what does antibiotic choice for treating cellulitis depend on?
- whether it’s a reccurrent infection
- contamination level e.g. by seawater
- site e.g. eyes/nose
- is it an atypical infection?
what is clostridium?
genus of gram +ve bacteria, has many species that are important human pathogens including c.difficile.
what does a maculopapular rash consist of?
macules (flat lesions) and papules (solid raised lesions).
how do you classify flat lesions?
macules- <1.5cm
patches- >1.5cm
how do you classify solid raised lesions?
papules- <0.5cm
plaques- >0.5cm
what family causes measles?
Paramyxoviridae family
what is a prodrome?
early sign or symptom
what are the prodromes of measles?
high fever
3Cs-cough, coryza, conjunctivitis
what family causes rubella?
Paramyxoviridae family
what are the (early+later) symptoms of rubella?
lymphadenopathy-head and neck
then: maculopapular rash-face→trunk→limbs
what are some other terms for the parvovirus b19 infection?
Erythema Infectiosum
Fifth disease
Slapped cheek disease
what are the symptoms of parvovirus b19?
prodromes: fever, coryza, nausea
then: slapped cheek rash, maculopapular rash-trunk, arthritis
what are the main things that cause a viral maculopapular rash?
measles rubella parvovirus b19 roseola infantum enteroviruses
what causes roseola infantum?
HHV6/7 (human herpes virus)
what is an example of an enterovirus?
coxsackie A
wtf is a vesicle?
raised, clear, fluid filled lesion <0.5cm
what is a bulla?
raised, clear, fluid filled lesion >0.5cm
what does HSV stand for ?
herpes simplex virus
what do HSV1 and HSV2 cause?
HSV1: oral or genital herpes
HSV2: genital herpes
what are the types of herpes simplex?
2 types: HSV1 and HSV2
what diseases does VZV cause?
chickenpox and shingles
what does VZV stand for?
Varicella zoster virus
who does chickenpox usually occur in?
children
who is shingles more common in?
adults and immunosuppressed
what is shingles caused by?
reactivation of the virus that causes chickenpox-can happen anytime after the initial infection.
what are the main causes of viral vesicular rash?
herpes simplex
varicella zoster virus
enterovirus
poxvirus
what is a purpuric rash?
red or purple, non blanching
when does Henoch-Schonlein purpura usually occur?
childhood
what causes Henoch-Schonlein purpura?
IgA immune complexes-present in small blood vessel walls-triggers inflammation.
what are the main cutaneous signs of polyarteritis nodosa?
tender papules and plaques purpura livedo reticularis skin necrosis ulceration
what are purpura?
purple, non blanching lesions
what are some endocrine disorders that can cause skin diseases?
diabetic dermopathy
Acanthosis Nigricans
Eruptive Xanthomatosis
Necrobiosis lipoidica diabeticorum (NLD)
diabetic dermopathy: cause, where does it happen, treatment?
no known cause-associated w damage to small blood vessels+nerves that happens w diabetes
over bony areas
no treatment required
what are the causes of Acanthosis Nigricans?
visualisation of insulin resistance
also: certain medication, GI cancers
what is the cause and treatment of Eruptive Xanthomatosis?
uncontrolled type 1 diabetes and raised triglycerides-manage their diabetes
who does Eruptive Xanthomatosis often occur in?
young men
who does Necrobiosis lipoidica diabeticorum (NLD) mainly occur in?
women, but it’s v rare.
how do you treat Necrobiosis lipoidica diabeticorum (NLD)?
no treatment required unless it’s an open sore.
what is a pustule?
elevated lesion containing purulent fluid which might be white, yellow or green in colour (pus)
what is the time scale for acne drugs?
treatments can take up to 8 weeks to work
have to continue them for at least 12 weeks
what does teratogenic mean?
when a drug/agent can disturb development of a fetus and can cause malformation or even death
what are the general side effects of acne medications?
dry skin
skin thinning
mood swings
depression
what is an extensor surface?
area of skin outside a joint-eg front of knee
what are flexor surfaces?
where folded skin touch-inside a joint-opposite the extensor surfaces. eg back of knee
DEFINE infection.
Inflammatory response to microorganisms or invasion of normally sterile tissues
DEFINE bacteraemia.
Presence of bacteria in the blood
DEFINE sepsis.
life-threatening organ dysfunction caused by a dysregulated host response to infection
what are the criteria for septic shock?
persisting hypotension despite fluid correction and vasopressors
hyperlactaemia-serum lactate>2mmol/L
why is identifying sepsis important?
can be triggered by any infection
as hours without antibiotics goes up, survival rate goes down
rapid progression
what are the 3 most common bacterias that cause sepsis?
staph aureus
e.coli
pseudomonas spp
When a patient goes into septic shock they can have raised blood glucose through the actions of…
cortisol
catecholamines
CRP (c reactive protein)
in the gram stain, which colour is positive and which is negative?
purple=positive
pink=negative
what gram type is more susceptible to beta lactams and why?
gram positive=because they target the cell wall.
what are 2 examples of antibiotics which target the bacterial cell membrane structures?
polymyxins
daptomycin
what are 2 examples of antibiotics which target bacterial folic acid metabolism?
trimethoprim
sulfonamides
what are 3 examples of vasopressors?
noradrenaline
vasopressin
metaraminol
what is the process of increased keratin production and migration toward the external surface called?
cornification
what is flexural psoriasis?
psoriasis found in the folds of ur body.
what type of skin has a lower concentration of touch receptors?
hairy (thin)
what are differences in sensitivity of different parts of skin related to?
differences to underlying neurophysiology.
where exactly are the Meissner’s corpuscles found?
Sitting in the dermal papilla
what is the embryological origin of the epidermis?
ectodermal
what do keratinocytes do?
produce keratin (a fibrous protein)
what is palmoplantar skin?
on palms and soles
why is palmoplantar skin so much lighter than nonpalmoplantar skin?
melanocyte density is five times lower.
what is the most commonly diagnosed cancer worldwide?
skin
what are NMSCs?
non melanoma skin cancers-from basal cells (BCC) or keratinocytes (squamous cell carcinoma)
what are the 3 key ways transformation into cancer can occur?
chemical carcinogens
radiation
viral oncogenes
what is a virulence factor of streptococcus pyogenes in the development of sepsis?
Protein F-facilitates attachment to various host cells in streptococcus pyogenes.
what does seborrheic refer to?
the sebaceous glands-diseases characterized by excessive secretion of sebum or an alteration in its quality, resulting in an oily coating, crusts, or scales on the skin.