formative questions Flashcards
A 58 year old man presents in July with blisters on the dorsal aspect of his hands which have been appearing over the last few months, crust over and heal leaving scarring. He works as a joiner and is aware that his skin has also been more fragile than usual. You notice that he has a lot of hair growing on his cheeks. He is generally well and on no medication
What is the most likely diagnosis?
porphyria cutanea tarda
what is porphyria cutanea tarda
a rare disorder characterised by painful blistering skin lesions that develop on sun-exposed skin (photosensitivity)
it is caused by the deficiency of the enzyme - uroporphyrinogen III decarboxylase
characteristics of mucosal membranes
-often affected by skin disease eg blistering disease
-are not keratinised
-have many sensory functions eg taste
-contain glands eg lacrimal glands / sebaceous glands
> they are highly specialised for function
which is the component of the MRSA stain which causes severe skin infection such as necrotising fasciitis
panton valentine leukocidin
-it is a cytotoxin associated with highly virulent strains of staph.aureus causing necrolytic skin infections
function of sebaceous glands
maintain skin barrier
function of meissners corpuscle
vibration sensation
function of pacinian corpuscles
pressure sensation
functions of apocrine glands
scent glands
function of eccrine glands
moisten palms/soles for grip
lymphatics function
immune surveillance
journey of RBC from big toe to heart
deep plantar vein >
great saphenous vein >
femoral vein >
external iliac vein >
common iliac vein >
abdominal vena cava >
inferior vena cava >
RA
T/F nails are biochemically similar to hair
T - nails are made of hard and densely packed keratin, similar to hair
fingernails grow at 0.1mm per day, toe nails are slower, are commonly affected by disease
journey of RBC from lungs to big toe
pulmonary vein >
left side of heart >
aorta >
abdominal artery >
common iliac artery >
external iliac artery >
femoral artery >
popliteal artery >
dorsalis pedis
what phases are: anagen, catagen, telogen
anagen = growing phase
catagen = involuting phase
telogen = resting phase
T/F type II sensitivity is IgG and IgM mediated
T
what is C
melanocytes
what is A
keratin layer
what is in F
epidermis and dermis
where are fibroblasts found
G - the dermis
which is the sebaceous gland
D
define skin failure
loss of normal temperature control with inability to maintain core body temperature
failure to prevent percutaneous loss of fluid, electrolytes and protein with resulting imbalance and failure of the mechanical barrier to prevent penetration of foreign materials
characteristics of Langerhan cells
-formed in bone marrow
-can be found in prickle cell layer of the epidermis
-can be found in dermis
-can be found in lymph nodes
-present antigen to sensitised lymphocytes
T/F type III sensitivity is immune complex mediated
T
functions of the skin
barrier function
thermo-regualtion
immune defense
metabolism and detoxification
communication
sensory
A 3 year old boy presents on a sunny day in June. His mother reports he keeps crying and rubs at his skin when playing outside and this has been going on for a few weeks. His skin is sometimes a bit red, but there is never a rash and his skin is clear on examination now. He is skin type 1 with a few freckles evident, generally well, on no medication and there is no family history of skin problems.
What is the most likely diagnosis?
erythropoietic protoporphyria
what is erythropoietic protoporphyria
an inherited porphyria resulting in the accumulation of protoporphyrins in RBCs that cause acute painful photosensitivity and potential liver disease
typically presents in early childhood with immediate pain and crying upon exposure to sunlight
caused by deficiency of ferrochelatase
what cell types are found in the dermis
fibroblasts
lymphatics
ground substance
what are the descriptions for each of these
what enzyme is deficiency in acute intermittent porphyria
PBG (porphobilinogen) deaminase
-results in acute neurotoxic reaction in many tissues
where is Vit D metabolised
keratinocytes - B
what provides tensile strength
collagen - found at G
where does epidermal proliferation occur
cells in epidermis proliferate form the basal layer
labelled C
where is energy stored
E - subcutaneous fat
what is the enzyme deficiency responsible for erythrpoietic porphyria
ferrochelatase
which is:
nail bed
nail matrix
nail plate
hyponychium
lunula
nail bed = F
nail matrix = E
nail plate = A
hyponychium = G
lunula = B
characteristics of normal skin
-cells taken 28 days to migrate from basal > keratin layer
-nuclei loss starts in the granular layer and is complete in the keratin layer
-80% of the keratin layer is keratin and filaggrin
-the granular layer is usually 2-3 cells thick
-filaments are intercellular
what percentage of skin problems make up all GP consultations
15-23%
where is the papilla and matrix
J
which is the arrector pili muscle
I
function of fibroblasts
produce collagen
function of sebaceous glands
produce sebum which lubricates the skin
melanocytes function
protect DNA by producing melanin which absorbs UV radiation
function of the keratin layer
impermeable to water
what is A, B and C?
