2nd yr rev Flashcards
in a lineweaver-Burk plot, which type of enzyme inhibition is occuring when both the lines cross the Y axis?
competitive
–> Vmax = same, Km = varies
(opposite for non-competitive)
which cranial nerves have afferent sensory fibres only?
CN I - olfactory
CN II - optic
CN VIII - vestibulocochlear
which Ig is actively transported across placenta from mother to baby + responsible for foetal immune protection?
IgG
–> most abundant Ig, only one that can cross placenta
which of these processes does NOT occur in phase 1 of drug metabolism: oxidation, conjugation, reduction, hydrolysis
conjugation
–> phase 2 - add endogenous compound, increasing polarity
transferases
what happens in phase 1 drug metabolism?
oxidation, reduction, hydrolysis
–> adds a chemically reactive group, cytochrome p450
how to calculate the negative predictive value?
true negative / (false neg + true neg)
ratio of those truly negative to those who had neg results
how does group A streptococcus stain on blood agar?
complete haemolysis (beta) - golden
how does strep pneumoniae stain on blood agar?
alpha haemolysis = partial = greenish
how does staph epidermis stain on blood agar?
gamma haemolysis = no haemolysis
mutation most assoc with breast cancer?
BRAC1 (also BRAC2)
which of the following is NOT included in the 4 Cs antibiotics most likely to cause Cdiff?
co-amoxiclav, clindamycin, ciprofloxacin, clarithromycin, cefuroxime
clarithromycin
co-amoxiclav
clindamycin
ciprofloxin
cefuroxime = cephalosporin
type of hypersensitivity is anaphylaxis
type 1 immediate
–> IgE most abundant
which cells secrete insulating material in the CNS?
ooligodendrocytes
schwann = PNS
length of TB treatment
2 months RIPE
4 months RI
side effects of TB meds
rifampicin = orange fluids isoniazid = neuropathy
pyrazinamide = joint pains ethambutamol = colour blindness
vichows triad
stagnant blood hypercoaguable state (eg pregnancy) endothelial damage
CURB 65 score of 3 + penicillin allergy, most appropriate antibiotic therapy?
IV levofloxacin
HIV positive with pneumonia, most likely causative organisim?
pneumocystitis jivrovecii
non-productive cough due to significantly increased mucous viscosity
3.5cm mass in left midzone of lung, non-smoker, found to be malignant, diagnosis?
adenocarcinoma
(midzone = peripheral)
(small cell - central + mestastasis early)
A 24 year old female asthmatic becomes increasingly breathless and wheezy and requires her reliever 4 times on most days and on at least 3 nights a week with coughing. She is taking salbutamol only. Serial peak flow measurement shows 30% diurnal variability.
What regular treatment would you consider starting?
inhaled corticosteroid alone
-> stepwise, add this then reasses before starting LABA
A 53yo woman has a cough. She has a history of central weight gain, easy bruising, abdominal striae and hyperpigmentation.
She undergoes investigation for suspected lung cancer.
What is the most likely histological diagnosis?
small cell
ectopic ACTH causing bilateral adrenal hyperplasia -> cushings
ST elevation in V1-V4
anteroseptal = left anterior descending (LAD)
ST elevation in II, III, aVF
inferior = right coronary artery
ST elevation in V4-6, I, aVL
anterolateral = left anterior descending or left circumflex
ST elevation in I, aVL +/- V5-V6
lateral = left circum flex
40 year old man presents with increased dyspnoea on exertion. On auscultation a mid-diastolic murmur is heard in the apex region when the patient lies in the left lateral position.
What is the most likely diagnosis?
mitral stenosis
MRS ASS
mitral regurg = systolic
Aortic stenosis = systolic
tetralogy of fallot
puulmonary stenosis
overriding aorta
VSD
right ventricular hypertrophy
A 52 year old Caucaisan woman has just been diagnosed with hypertension with no past medical history of note. Which of the following is the most appropriate first-line treatment?
lisinopril - ACEi
Which of the following is not a direct branch of the aorta? Right coronary artery Left common carotid artery Brachiocephalic artery Left coronary artery Right common carotid artery
right common carotid
brachiocephalic splits into right subclavian + right common carotid
first degree heart block
prolonged PR interval (>0.2s/5small square)
second degree heart block, mobitz 1 vs mobitz 2
mobitz 1 = progressive prolongation of PR intergal until eventually QRS is dropped
mobitz 2 = consistent PR interval duration with intermittently dropped QRS complex
heart condition assoc with Ehlers-Danlos
aortic dissection
aortic dissection vs ruptured AAA
aortic dissection = tear in aortic intima creating false lumen with ortic media, tearing chest pain, aortic regurg (diastolic murmur), hypertension
AAA = hypotensive, pain lower down
septal, anterior and lateral ECG leads
V1 = septal V2 = septal V3 = anterior V4 = anterior V5 = lateral V6 = lateral
scoring system for infective endocarditis
duke criteria - diagnosis of infect endocard)
*dukes staging = severity of colorectal cancer
DVT risk calculation
Wells score
drug to stop oesophageal varice bleeding?
terlipressin - causes vasoconstriction
–> secondary prevention = propanolol
skip lesions on endoscopy
crohns
what do G cells secrete
gastrin
what do enterochromaffin like cells secrete
histamine
what do chief cells secrete
pepsinogen
pepsin formed by pepsinogen secreted by the chief cells
which cells secrete hydrochloric acid?
parietal
which cells secrete somatostatin
D cells
A 47 year-old lady presents with RUQ pain. She appears is confused and systemically unwell with a high fever and low blood pressure. Physical examination reveals jaundice. She is known to have gallstones.
most likely diagnosis?
cholangitis
- > charcots triad = RUQpain, jaundice, fever
- history of gallstones
Mx of cholangitis
IV antibiotics + ERCP to relieve obstruction
acute cholecystitis vs cholangitis
cholangitis = RUQ pain, jaundice, fever
acute cholecystitis = positive murphys sign, no jaundice or hypotension
murphys sign positive
acute cholecystits
unresponsive peptic ulcer disease + urea breath test positive, management?
omeprazole + amoxicillin + metronidazole/clarithromycin
pen allergy = omeprazole + clarithromycin + metronidazole
coeliac findings on biopsy
villous atrophy
crypt abscesses on biopsy
UC
difference between wilsons + haemochromatosis?
wilsons = copper, kayser-fleischer rings
haemochromatosis = iron, ferritin, bronzed diabetic
A 27 year old woman presents to her GP with a unilateral hand tremor. She is also concerned because she feels that she has been experiencing mood changes. On examination, greenish-brown discolouration is seen around her eyes. The patient reports that her uncle died of liver cirrhosis at the age of 40 years.
What is the most likely diagnosis?
Wilsons
-> copper accumulation, tx = copper binding drugs (penicillamine)
COPD vibes in non-smoker
alpha1 anti-trypsin deficiency
-> emphysema + cirrhosis due to excessive breadown of elastin
gastroenteritis 24hr history after cruise ship holiday
norovirus
tumour marker of hepatocellular carcinoma
alpha-fetoprotein
CEA tumour marker
colorectal cancer
