Miscellaneous Flashcards
(56 cards)
A 41 year old woman has nyctalopia. Upon taking a history, she had bariatric surgery about 6 months ago. Which vitamin or mineral supplementation is most needed?
vit A
Nyctalopia (night blindness) can occur after bariatric surgery such as gastric bypass surgery due to vitamin A deficiency. Another potential ocular complications of vitamin A deficiency post bariatric surgery is xerophthalmia.
Action to Control Cardiovascular Risk in Diabetes (ACCORD) study
The Action to Control Cardiovascular Risk in Diabetes (ACCORD) study had a few arms studying:
Intensive glycaemia control: target glycated haemoglobin level <6% VS standard therapy
Intensive lipid control: Combination therapy with a statin plus a fibrate VS statin monotherapy
Intensive blood pressure control: Targeting a systolic blood pressure (SBP) of <120 mm Hg VS <140 mm Hg
All of these were in patients with type 2 diabetes, not type 1 diabetes. Participants were “high-risk” i.e. aged 40–79 years with history of cardiovascular disease, or 55–79 years with evidence of significant atherosclerosis, left ventricular hypertrophy, albuminuria or have at least two risk factors for cardiovascular disease.
In summary, slowing down of progression of retinopathy was observed in patients treated intensively for glycaemia and those who were treated with fenofibrate in addition to statin but NO effect was observed in those treated with intensive blood pressure control.
However, the as for the non-ocular related arms:
the addition of fenofibrate to simvastatin did NOT reduce rate of fatal cardiovascular events, non-fatal myocardial infarction or non-fatal stroke as compared to simvastatin alone
Intensive glycaemic control did NOT significantly reduce major cardiovascluar events, and risk of advanced measures of microvascular outcomes but delayed the onset of albuminuria and some measures of neuropathy
Targeting a SBP of <120 mm Hg, as compared with <140 mm Hg, did NOT reduce the rate of a composite outcome of fatal and nonfatal major cardiovascular events.
Quality of life years (QALY) is a measure of:
Qost -utility
Quality of life years (QALY):
= number of years of life gained x quality of life (compared to perfect health, also called utility)
Death = 0 QALY
1 year of perfect health = 1 QALY
Assessment of the value of an intervention relative to its cost is an important aspect of health economy. There are a few ways to assess this:
Cost-benefit analysis: Cost and benefits are all expressed as a monetary units, and usually cost/benefit ratio is calculated.
Cost-utility analysis: Costs measured in monetary unit and utility measured in non-monetary unit, and reported in years of life, QALYs, disability-adjusted life years (DALYs), health utility index
Cost-effectiveness: Cost measured in monetary unit, effectiveness measured in non-monetary unit; computes a cost effectiveness ratio.
You are working in an eye centre of a hospital in England. A 15 year old is found to have a right retinal detachment after he was hit by a football. After discussing the intended benefits and risks of surgery, the patient declined surgery. You deem him Gillick competent. His parents however, are pushing for surgery. Which of the following is likely the best next step?
seek legal advice
This is a tricky situation that needs to be approached carefully.
Of all the options, as you think surgery is in the best interest of this competent young person, it is likely best to seek legal advice.
First of all it is important to note that the legal framework for children who refuse treatment is different across the UK.
In Scotland, children can refuse treatment and the child’s decision cannot be overridden by the parents In England, Wales and Northern Island, the law on parents overriding young people’s competent refusal is complex. The GMC advocates involving other members of the multi- disciplinary team, an independent advocate, or a named or designated doctor for child protection or seek legal advice if you think treatment is in the best interests of a competent young person who refuses.
An intervention costs £100,000 and is expected to extend patients’ life by 10 years. Patients affected by disease reported that the quality of life is on average 50% of normal after this intervention. What is the QALY for this intervention?
Quality of life years (QALY) combines:
quality (compared to perfect health, also called utility) quantity (no of years of life gained)
Death = 0 QALY
1 year of perfect health = 1 QALY
In this question, the intervention extends life by 10 years, and quality of life is 0.5.
10 x 0.5 = 5 QALY
defines the sensitivity of a test?
Sensitivity is the proportion of subjects with the condition (when tested using gold standard test) who have a positive result when using the test. In another words, sensitivity is the true-positive rate.
It is calculated by dividing the number of individuals who tested positive using the test
by (÷)
the number of individuals who tested positive using the gold standard test
If you refer to this table below:
Sensitivity = a/(a+c)a/(a+c)a/(a+c)
The other options given are referring to other characteristics of a test.
