher frequency in COPD, CHF, Congenital immunodeficiency and people of absent spleen function.
route of entry of Lobar pneumonia
enters in water droplets and deposits in the little anatomical slits in between the alveoli the pores of Kohn, they keep spreading this way and this is how the whole lobe gets infected.
in lobar pneumonnia X-Ray
you will see a whole lobe as white
4 stages of pneumonia
congestino stage, red hepatization, grey hepatization, resolution.
congestion stage
lobes appear red, boggy and heavy with vascular congestion appearance histologically. This is also proteinaceous fluid scatterd with neutrophils. Dilation occurs and the alveoli becomes engorged with pus
Red hepatization.
occurs within a few days alveolar spaces are packed with neutrophils and looks red due to RBC’s and fibrin. feels like a liver
Grey hepatization.
the lungs appears dry and grey and firm because of lysing RBC and persistance of fibrino suppurative exudate. congestion and fibrin disappear and Nuetrophils are replaced by macrophages
REsolution
is more in mild cases where the exudate is enzymatically digested. you won’t see scarring in this one.
Lobar Pneumonia is found more in
older and immunocompromised individuals. people with chronic diseases.
The infection in Bronchopneumoia becomes persistent becasue
the bronchus infection is invading the surroundning alveoli.
Atypical pneyumonia
most commonly caused by mycoplasma pneumonea. no correlation between repiratory dysfunction and clinical findings.
Meningitis
pyogenic inflammation of the meninges and subarachnoid space, gross you can see dull congested purulent exudate, micro you can see PMN, fibrin, vascular
Clinical symptoms of Meningitis
Fever- Headache, cloudy conscoiousness, neck stiffness
diagnose meningitis with
Spinal tap
Meningitis in infancy to childhood is caused by
Strep. Pneumoniae, N. Meningitidis, H. Influenzae
Meningitis in adolescence is caused by
N. Meningitidis
Meningitis in 20-60 years is caused by
strep. Penumoniae, N. Meninigitidis, L. Monocytogenes, Gram Negative Bacilli.
Nisseria Gonorrhoeae
Gram -ve dipplococci, sexually transmitted disease
Gonorrhea male symptoms
urethritis, epididymitis, urethral discharge and dysuria, Oropharyngitis and proctitis discharge is thick creamy and yellowish in color
Gonorrhea female symptoms/diagnosis
cervicitis, salpingitis, perotnitis, Dysuria, Vaginal discharge, inter menstrual bleeding. Pelvic inflammatory Disease, scarring of fallopian tubes and infertility
Gonorrhea dissemination/diagnosis.
hematogenous, is rare and can cause, Tenosynovitis, arthritis, hemorrhagic skin lesions, endocarditis, and rarely meningitis.
Daignosis- microscopy of exudate you wil see PMN and Gram negative diplococci
Gonorrhea in a newborn
passed on during travel through cervix. can cause purulent conjunctivitis and opthalmia neonatorum. use erythromycin and silver nitrate eye drops after birth. Diagnosis- you need to culture the exudate- essential because gram negative diploccoi are normal part of vaginal flora.
Gonorrhea differential
Chlamydia- (is actually a more common disease in the US)
Typhoid Fever (Salmonella typhi)
gram -ve bacilli, aquired through ingestion, inters the ieal wall and into the blood stream, during first week causes bacteremia, liver enlarged, typhoid nudels of kumpffer cell hyperplasia, hemorrhagic necrosis, collection of macrophages- second weedk. spleen enlarged and softend with splenitis and typhoid nodules. Organism now excreted through the gall bladder and reenter gut wall. Sensitization occurs and contact with organisms produces lymphoid hypertrophy and necrosis in the mucosa -week 3
Lesions of enteric fever
Ileum you will see lymphoid hypertrophy of peyer’s patches, necrosis, ulceration. you won’t see PMN only macrophages and erythrophagocytosis. Mesenteric lymph nodes will be enlarged with hemorrhagic necrosis.
Clinical features of enteric fever.
Fever, toxic appearance, leukopenia, bradycardia, endotoxin produces depression of heart and bone marrow, ulcers heal without scarring, complications are perforation peritonitis, bleeding in the 3rd and 4th weeks.
Diagnosis of enteric fever
end of week 1 do a blood culture and look for lysis of macrophage releasing large number of bacilli, week 2 you can check feces and urine, week demonstrate antibodies and do a WIdal test,
Chronic colonoization of gall baldder takes place then you need to
undergo a cholecystectomy
Three common species of Staphylococci
S. aureus, S. Epidermidis, S. Saprophyticus.
two typs of lesions caused by staph
inflammatory and toxin mediated
Postpartum mastitis is caused by
Staphylocci
Osteomyelitis
organisms reach bone hematogenously or directly adjacent abscess or through traumatic implanttation.
inflammatory lesions of Staphylococci
Folliculitis, furuncle, carbuncle, cellulitis, impetigo, paronychia, surgical wound infection, postpartum mastitis, bacteremia, endocarditis, osteomyelitis, bronchopneumonia, bacteremic abscesses, 80% are penicillin resisitant
Toxin mediated lesions of staphylococci
food poisoning- enterotoxin
Toxic shock syndrome- exotoxin
Scalded Skin Syndrome- Exfoliatintoxin
Streptococci vs staphylocci
sterpto presents in pairs or chains and staphy in clusters, Strepto produces hemolysis. Staph doesn’t.
