Clinical Science Flashcards
Symptoms and Mx of hereditary angioedema
Painful macular rash followed by painless subcutaneous/submucosal swelling. May have abdo pain from visceral swelling
Mx: IV C1-inh concentrate or FFP if not available
Steroids may help prophylaxis
Hereditary angioedema: inheritance, what’s the problem, investigations during attacks and between them
Auto dom
Low C1 inhibitor
During attacks: low C1-inh
Between attacks: low C4 (and C2)
Action of alpha-1 adrenoceptor
Vasoconstriction
GI sm relaxation
Salivary secretion
Action of beta1 and beta2 adrenoceptors
Beta-1: in the heart, positively chronotropic and ionotropic
Beta-2: vasodilatation, bronchodilation, relax GI sm
Causes of hyperuricaemia
Associations with hyperuricaemia
Increased production: high purine diet, increased cell turnover, cytotoxics, psoriasis, exercise, myeloproliferative disease
Decreased excretion: renal failure, lead, alcohol, aspirin, diuretics, pre-eclampsia
Associations: HTN, hyperlipidaemia, metabolic syn
Genetic abnormality and symptoms of kleinfelters
47 XXY
Tall, infertile, gynaecomastia, small hard testes, lack secondary sexual characteristics, increased gonadotropin levels
name the gram positive rods
what’s the mneumonic
A - actinomyces B - bacillus anthracis C - clostridium D - diphtheria (corynebacterium diphththeriae) L - listeria monocytogenes
which antibiotic is active against both MRSA and VRE (vanc resistant enterococci)?
how does it work?
SEs
linezolid
inhibits bacterial protein synthesis therefore bacteriostatic
also effective against GISA (Glycopeptide Intermediate Staphylococcus aureus)
thrombocytopenia, monoamine oxidase inhibitor
What is the role of the p53 gene?
What is the effect of its mutation?
Tumour suppressor gene
Mutation seen in breast, colon and sarcomas
Mutation seen in Li-Fraumeni syndrome (lots of cancers)
type 1 hypersensitivity
pathology, example
Anaphylaxis
antigen reacts to IgE on mast cells
anaphylaxis, atopy
type 2 hypersensitivity
pathology, example
Cell Bound
IgG or IgM binds to antigen
Goodpasture’s, pernicious anaemia, acute haemolytic transfusion reaction
Type 3 hypersensitivity
pathology, example
Immune complex
free antigen and antibody (IgA, IgG) form complex
SLE, EAA, post strep glomerulonephritis
Type 4 hypersensitivity
pathology, example
Delayed hypersensitivity
T cell mediated
Graft vs host, allergic contact dermatitis, MS, Guillian-Barre syn
Type 5 hypersensitivity
pathology, example
Autoimmune
Antibodies recognise and stimulate or block cell receptors
Graves, myasthenia gravis
Give examples of live attenuated viruses (7)
BCG MMR influenza (intranasal) rotavirus polio yellow fever typhoid
Mx of eclampsia
IV magnesium sulphate
should be given once decision to deliver has been made
what is rheumatoid factor?
IgM antibody against IgG
Action of antiemetics:
Ondansetron
Metoclopramide
Cyclizine
Ondansetron - 5HT3 r antagonist
Metoclopramide - D2 r antagonist
Cyclizine - H1 r antagonist
HLA associations:
A3
B5
B27
A3 - haemochromatosis
B5 - Bechet’s
B27 - ank spond, reiter’s syn, acute ant uveitis
HLA associations DQ2/DQ8 DR 2 DR 3 DR 4
DQ2/DQ8 - coeliacs
DR 2 - narcolepsy, goodpastures
DR 3 - dermatitis herpetiformis, Sjögren’s syndrome, primary biliary cirrhosis
DR 4 - T1DM, RA
what are the LH and FSH levels in Kleinfelters and Kallman’s?
