Neural Tube Defects

NEURAL TUBE DEFECTS

Q. 1

Pre-conceptional intake of which of the following results in decrease in incidence of neural tube defect?

 A

Vit.A

 B

Folate

 C

Vit.E

 D

Vit. C

Q. 1

Pre-conceptional intake of which of the following results in decrease in incidence of neural tube defect?

 A

Vit.A

 B

Folate

 C

Vit.E

 D

Vit. C

Ans. B

Explanation:

Prophylactic folic acid can significantly lower the incidence and recurrence rate of neural tube defects, if the intake of the folic acid starts at least 3 months prior to conception and continues for the first month of pregnancy, at a dose of 4 mg/d for women at increased risk.

For women of childbearing age without a family history of neural tube defects, the dose is 0.4 mg of folic acid daily. 

Ref: Tsaic A.C., Manchester D.K., Elias E.R. (2012). Chapter 37. Genetics & Dysmorphology. In W.W. Hay, Jr., M.J. Levin, R.R. Deterding, J.J. Ross, J.M. Sondheimer (Eds), CURRENT Diagnosis & Treatment: Pediatrics, 21e. 


Q. 2

All of the following are neural tube defects except:

 A

Myelomeningocele

 B

Anencephaly

 C

Encephalocele

 D

Holoprosencephaly

Q. 2

All of the following are neural tube defects except:

 A

Myelomeningocele

 B

Anencephaly

 C

Encephalocele

 D

Holoprosencephaly

Ans. D

Explanation:

Holoprosencephaly is a developmental disorder of the brain that results from defective cleavage of the prosencephalon. It is thus a malformation of cortical development and not a neural tube defect (NTD) otherwise known as dysraphism.

Ref: O P Ghai Essential Pediatrics, 6th Edition, Pages 531, 532


Q. 3

Which of the following is a marker for neural tube defects?

 A

↑Phosphatidylesterase

 B

↑Pseudocholinesterase

 C

↑Acetylcholinesterase

 D

↑Butyrylcholinesterase

Q. 3

Which of the following is a marker for neural tube defects?

 A

↑Phosphatidylesterase

 B

↑Pseudocholinesterase

 C

↑Acetylcholinesterase

 D

↑Butyrylcholinesterase

Ans. C

Explanation:

Neural tube defects are associated with high levels of Acetylcholinesterase.

Ref: Genetic disorders and Fetus, 4th Edition, Page 673; Ian Donald’s Practical Obstetric Problem By Renu Misra, 6th Edition, Page 44


Q. 4

Most useful maternal serum test used for distinguishing open neural tube defects and ventral wall defect in a fetus?

 A

Carcinoembryogenic antigen

 B

Sphingomyelin

 C

Alpha-feto protein

 D

Acetylcholinesterase

Q. 4

Most useful maternal serum test used for distinguishing open neural tube defects and ventral wall defect in a fetus?

 A

Carcinoembryogenic antigen

 B

Sphingomyelin

 C

Alpha-feto protein

 D

Acetylcholinesterase

Ans. D

Explanation:

Acetylcholinesterase is derived mostly from the tissues of the fetal nervous system.

Amniotic fluid acetylcholinesterase is a biochemical marker that is positive in 95% fetuses with open neural tube defects.

When both AFP and AChE is positive, likelihood of an open spine defect is greater than 99.5%.

High acetylcholinesterase and low butrylcholinesterase in seen in open neural tube defect.

Opposite occur in open ventral wall defect.

Ref: Clinical Laboratory Medicine By Kenneth D. McClatchey, 2nd Edition, Page 644 ; Genetic Disorders and The Fetus: Diagnosis, Prevention and Treatment Edited By Aubrey Milunsky, 6th Edition ; Diseases of The Liver and Biliary System in Children By Deirdre A. Kelly, 3rd Edition, Page 306 ; Fundamentals of Surgical Practice By A. N. Kingsnorth, 2nd Edition, Page 172


Q. 5

Which one of the following biochemical parameters is the most sensitive to detect open spina bifida?

 A

Maternal serum alpha fetoprotein

 B

Amniotic fluid alpha fetoprotein

 C

Amniotic fluid acetyl cholinesterase

 D

Amniotic fluid glucohexaminase

Q. 5

Which one of the following biochemical parameters is the most sensitive to detect open spina bifida?

 A

Maternal serum alpha fetoprotein

 B

Amniotic fluid alpha fetoprotein

 C

Amniotic fluid acetyl cholinesterase

 D

Amniotic fluid glucohexaminase

Ans. C

Explanation:

Amniotic fluid cholinesterase level is elevated in most cases of open neural tube defect.