Specificity: The proportion of subjects without the condition and who have a negative test when using the test
Positive predictive value: The proportion of subjects with a positive test result who do have the condition
Negative predictive value: The proportion of subjects with a negative test result who do not have the condition
Which investigation is likely to be most useful in cases of hemifacial spasm?
MRI brain and orbit
Hemifacial spasms can either be primary or secondary. It is characterised by unilateral involuntary spasms of the facial musculature. Primary hemifacial spasm is when there is compression of the facial nerve when it exits from the brainstem. The most common mechanism is said to be compression from dolichoectasia of an artery, and the artery that is most commonly implicated is the anterior inferior cerebellar artery (AICA). Other arteries that can be implicated are posterior inferior cerebellar artery (PICA) and vertebral artery.
Secondary causes of hemifacial spasms include atherosclerosis, aneurysms, arteriovenous malformations, peripheral facial nerve trauma, parotid gland tumours and cerebellopontine angle tumours, brainstem strokes, demyelinating lesions and Bell’s palsy.
The main aim of a scan for hemifacial spasm would be to identify if there is a point at which the facial nerve is being compressed by a vascular structure. The combination of high-resolution 3D T2-weighted imaging with 3D time-of-flight angiography and 3D T1-weighted gadolinium-enhanced sequences is said to be the standard for investigation for any neurovascular conflict.
Out of the options, an MRI orbit and brain would capture the posterior fossa which is important, and captures the entire course of the facial nerve. The MRI of the internal acoustic meatus would miss a proportion of the facial nerve’s trajectory.
A patient is known to have a field defect. His previous full driving entitlement was removed. In which circumstance may a relicensing consideration be most likely considered under the DVLA guidance?
There are some exceptional cases pertaining to field of vision for group 1 drivers in the DVLA guidance.
Group 1 drivers whose previous full driving entitlement was removed because of a field defect may be eligible for individual relicensing consideration as exceptional cases under the following strict criteria:
Defect must have been present for at least 12 months caused by an isolated event or a non-progressive condition
Sight in both eyes
No other condition or pathology regarded as progressive and likely to be affecting the visual fields
No uncontrolled diplopia
No other impairment of visual function, including no glare sensitivity, contrast sensitivity or impairment of twilight vision
Clinical confirmation of full functional adaptation
In this question, the lorry driver would not be considered as this applies only to group 1 drivers. The field defect must be caused by a non-progressive condition, and some medical conditions such as glaucoma and retinitis pigmentosa would always be considered progressive so would not be considered.
Driver and Vehicle Licensing Agency (last updated March 2021). Visual disorders: Assessing fitness to drive. Retrieved 24 August 2024, from https://www.gov.uk/guidance/visual-disorders-assessing-fitness-to-drive
Caldicott guardianship
Each NHS organisation is mandated to have a Caldicott Guardian, who is a senior person responsible for protecting the confidentiality of patient and service-user information and enabling appropriate information-sharing. The Caldicott guardian’s role and responsibilities centre around upholding eight general principles of information governance, also known as the Caldicott principles.
The Caldicott guardian should be notified of all research and clinical education activities, and approval should be sought from them to verify appropriate use of personal identifiable information for these purposes as part of permissions to conduct research projects within a trust.
Some organisations may have a Senior Information Risk Owner (SIRO), and this person is not the same as a Caldicott Guardian. A SIRO is usually an executive director or senior member of the board. It would not normally be appropriate for the same person to be both SIRO and Caldicott Guardian, due to the possibility of a conflict of interest and the decision-making role that the SIRO may hold.
Reference(s)/further reading:
Shropshire Community Health, NHS Trust. Caldicott Guardian. Retrieved 25 August 2024, from https://www.shropscommunityhealth.nhs.uk/caldicott-guardian
National Data Guardian for health and social care (2021). Guidance about the appointment of Caldicott Guardians, their role and responsibilities published by the National Data Guardian for Health and Social Care Guidance version 1.0 National Data Guardian for Health and Social Care. Retrieved 25 August 2024, from https://assets.publishing.service.gov.uk/media/6127b6d6e90e0705437230da/Caldicott_Guardian_guidance_v1.0_27.08.21.pdf
NHS Scotland. Caldicott Guardians – Principles into Practice (June 2012). Retrieved on 28 August 2024, from https://www.informationgovernance.scot.nhs.uk/wp-content/uploads/2016/03/CaldicottGuardianManualScotland-June2012v2.pdf
A double blinded randomised controlled trial was conducted to study the effects of treatment X on scleritis . The study showed that 70% of patients responded to treatment A compared to only 20% who responded in the placebo group.
