PAEDIATRICS
Questions&Answers
Q-1
A 3 month old infant presents with recurrent infections and feeding difficulties.
His face looks dysmorphic and has a cleft palate. A chest X-ray shows absent
thymic shadow. What is the SINGLE most likely diagnosis?
A. Down’s syndrome
B. Fragile X syndrome
C. DiGeorge syndrome
D. Marfan’s syndrome
E. Edward’s syndrome
ANSWER:
DiGeorge syndrome
EXPLANATION:
DiGeorge syndrome is a deletion of chromosome 22q11.2. It causes absent thymus,
fits, small parathyroids (thus decreased Ca2+), anaemia, lymphopenia, low levels of
growth hormone, low T-cell immunity.
It is related to velo-cardiofacial syndrome: characteristic face, multiple anomalies, eg
cleft palate, heart defects, cognitive defects
Developmental delay, facial dysmorphism, palatal dysfunction and feeding difficulties
are seen in most infants with this syndrome.
The facial dysmorphism is typicallymild but fairly typical. These include hypertelorism,
hooded eyelids, tubular nose, broadnose tip, small mount and mild ear abnormalities.
Note that you do not need to remember these features for PLAB. The most important
factor to memorize here is the absent thymic shadow which is pathognomic for
DiGeorge syndrome
Mnemonic: CATCH-22
• Cardiac abnormality (commonly interrupted aortic arch, truncus arteriosus and
tetralogy of Fallot)
• Abnormal facies
• Thymic aplasia
• Cleft palate
• Hypocalcaemia/Hypoparathyroidism
,• With the 22 to remind one the chromosomal abnormality is found on the 22
chromosome
Q-2
A 4 year old boy is referred by the GP to the paediatrician with a cervical
lymphadenopathy that is 2 cm in size. His mother says that she thinks the lymph
node is growing. It was first noticed 6 weeks ago. The child is generally well with
no complaints of tenderness. He has no history of fever. On examination, the
spleen is not palpable and there are no other palpable lymph nodes around the
body. The cervical lymph node is firm, non-tender and immobile. His throat is
clear with no signs of infection. What is the SINGLE most appropriate initial
investigation to perform?
A. Full blood count and blood film
B. Ultrasound of lymph node
C. Lactate dehydrogenase
D. Liver function test
E. Epstein Barr virus and cytomegalovirus serology
ANSWER:
Full blood count and blood film
EXPLANATION:
All the above tests are appropriate but the number one test to do if you had to choose
would be to perform a full blood count and blood film to look for evidence of
haematological malignancies such as leukaemia or lymphoma. A lymph node that is
increasing in size and larger than 2 cm should be a worry. There are many causes of
lymphadenopathy in children which include CMV, EBV, Kawasaki’s disease,
tuberculosis but the one diagnosis that you do not want to miss are haematological
malignancies.
An ultrasound of the lymph node is appropriate since it is persisting beyond 16 weeks,
isolated, larger than 2 cm and increasing in size. However, it would not be the initial
test to perform.
Q-3
An 8 year old boy is brought by his mother to the emergency department with
bruises on his lower back and a left shoulder dislocation. The child currently
lives with his stepfather. The young boy is quiet and makes no eye contact while
in conversatikon. What is the SINGLE most likely diagnosis?
A. Non accidental injury
B. Malnutrition
C. Thrombocytopaenia
D. Osteogenesis imperfecta
E. Haemophilia
ANSWER:
Non accidental injury
,EXPLANATION:
This is a frequent paediatric topic on PLAB 1. This is a case of non-accidental injury.
Having a non biological father in the picture is always a hint for non accidental injury in
PLAB.
Non accidental injury
Presentation:
- Delayed admission into hospital or clinic by carer
- Child usually brought in by step-father or boyfriend
- Bruising – of varying degrees, color variations (means long term abuse)
- Fractures
Diagnosis:
- Mostly clinical history
Treatment:
- Admit to ward and manage pain
- Refer to social services
- Treat any other underlying medical conditions
Q-4
A 5 year old boy is brought to clinic by his mother. The young boy has a distinct
nasal speech and snores heavily at night. He is hyperactive during the day but
has poor concentration. He is noted to be constantly breathing through his
mouth. What is the SINGLE most appropriate action?
A. Arrange hearing test
B. Assess developmental milestones
C. Refer to ENT surgeon
D. Refer to speech therapist
E. Arrange a magnetic resonance imaging scan
ANSWER:
Refer to ENT surgeon
EXPLANATION:
The likely diagnosis here is obstructive sleep apnoea syndrome. Referrals are usually to
paediatric physicians, although sometimes paediatric neurologists, respiratory doctors
or ENT consultants may have a specialist interest.
