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