Miscellaneous 4 Flashcards
Pathogenesis of calcific aortic stenosis?
Lipid deposition
Inflammation
Calcification
Valve thickening and stenosis
T wave inversion in lateral leads (V5/6) suggests what?
Left ventricular strain
What is aortic sclerosis vs stenosis?
Sclerosis = calcific disease without significant graident across valve
May progress to stenosis
Organisms implicated in infective endocarditis?
S aureus - most common overall Strep e.g. viridans HACEKs Enterococci Pseudomonas Fungi
What does amyloid look like histologically?
When congo red staining - shows apple green birefringence under polarized light
Classifications of amyloid?
AL (primary)
AA (secondary - chronic inflammation)
Hereditary ATTR
5 organs commonly invovled in AL amyloid? Pathogenesis?
Clonal proliferation of plasma cells producing amyloid monoclona Igs, soluble precursors to AL
Skin, heart, peripheral nerve,s kidneys, GI tract
PAthogenesis of AA amyloid?
Secondary to chronic inflammation
Macrophages release ILs that stimulate hepatocytes to secrete serum amyloid protein A which is an acute phase protein - soluble precursor to amyloid
Commonest cause of AA amyloid in the UK? 4 other causes?
Rheumaoid arthritis TB IBD Bronchiectasis RCC
Commonest renal manifestation of amyloid?
Proteinuria, nephrotic syndrome
Common features of AA amyloid? What is less common?
Hepatosplenomegaly
Kidney - proteinuria, nephrotic syndrome
Nerve etc. involvement less common
Potential treatments for amyloid?
AA - control underlying disease
AL - chemo, stem cell transplants
Most common cause of death in amyloid?
Cardiomyopathy or fatal arrhythmia
What thyroid cancer has amyloid depostion and what is it?
Medullary -calcitonin
Where may isolated amyloid deposits be found in body?
Thyroid Larynx Aorta Urinary tract Pituitary gland
What is pus?
Neutrophils with dead/dying microorganisms
What is a cyst and how is this different to a pseudocyst?
cyst = abnorma membranos sac containing gaseos, liquid or semisolid substance
Vs pseudocyst which lacks epithelial/endothelial cells
What is a diverticulum?
Abnormal outpouching of hollow viscus into surrounding tissues
Difference betwen clot, thrombus and embolus?
Thrombus = solid material formed by constituents of blood formed in flowing blood Clot = this but in static blood Embolus = abnorma mass of undissolved material transported from one site to another
Define hypersensitivity reaction?
Exaggeerated response of host’s immune system to particular stimulus
What is a polyp?
Mass of tissue arising from a mucosal (epithelail) surface
What is a neoplasm?
Abnormal growth of tissue which displays:
uncoordinate growth
growth exceeding normal tissue
growth which continues despite removal of initial stimulus
What is hyperplasia vs hypertrophy?
Hyperplasia = increase in size of organ due to increase in number of cells Hypertrophy = increase in size e.g. muscle fibres
What is a hamartoma?
Malformation composed of disorganised arrangement of different tissues normally found at that site
What is metaplasia?
Reversible replacement of one fully differentiated cell type with another
What is dysplasia?
Disrodered cellular development characterised by increased mitotic rate and pleomorphism WITHOUT invading basement membrane - may resolve if stimulus removed
Carcinoma vs sarcoma?
Carcinoma = epithelial cell tumour Sarcoma = connective tissue tumour
What is atrophy?
Reduction in size of organ due to reduction in size, number of cells (or both)
What diameter of the infrarenal aortra is aneurysmal?
2cm is normal so 3cm is aneurysmal
Complciations of aneurysm?
Rupture Thrombo/embolism Local pressure effects Fistulation Infection
Criteria for considering elective AAA repair?
over 5.5cm
or over 4cm and grown by more than 1cm in 12 months
or if symptomatic e.g. painful
Management of AAA by size (elective)?
Less than 3cm = no follow up
3-4.4cm = annual US
4.5-5.4cm = 3m US
5.5 or above consider repair
What exits the posterior wall of the abdominal aorta and may be a source of back bleeding in AAA repair? How do you manage them?