Obstructive sleep apnoea syndrome in children
Obstructive Sleep Apnoea Syndrome in Children is mainly due to enlarged tonsils and
adenoids
Presentation
- Snoring - usually parents seek attention; many will just get better as they grow older
- Mouth breathing
- Witnessed apnoeic episodes
- Daytime sleepiness and somnolence is common in childhood OSAS, in contrast with
adults who often fall asleep during the day
- Sleep-deprived children tend to become hyperactive, with reduced attention spans,
, and be labelled as difficult or disruptive, or even ADHD. They may not be doing well at
school due to poor concentration
Investigations:
- Overnight in-laboratory polysomnography (PSG) continues to be the gold standard
instrument
o During sleep studies the following are usually monitored:
▪ Oxygen saturations and heart rate.
▪ Airflow at nose or mouth.
▪ Chest and abdominal movements.
▪ ECG, electroencephalogram, electromyogram and sometimes electro-oculogram
(eye movements)
Q-5
A 4 week old female infant presents to the Emergency Department with vomiting
after every feed. The mother describes the vomiting as projectile and non-bilious.
The child is also constipated. On examination, there is a right sided olive-sized
abdominal mass on palpation. What is the SINGLE most appopriate next step of
action?
A. Abdominal ultrasound
B. Abdominal X-ray
C. Intravenous fluids
D. Serum potassium level
E. Nasogastric tube insertion
ANSWER:
Serum potassium level
EXPLANATION:
This is a classic presentation of pyloric stenosis on PLAB 1. As the child is vomiting
profusely, there will be electrolyte imbalance. Hypokalaemia may be present and
therefore need to be corrected immediately.
In reality, one would take blood for serum potassium levels and arrange an abdominal
ultrasound while waiting for the serum potassium results. However, the exam writers
want you to think which is the most important given the stem.
Pay attention to the final line of the question. If the question is asking for the NEXT
STEP of action, serum potassium levels would be appropriate. If the question is asking
for the NEXT STEP TO DIAGNOSE the condition, then abdominal ultrasound would be
the answer.
Intravenous fluid should follow after taking bloods.
Presentation:
- Projectile non-bilious vomiting
- Age group: 3-8 weeks
- Olive sized abdominal mass
- The child will feel hungry and want to feed despite constant vomiting
Questions&Answers
Q-1
A 3 month old infant presents with recurrent infections and feeding difficulties.
His face looks dysmorphic and has a cleft palate. A chest X-ray shows absent
thymic shadow. What is the SINGLE most likely diagnosis?
A. Down’s syndrome
B. Fragile X syndrome
C. DiGeorge syndrome
D. Marfan’s syndrome
E. Edward’s syndrome
ANSWER:
DiGeorge syndrome
EXPLANATION:
DiGeorge syndrome is a deletion of chromosome 22q11.2. It causes absent thymus,
fits, small parathyroids (thus decreased Ca2+), anaemia, lymphopenia, low levels of
growth hormone, low T-cell immunity.
It is related to velo-cardiofacial syndrome: characteristic face, multiple anomalies, eg
cleft palate, heart defects, cognitive defects
Developmental delay, facial dysmorphism, palatal dysfunction and feeding difficulties
are seen in most infants with this syndrome.
The facial dysmorphism is typicallymild but fairly typical. These include hypertelorism,
hooded eyelids, tubular nose, broadnose tip, small mount and mild ear abnormalities.
Note that you do not need to remember these features for PLAB. The most important
factor to memorize here is the absent thymic shadow which is pathognomic for
DiGeorge syndrome
Mnemonic: CATCH-22
• Cardiac abnormality (commonly interrupted aortic arch, truncus arteriosus and
tetralogy of Fallot)
• Abnormal facies
• Thymic aplasia
• Cleft palate
• Hypocalcaemia/Hypoparathyroidism
,• With the 22 to remind one the chromosomal abnormality is found on the 22
chromosome
Q-2
A 4 year old boy is referred by the GP to the paediatrician with a cervical
lymphadenopathy that is 2 cm in size. His mother says that she thinks the lymph
node is growing. It was first noticed 6 weeks ago. The child is generally well with
no complaints of tenderness. He has no history of fever. On examination, the
spleen is not palpable and there are no other palpable lymph nodes around the
body. The cervical lymph node is firm, non-tender and immobile. His throat is
clear with no signs of infection. What is the SINGLE most appropriate initial
investigation to perform?
