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80 |
Martino Zacchè. Uro-gynaecology |
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81 |
Role-play. Previous SB. ↑ BP. IUGR. Complaint. |
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82 |
EMQ: Phenylketonuria. |
80. Tutorial. Urogynaecology. Martino Zacchè
81. Role-play.Booking. Previous SB. ↑ BP.
IUGR. May wish to complain.
Candidate’s instructions.
You are a year 5 SpR. Andrea Mather has booked for care
in her second pregnancy. Her first baby was stillborn at 39 weeks. The midwife
who did the booking has asked you to see her to discuss the implications for
this pregnancy. Dr. Reid, the consultant has said that you need to learn how to
deal with difficult situations, but to discuss your proposed management with
her before the patient leaves the clinic.
GP referral letter.
Please see Andrea Mather who is pregnant for the 2nd.
time, LMP 26th. June. Dr. Jones, a young colleague, who has a
particular interest in obstetrics and is a member of the RCOG, scanned her
today and the pregnancy is viable, looks normal and the gestation fits with the
LMP.
Sadly, Andrea’s first pregnancy ended disastrously: the
baby was stillborn. Andrea and her family have concerns about the care she
received at the hospital and believe that she should make a formal complaint. I
have spoken to Dr. Reid by phone to alert her to this sensitive issue. The
problem is that Andrea was referred by Sister Williams, our midwife, at 38
weeks with hypertension and an impression of IUGR. Andrea says that no
investigation was done, not even a scan. She was discharged and told to see Sister
Williams a week later. When she saw her, Sister Williams had the nasty
experience of having to inform Anrea that fetal heart activity could not be
detected. Dr. Jones was not available to scan her, but a scan at the hospital
confirmed FDIU. The baby only weighed 3 lb. I had a letter from a Dr. Reynold’s
after Andrea’s follow up visit six weeks later. He indicated that he was a SpR.
The letter was very brief and only stated that no explanation was found. I
presume that some kind of perinatal review process was instituted, but I have
not received any information about this or any conclusions or recommendations.
Andrea has been greatly traumatised but has had good
support from Jane, your bereavement midwife, Sister Williams, Dr. Jones and
Susan, our health visitor. Andrea’s mother, who used to be a nurse, has made it
clear that she believes Andrea’s care was negligent and that Andrea should
complain. Dr. Reid is aware of this. I should be most appreciative if Andrea
could be under senior review and I could have a comprehensive plan for the
pregnancy and delivery so that Dr. Jones, Sister Williams and I can give her
the maximum support during what is bound to be a very stressful time.
Yours sincerely,
Mary Goodfellow.
82. EMQ.
Topic. Phenylketonuria in pregnancy.
Abbreviations.
PA: phenylalanine.
PAH: phenylalanine
hydroxylase.
PAHD: phenylalanine
hydroxylase deficiency.
PKU: phenylketonuria .
Tyr: tyrosine.
Option
list.
|
A. |
autosomal dominant |
|
B. |
autosomal recessive |
|
C. |
X-linked dominant |
|
D. |
X-linked recessive |
|
E. |
1 in 100,000 |
|
F. |
1 in 50,000 |
|
G. |
1 in 10,000 |
|
H. |
1 in 5,000 |
|
I. |
deficiency in phenylalanine
hydroxylase |
|
J. |
deficiency in phenylalanine
oxidase |
|
K. |
deficiency in phenylalanine
transferase |
|
L. |
deficiency in phenylketone
hydroxylase |
|
M. |
deficiency in phenylketone
oxidase |
|
N. |
raised PA levels |
|
O. |
reduced PA levels |
|
P. |
raised tyrosine levels |
|
Q. |
reduced tyrosine levels |
|
R. |
normal tyrosine levels |
|
S. |
No |
|
T. |
Yes |
|
U. |
unknown |
What is PKU? Write your answer – there is no option list.
Question
2.
What is PKU due to? Use the option
list.
Question
3.
What levels of PA and Tyr are
typical in PKU? Use the option list. This is not a real EMQ as there are two
answers.
Question
4.
Is PKU subdivided into different
categories? If “yes”, what are the categories? Write your answer – there is no
option list.
Question
5.
Which, if any, of the following
statements is true about hyperphenylalaninaemia? This is not a true EMQ as more
than one answer may be correct.
Option
List
|
A.
|
it blocks growth hormone |
|
B.
|
it destroys astrocyte miosis |
|
C.
|
it disrupts folic acid activity |
|
D.
|
it enhances vitamin A activity |
|
E.
|
it interferes with myelin
synthesis |
|
F.
|
it negates the effects of vitamin C |
|
G.
|
nobody knows, nobody cares; especially me |
Question
6.
How is PKU inherited? Use the
option list.
Question
7.
Which chromosome houses the gene
related to PKU transmission?
Question
8.
How many mutations of the gene
related to PKU have so far been identified?
Question
9.
Is a person with PKU likely to
have one or two mutations of the relevant gene?
What is BH4?
Question 11.
What is pegvaliase?
Question 12.
What is the approximate prevalence of PKU in Caucasians?
Question 13.
What is the approximate prevalence of PKU carrier status
in Caucasians?
Question 14.
The prevalence of PKU varies between ethnic groups.
Match each of the following
ethnic groups to the closest prevalence given in the option list.
