Professor
Brian Andrews NEJM Recommendations for Medical Students and Tutors
Week
of 17th March 2016 (#34)
University
of Notre Dame Australia (Fremantle Campus)
Occasional Editorial Comment
None
Must Read Articles
None
Must Save Articles
REVIEW ARTICLE
Colorectal
Adenomas
Colon
cancer begins with the malignant transformation of benign adenomas and polyps.
When adenomas are large or multiple, the risk of subsequent cancer is highest.
Screening techniques, although imperfect, can reduce the incidence of
colorectal cancer
This is an excellent updated review with extensive
bibliography on colorectal adenomas. The hyperlink should be stored in your
database for future reference. For those not wishing to read the entire article,
I suggest you read both the section on “Adenomas and Sessile Serrated Polyps,” and,
perhaps more importantly the “Conclusions” section at the end for an overview.
Articles Recommended for Medical Students
EDITORIAL
Endarterectomy,
Stenting, or Neither for Asymptomatic Carotid-Artery Stenosis
ORIGINAL ARTICLE
Randomized
Trial of Stent versus Surgery for Asymptomatic Carotid Stenosis
In
this trial involving asymptomatic patients with severe carotid stenosis,
stenting was noninferior to endarterectomy with regard to the primary composite
end point of death, stroke, or myocardial infarction within 30 days or
ipsilateral stroke within 1 year after the procedure.
ORIGINAL ARTICLE
Long-Term
Results of Stenting versus Endarterectomy for Carotid-Artery Stenosis
In
this long-term follow-up of a randomized trial comparing endarterectomy with
stenting for carotid-artery stenosis, the risks of periprocedural stroke,
myocardial infarction, or death and subsequent ipsilateral stroke did not
differ between groups over a 10-year period.
These two studies show that there are no significant
differences in perioperative and long term outcomes in repairing carotid artery
stenosis using endarterectomy or stent placement with embolic protection.
Protocols for anticoagulation differed slightly between the studies.
The study by Rosenfield
et all. follows 1453 asymptomatic
patients with ipsilateral stenosis, from 70 to 99%, and contralateral of less
than 60%, defined by ultrasonography or angiography. These patients were studied
for up to five years after surgery. In the Supplemental data, the authors state
that their entry criteria for surgery on the involved site ranged from 80 - 99%
stenosis, but in the article from 70 – 99%.
This may be because of the difficulty recruiting patients who fulfilled
the initial entry criteria. Previous studies have indicated that greater than
70% stenosis in the asymptomatic patient can be an indication for surgery.
The study by Brott
et al. is a 10-year follow-up on an originally reported four-year study of
2502 patients with both symptomatic and
asymptomatic carotid artery stenosis comparing endarterectomy with
stenting. In this study, stenosis is defined by either ultrasonography, CT
tomographic angiography, or MR angiography.
The overall data from the two studies indicate that
there are no significant differences between the results of either procedure. There
is a good summary and analysis of the area in the accompanying review.
Recommended
learning: The role carotid artery stenosis plays in stroke, the clinical presentations of carotid artery stenosis and its diagnosis and management.
IMAGES IN CLINICAL MEDICINE
Froin’s
Syndrome
A
64-year-old man presented with progressive weakness in the legs. Neurologic
examination showed paralysis of the legs and decreased sensation starting at
the L1–L2 level. There was concern about a possible spinal hematoma.
Froin’s syndrome is seen infrequently today because
spinal cord compression with obstruction to CSF flow is diagnosed with early use
of MRI. In this patient who was unable to have an MRI due to a pacemaker and a
non-contributory CT scan, a schwannoma was demonstrated using CT myelography.
Prior to the availability of CT and MRI, myelography wit tomography was the
standard method for demonstrating such a lesion.
IMAGES IN CLINICAL MEDICINE
Scabies
A 61-year-old woman presented with a severe pruritic rash. Excoriated papules with honey-colored crusting were present on the abdomen, arms, and legs. Treatment for suppurative folliculitis and prurigo nodularis produced no improvement. A biopsy of the rash was performed.
This case is an important reminder to always consider
the diagnosis of scabies, which is readily cured, in a patient with an
undiagnosed pruritic cutaneous eruption. I remember many years ago, during my
MD research involving a study of patients with cutaneous vasculitis, when I
received a referral from a prominent dermatologist of a patient with suspected
vasculitis on systemic corticosteroids.
After processing and reviewing the biopsy I performed, I was surprised
to find a strange looking creature in the dermis which turned out to be the
burrowing mite Sarcoptes scabiei .
Don’t forget to always look for burrows in the web
spaces of the hands.
Recommended
learning: Scabies – the cause, epidemiology, clinical
presentation and the management.
Important Articles Related to Mechanisms of Disease and
Translational Research
CLINICAL IMPLICATIONS OF BASIC RESEARCH
A
CRISPR Way to Block PERVs — Engineering Organs for Transplantation
A
challenge to xenotransplantation is the transmission of infectious agents,
including endogenous retroviruses. A study of porcine endogenous retroviruses,
and the use of a new tool (CRISPR-Cas9) to inactivate them, represents a step
toward addressing this challenge.
