Misc 7 Flashcards
What is the mechanism behind dilutional hyponatraemia e.g. in heart failure?
Activation of RAAS and also ADH release from posterior pituitary
Both lead to fluid retention but only one of these leads to Na retention so relative hyponatraemia (TBS actually high)
3 ways in which patients lose heat intraoperatively?
Radiation - from skin (there is also vasolidation which worsens this)
Evaporation - body surfaces and open cavities
Conduction into air and theatre table
Also cold fluids/anaesthetic agents, and shivering prevented due to paralysis
Normal response to hypothermia?
Symp response - shivering, piloerection, periph vasoconstriction
RFs for intra/post op hypothermia?
Pre op hypothermia
Worsening ASA grade
Major/exposed or prolonged surgery
Combined GA and regional
What is the classic ECG finding in hypothermia and what is it? When is it seen?
J - Osborn wave
Usually seen at less than 32 degrees
Upward deflection between QRS and ST
Complications of hypothermia in relation to surgery?
Coagulopathy
Decreased metabolism and CO
Decreased drug metabolism - prolonged mechanism of action
Discuss division of total body water e.g. for 70kg male?
TBW = 42L 28L = intracellular 14L = extracellular 11.5L = interstitial 3.5L = intravascular
Hartmanns composition?
Na 131 Cl 111 K 5 Ca 2 Bicarb (as lactate) 29
0.9% NaCl composition?
154 Na
154 Cl
What is the classification system for traumatic pelvic fractures? What are the 3 types?
Young and Burgess
AP compression - open book fracture
Lateral compression
Vertical shear - fall from height, superior displacement of one hemipelvis on the other
What level do you apply a pelvic binder at?
Greater trochanters
Discuss management of major bleeding due to pelvic fracture?
Any hypotenisve major trauma should have pelvic binder
Then discuss with IR if active bleeding and pelvic fracture
If no target - preperitnoeal packing
If large vessel injury not amenable to IR - vascular opinion
Where do the majority of bleeds come from in pelvic fractures with blunt trauma?
Pelvic venous plexus
Lethal triad of trauma?
Hypothermia, acidosis and coagulopathy
What is the difference between Early Total Care and Damage Control Surgery?
DCS = haemorrhage control, compression of major cavities and decontamination ETC = early definitive treatment of injuries after period of initial resus
Pathophysiology of Type 1 hypersensitivity reactions?
Antigens bind to IgE antibodies on mast cells and basophils/eosinophils
Then degranulate to produce histamine, heparin, platelet activating factor
Increase in leukotrienes, prostaglandins
Above cause vasodilation, smooth muscle spasm, capillary leak due to increased vascular permeability and excessive epithelial glandular secreteion
Treatment of type 1 hyypersensisitvty reaction?
IM adrenaline 500 micrograms (0.5ml 1/1000) - can repeat after 5 mins if doesnt help
Chlorphenamine 10mg IV/IM
Hydrocortisone 200mg IV
IV fluid challenge 500ml
How to size guedels and nasopharyngael airways?
Guedel = incisor to angle of mandible
NP airway = external nare to tragus
What effect may jaundice have on pulse oximetry?
Bilirubin can falsely lower reading
Complications of colloids?
Anaphylaxis
Coagulopathy
3 causes of increased CVP?
Fluid overload/ventricular failure
Cardiac tamponade
Chronic respiratory disease
Level 0 - 3 care?
0 = normal ward patient 1 = ward with critical care input 2 = HDU = single organ failure, 2:1 nursing 3 = ICU = multi organ failure, 1:1 nursing
Caring for post op trache patient?
Humidified oxygen
Regular tube care and suction
Emergency kit availability
Under what circumstance would you be fully immune to tetanus?
When you’ve had 5 doses - 3 in early months then 2 boosters
What causes tetanus?
Clostridium tetani
What is the neurotoxin produced by c tetani?
Tetanospasmin
Differences between exotoxin and endotoxin?
Exo= gram pos or neg, immunogenic Endo = gram neg only, non-immunogenic
Alpha 1 activation causes?
