“All the world’s a stage, And all the men

and women merely players”

TC’s potpurri : The OSCE/Viva edition

Disclaimer: If something is wrong then look it up and correct me please.

What is happening?

A patient presents after stepping on a rusty nail and is worried about tetanus. We will start with pathology.

Questions Knowledge essentials in bold NotesWhat is tetanus?

Caused by Clostridium tetani toxin, C. tetani is a G+ve anaerobic rod. The toxin causes muscle spasm starting in the jaw and can progress to the whole body

2 to pass

What are the chemicalmediators of acuteinflammation and what aretheir actions?

Histamine: vasodilation, inc vasc perm, endoth activationPG: vasodilation, inc vasc permLeukotrienes: inc vasc perm, chemotaxis, WC adhesion & activationPAF: vasodil, inc vasc perm, chemotaxis, WC adhesion, degranComplement: WC chemo and activation, vasodilatCytokines (TNF, IL-1): endo activation (adhesion), fever, pain, hypotension, dec vasc resistChemokines: chemotaxis, WC activationKinins: inc vasc perm, vasodil, pain, sm m contraction

4 to pass including names and actions

We will now move on to Anatomy. The nail has punctured the sole of his foot.

Questions Knowledge essentials in bold NotesWhat are the 4 layers of the foot from superficial to deep?

1. abductor hallucis, Flexor digitorum brevis, abductor digiti minimi

2. Quadratus plantae, lumbricals, tendons: FDL, FHL, arteries: medial and lateral plantar

3. Flexor hallucis brevis, adductor hallucis, flexor digiti minimi brevis

4. Dorsal interosseus, plantar interosseus, Tendons: Peroneus longus and Tibialis posterior

1 structure from each layer to pass

What is the cutaneous enervation of the sole of the foot?

Medial plantar, lateral plantar, saphenous, tibial, sural

bold plus one other to pass

Now we will discuss pharmacology. The wound appears infected and you prescribe Amoxycillin and clavulanic

acid.

Questions Knowledge essentials in bold NotesWhat are amoxycillin and clavulanic acid?(prompt: why include clavulanic acid)

A beta lactam antibiotic susceptible to beta lactamase producing bacteria. Clavulanic acid is a beta lactamase inhibitor.

2 bold to pass

Describe the pharmacodynamics of amoxycillin.

Inhibits transpeptidation reaction of bacterial cell wall synthesis. Halts peptidoglycan synthesis, leading to inhibition of growth, and ultimately cell death (Bacteriocidal)

3 bold

What are some of the adverse effects of amoxycillin and clavulanic acid?

Allergy, anaphylaxis, nausea, vomiting, rash esp in presence of EBV, antibiotic related colitis, hepatitis/ liver dysfunction.

4 to pass

Physiology is next. Prior to starting antibiotics you do some blood tests

that show the patient is in renal failure.

Questions Knowledge essentials in bold NotesWhat are the major physiological features of acute intrinsic renal failure? ( prompt: what happens to urine concentration?)

Loss of urine concentrating and diluting capacity due to loss of countercurrent mechanism and nephron number. Polyuria->oliguria-> anuria Uraemia due to urea and creatinine and toxins (phenol and acids) build up. Acidosis. Anaemia Na+ retention and oedema and heart failure

3/5 bold

What are common findings in urinalysis of acute intrinsic renal failure?

Proteinuria, leucocytes, red cells and casts 3

What are urinary casts? Proteinaceous material precipitated in tubules washed into bladder.

bold

Who is the artist?Scenario: A 34yo lady presents to your ED with pleuritic chest pain.

Her vital signs areHR 115, BP 105/85, T 37.6, sats 94% RA

The patient is 8/40 pregnantYou will not need to examine the patientThe RMO has told the patient she may have a clot in her lung and she is now very anxious and wants to speak someone senior

Information to actorYou are 34yo, 8/40 pregnantYou had difficulties conceiving and this is your first pregnancy via IVFYou have a FHx of breast ca - your mother who died from the disease, she was Dx at 55yo and died at 60yoYou have had pleuritic CP for 2 days, it is getting a bit worse and you are a bit SOBOE

Details and comments

Medical expertise Pain Hx, anything pointing to infection, risk factors for PE, cardiac risk factors, other PMHx

Prioritisation and decision making

PE is the diagnosis of concernreferencing the DIP - needs D-dimer and if positive

then USS lower limbs if negative then CTPA

CommunicationPatient very worried about radiation risk, especially considering this baby is product of IVF, worried as

well as has a family Hx of breast Ca, does she really need the scan?

Scholarship and teaching Familiar with amounts of radiation and risk to the patient and foetus

Leadership and management

Management of a highly emotive and challenging situation

Teaching PointsRisks of inappropriate use of anticoagulation or missing the diagnosis of PE in pregnancy far outweigh the risks of exposing the mother and foetus to ionising radiation.D-Dimer test is less useful in pregnancy. But negative is negative.The evidence to recommend either CTPA or nuclear scintigraphy is complex.?MRI

The National Radiological Protection Board (NRPB) estimates the risk of inducing a fatal or non-fatal cancer in a foetus till the age of 15 to be approximately 1/33,000 per mGy.

Therefore the risk from a single V/Q study would be approximately 1/165,000. The risk from a CTPA would be as little as one-tenth of this, early in pregnancy.

Foetus

Of importance is the radiation dose to the breast caused by CTPA.The average radiation dose to the breast from a CTPA is typically 10-20 mSv and 0.28-0.5 mSv for V/Q respectively. The lifetime attributable risk for breast cancer from a dose of 20mGy is approximately

1/1200 for a woman aged 20 1/2000 for a woman age 301/3500 for a woman aged 40

That is, if a woman aged 30 has a CTPA with a breast dose of 20 mGy, there would be an additional 1/2000 chance of her developing breast cancer. The lifetime risk of breast cancer for women is approximately 1/8.

Breasts

SEATTLE II

Other causes SOB in pregnancy?

Flexor origin?