Lumbar arteries
Oversew them
Complications of EVAR?
Rupture intra-op Endoleak Mesenteric ischaemia, renal failure or MI SPinal cord injury Infection
Where is the blood in an aortic dissection?
Between intima and media
3 conditions linked to aortic dissection?
Marfans
EDS
Osteogenesis imperfecta
2 classification systems for aortic dissections?
Stanford - A and B
DeBakey 1, 2 (A) and 3 (B)
Classification of ascites?
Transudative (high SAAG)
Exudative (low SAAG - because high protein in ascitic fluid)
Causes o transudative ascities?
Increased portal venous pressure - crirrhosis, heart failure/pericarditis (constrictive), Budd Chiari, thoracic duct obstruction
Low albumin - protein losing enteropathies,liver failure, starvation/cachexia, nephrotic/nephritic syndrome
4 Ps of causes of exudative ascites?
Pancreatitis, peritoneal metastasis, peritonitis (incl TB), post-irradiation
What is atherosclerisis?
Artery wall thickens as a result of accumulation of fatty materials such as cholesterol
Pathophysiology of atherosclerosis?
Endothelial dysfunction resulting in migration of macrophages, some of which form foam cells and lipid core
Migration of vascular smooth muscle forming a fibrous cap
Eventually causes stenosis and rupture of the cap can lead to thromboembolism
Define wound healing?
Process by which tissue restores its normal architecture, structure and function, with return of tissue integrity and tensile strength
What are the 2 ways by which wounds can heal?
Resolution - no scar
Organisation adn repair - scar
Which cells are particularly important in healing by secondary intention?
Myofibroblasts - cause wound contraction and deposit collagen
What is healing by tertiary intention?
Relook surgery - e.g. open fractures
Stages of wound healing?
Haemostasis and platelet aggregation/coagulation
Acute inflammation
Proliferative/fibroblastic
Maturation and remodelling
Why might a wound fail to heal?
Local factors - ischaemia, infectino, surgical techinque, radiotheapy
Stystemic - DM, steroids/immunospresi/ chemo, heart/renal/liver failure, malnutrtion cancer or hypoxia
What are mycobacterium?
Gram positve, aeoribc, non motile and non-spore forming rods
Acid fast
Testing for active TB infection?
Fluid sample e.g. BAL, aspirate - for AFB, Ziehl Neelson staining
PCR - guide type of mycobacterium adn drug resistance
CXR, CT chest/abdo pelvis
Testing for latent TB infection?
Quantiferon
Mantoux or tuberculin skin test
Probelems with mantoux test?
May be falsely positive in people who have had bCG or galsely negative in immunocompromised
Drug treatment of TB?
Rifampicin, isoniazid, pyrazinamide, ethambutol
What is a granuloma?
Collection of macrophages - often surrounded by rim of lympocytes
What is necrosis?
Energy-independent pathological cell death related to inflammation
5 kinds of necrosis? examples?
Coagulative - kidney, heart, spleen. also dry gangrene
liquefactive - brain. also wet/gas gangrene is a type of this
caseous - seen in TB
fat - due to trauma, e.g. breast or pancreas
fibrinoid - type 3 hypersensitivty, SLE, vasculitis
What is apoptopsis?
Energey dependent programmed cell death, resulting in apoptotic bodies which are phagocytosed and do not stimulate inflammatory response
What is grading of a cancer?
How well/poorly differentiated the cancer is histologically - therefore potential for growth and prognosis
What is staging of a cancer?
Spread and size. Requires clinical examination and imaging
Broadly describe Dukes staging for CRC?
A - confiend to bowel wall - 95% plus 5 5year survival
B - Through bowel wall but no LN mets
C - LN mets - 30%
D - distant mets - 5-10%
Staging systems for melanoma?
Breslow thickness
Clarks level
TMN
Give an example of a grading system used in cancer?
Gleason score - prostate
Define acute kidney injury? Cut off system?