A = keratin layer
B = granular layer
C = prickle cell layer
what is D, E, F?
D = basal layer
E = dermo-epidermal junction
F = dermis
what is the definition of prevalence
the proportion of a population affected by a disease at any given time
function of impedin
enables the organism to avoid the host defence mechanisms
function of invasin
enables the organism to invade a host tissue
function of aggressin
causes damage to the host directly
function of adhesin
enables binding of the organism to host tissue
function of modulin
causes damage to the host indirectly
which systems are important in maintaining good circulation in the lower limbs
muscle pump
venous valves
pulse pressure
what is the description of each these
foetal development facts …
sweat glands do not develop until 6 months gestation
melanocytes migrate to the skin from the neural crest
blaschko patterns is developmental and not along nerves, vessels or lymphatics
the basal layer is the most metabolically active
where can highly metabolically active small cuboidal cells be found
basal layer
where can odland bodies be found
granular layer
where can corneocytes be found
keratin layer
where can polyhedral cells and desmosomes be found
prickle cell layer
T/F topical steroids are lipophilic
T
- this allows passive diffusion across the plasma membrane where they combine with cell receptors and bind to steroid responsive elements in the DNA
topica steroids are:
anti-proliferative
anti-inflammatory
vasoconstrictive
describe this lesion
plaque
well-defined
scaly
T/F the developmental growth pattern of skin follows Blaschko’s lines
T
where do these dermatophyte infections reside :
tinea cruris = A
tinea unguium = B
tinea barbae = C
tinea pedis = D
tinea capitis = E
tinea magnum = F
tinea corporis = G
A = groin
B = nails
C = beard
D = foot duh
E = scalp
F = hands
G = body
sorry cba making a q for this
description of creams
semisolid emulsion of oil in water - cosmetically acceptable, non-greasy
description of ointments
semisolid grease/oil - has no preservative in it, greasy, less cosmetically attractive
description of lotions
liquid formation
description of gels
thickened aqueous solutions
descriptions of pastes
semisolids, stiff, greasy, difficult to apply, often used in cool/drying/soothing bandages
investigation for:
ring worm
shingles
scabies
impetigo
T/F cafe au lait macules are present in 90% of cases of Neurofibromatosis type 1
T
what type of inheritance is this ?
autosomal dominant
which strains of HPV are most common in warts and verrucas
types 1-4
T/F cream are more likely than ointments to cause sensitisation
T
-creams contain preservatives
T/F an adult requires 10mg of ointment for an overall application
F - at least 30mg
A 18 month old child presents with his mother in your GP surgery. He has been affected with a flexural rash for the past month. The rash is seen on examination as shown in the diagram. The child scratches the rash, often leaving excoriations. The child has no other known health problems, however his 6 year old sister has asthma.
what is it
atopic eczema
A 20 year old woman presented with gradually worsening areas of scale and erythema with slight itch in the distribution shown. There is no previous or family history of skin problems and she is generally well. She is not currently using any therapies. Most likely diagnosis ?
psoriasis vulgaris
A 28 year old surgical theatre nurse with no history of skin disease presented with chronic erythema, scale and itch of both hands as shown. It improved when she was on holiday but then steadily deteriorated on return to work and she has since been off on sick leave.
patch testing
A 66 year old man presented with a 2 week history of a blistering rash. Which clinical feature would be typical of diagnosis of Bullous Pemphigoid?
a history of itch in the months preceding the onset of blistering
what is bullous pemphigoid
a rare autoimmune disease, typically affects people over 60
is a result of an attack on the basement membrane of the epidermis by IgG/ IgE
what makes up the Atopic Triad
(atopic) eczema
asthma
hayfever
T/F barley doesn’t contain gluten
F - does contain gluten
(derm relevance = dermatitis herpetiformis is managed with a gluten free diet)
The woman is a 20 year old waitress. She is already very conscious of her skin at work and does not want to have to put any greasy or smelly treatment on as it may show on her shirt.
which therapy is best suited for her?
vit D analogue cream
1st line treatment of rosacea
topical metronidazole
what pathology is this ?
intra-epidermal bulla = bullous pemphigoid
what pathology is this ?
hyperkeratosis = psoriasis
what pathology is this ?
papillomatosis
what pathology is this ?
sub-epidermal bulla = pemphigus vulgaris
what pathology is this ?
spongiosis