Vasoconstriction and increased duration of contraction
Beta 1 activation causes?
Positive inotropy and chronotropy with minimal vasoconstriction
Beta 2 activation causes?
Vasodilation
Dopamine1/2 activation causes what?
Kidneys - induces diuresis
What is dobutamine most useful for and why?
Beta 1/2 activation to cause improved cardiac contractility and reduce afterload
Why is norad preferred in e.g. septic shock?
Acts primarily on alpha 1 to cause vasoconstriction with relatively little tachycardia
2 ways of calculating MAP?
(SBP + (2xDBP))/3
(COxSVR) + CPP
What is CVP monitoring useful for?
Gives indication of volume status (cardiac filling)
What is preload?
Ventricular filing - how fmuch its stretched pre systole (end of diastole)
Why would you consider ET intubation for mechanical ventilation?
Airway reasons - low GCS, facial/upper airway trauma etc., obstruction from inhalation smoke etc
Breathing - respiratory failure due to lung pathology, due to neuromuscular failure or to manage head injuries
Just intubated somoene and they are still hypoxic? What do you do?
call for help, apply 100% O2
Check tube position, if in doubt take it out
Check tube blockage
Check for kinking/disconnection
Manually bag to assess compliance - ?bronchospasm
Rule out pneumothorax
Check ventilator working properly
Define ventilation?
Tidal volume x respiratory rate
3 basic types of mechanical ventilation?
Prsesure controlled
Volume controlled
Pressure suport - supports patients own work of breathing
Normal tidal vlume by weight?
7ml/kg
Immediate, early and late complications of mechanical ventilation?
Immediate - airway trauma, failure, dental damage
Early - baro/volume trauma - pneumothorax/pneumoed/emphysema, raised intrathoracic pressure and reduced preload leading to CV collapse
Late - VAP, respiratory muscle atrophy, tracheal stenosis, tracheal fistula
3 rerquirements for weaning ventilation?
Resolution of intiial reason for ventilation
Adequate gas exchange - reducing O2 req
Adquate resp drive and power - spontaneous breathing trials
Managing new AF (acute) that doesnt resolve with correction of cause?
If stable - oral cardioversion e.g. amiodarne, digoxin
If unstable - DC or chemical cacrdiovert
Give 4 specific post op complications of open AAA repair?
Abdo copmartment syndrome
Bleeding
Lower limb ischaemia
Post op ileus
What postiion for remove central line? Why?
Head down or supine
To reduce risk of air embolus
How might teunnelled lines need to be removed?
In theatre - larger incision needed to dissect to plastic retaining cuff
5 causes of ischaemia?
Obstruction of arterial supply Obstruction of venous outflow e.g. compartment syndrome Anaemia CO poisoning Pulmonary disease and poor oxygenation
Likelihood of reinfarction if major surgery within 1 month post MI? Vs over 6 months?
30%
vs 5%
Clopidogrel lasts for how long?
8 days - lifespan of platelets
Mechanisms of actino of aspirin?
COX 1 (blocks thromboxane A2 formation, platelet aggregation) and COX 2 (analgesia ,antiinflammatory/pyriexa) inhibition
Mechanism of action of clopidogrel?
Prevents platelet aggregation oby irreversibly inhibitring plaetelet ADP receptor
What are the 2 phases of metabolic response to injury?
Ebb - decreased CO, metabolic rate, energy expenditure and temperature
Flow - catabolic then anabolic phase
Risks/beenfits of NJ tubes?
Good - thinner, less uncomfortable, less risk of aspiration
Bad - more prone to kinking/blockign, may need radiological insertion
What kind of enteral feeding is preferred in pancreatitis and why?
NJ
Because bypasses DJ flexure, reducing secretion of cholecystokinin (which worsens pancreatic inflammatory process)
How is respiratory quotient calculated?
CO2 excreted / O2 consumed
WWhat is usually in an epidural?
Local anaesthetic and opiate
ee.g. bupivocaine and fentanyl
What are the 4 stages of pain sensation transmission? Which drugs act at each?