Abrupt fall in rate of glomerular filtration resulting in ability of kidney to filter waste products
RIFLE or AKIN
Rise in creat over 1.5-2x baseline, or absolute by 26.5
Normal range urea and creatinine?
2.5-6.7
70-150
What is acute tubular necrosis?
Acute damage to renal tubular cells resulting from ischaemic insult or nephrotoxin build up
Causes of ATN?
Hypovolaemia, haemorrhage
Sepsis
Cardiac failure
Renal artery stenosis
Minimal normal UO for adult vs child?
0.5ml/kg/hr for adult
1ml for child
Define oliguria? vs anuria?
UO les than 0.5ml/kg/hr for 6 hours, or less than 400ml in 24 hrs
Anuria is no urine output
Give an example of a document used to guide end of life care?
One Chance to Get it Right - 2014
How do brainstem death testing?
2 doctors, one a consultant, both qualified over 5 years with full GMC licence, not involved with patients who may receive organs
Exclude reversible causes
Fixed pupils non reactive to light
absent corneal relfexes
absent oculovestibular reflexes
no motor response in CNs in response to stimulation - no gag or cough to bronchila stimulation
apnoea tes t - no spontaneous breathing
Absolute contraindications to organ donation after brain death? Relative ones?
CJD HIV disease (not just infection)
Rleative include TB, age over 90, sepsis, recent disseminated cancer
Differentials for acute limb ischaemia/ pale pulseless limb?
Artieral dissection Acute venous thrombosis Chornic limb ischaemia Tramautic vascular injury Neurological e.g. spinal cord infarct
AMPLE history?
Allergies Medications PMH Last ate Events leading to admission
What to examine when assessing for ?acute limb ischaeima?
Abdominal exam ?masses ?AAA Lower limb pulses - femoral, popliteal, dorsalis pedis, posterior tibial ABPI Buerger's test Doppler US
How calculate ABPI?
Check brachial on each arm (twice) and DP / PTA on each foot
Systolic over systolic - highest each time
Causes of acute limb ischaemia?
Thombosis - most common Embolism Mural thrombi Proximal aneurysms Infective emboli
Classification of acute limb ischaemia in terms of salvagability?
1 - not immediately threatened - audible doppler, no sensorimotor deficit
2a - salvageable if prompt - sensory deficit, no motor
2b - salveagable if immediate - incomplete sensorymotor deficit
3 - amputate - complete sensoryimotor deficit
How does the classification of acute limb ischaemia guide whether investigations are done and how quikcly?
1 or 2a may have time to complete investigations, especially if thrombotic to define extent and level of occlusion
5 specific complications to embolectomy?
Reperfusion Intimal damage Arterial puncture Psuedoaneurym formation Amputation
Where is the femoral artery - surface marking?
Below inguinal ligament at midinguinal point, half way between pubic symphysis and ASIS
What is in the femoral sheath?
Artery, vein, canal
Physiological function of the femoral canal?
To allow expansion of the femoral vein e.g. during exercise
Boundaries of femoral canal?
Anteriorl y- inguinal ligaement
Medially - lacunar ligament
Laterally - femoral evin
posteriorly - pectineal ligament
Describe split of popliteal artery in leg?
Divdes into tibioperoneal trunk and anterior tibial artery (ant comp)
Tibioperoneal divides to peroneal (lateral comp) artery and posterior tibial (posterior 2)
Define pain?
An unpleasant sensory and emotional experience associated with acutal or potential tissue damage
What 3 stimuli are nociceptors responsive to?
Thermal
Mecahinkcal
Chemical
3 orders of neurones transmitting pain?
first order - cell bodies in DRG, synapse in cord
second order - spinothalamic tract
third - thalamus to primary somatosensroy cortex
What are the different kinds of fibres involved in pain reception?
A-delta = sharp, loclised C = dull, poorly localised
How do NSAIDS work for pain?
Inhibit cyclo-oxygenase enzymes to inhibit inflammatory prostaglandin production
6 RFs for chronic post surgical pain?
Prolonged surgery Nerve injury Pre-op pain Chemo/radiotherapy Severe post op pain Patient psychological factors
What causes allodynia?