P value is the measure of statistical significance while number needed to treat (NNT) is the measure used to assess the effectiveness of a particular intervention.
When comparing two interventions, the NNT is the number of subjects who need to be treated with the intervention, compared with the control, for one additional subject to experience the beneficial outcome. It is the reciprocal of the absolute risk reduction (ARR) between two interventions. The lower the NNT value the better.
NNT = 1/ARR
NNT = 1/ (0.70-0.20) = 2
For every two patients in the treatment group, one additional person gets the beneficial outcome.
The Diabetes Control and Complications Trial (DCCT)
The Diabetes Control and Complications Trial (DCCT) only studied participants with type 1 diabetes, not type 2 diabetes. It only looked at blood glucose control, not blood pressure and lipid control.
Type 1 diabetics were assigned randomly into either one of the two groups:
Intensive diabetes treatment:
->receiving ≥3 insulin shots/day or
->insulin pump with self-monitoring of blood glucose ≥4 times/day
OR
Conventional treatment:
->receiving 1-2 insulin shots/day or
->daily self monitoring of urine or blood glucose
The DCCT demonstrated that compared to participants with type 1 diabetes who used conventional treatment, those who used intensive treatment:
Lowered their risk of diabetic retinopathy by 76%
Slowed progression by 54%
Lowered their risk of developing diabetic neuropathy and nephropathy
Tips: It can be overwhelming to try to remember all the studies. This does not encompass all the studies out there but the common ones are summarised here:
DCCT is one of the few that looked at type 1 diabetics, and only looked at intensive blood glucose control
UKPDS and ACCORD studied type 2 diabetics
UKPDS and ACCORD studied intensive blood glucose control too
Blood pressure control was investigated in the UKPDS and ACCORD
Lipid control was investigated in the ACCORD study
An 85 year old patient presents with an intraocular pressure of 27mmHg in the right eye and 26mmHg in the left eye, and central corneal thickness of 580µm in both eyes. There is no visual field defect and optic discs are healthy. Which of the following would be the most likely appropriate next step?
Discharge from hospital eye service, resume monitoring with optometrist
According to the NICE guidelines last updated in 2022, people with newly diagnosed ocular hypertension and an intraocular pressure of 24 mmHg or more who have a risk of visual impairment within their lifetime should be offered selective laser trabeculoplasty (SLT) as first line treatment, excluding cases of pigment dispersion syndrome.
This patient has ocular hypertension but also has increased central corneal thickness, which means his IOP may be over-estimated by tonometry. In addition, this patient is quite elderly and has no evidence of glaucoma. Therefore, the risk of visual impairment within their lifetime is likely to be low. Discharging the patient from the hospital eye service, and resuming monitoring with local optometrist is likely to be most appropriate.
A 15 year old girl has congenital ptosis of her right lid and would like surgery to correct this.
explain Gillick competence
This patient is 15 years old, so she needs to be deemed Gillick competent in order to give consent to any examination, investigation or treatment. She cannot be assumed to have the capacity to make decisions or treated the same way as an adult. Only children aged 16 or above can be assumed to have capacity to make decisions about their care.
A child is deemed Gillick competent if they can understand, retain, use and weigh the information given and their understanding of benefits, risks and consequences.
However, even if a child is Gillick competent, effort should be made to encourage the child to involve their parents.
It is important to note however, the consent given by Gillick competent child cannot be overridden by parents.
With regards to the ocular trauma score, which variable is associated with better visual prognosis?
presence of RAPD
The ocular trauma scoring (OTS) system was developed by Kuhn and colleagues to predict final visual outcome of an injured eye.
Raw points are based on the initial visual acuity and points were subtracted if there were certain features. The raw points are then converted into the OTS and likelihood of final visual categories is given as below:
Compared to the other options given, the least points were subtracted with the presence of RAPD.
Quality of life years (QALY) is a measure of:
cost - utility
Quality of life years (QALY):
= number of years of life gained x quality of life (compared to perfect health, also called utility)
Death = 0 QALY
1 year of perfect health = 1 QALY
Assessment of the value of an intervention relative to its cost is an important aspect of health economy. There are a few ways to assess this:
Cost-benefit analysis: Cost and benefits are all expressed as a monetary units, and usually cost/benefit ratio is calculated.