Strepto causes direct damage in
suppurative, cellulitis, abscess, penumonia,
Strepto as exotoxin damage in
Scarlet fever
Strepto has indirect damage by
immune response
Strep Pneumonia aka pneumococcla pneumonia
causes lobar pneumonia, happens in healthy strong young adults exposed to cold strain or exhaustion, causes caugh fever, chest pain, bloddy sputum passes thorough different stages
Streptococci damage by immune response
there can be cross reacting antibodies that get deposited on normal tissue antigens and can cause rhumatic fever, also immune complex deposition in organs in teh glomerulonephriits
Rheumatic fever
Cross reacting antibodies, intial infection is a strepto sore throat or a skin infection, there is a lag period of 2-3 weeks then you develop a fever, polyarthritis, cardits, chorea, skin nodules, erythema. Antibodies generated to M protein cross reacting with tissue glycoprotein of joints, heart skin etc.
in rheumatic fever, antibodies get deposited
n the tissues and elicit an inflammatory repsonse. this is not a direct damage of bacteremia or damage by the bacteria,
Carditis
aschogg bodies in the heart, can become chronic and cause mitral stenosis.
Actinomyocosis
is a branching filamentous gram positive Facultative anaerobe. presents in gingival areas, nose throat and femal genitalia. OPPORTUNISTIC pathogen. needs penetration of the basement membrane. can also be seen in the cervical, thoracic, pelivic or abdominal cavity following surgery. usually a dental injury that develops an abscess that can burst with sulfur like granules. you can see bacteria in puss, in a gram stain, they are comprised of branching rods,
Actinomyoces vs Nocardia
Actiomyces is acid fast negative, nocardia is positive.
Clinical signs of actinomycosis
sores in skin, weight loss and fever, presentation of tender, palapable reddish purple swelling in jaw with abscess containing sulfur granuels.
Cytomegalovirus
Herpes viral infection, prominent in immunocomprimised individuals so it is opportunisitc, also seen in transplant patients and vertical transmission. transmission can happen at any age, if you are immunocompetent you will be asymptomatic but it then hides in the lympohcytes. can cause retinitis with kids. can go anywhere in the body.
Body response to CMV
a lymphocytic response, you will also see cytopathic effects like inclusion bodies . Inclusion bodies will have owl eye appearance with inlusion bodies in the cytoplasm and intranuclear.
Herpes Zoster
primary infection is chicken pox, secondary infection is a latent infection shingles. you will see inclusion bodies when using a Tzank spmear, lok for three M’s multinucleation, Molding of the nucleus and margination of the chromatin to the periphery you will also see only intranuclear inclusion bodies. is infected by contaminated water. recurrence can be caused by stress due to immunosuprresion of cortisol. can lead to meniingitis.
Rabies- Rhabdovirus
has negri bodies which are cytoplasmic inclusion bodies only and appear lighter. incubation time is going to be long because t takes time for the infection to travel up the nerve, causes fever chills, nausea, malaise, fatigue, occasional photphobia hydrophobia, the pharyngeal muscels will spasm wheneating or drinking. CNS excitability, where slightes touch hurts.
Viral Myocarditis
dilated heart may be normal, cut surface: mottled surface due to hemorrhages and pale flabby myocardium you will see interstitial inflammation mainly lymphocytes and a few plasma cells, you will also see focal necrosis adjacent to inflammatory cells. is direct viral toxicity, cell mediated reactions against infected myocytes.
myocarditis vs. MI
you will see Nuetorphils in acute and macrophages in chornic MI, and sheets of necrosis, in viral infection you will see lymphocytes, monocytes inflitration cuasing inflammation, plasma cells may be antibody response.
Rocky Mountain Spotted Fever R. rikettsii
will see petechial rash, thrombus, vascular necrosis, hemorrhagic vasculitis, inflammtory cells. Obligate intracellular bacteria, as it infects the lining of blood vessels it causes damage that can lead to thrmobi formation and hemorrhage. can also cause vasculitis. Spreads through venous and lymphatic systems. found in georgia, tennesse arkansas and oklahoma.
endemic typhus vs, R. rickettsii
R. rickettssi is centripital where it starts in periphery and moves toward trunk, typhus moves from trunk to extremities but not palms and soles. found in Georgia, tennessee arkansas and oklahoma
Oral Thrush, Candida Albicans
gross: white patchy plaques and inflamed oral cavity, micro is pseudohypae with single chain of bdded cells. can be easily scrapted off to reveal hyperemic and inflamed mucosa. found in immuncompromised babies and young childre, aids’ patients. use of broad spectrum antibiotics can also cause it. can disseminate to cause abscesses in the liver kidney and heart. can also be found in esophagus, nails skin, hair, vagina and GIT
Pneumocystis jiroveci
opportunistic fungi, micro has foamy pink staining exudate, septae are thickend by edema and minimal mononuclear infiltrate. you can visual the actual organism with a silver stain and it is shaped like cups or round balls. all are exposed to this but it affects immuno compromised. it waits until CD 4 t cell coundt is low. confined to lungs. dry cough because supparte is too thick.