Cross talk between sympathetic/A beta fibres and nociceptive fibres
Shelf life of RBCs when appropriately stored?
35 days
Define massive transfusion?
Transfusing entire circulating volume in 24 hours, or over 50% in 4 hours
4 complications of massive transfusion?
Fluid overload
Coagulopathy
Electrolytes - hyperkaelamia, hypocalecamia
Hypothermiaa
Alterantives to blood transfusion for e.g. Jehovah’s witnesses? Other measures surrounding surgery?
Subsitutes - colloids, crystalloids
Pharmacological - iron tabs, TXA, epo, factor 7a, cell saver for autologous transfusion
Surgical - meticulous haemostasis
Anaesthetic - monitor BP, prveent hypothermia
Things that need excluding prior to brainstem death testing?
Reversible causes
e.g. metabolic derangements - Na, Mg, Ca etc, drugs/benzos/alcohol etc, hypothermia, addisons/myxoedema coma
also non-neurological causes of apnoea e.g. c spine injury, myaesthenia/NMJ disorders
How do perfrom apnoea testing in brainstem death?
adequately preoxygenate
hypoventilate to CO2 of at least 6, pH of less than 7.4
disconnect from cicruit and maintain oxygen flow
observe for 5 mins for apnoea
repeat ABG - if rise in CO2 over 0.5 confirms loss of respiratory drive
Differences between CSF and plasma?
CO2 higher in CSF so pH lower
protein very low, less buffering capacity
glucose concentration lower
chloride higher
What is a steroid?
Organic compound with characteristic arragement of 4 cycloalkane rings joined together
Give 5 examples of endgenous steroids?
Cholesteroll Cortisol Testosterone Aldosterone Progesteron
Layers of adrenal cortex and produce?
Zona glomerulosa - aldosterone
Zona fasciculata - glucocorticoids
Zona reticularis - androgens and oestrogens
Potential blood loss volume for limb fractures/ pelvis?
Tibia or humerus 750ml
Femur 1.5L
Pelvis entire circulating volume
Describe transfusion regimes in trauma?
Local policiiy but NICE advocate inital volume replacement (Pack A) then coagulation factor replacement (Pack B - FFP, platelets, cryo) - O neg
Then continue to transfuse at ratio of 1:1:1 e.g. red cells to FFP
Discuss different suture classifications?
Aborbable vs non aborsable
Synthetic vs natural
Monofilament vs braided
Give examples of absobrable sutures?
Synthetic - monofilament = monocryl, PDS braided - vicryl,
Natural - collagens
Give examples of non-absorbable sutures?
Synthetic - prolene, ethilon (nylon) - both monofilament
Natural - braided silk, steel
What would you close vascular anastomosis with?
Non-absorbable suture such as prolene
What would you close a hand sewn bowelanastomsis with?
Absorbable suture such as vicyrl
Common uses for absorabble sutures?
Skin or fast healing deep tissues
Bowel anastomosis
Biliary or urinary suturing
Tying off small vessels near skin
Complete absoprtion times for vicryl rapide and vicryl?
42 days for rapide, 60 for vicryl
Complete absorption time for monocryl?
100 days
Complete absorption time for PDS?
200 days
What kind of things are non-absorbable sutures useful for?
Ones which need constant reinforcement e.g. vascular anastomosis
Fascia/tendon repairs
Abdo wall erpairs
Which of synthetic and natural sutures are more comonly used ? Why? Give example of a commonly used natural
Natural used less as incite more of a tissue reaction
However silk used for e.g. drain sites
Differences between mono/polyfilament sutures?
Mono = less risk of infection but poor knot security/ease of handling Poly = higher risk infection, easier to handle and knot more securely
2 examples of braided sutures?
Silk
Vicryl
What are reverse cutting needles goof for?
Tough tissue such as tendons, fascia
What is the difference between a true and false diverticulum?
True = all layers of structure involved False = only part of wall e.g. sigmoid diverticulum, pharyngeal pouch
What enzymatic process is implicated in pathogenesis of pancreatitis?
