Case 1. 25 minutes.
The questions in this case relate to the following paper:
Iwuji CC, Orne-Gliemann J, Larmarange J, Balestre E, Thiebaut R, Tanser F, Okesola N, Makowa T, Dreyer J, Herbst K, McGrath N, Bärnighausen T, Boyer S, De Oliveira T, Rekacewicz C, Bazin B, Newell M-L, Pillay D, Dabis F. Universal test and treat and the HIV epidemic in rural South Africa: a phase 4, open-label, community cluster randomised trial. Lancet HIV 2018; 5: e116-25.
Retrieve the paper and appendix
Part A. 5 minutes.
Question 1 In your own words, outline the researchers’ rationale for undertaking this randomised controlled trial.
Part B. 5 minutes.
Question 2
- Identify ONE (1) source of bias that could occur within this randomised controlled trial.
- For the source of bias that you have identified, explain how this bias may have influenced the result relating to the primary outcome.
Part C. 5 minutes.
Question 3 In your own words explain the results relating to the primary outcome measure. Your answer should include an interpretation of the intervention effects, and confidence intervals.
Part D. 5 minutes.
A recent systematic review and meta-analysis examined whether integration of HIV services with other health services could improve antiretroviral therapy (ART) initiation among those who are found to be HIV+. Integration of care can be uni-directional (from HIV to non-HIV services, or from non-HIV services to HIV services), or bi-directional (to and from HIV and non-HIV services). This analysis synthesises studies that compare people who have received an integrated care approach vs those who have not received an integrated care approach. The results of the meta-analysis for the primary outcome ( (A) ART Initiation) appear below.
Question 4 Explain the result of the summary measure (“Overall effect”), commenting on the point estimate and 95% confidence interval.
Part E. 5 minutes.
Question 5 In the description of forest plot (Fig 3. Results of integration of HIV services: ART initiation, shown above), the authors state: “Outcomes are related to the ‘second 95’ of the 95-95-95 HIV cascade of care.”
What is meant by this statement?
Case 2. 40 minutes
Sione is a 39 year-old Pacific Islands male. Sione migrated to Aotearoa New Zealand with his family 5 years ago. He works as a teacher. He presented to his GP with a 2-month history of progressive shortness of breath on effort. Physical exertion was often associated with central chest pain and irregular palpitations. Sione also reported that on two occasions in the last month he had woken from sleep with attacks of frightening breathlessness and was unable to lie flat. His general health was good, with no weight loss or anorexia. He said he had no past history of significant health problems apart from a vague memory of being in hospital as a child but did not understand why, “it was something to do with a sore throat”.
Part A. 10 minutes
Question 6 Considering only the heart valves associated with the LEFT side of the heart:
- Name the valves
- Identify the surface anatomy sites for auscultation of the heart sounds associated with these two valves
- Describe the normal gross anatomical structure of both valves.
The 2 valves are the mitral and aortic valves. The place for auscultation of the mitral valve is the apex (5th intercostal space intersecting with the midclavicular line.) The place for ausculatation of the aortic valve is the right 2nd intercostal at the right sternal border. The mitral valve as 2 leaflets and chordae tendiniae the aortic has 3 leaftlets and no chordae tendiniae.
Each valve leaflet has 3 laysers lamina ventricle
Part B. 10 minutes.
Sione’s current presentation and past history could indicate cardiac valve dysfunction.
Question 7 With reference to the LEFT side of the heart and starting from the END OF DIASTOLE, describe the sequence of valve movements through a complete cardiac cycle. You should indicate:
- which valves move and when,
- what pressure differences cause each valve movement, and
- any associated heart sounds.