Ref: Williams Obstetrics, 22nd Edition, Page 322; Textbook of Gynecology By D C Dutta, 6th Edition, Page 107


Q. 6

A mother with 10 weeks pregnancy and who had previously delivered a baby with open neural tube defect which statement is true :

 A

Sodium valproate causes open neural tube de­fect

 B

Risk of recurrence is 10%

 C

Amniocentesis should be done

 D

Give multivitamin

Q. 6

A mother with 10 weeks pregnancy and who had previously delivered a baby with open neural tube defect which statement is true :

 A

Sodium valproate causes open neural tube de­fect

 B

Risk of recurrence is 10%

 C

Amniocentesis should be done

 D

Give multivitamin

Ans. A

Explanation:

Ans. is a i.e Sodium valproate causes open neural tube defect

Sodium valproate “used during pregnancy. has produced neural tube defects in the offspring; therefore should be avoided”.

Therefore option “a” is correct

“The risk of recurrence of anencephaly is 5% after one affected child and 13% after two affected children.°

Therefore option “b” is incorrect.

Diagnostic protocol in case of patients who have had a child with neural tube defect :

In such patients At 16 weeks of gestation –                                                                        

  • Level II ultrasound
  • Maternal serum alpha feto protein (MSAFP).

Based on the results of these two investigations : the need for amniocentesis is decided.


Q. 7

Amniotic iiuid contains acetyl cholinesterase enzyme. What is the diagnosis ?

 A

Open spina bifida

 B

Gastroschisis

 C

Omphalocele

 D

Osteogenesis imperfecta

Q. 7

Amniotic iiuid contains acetyl cholinesterase enzyme. What is the diagnosis ?

 A

Open spina bifida

 B

Gastroschisis

 C

Omphalocele

 D

Osteogenesis imperfecta

Ans. A

Explanation:

Ans. is a i.e. Open spina bifida

Amniotic fluid Acetylcholineesterase level is elevated in open neural tube defect.

  • It has a better diagnostic value than AFP.
  • In case of Suspected Neural Tube defect, on Amniocentesis if amniotic fluid AFP levels are raised but Acetyl cholinesterase levels are normal, patient should be reassured that elevated AFP levels are probably caused by fetal blood contamination but if acetyl cholinesterase is also elevated along with AFP it is indicative of NTD.
  • It also helps to distinguish between Neural Tube defect and Abdominal wall defects (both of which cause elevated MSAFP).

—   Acetyl cholinesterase is raised in open NTD, but is low in abdominal wall defects.

—   In patients with NTD, the ratio of acetyl cholinesterase to butyrl cholinesterase levels is 0.14 or more. In case of abdominal wall defects this ratio is less than 0.14.


Q. 8

All of the following are true about anencephaly except :

 A

Facial presentation

 B

Increased alpha-fetoprotein

 C

Enlarged adrenal gland

 D

Polyhydramnios

Q. 8

All of the following are true about anencephaly except :

 A

Facial presentation

 B

Increased alpha-fetoprotein

 C

Enlarged adrenal gland

 D

Polyhydramnios

Ans. C

Explanation:

Ans. is c i.e. Enlarged Adrenal gland

Anencephaly :

  • It is characterised by absence of the cranial vault and cerebral hemispheres.°
  • It is the most common type of neural tube defect.°
  • Caused by failure of closure of Rostra! Neuropore at an early embryonic stage.

Pathological features :

  • Forebrain and midbrain are absent.
  • Cerebellum and Hindbrain are less involved or completely spared.
  • Base of skull and facial bones are not affected.
  • Pituitary gland is either absent or hypoplastic.°
  • As a result : Adrenal gland is diminisnea in size.° Such fetuses have bulging eyes, short neck and a large tongue.

Complications caused by Anencephaly during Pregnancy :

  • Polyhydramnios : seen in 35% cases.°

Causes :— Diminished fetal swallowing°

—                   Secretion of CSF directly into the amniotic cavity°

—                   Excessive micturition.°

  • Preterm labour : due to associated polyhydramnios.
  • Malpresentation : Face presentation (Most common)° and Breech presentation. Rather most common fetal anomaly responsible for face presentation is Anencephaly
  • Tendency for post maturity.°

Cause : — Insufficient production of cortisol from fetal adrenals leading to diminished oestriol.

Complications during Labour

  • Shoulder dystocia° : Most common complication of anencephaly during labour.
  • Obstructed labour°
  • Risk of recurrence is 5% after one affected child and 13% after two affected children.°

psis :

  • By ultrasound : Demonstration of –          

a. Absence of cranial vault and

b. Angiomatous brain tissue.

Time >14 weeks and Accuracy – 100%

It can be diagnosed earliest by 8-10 weeks on ultrasound.°

  • Elevated levels of maternal serum alpha feto proteins.°
  • By amniocentesis : Purpose of amniocentesis is to measure concentration of alpha – feto protein (AFP) and acetylcholinesterase in amniotic fluid.