Over the past three months in the Journal, there has
been a particular interest in the lack of organ availability for transplantation,
particularly renal transplantation.
Related indirectly to this area was an article on the development
of a complete 3D kidney organoid containing a formed nephron, collecting duct,
stroma, and blood vessels. This was formed from induced pluripotent stem cells,
in this case derived from autologous skin stem cells (http://www.nejm.org/doi/full/10.1056/NEJMcibr1514351). Last week in the Journal (http://www.nejm.org/doi/full/10.1056/NEJMe1601379)
was the excellent eight-year survival results from transplanting living donor
kidneys to HLA mismatched recipients, some of whom also had an ABO mismatch.
This week in the Journal we enter the previously taboo
area of grafting across species (xenografting), specifically pig to human. A
major problem, apart from obvious rejection of the xenograft, is reactivation
of porcine endogenous retroviruses (PERV, an abbreviation I assume was used to
capture the attention of the reader). Yang el al (Science 2015) used the increasingly
available gene editing technique of CRISPR-Cas9 (clustered regularly
interspaced short palindromic repeats) which targets a specific DNA sequence
for disruption. They were able to knock-out not just one, but up to 60
different copies of PERV polymerase genes in a single porcine kidney cell. This
removed most of the potentially dangerous sequences should they become
reactivated in an immunosuppressed recipient. CRISPR-Cas9 will open up many
area of research and this technique on gene editing may well end up receiving a
Noble Prize.
Other articles which should be of interest to medical students
Perspective
Health
Care Tax Inversions — Robbing Both Peter and Paul
To
avoid higher taxes, U.S. health care companies have been merging with companies
based in countries with lower tax rates. We need to discourage this practice:
developing new therapies, not avoiding taxes, should be the route to sustained
profitability.
This is what the US has to contend with: tax evasion
(should be regarded as theft from US taxpayers who have to pay extra taxes to
fund Medicare) by corporate giants like Pfizer who do mergers with other
companies (Allergan) who are centred in lower corporate tax havens such as
Ireland where the new corporation will now reside. This is technically legal in
the US because Congress, in the financial pockets of multinational
corporations, is unwilling to change the laws. Australia needs to be aware of this potential problem.
ORIGINAL ARTICLE
A
Randomized Trial of a Cervical Pessary to Prevent Preterm Singleton Birth
In
a trial involving girls and women with singleton pregnancies who had a cervical
length of 25 mm or less at 20 to 24 weeks of gestation, placement of a cervical
pessary did not result in a lower rate of spontaneous early preterm delivery
than the rate with expectant management.
The results of the study are summarized in the Journal
review of the article. This is recommended to those particularly interested in
this area.
SPECIAL ARTICLE
Safer
Prescribing — A Trial of Education, Informatics, and Financial Incentives
Primary
care practices in Scotland were randomly assigned to various start dates for an
intervention with financial incentives to review patients at high risk for
adverse effects from antiplatelet agents or NSAIDs. The intervention was
associated with reduced high-risk prescribing.
This
is a costly Scottish public health study with results which are somewhat
predictable.
The
study describes a series of complex interventions involving initial
professional education, ongoing informatics, and financial incentives for GPs
and their staff from 33 of 66 practices initially approached. The early phase and the informatics phase of
the interventions in the study of counselling of high-risk prescribing of
antiplatelet medications and NSAIDs produced beneficial effects which were
sustained over the short term study of 96 weeks (see Figure 1). While these
interventions reduced high-risk prescribing and improved clinical outcomes by
reducing the rate of hospitalizations for heart failure and GI bleeding, the
interventions had no effect on admissions for acute kidney injury. The
disadvantages to the patients of not prescribing the anti-platelet medications
and NSAIDs were not considered.
What was missing from this study was a cost/benefit
analysis of the study which I hope will be published in a subsequent paper. What
was also missing were the data on: i)
the total cost of the interventions, ii) the amount of money saved because of
the interventions, particularly hospitalization costs and, iii) the change in
mortality rates. If GPs spent more time
on the study, I am sure they would still have had to see the same number of
patients each day and would have finished their working day at the same time.
In terms of time spent each day, something may well have been neglected. These
intangibles are very difficult to quantify.
CASE RECORDS OF THE MASSACHUSETTS GENERAL HOSPITAL
Case
8-2016 — A 71-Year-Old Man with Recurrent Fevers, Hypoxemia, and Lung
Infiltrates
A
71-year-old man presented with recurrent fevers, dyspnea, and hypoxemia. Chest imaging
showed consolidation predominantly in the lower lobes and diffuse bilateral
ground-glass opacities that had waxed and waned over a 6-month period. A
diagnostic procedure was performed.
This interesting CPC reviews the differential diagnosis
of lung infiltrates and diffuse ground-glass opacities on lung CT in a
71-year-old male.
Videos in Clinical medicine
Transfusion of Red Cells
Blood
transfusion is often performed by health care workers. This video demonstrates
a commonly used method for the nonemergency transfusion of red cells in an
awake, competent adult.
A video worth watching.