Option
List
|
H.
|
1 in 1,000 |
|
I.
|
1 in 2,500 |
|
J.
|
1 in 5,000 |
|
K.
|
1 in 10,000 |
|
L.
|
1 in 100,000 |
|
M.
|
1 in 150,000 |
|
N.
|
1 in 200,000 |
|
O.
|
1 in 1,000,000 |
|
Ethnic group |
Prevalence |
|
Turkish |
1 in 2,600 |
|
Irish |
1 in 4,500 |
|
Caucasian |
1 in 10,000 |
|
East Asian |
1 in 10,000 |
|
Japanese |
1 in 143,000 |
|
Finnish |
1 in 200,000 |
Question
15.
Which, if any, of the following
are characteristic of PKU?
Option
list.
|
A. |
alopecia |
|
B. |
angst |
|
C. |
facial dysmorphism |
|
D. |
facial hair in females and
pre-pubertal males |
|
E. |
kyphosis |
|
F. |
macroorchidism in post-pubertal
males |
Question
16.
Are fetal PKU levels higher or
lower than maternal? There is no option list.
Question
17.
Which, if any, of the
following are true in relation to the
maternal phenylketonuria syndrome? This is not a true EMQ as there may be more
than correct answer.
Option list.
|
A. |
asymptomatic bacteruria is more
common |
|
B. |
cholestasis of pregnancy is
more common |
|
C. |
early onset gestational
hypertension is more common |
|
D. |
eczema is more common |
|
E. |
gallstones are more common |
|
F. |
miscarriage is more common |
|
G. |
MPKUS is usually due to
non-adherence to a low phenylalanine diet |
|
H. |
porphyria is more common |
|
I. |
reversible posterior cerebral
syndrome is more common |
|
J. |
urinary tract urea stones are
more common |
|
K. |
none of the above |
Question
18.
What are the main consequences
for the offspring of untreated PKU in the mother?
Question
19.
Is screening for PKU a routine
part of the neonatal screen in the UK?
Question
20.
The test for PKU used to be known
by the name of its inventor. Who was he and why did he have a particular
interest? There is no option list and no one is going to ask you except me!
What conditions are included in the routine neonatal
‘heelprick’ screening test? There is no option list.
Question 22.
Is neonatal screening for PKU still done using Guthrie’s
bacterial inhibition method? If not, what method is used? There is no option
list.
Question 23.
What is the main treatment of PKU and what problems are
associated with it? There is no option list.
Question 24.
How long should the main treatment of PKU be continued
and why? There is no option list.
Question
25.
Lead-in
A woman with PKU is planning her
first pregnancy at the age of 22. She has been off the PKU-restricted diet
since the age of 10 and can barely remember being on it. Should she be advised
to re-start the diet? If ‘yes’, when should she start and what explanation
would you give for the advice?
Question
26.
Lead-in
Which if any of the following
statements are true about screening for PKU and its effects in the neonate born
to a woman with PKU ?
Option list.
|
A. |
routine bloodspot screening
alone is required |
|
B. |
the neonate should be examined
by a paediatrician for signs of PKU |
|
C. |
the baby should have
developmental assessment, even if it does not have PKU |
|
D. |
an ultrasound scan should be
done because of the increased risk of developmental dysplasia of the hip |
|
E. |
the baby should be started on a
low PA diet until all assessments are complete |
|
F. |
none of he above. |
Question
27.
Lead-in
Is breast-feeding advisable for
women with PKU?
Question
28.
Lead-in
Are any other therapeutic
approaches available? If ‘yes’, what are they and how do they work? If ‘yes’
use the option list for the mode of action.
Option
List
|
A.
|
it binds PA to circulating
plasma proteins, reducing its free levels |
|
B.
|
it increases hepatic metabolism of PAH. |
|
C.
|
it increases renal excretion of PA |
|
D.
|
it is a co-factor for PAH, increasing its efficacy in reducing
PA levels |
|
E.
|
it is phenylalanine ammonia lyase, capable of breaking down PA |
|
F.
|
it is a synthetic PAH enzyme |
|
G.
|
it reduces absorption of PA from the small bowel |
TOG
CPD questions.
Regarding
phenylketonuria (PKU):
1. it is a
deficiency of the amino acid phenylalanine (Phe). True False
2. it is an
X-linked recessive inherited metabolic disease. True False
3. it results
in a deficiency in the amino acid tyrosine. True False
4. it is
treated with a low-phenylalanine restricted diet. True False
5. the
incidence is approximately 1:1000. True False
6. the Newborn
Screening Programme has been a great success in the diagnosis and management of
children with PKU. True False
7. neonates
with fetal alcohol syndrome and PKU are clinically difficult to distinguish at
birth. True False
8. in utero
exposure to very high levels of phenylalanine results in reversible
neurological damage to the fetus. True False
9. pregnancy
outcome is improved substantially when treatment results in low maternal
phenylalanine concentrations ideally before conception.
True False
10. oral methods
of contraception should be switched to barrier methods at least 12 months
before conception. True False
11. the risk of
congenital heart defects is estimated to be 7–10%. True False
12. it is an
indication for early delivery by caesarean section. True False
13. neonates
born to mothers with PKU should be offered screening for PKU as per the routine
national screening programme. True False
14. breastfeeding
is contraindicated in women with PKU. True False
With regard to the biochemistry of
PKU:
15. Phe is
passively transported across the placenta. True False
16. fetal Phe
levels are approximately 1.25-2.5 times > than maternal levels. True False
Children
born to women with PKU:
17. tend to have
blue eyes. True False
18. are fair
skinned. True False
With regard to the effect of high
Phe levels on loss of IQ or behavioural changes:
19. these
changes are reversible in utero. True False
20. they are
reversible with resumption of diet deficient of Phe. True False
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