1 - transduction - e.g. NSAIDs
2 - transmission - LA
3 - modulation - TENS
4 - perception - opioids
Where are pancreatic pseudocysts usually found?
In leser sac, obstructing epiploi foraemn of winslow withi inflammatory adhesions
4 methods of drainage of pancreatci psueodcysts?
Percutaneous/IR
Endoscopic - via posterior wlal of stomach
Open pseudocystogastrostomy
Open psuedocystojejunostomy if inferior
Complicatinos of chronic pancreatitis?
Psueodcyst Peripancreatic fluid collections DM Malnutrtition Biliary obstruction Fistula formation - pancreatic ascites
RFs for breast cancer?
Early menarche, late menopause Increasing age FH/genetics Nulliparous or late 1st baby Smoking Obesity Use of HRT Prev breast Ca
What is BRCA 1 associated with?
Breast, ovarian and fallopian Ca
What is BRCA 2 associated with?
Breast, pancreatic Ca, melanoma
What is the breast sceening programme?
Mammogram ervery 3 years from 50 to 71 routinely
How is sentinel node biopsy performed?
Radio isotope/blue dye injected to subdermal layer around areola pre-op - at surgery sentinel lymph node identified with dye/geiger counter and excised, frozen section - if positive all LNs removed
What is DCIS?
Most common non invasive breast Ca, microcalcifications, histologically looks like abnormal cells within BM
What is the difference between simple and skin sparing mastectomy?
In simple, whole breast taken. In skin sparing, nipple-aerolar complex is preserved
What layer is dissected down to in WLE breast Ca? What is placed on this layer?
Down to pectoral fascia
Titanium clips placed on fascia to facilitate accurate radiotherapy
What are the levels of axillarry LNs?
1 = inferolateral to pect minor 2 = posterior to pect minor 3 = superomedial to pect minor
Complications of masteectomy?
Primary haemorrhage or haematoma Wound infection Skin flap necrosis Wound dehiscence Numb scar Cosmetically poor scar Seroma formation Long thoracic or thoracodorsal nerve damage Tumour recurrence
What 2 parts of the breast are rebuilt post mastectomy?
Breast mound
Nipple areolar complex
Options for rebuilding breast mound?
Implant alone
Implant and flap e.g. lat dorsi myocutaneous flap
Autologous flap alone
Options for rebuilding nipple areolar complex?
Nipple reconstruction - usually done 6 months after treatment finished
Tattooing for areolar reconstruction
What are 3 kinds of flaps for breast reconstructino?
TRAM
DIEP
SGAP/IGAP (super/inf gluteal artery perforators)
Role of radiotherpay in breast cancer?
Offered to everyone who has had WLE to reduce recurrence
Recommended if tumour over 5cm, positive resection margins, 4 or more pathological nodes in axilla, node positive
Local complications of radiotherapy in breast cancer?
Skin erythema or permanent discolouration
Lymphoedema
Swelling of remaining breast tissue
Discuss oestrogen receptors in breast cancer?
ER = 70% of breast cancers
Pre-menopausal - block production with tamoxifen for 5 years
Post-menopausal - block peripheral conversion with letrozole/anastrazole
What is herceptin used for?
Monoclonal Ab Trastuzumab used for HER-2 positive cancers
Is ER positivity a good thing in breast Ca? What about HER-2?
ER is good
HER-2 is bad
with respect to recurrence
First differential to rule out in acute flank/loin pain?
Rupture AAA
Potential outcomes of a mid ureteric stone?
Resolution Ongoing colic Obstruction Obstruction and infection Haematuria SCC (if longstanding)
3 sites of stone obstruction in kidney stones?
Pelvi-ureteric junction
Pelvic brim, where ilaics cross
Vesico-ureteric junction
Causes of renal stones?
MEtabolic states Abnormal anatomy eg horseshoe Infections e.g proteus Gastric e.g. IBD Dehydration High BMI, diet
Why does proteus cause renal stones?