At the end of diastole atrial systole begins. The SA node sends a AP which triggers contraction of left atrium. The leads to increase in pressure and the blood flows to lower pressure, the LV. Then the Ventricles are pulsed and they contract. The ventricular pressure rises above the atria and the mitral valve closes gently (assisted by the Chordae tendiniae) (S1 sound.) . Then isovolumetric contraction occurs, where the ventricles are contraction but the blood cant go anywhere, the mitral valve is closed and the aorta has too high pressure for the blood to flow down the pressure gradient into. This keeps occurring until the pressure is above the aorta and ventricular ejection occurs. this keeps going until contract starts to let off and the moment the ventricular pressure falls below aortic the Aortic valve will close (S2 sound) and isovolumetric relaxation occurs where the ventricles relax but blood cannot go anywhere, the aorta is too high pressure and the mitral valve is closed, then the ventricle fully relaxes. It are once again the lowest point of the pulmonary circuit and the blood passively flows into it
Question 8 Cardiac valve problems can eventually lead to heart failure, features of which include breathlessness and peripheral oedema. Briefly outline the processes that cause breathlessness and peripheral oedema in heart failure.
***Heart failure is there the heart does not pump enough blood to meet the bodies needs. This is often characterised by low MAPB therefore CO. This leads to breathlessness as there is a VQ mismatch in the lungs there is not enough perfusion to supply the body at higher rates of use. We see peripheral oedema as a result of starlings equilibrium not working. Usually the arterial side the hydrostatic pressure in the arterioles lead to water flowing into the tissues and then equalise on the venous side as the osmolarity of the blood is comparitively higher. But with HF we cannot clear the venous side as well and this means that we start to get higher and higher venous pressure which leads to less and less water being removed from tissue. In essence we are adding water to the tissues and clearing less than we added, leading to fluid accumulation. ***
Case 3, 35 mins
Heather is a 26 year-old Pākehā female. In the pedigree below she is individual III:2. She presents with questions regarding her family history of severe global developmental delay and congenital heart disease in three male members of her family.
All three males are deceased because of this condition and no blood or DNA samples have been stored that can be analysed.
The deceased males are Heather’s:
- son (IV:1) died at 4 years of age.
- brother (III:3) died at 12 years of age.
- maternal uncle (II:1) died in childhood of the same condition.
Due to the strong family history, it is assumed the same genetic mechanism is responsible for this lethal disorder in all three deceased males.
All remaining family members in the pedigree are fit and well. Heather’s sister (III:4) is currently 28 weeks pregnant. The biological sex of her fetus is unknown.
Part A. 15 minutes.
Question 9 Assume that this fatal condition is caused by a reciprocal chromosomal translocation.
Identify the individuals in the pedigree who must be obligate carriers. Use pedigree notation, e.g. II:4, IV:1, etc to indicate your choices.
II:2 ,III:2
Question 10 Explain why the obligate carriers you identified, can carry this genetic factor but remain unaffected by the disorder, while the three deceased males suffered a fatal phenotype:
If the reciprocal chromosomal translocation is on the X chromosome, making it dysfunctional, A working copy of the X chromesome can provide the correct information. If you only have a single X chromesome you acnnot compensate. When each of the affected males were born there was w 50/50 chance that they would have a fatal phenotype and all of them got it.
Question 11 What would be the best test to perform on one of the healthy obligate carriers to evaluate whether a reciprocal chromosomal translocation is the basis for this clinical scenario?
KAryotype for carrier A chromosomal microarray, as it shows modifications in the whole genome.
Question 12 To evaluate the chromosomal status of individual IV:3 after their birth, which widely used test in New Zealand would be implemented?
Justify your answer.
The guthrie test would be administered to look for biochemical abnormalities in the child. It is administered to all the neonates (with consenting parents) and is our widely used afterbirth screen
Question 13 The pedigree is also consistent with X-linked (Choose between: recessive or dominant) inheritance of a single gene disorder.
If that is the case, what is the chance of the unborn child (IV:3) being a male carrying the genetic abnormality? Show your calculations.
Recessive
1/4 as Grandmother of fetus def has it and has a 1/2 change of passing mutation to mother of fetus, who has 1/2 chance of apssing it to fetus. 1/2 of 1/2 is 1/4th.
Part B. 10 minutes.
Heather’s now deceased son was assessed regularly by a paediatrician and clinical psychologist at the Child Development Service.
Question 14 Describe TWO (2) of the developmental tasks of infancy AND Describe or summarise the goal of the various tasks within this developmental stage (infancy).