A. Full blood count and blood film
B. Ultrasound of lymph node
C. Lactate dehydrogenase
D. Liver function test
E. Epstein Barr virus and cytomegalovirus serology
ANSWER:
Full blood count and blood film
EXPLANATION:
All the above tests are appropriate but the number one test to do if you had to choose
would be to perform a full blood count and blood film to look for evidence of
haematological malignancies such as leukaemia or lymphoma. A lymph node that is
increasing in size and larger than 2 cm should be a worry. There are many causes of
lymphadenopathy in children which include CMV, EBV, Kawasaki’s disease,
tuberculosis but the one diagnosis that you do not want to miss are haematological
malignancies.
An ultrasound of the lymph node is appropriate since it is persisting beyond 16 weeks,
isolated, larger than 2 cm and increasing in size. However, it would not be the initial
test to perform.
Q-3
An 8 year old boy is brought by his mother to the emergency department with
bruises on his lower back and a left shoulder dislocation. The child currently
lives with his stepfather. The young boy is quiet and makes no eye contact while
in conversatikon. What is the SINGLE most likely diagnosis?
A. Non accidental injury
B. Malnutrition
C. Thrombocytopaenia
D. Osteogenesis imperfecta
E. Haemophilia
ANSWER:
Non accidental injury
,EXPLANATION:
This is a frequent paediatric topic on PLAB 1. This is a case of non-accidental injury.
Having a non biological father in the picture is always a hint for non accidental injury in
PLAB.
Non accidental injury
Presentation:
- Delayed admission into hospital or clinic by carer
- Child usually brought in by step-father or boyfriend
- Bruising – of varying degrees, color variations (means long term abuse)
- Fractures
Diagnosis:
- Mostly clinical history
Treatment:
- Admit to ward and manage pain
- Refer to social services
- Treat any other underlying medical conditions
Q-4
A 5 year old boy is brought to clinic by his mother. The young boy has a distinct
nasal speech and snores heavily at night. He is hyperactive during the day but
has poor concentration. He is noted to be constantly breathing through his
mouth. What is the SINGLE most appropriate action?
A. Arrange hearing test
B. Assess developmental milestones
C. Refer to ENT surgeon
D. Refer to speech therapist
E. Arrange a magnetic resonance imaging scan
ANSWER:
Refer to ENT surgeon
EXPLANATION:
The likely diagnosis here is obstructive sleep apnoea syndrome. Referrals are usually to
paediatric physicians, although sometimes paediatric neurologists, respiratory doctors
or ENT consultants may have a specialist interest.
Obstructive sleep apnoea syndrome in children
Obstructive Sleep Apnoea Syndrome in Children is mainly due to enlarged tonsils and
adenoids
Presentation
- Snoring - usually parents seek attention; many will just get better as they grow older
- Mouth breathing
- Witnessed apnoeic episodes
- Daytime sleepiness and somnolence is common in childhood OSAS, in contrast with
adults who often fall asleep during the day
- Sleep-deprived children tend to become hyperactive, with reduced attention spans,
, and be labelled as difficult or disruptive, or even ADHD. They may not be doing well at
school due to poor concentration
Investigations:
- Overnight in-laboratory polysomnography (PSG) continues to be the gold standard
instrument
o During sleep studies the following are usually monitored:
▪ Oxygen saturations and heart rate.
▪ Airflow at nose or mouth.
▪ Chest and abdominal movements.
▪ ECG, electroencephalogram, electromyogram and sometimes electro-oculogram
(eye movements)
Q-5
A 4 week old female infant presents to the Emergency Department with vomiting
after every feed. The mother describes the vomiting as projectile and non-bilious.
The child is also constipated. On examination, there is a right sided olive-sized
abdominal mass on palpation. What is the SINGLE most appopriate next step of
action?
A. Abdominal ultrasound
B. Abdominal X-ray
C. Intravenous fluids
D. Serum potassium level
E. Nasogastric tube insertion
ANSWER:
Serum potassium level
EXPLANATION:
This is a classic presentation of pyloric stenosis on PLAB 1. As the child is vomiting
profusely, there will be electrolyte imbalance. Hypokalaemia may be present and
therefore need to be corrected immediately.
In reality, one would take blood for serum potassium levels and arrange an abdominal
ultrasound while waiting for the serum potassium results. However, the exam writers
want you to think which is the most important given the stem.
Pay attention to the final line of the question. If the question is asking for the NEXT
STEP of action, serum potassium levels would be appropriate. If the question is asking
for the NEXT STEP TO DIAGNOSE the condition, then abdominal ultrasound would be
the answer.
Intravenous fluid should follow after taking bloods.
Presentation:
- Projectile non-bilious vomiting
- Age group: 3-8 weeks
- Olive sized abdominal mass
- The child will feel hungry and want to feed despite constant vomiting