Cost-utility analysis: Costs measured in monetary unit and utility measured in non-monetary unit, and reported in years of life, QALYs, disability-adjusted life years (DALYs), health utility index
Cost-effectiveness: Cost measured in monetary unit, effectiveness measured in non-monetary unit; computes a cost effectiveness ratio.
A 41 year old woman has nyctalopia. Upon taking a history, she had bariatric surgery about 6 months ago. Which vitamin or mineral supplementation is most needed?
Nyctalopia (night blindness) can occur after bariatric surgery such as gastric bypass surgery due to vitamin A deficiency. Another potential ocular complications of vitamin A deficiency post bariatric surgery is xerophthalmia.
How should evidence from studies with different designs be ranked from highest quality to poorest quality based on the Scottish Intercollegiate Guidelines Network?
Scottish Intercollegiate Guidelines Network (SIGN) published “A Guideline Developer’s Handbook (SIGN 50) which describes their approach to levels of evidence.
There are levels of evidence with 1++ being highest quality and 4 being poorest quality.
Figure E.9. Adapted from Scottish Intercollegiate Guidelines Network (published 2008, Revised edition published 2019). A guideline developer’s handbook. Retrieved 24 August 2024, from https://www.sign.ac.uk/media/2038/sign50_2019.pdf
eligible for sight impairment registration in the UK?
When it comes to certificate of vision impairment, there are two categories, “sight impaired” and “severely sight impaired”.
Patchy loss of field of vision with a visual acuity of 6/24 would most likely qualify for sight impairment registration.
Full field of vision and visual acuity of 6/36 would not quality for sight impairment registration.
A person with bitemporal hemianopia with visual acuity of 6/24 and a person with visual acuity of 3/12 would qualify for severe sight impairment registration.
A summary of who qualifies for each category is as below:
Sight impaired:
Full field of vision + VA 6/60-3/60
Moderate constriction of field (superior or patchy loss), media opacities or aphakia + VA 6/24-6/60
Marked field defect (e.g. homonymous hemianopia, glaucoma or RP) + VA 6/18 or better
Severely sight impaired:
Legally defined as so blind that they cannot do any work for which eyesight is essential
VA is worse than 3/60
Contraction of visual field + VA 6/60-3/60
Clinically significant contracted visual field which is functionally impairment the person e.g. loss of inferior field or homonymous or bitemporal hemianopia + VA 6/60 or better (Note: Homonymous or bitemporal hemianopia is specifically excluded unless VA worse than 6/18)
Reference(s)/further reading:
Department of Health (August 2017). Certificate of Vision Impairment Explanatory Notes for Consultant Ophthalmologists and Hospital Eye Clinic Staff in England. Retrieved 24 August 2024, from https://assets.publishing.service.gov.uk/media/5a74fffbed915d3c7d5299be/CVI_guidance.pdf
conditions are not DVLA notifiable?
DVLA driving rules
Group 1
6/12 in one or with both eyes open
Read number plate at 20m
Field of vision: 120 degrees horizontally, extension at least 50/50 left and right
Central: allowed scattered singles or 3 clustered missing points in central 20 of fixation above or below horizontal meridian
Peripheral: allowed 3 clustered missing points unattached to other defect on or across horizontal meridian; a vertical defect of a single point width but any length unattached to any other defect on or across horizontal meridian
Group 2
6/7.5 in one eye, 6/60 in the other eye
Not more than +8D if where glasses
Field: 160 degrees, 70/70, 30/30 above and below horizontal plane
Central: allowed defect 3 points outside of central 30 + no defects (at ALL) within radius of central 30
No other impairment, including no glare sensitivity, contrast sensitivity or impairment of twilight vision
But if you held licence before 1 Jan 1997 you may still be able to renew even if you do not meet these standards
Others:
Disorders e.g. bilateral glaucoma, bilateral retinopathy, retinitis pigmentosa, other field defects e.g. partial or complete homonymous hemianopia/quadrantanopia or complete bitemporal hemianopia – must notify DVLA
Diplopia – both groups must not drive, group 1 – can resume if diplopia controlled; group 2 will likely lose licence (patching not acceptable)
Blepharospasm: must not drive and notify DVLA
Nystagmus – do not need to notify DVLA provided vision standards for driving and any associated medical condition is declared
TIA:
Group 1: No driving for 1 month and only restart when doc tells patient safe to resume driving, do not need to inform DVLA if patient had a TIA and have recovered;
group 2 same but 1 year cannot drive
Registering disability
Sight impaired (partially sighted)
Full field: 6/60-3/60
Moderate constriction of field (superior or patchy loss), media opacities or aphakia 6/24-6/60
Marked field defect (e.g. homonymous hemianopia, glaucoma or RP): 6/18 or better
Severely sight impaired
Legally defined as so blind that they cannot do any work for which eyesight is essential
VA is worse than 3/60
VA 6/60-3/60 + severe contraction of their visual field
VA 6/60 or better with a clinically significant contracted visual field which is functionally impairment the person e.g. loss of inferior field
Homonymous or bitemporal hemianopia is specifically excluded unless VA worse than 6/18
Registration is optional but will enable the local authority to be aware and enable them to support you. They will contact you to arrange an assessment and the support will be tailored to your situation, may include aids and equipment or training to help you do things for yourself and be more confident.