Premature and inappropriate activation of trypsinogen to trypsin starting activation cascade of autodigestion
Enzymes invovled in pathogenesis of pancreatitis?
Typsin and other proteases - pancreatic parenchymal damage
Elastases - vascular damage
Amylase
Lipase
Radiological scoring system for pancreatiits?
Balthazar score
Modified glasgow score for pancreatitis includes what?
PaO2 under 8 Age over 55 Neutrophilia ovre 15 Calcium under 2 Renal - urea over 16 Enzymes - LDH or AST Albumin low Sugar - BM high 3 or more of above within first 48 hours suggests severe
Theoretical risk of giving morhpine in pancreatitis?
Thought to contract sphincter of oddi
Blood supply to pancreas?
Superior pancreaticodudodeanl (celiac) and inferior pancduod (SMA) to head Splenic artery (celiac) to rest
How high should amylase be to diagnose pancreatitis?
3x UL of normal
Differentials for BPH?
Bladder outlet obstruction secondary to prostatic carcinoma, urethral stricture, bladder neck dysfunction or urethral sphincter dyseynergia
Bladder dysfunction due to oversensitivity, detrusor overactivity or low detrusor contractility
What is bladder outlet obstruction?
Urodynamic condition implying voiding with high pressure and low flow rate
What does PSA do?
Peptidase that liquifies semen to allow sperm to move freely and dissolve cervical mucus
How would you manage raised PSA and abnormal PR exam?
Repeat PSA
TRUSS and biopsy
MRI +/- bone scan
Urology MDT
How is the gleason score used?
2-10 where 10 is worst
2 scores of 1-5 for most commonly seen histological patterns
Grading vs staging of tumours?
Grading = level of cell differentiation, roughly corresponds to rate of growth Staging = size and spread
How frquently should PSA be checked post radical prostattectomy for prostae Ca?
6 weeks after treatment, then every 6 months for 2 years, then annually
If PSA is even slightly raised at first check (6 weeks) post radical prostatectomy, what does this suggest? Why?
Disseminated malignancy - because half life is only 2-3 days, so should be undetectable within 4-6 weeks
Mechanism of hormone therapy in prostate Ca? Example?
Competitive antagonism of androgen receptors, preventing testosterone from binding to prostate cancer cells and inhibiting their growth
Bicalutamide
Prophyalctic antibiotics are indicated for which surgeries?
Clean involving prosthesis or implant
Clean contaminated
Conatminated
What and when are the key parts of the WHO surgical safety checklist done?
Sign in - before induction of anaesthesia
Time out - before skin incision
Sign out - after operation
What instrument is typically use to grasp umbilicus for laparoscopic surgery?
Littlewoods
What ratched forcep is typically used to handle e.g. bowel in an atraumatic fashion?
Babcock
What non-ratched forcep is non-toothed and used to grasp tissues without damaging them? What is its toothed alternative?
Debakey
Lanes is toothed
What is the self retaining retractor for deep wounds called?
Norfolk and Norwhich
What is the self retaining retractor for superficial wounds called?
Travers
How might an incision for a lipoma excision vary vs a sebaceous cyst?
Lipoma often short as it will squeeze through
More elipitcal incisions centred around punctum for sebaceous cysts
Ensure length is 3x width for incision
What are the 2 phases of acute inflammation?
Vascular - vasodilation, incrsaed permeability, exudate and incresaed tissue lfuid
Cellular - neutrophil migration - margination, rolling, adhesion and emigration - then phagocytosis
4 stages of wound healing by primary intention?
Haemostasis
Inflmamation
Proliferation incl angiogenesis and formation of granulation tissue, collagen via fibroblasts
Remodelling - collagen deposition and fibroblast apoptosis
Which cells are more important in secondary intention than primary for wound healing?
Myofibroblasts
When is suturing appropraite to close a wound?
Lac greater than 5cm
Deep dermal wounds
Locations prone to flexion, tension or wetting
Scoring system for severity of otitis externa?
Brighton Grading system
Incision for Ivor Lewis procedure?
Right thoracotomy and laparotomy