Kleinfelters (47 XXY) - raised LH and FSH
Kallman’s (hypogonadotrophic hypogonadism) - inappropriately low-normal LH and FSH
What is the pathology of Kallman’s syndrome?
features?
x-linked recessive
failure of GnRH secreting neurones to migrate down into hypothalamus
anosmia
‘delayed puberty’
hypogonadism
low sex hormones and inappropriately low LH and FSH
What is premature ovarian failure?
onset of menopausal features before 40
elevated FSH and LH
Complement deficiencies; what is the effect C1 inhibitor deficiency C3 def C5 def C5-9 def
C1 inh deficiency - hereditary angiodema
C3 deficiency - recurrent bacterial infections
C5 deficiency - Leiner disease (severe seborrheic dermatitis, diarrhoea, infections)
C5-9 def - encodes the membrane attack complex (MAC) prone to N.meningitidis infection
Which immunoglobulin has the highest and lowest concentration in the blood?
what are the roles of IgA, D,E,G,M?
IgG - most (75%). Monomer, enhances phagocytosis
IgA - monomer/dimer. found in secretions.
IgM - anti A and B antibodies. pentamer
IgD - activates B cells. monomer
IgE - least. involved in allergic reactions.
what is endothelin?
in which diseases are the levels raised?
potent vasoconstrictor and bronchoconstrictor
MI, primary pulmonary hypertension, HF, raynauds, ARF, asthma
What promotes and inhibits endothelin release
endothelin (a potent vaso- and broncho-constrictor)
promotes: angiotensin II, vasopressin (ADH), hypoxia, mechanical sheering forces
inhibits: nitric oxide, prostacyclin
What does the cyanide-nitroprusside test identify?
features
treatment
To identify cystine in the urine (cystinuria)
- autosomal recessive, leads to renal stones.
Rx by hydration, D-penacillamine, urine alkalisation
what is the enzyme deficiency in homocystinuria?
what is the amino acid affected?
cystathionine beta synthase (CBS) deficiency
methionine
features of homocystinuria
treatment
cystathionine beta synthase (CBS) enzyme deficiency
marfanoid appearance, learning difficulties, downwards dislocation of the lens, increased arterial and venous thomboembolism
Rx with pyridoxine (B6)
normal distribution
how many values lie in 1SD? 2SD? 3SD?
how do you calculate SD?
1SD - 68.3%
2SD - 95.4%
3SD - 99.7%
SD = square root (variance)
what is the amount of sodium and chloride in normal saline?
how much salt do we need per day?
150mmol/l of Na and Cl
need 6g of salt/day
how much Na Cl K and bicarb is there in hartmann’s solution?
Na 131
Cl 111
K 5
HCO3 29
what are the features of pseudoxanthoma elasticum?
auto rec abnormality in elastin fibres
plucked chicken skin appearance - small yellow papules on neck and axillae
retinal angoid streaks
cardiac: mitral valve prolapse, increased risk of IHD
GI haemorrhage
What are T-helper 1 cells involved in and what do they secrete?
Th1 - involved with cell mediated response (type 4 hypersensitivity)
secrete IFN-gamma, IL-2, IL-3
What are T-helper 2 cells involved in and what do they secrete?
Th2 - involved with humoral (antibody) immunity
secrete IL 4/5/6/10/13
What is the main action of atrial natriuretic peptide
powerful vasodilator
also promotes sodium excretion and antagonises angiotensin II and aldosterone.
what would you test for to establish an anaphylaxis reaction?
serum tryptase
how do you calculate standard error?
SD/ square root (number of subjects)
standard error gets smaller as the sample size increases.
Mechanism of clopidogrel
inhibits ADP binding to platelet receptors, inhibiting platelet activation
concurrent use of PPIs makes clopidogrel less effective
Dx and Mx of Wilson’s disease
Dx: low caeruloplasmin, raised urinary copper excretion
Mx: penacillamine or trientine (chelates copper)
In statistics what is a type 1 error?
null hypothesis is rejected when it is true (false positive)
found if the study has too many end points
In statistics what is a type 2 error?
accepting null hypothesis when it is false (false negative)
found if the sample is too small