Partially sight impaired – free travel on bus, trains and some ferries
Severely sight impaired – as above plus:
Concession travel on bus and trains with a companion
50% TV licence
Income tax relief
Blue badge + car park concessions
It does not entitle you to benefits automatically but can be used as evidence of sight loss in your applications.
What does it mean when the power of a study is said to be 80%?
There is 20% chance of falsely accepting null hypothesis
Power of a study is the probability a type 2 error will NOT be made in the study. In another words, it is a measure of the study’s ability to detect smallest possible difference between groups considered clinically worthwhile if a true difference exists. Generally, the larger the sample size, the more power the study has.
A study that has a power of 80% means there is an 80% probability of finding a significant difference with a given sample size, if such a difference truly exists. It accepts a 20% chance of missing such a true difference, i.e. falsely accepting a null hypothesis.
What is the recommended screening interval for patients on hydrochloroquine without additional risk factors?
Annual screening after 5 yrs
Hydroxychloroquine is a medication used by our rheumatology and rheumatology colleagues for the treatment of some autoimmune diseases. Unfortunately it can cause damage to photoreceptors and RPE, leading to irreversible structural and functional retinal deficits.
According to the RCOphth clinical guidelines titled Hydroxychloroquine and Chloroquine Retinopathy: Recommendations on Monitoring published in 2020, annual screening should be commenced after 5 years of use of hydroxychloroquine. Baseline screening is not recommended. There are exceptions though, and this would be if patients have additional risk factors:
Concomitant tamoxifen use
Impaired kidney function
Dose of hydroxychloroquine >5mg/kg/day
Chloroquine use
For these patients, screening should begin 1 year after commencement of the medication.
Reference: Royal College of Ophthalmologists (2020). Clinical Guidelines - Hydroxychloroquine and Chloroquine Retinopathy:
Recommendations on Monitoring. Retrieved 2 June 2024, from https://www.rcophth.ac.uk/wp-content/uploads/2020/12/Hydroxychloroquine-and-Chloroquine-Retinopathy-Monitoring-Guideline.pdf
Which of the following is most likely implicated in a patient who has nyctalopia several weeks after bariatric surgery?
vitamin A
Bariatric surgery cause deficiencies of fat-soluble vitamins i.e. vitamin A,D,E,K. This is caused by reduced food intake, reduced absorption and changes in neural and gut hormonal signals.
Clinical manifestation of vitamin A deficits are night blindness, xerophthalmia and dry hair.
The United Kingdom Prospective Diabetes Study (UKPDS)?
The UKPDS was a large multi-centre RCT of subjects with type 2, not type 1 diabetes mellitus. Subjects were randomly assigned to:
Tight blood pressure control vs less tight blood pressure control
Tight blood glucose control vs conventional blood glucose control
This study demonstrated that both intensive blood glucose and intensive blood pressure control independently reduced the risk of microvascular complications in type 2 diabetics.
References/further reading:
UK Prospective Diabetes Study (UKPDS) Group (1998). Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet, 352(9131):837-53. Erratum in: Lancet 1999 Aug 14;354(9178):602. PMID: 9742976.
UK Prospective Diabetes Study Group (1998). Efficacy of atenolol and captopril in reducing risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 39. BMJ. 1998 Sep 12;317(7160):713-20. PMID: 9732338; PMCID: PMC28660.