Secure relationship with caregivers. This is the goal of having a loveing relationship with their caregivers
Differentiation of self from environment.. This is understanding that they themselves are a discrete agent in their environment, that they are an individual and recognising the self. classic test is to put like paint or smth on their nose and putting them in front of a mirror. if they try to rub it off themselves they recognise themselves apart from the environment around them.
The end goal for infancy is understanding and developing influence of people and place. It is understanding people and the world around them as well as developing the ability to be an agent of change in the world
Question 15: Considering a child around 2 years old, for each of these domains:
- physical development
- language and communication give an example of:
- ONE milestone that should have been achieved
and- ONE milestone that would be expected to be emerging.
Physical development Walking unaided should be achieved emerging is running
language and communication babbling should be present should be near or able to speak with a vocabulary of 15—300 word in 2-3 word sentences
Part C. 10 minutes.
Heather is hoping to have another baby and asks her GP, Dr Ward, whether there are any tests she could do to reduce the chance that she will lose another child. Dr. Ward explains that Heather could undergo genetic testing to understand more clearly what her risks are.
Question 16 What ethical considerations does this option raise AND What advice should Dr. Ward give Heather?
The ethical consideration of this is that other illnesses can be discovered and they might be in the family.
Case 4. 55 minutes.
Mr. Jones is a 40 year-old Pākehā male. He was involved in a motor vehicle accident while driving home from a night shift. His car collided with another vehicle traveling in the opposite direction. The ambulance staff at the scene found a deep laceration in his right anterior forearm, located closer to the wrist. He also had signs of a posterior dislocation of the right hip joint.
Following initial management the ambulance staff brought Mr. Jones to the Emergency Department. He was fully assessed and a CT was done.
The hip dislocation was confirmed, and this was reduced under sedation.
The forearm laceration was treated at the same time. The plastic surgeon sutured the laceration.
About 6 months after the accident, Mr. Jones developed a characteristic claw hand.
Part A. 5 minutes.
Question 17 If the wound was not sutured, by which process would the wound heal?
Scarring
Question 18 By day 4 of healing, what tissue is seen forming in the dermis?
granulation tissue (new blood vessels and proliferating fibroblasts in a loose ecm)
Question 19 Name:
- TWO (2) local causes of delayed healing,
AND- TWO (2) systemic causes of delayed healing.
Local: infection, immunosuppressants (attenuate the immune system) Systemic: nicotine usage (vasoconstrictor), malnutrition (not enough resources to repair wound.)
Part B. 10 minutes.
Question 20 Given the description of the location of the wound, and the subsequent condition Mr. Jones developed, what is the nerve involved?
Median nerve
Question 21 If this nerve is damaged at a higher level, this clinical presentation would be more prominent. (True / False)
True
Question 22 Which cord of the brachial plexus does this nerve originate from?
Lateral
Question 23 What are the THREE (3) spinal nerve root levels associated with this nerve? (pick 3 between C5 and T4)
c6 c7 c8
Question 24 Name the muscles supplied by this nerve in the forearm.
anterior except for FCU and FDP
Question 25 What is the anatomical basis for this clinical presentation in Mr Jones?
The damaged median nerve leads to paralysis of anterior compartement and unopposed extension of the hand and digits, as well as abduction of thumb*
Question 26 Name the main arteries supplying the anterior compartment of the forearm.
Anterior interosseal artery radial artery ulnar artery
Question 27 From the arteries supplying the anterior forearm, which arterial pulse can be detected at the anatomical snuffbox?
distal radial artery
Part C. 5 minutes
This is a histological image of a dorsal root ganglion.
Question 28 What type of neuronal cell bodies are indicated by A?
Unipolar or pseudounipolar?
Question 29 What is the function of the cells indicated by B?
Support neurons metabolically and structurally
Question 30 State THREE (3) differences between a somatic (dorsal root) ganglion and an autonomic ganglion.
dorsal root has more satellite cells, clustured neuronal cell bodies and more ordered satellite cells
Part D. 10 minutes.
Investigation of Mr. Jones’ claw hand would have included electromyogram (EMG) measurements of action potential (AP) conduction velocity in his arm.
Question 31 Explain the mechanism by which action potentials are conducted along axons AND the factors that affect the velocity of conduction.