Proteus cleaves urea to alkalaize urine
This reduces solubility of PO4, prompting formation of struvite (magnesium ammonium phosphate stone)
5 kinds of renal stones?
Calcium oxalate Calcium pyrophosphate Struvite Cystine Uric acid
Differences between smooth and skeletal muscle?
Smooth = circumferential, autonomic (voluntary) and lines walls of viscera Smooth = calmodulin, skeletal = troponin (calcium binding protein)
How is micturition controlled neurologically?
Storage phase - SNS - L1-3 relaxes detrusor and contracts internal sphincter
Micturition - PNS - S2-4 contracts detrusor and relaxes internal sphincter
External sphincter is under somatic control
3 ways of defining AKI?
UO under .5ml/kg for 6 hours
Creat rise over 26 in 48 hours
Creat rise in over 1.5x baseline in 1 week
Give 6 indicitions for renal replacement therapy?
Refractory hyperkalaemia Fluid overload Severe acidosis Complications of uraemia e.g. pericarditis Acute poisonoing CKD 5
Divisions of types of renal replacement therapy?
Intermittent - haemodialysis, peritoneal dialysis
Continuous - haemofiltration, haemodiafiltration, renal transplant
What is dialysis disequilibrium syndrome?
Acute onset of neurological symptoms in patients undergoing dialysis, due to rapid change in serum osmolality causing cerebral oedema
What is a naevus?
Benign proliferation of normal constituent cells of skin
Give 4 kinds of naevi?
Melanocytic
Vascular e.g. strawberry, port wine
Epidermal - warty
Connective tissue - Shagreen patch in TS
Act governing tissue donation in UK?
Human tissue act 2004
Indication for renal transplant?
End stage renal disease regardless of cause
Contraindications for renal transplant?
Malignancy that is not curative or not been in remission for 5 years
Untreated HIV/AIDS
IHD with 5 year predicted death of 50% or more
Chronic or persistent infection
Unlikely to comply w medications, regular class A drug taker etc
Where are transplanted kidneys normally put? Where does tranpslanted ureter go?
RIF
Anastamosed to kidney
Blood supply/venous drainage of transplanted kidneys?
External iliac arery and vein
What are the main stages of organ recovery e.g. kidney?
Warm ischaemic - from when donor circulation stops to when perfusion solution flowing
Cold ischaemic - from when perfusion solution flowing to when kidney transplanted into recipient (kidney is on ice for transplant and shold be tx within 24 hours)
What is perfusion solution and what is it used for?
Ice cold solution of solutes, pH buffers, adenosine, membrane stabilisers etc to keep kidney viable
How is immunosuppression achieved with regards to transplant surgery?
At time - pred and an anti-CD drug of some sort
Maintenance triple therapy - pred, calcineurin inhibitor (tacro/serolimus/ciclosporin) and purine synthesis inhibitor (azathioprine)
Complications of immunosuppression associated with transplant?
Nephro/hepatotoxicity/neurotoxicity Leukopenia Skin changes HTN, fluid retention Effects of steroids Malignancy e.g. skin Infections esp atypicals
What is acute transplant rejection, what are the subdivisions and why does it happen? Treatment?
Accellerated if within first week, acute if within 100 days
T cell mediated, diffuse infiltration/arteritis/tubulitis etc
Treat with steroids at high dose
Why does chronic transplant rejection occur?
Humeral system - graft fibrosis and atrophy
Features of renal transplant rejection?
Pain, swelling, redness at site
Temperatures
Decreasing urine output and worsening renal function
Fluid retentino
How is renal transplant rejection diagnosed?
Biopsy
Complications of renal transplant other than rejection/complications of immunosuppression?
Delayed primary function - may be due to long cold ischaemic time or re-perfusion injury
Vascular - anastamotic leak, thrombosis, stenosis, vessel kinking
Urological - urine leak, ureteric stricture
Lymphocele - may need drainage
What is primary donor dysfunction in e.g. renal transplant?
Failure of donor organ to function in absence of any other obvious cause
1 year graft survival of renal transplants? Better or worse than other kinds?
Over 90% This is better than the other kinds
Symptoms of BPH?
Filling - frequency, urgency, nocturia
Voiding - hesitancy, incomplete voiding, terminal dribbling, poor stream
Other - retention, freq UTIs, haematuria, bladder stones
Invstigating BPH?
Exam incl PR IPSS - prostate symptom score urine dip PSA TRUS (trans rectal US) IVU - IV urography voidingi charts urodynamics
Management of BPH?
Conservative - bladder training, avoiding drinks before bed, exercise, patient support etc
Medical - alpha blockers/5a reductase inhibitors
Surgery - TURP, open prostatectomy, laser enucleation
RFs for prostate Ca?
Age, Afrocaribbean/African, Obesity, FHx, diet
Scoring/grading system for prostate Ca?
Gleason score
Management of prostate Ca?
Stratify into local, locally advanced and advanced with MDT
Options include serveillance, radio/brachyterhapy, hormonal therapy (gosurelin, flutamide), TURP, chemo or steroids, radical prostatectomy or high intensity focused US/cryotherapy
Complications of TURP?
Bleeding Infection TURP syndrome Retention or incontinence Retrograde ejaculation Strictures Erectile dysfunction
Where are the urethral sphincter muscles in relation to the prostate?
Internal = above gland, at bladder neck External = below gland, in deep perineal pouch
What is the prostatic utricle?
Small blind ended pouch opening in centre of seminal colliculus - openings of ejaculatory ducts are either side of utricle
Causes of bilateral parotid swelling?
Infection - viral e.g. mumps, bacterial e.g. TB
Inflammation - sarcoid/sjogrens
Metabolic - cirrhosis, cushings, myxoedema, bulimia, diabetes, malnutrition, gout
Local - sialectasis
Drugs - thiouracil, isoprenaline, high oestrogen OCP
Causes of unilateral parotid swelling?
Any of bilateral plus:
Cancer - benign or malignant
Stones or external ductal compression
What is pseudoparitomegaly and what causes it?
Mimics parotid swelling
Due to either masseter hypertrophy or periauricular lymphadenopathy
Are stones more common in submadibular, sublingual or parotid glands? Why?
Submandibular - because saliva here has higher mucous content and increased concentration of calcium/phosphate than saliva of the others
Also submandibular secretion is against gravity, causing stasis
How might parotid/submandibular stones differ?
Parotid often small and multiple, 50% within gland
Most submandibular are larger, solitary and intraductal
Pathology of salivary gland calculus formation?
Saliva is rich in calcium and phosphate
Slow flow predisposing
Are salivary stones usually radio opaque?
Yes - majority of submandibular, and most parotid ones
Discuss parotid cancers?
Most benign e.g. pleomorphic adenoma or Whartins tumour, small amount malignant e.g. mucoepidermoid carcinoma or adenoid cystic carcinoma
Complications of parotidectomy?
Immediate - CN7 palsy, greater auricular nerve damage (and earlobe numbness)
Early - haematoma, infection
Late - Freys gustatory sweating, salivary fistula
What is Freys syndrome and why does it happen?
Gustatory facial sweating in region of auriculotemporal nerve (V3 branch) in response to gustatory stimulus
Due to autonomic nerve rewiring - following injury to auriculotemporal nerve as it reattaches to sweat glands in skin via symp fibres (rather than salivary gland)
What does the auriclotemporal nerve come from and what does it normally do?
V3 branch
Usually PNS to parotid secretion/salivation, and SNS to face for sweating/flushing
What are the innervations of the rotator cuff muscles?
Supra and infraspinatus - suprascapular nerve
Subscapularis - subscapular nerve (also teres major)
Teres minor - axilalry nerve
Outline how you would test all the myotomes?
C5 - shouulder abduction/elbow flexion C6 - wrist extension/elbow flexion C 7- elbow extension c8 - finger flexion T1 - finger abduction L2- hip flexion L3 - knee flexion L4 - ankle dorsiflexion L5 - EHL S1 - ankle plantarflexion