To explain the mechanism we must understand action potentials themselves these are waves of electrical impulse that propagate down the axon. at the hillock there are voltage gated sodium channels and voltage gated potassium channels. If there is enough change in the membrane potential of the cell, tha VGNaC open leading to sodium rushing into the cell. This massive positive change in the cell leads more VGNaC to open, leading to the wave of positive potential going down the axon and triggering release of neurotransmitters at the synapse. The depolarisation of the cell also leads to K+ channels opening, a little later than the Na+ channels. These cause the positive K+ ions to leave the cell making it more negative and taking the membrane potential back down to the resting membrane potential, which allows restitution for the next AP to be sent.
Question 32 Some results for EMG measurement of ulnar nerve conduction velocity from a different patient are shown below.
| RESULTS – ULNAR NERVE CONDUCTION VELOCITY | |
|---|---|
| Delay (latency) between stimulation at the wrist and muscle response | 2.3 ms |
| Delay (latency) between stimulation at the elbow and muscle response | 6.3 ms |
| Distance between the two stimulation sites | 24 cm |
a. Calculate the conduction velocity (m/s) for this section of nerve. b. How does this compare with normal ulnar nerve conduction velocity?
0.24/0.004 is 60 ms normal.i s 50-75 so is normal
Part E. 10 minutes.
This is picture of a normal x-ray of a sacroiliac and hip joint.
Question 32 Name the muscles that attach to the bony structure labelled A.
Illiacus, psoas major,.
Question 33 What is the function of the muscle that attaches to A at the hip joint?
HIp flexion
Question 34 Name two principal arteries supplying the hip joint.
Femoral circumflex artery, artery of the ligament of the head of femur
Question 35 List the capsular ligaments found in the hip joint.
ileofemoral, pubofemoral, ischialfemoral
Question 36 Name two structures passing through the foramen labelled B.
Obturator nerve, obturator artery
Question 37 a. Name ONE (1) muscle positioned immediately anterior to foramen B and ONE (1) muscle positioned immediately posterior to foramen B.
b. Concentric contraction of these muscles produce what movement of the hip joint?
obturator interunus and obturator externus
abduction and lateral rotation
Question 38 What type of joint is labelled C?
anteriorly its synovial posteriorly its fibrous?
Question 39 Name the ligaments that stabilise the joint labelled D.
suproirs pubic and inferior pubic
Part F. 5 minutes.
This histological image shows a cross-section of a muscle.
Question 40 Name the connective tissue covering labelled A. endomysium
Question 41 Name two functions of this connective tissue (which covers the muscle).
stability and protection?
Question 42 What structures contribute to form a T-triad?
Tubules and 2x terminal cisternae
Question 43 In which part of a sarcomere are T-triads commonly located?
A band m
Part G. 10 minutes.
Mr. Jones’s goes to see his GP for a routine check-up. He appears distressed upon arrival. The GP asks Mr. Jones how he has been feeling lately. Mr. Jones informs the GP that he has been feeling stressed as he has been unable to return to work since the accident several months ago.
During this time, Mr. Jones has been watching more TV and spending more time online than before the accident. One day he saw an advert about an online racing and sports betting gambling app and decided to download it as he has always loved sports. He was feeling bored anyway and thought it would be a great way to occupy himself. He instantly started enjoying the excitement caused by using it and gradually started spending more time on it. He gambled with free credits at first which he felt was okay because he wasn’t spending any real money.
After a few weeks he found this was not exciting enough even though he was winning. This convinced him to spend a few of his own dollars. Soon he started spending larger sums of money and over time started to lose more than he was winning. Upon realising this, he tried to stop by deleting the app, but soon afterwards started feeling restless, agitated, and depressed.
He couldn’t stop thinking about gambling and missed the excitement of it, so he downloaded the app again and immediately felt much better when he started to use it again. He has incurred a lot of financial debt due to this over the past months and wants to stop but doesn’t think he can do it on his own.
Mr Jones asks the GP why he is experiencing this, and whether GP believes Mr. Jones has become addicted to gambling?
Question 44 Use the brain’s pleasure-pain balance in addiction, to explain why Mr. Jones has been experiencing what he told the GP.