Amniotic fluid acetyl cholinesterase has better diagnostic value than amniotic fluid AFP.°


Q. 9

Anencephaly is best diagnosed using :

 A

Maternal serum alpha feto protein

 B

Amniotic fluid alpha feto protein

 C

USG

 D

X-ray

Q. 9

Anencephaly is best diagnosed using :

 A

Maternal serum alpha feto protein

 B

Amniotic fluid alpha feto protein

 C

USG

 D

X-ray

Ans. C

Explanation:

Ans. is c i.e. USG

“In the early days of AFP screening, an elevated maternal serum AFP level prompted amniocentesis to determine the amniotic fluid AFP level. If the AFP level was elevated, then an assay for acetylcholinesterase was done. These tests were considered diagnostic for fetal NTD. Today, however nearly 100% of NTDs are identified by ultrasonography used alone.”

Diagnosis of Anencephaly/ NTD in brief:

  • Best screening test for NTD : Maternal serum Alpha protein (between 14 and 22 weeks, best at 16 weeks).
  • Best marker for NTD/Open spina bifida / Anencephaly is Acetyl cholinesterase.
  • Best investigation for Anencephaly – ultrasound.
  • Best time for diagnosis of Anencephaly is > 14 weeks by USG.°
  • Earliest diagnosis of Anencephaly by 8 – 10 weeks° (1st choice) 10 – 12 weeks (1Ind choice).
  • Best investigation for hydrocephalus is Ultrasound.°

Q. 10

Most common presentation in anencephaly is :

 A

Breech

 B

Face

 C

Brow

 D

Shoulder

Q. 10

Most common presentation in anencephaly is :

 A

Breech

 B

Face

 C

Brow

 D

Shoulder

Ans. B

Explanation:

Face


Q. 11

Anencephaly causes all except :

 A

Prematurity

 B

Face presentation

 C

Hydramnios

 D

None

Q. 11

Anencephaly causes all except :

 A

Prematurity

 B

Face presentation

 C

Hydramnios

 D

None

Ans. D

Explanation:

None


Q. 12

Banana sign seen in the foetal brain suggests ‑

 A

Renal agenesis

 B

Encephalocele

 C

Spina bifida

 D

Porencephaly

Q. 12

Banana sign seen in the foetal brain suggests ‑

 A

Renal agenesis

 B

Encephalocele

 C

Spina bifida

 D

Porencephaly

Ans. C

Explanation:

Ans. is ‘c’ i.e., Spina bifida


Q. 13

Most common birth defect in north India is ?

 A

CTEV

 B

Neural tube defects (Spina bifida)

 C

Down’s syndrome

 D

Hemoglobinophathies

Q. 13

Most common birth defect in north India is ?

 A

CTEV

 B

Neural tube defects (Spina bifida)

 C

Down’s syndrome

 D

Hemoglobinophathies

Ans. B

Explanation:

Ans. is ‘b’ i.e., Neural tube defects (Spina bifida)


Q. 14

True about MRI/CT appearance of lateral meningocele:

 A

Solid dural masses

 B

Usually outside the spinal canal

 C

Widened neural foramen

 D

Generally there is no spinal cord compression & deformity

Q. 14

True about MRI/CT appearance of lateral meningocele:

 A

Solid dural masses

 B

Usually outside the spinal canal

 C

Widened neural foramen

 D

Generally there is no spinal cord compression & deformity

Ans. C

Explanation:

C i.e. Widened neural foramen 

–  Lateral meningocele is non solid, CSF containing leptomeningeal outpouching through widened neural foramen usually into paraspinal, intrathoracic spaceQ. And it is generally associated with spinal deformities like, posterior (dorsal) scalloping, erosion of pedicles, thinning of neural arch & ribs, widening of spinal canal & neural foramen and kyphoscoliosis.


Q. 15

Sonographic finding of Spina bifida

 A

Ventriculomegaly

 B

Obliteration of cisterna magna

 C

Small BPD

 D

a and b

Q. 15

Sonographic finding of Spina bifida

 A

Ventriculomegaly

 B

Obliteration of cisterna magna

 C

Small BPD

 D

a and b

Ans. D

Explanation:

A, B i.e. (Ventriculomegaly), (Obliteration of cisterna magna) 

Spina bifida is most common in lumbosacral region (90%).

Sonographic findings of Spina bifida

  1. VentriculomegalyQ with hydrocephalus
  2. Banana sign – Cerebellum is stretchedQ around the brain stem with effacement of cisterna magnaQ.
  3. Lemon sign – Flattening of frontal bones on transverse image.
  4. Bony decept in spine
  5. V shaped profile d/t outward flaring of two posterior ossification centres.
  6. Presence of intact sac on posterior aspect of spine
  7. Sac filled with fluid or solid tissue in meningocele or myelomeningocele.

Q. 16

Which one of the following congenital malformation of the fetus can be diagnosed in first trimester by ultrasound?

 A

Anencephaly

 B

Inencephaly

 C

Microcephaly

 D

Holoprosencephaly

Q. 16

Which one of the following congenital malformation of the fetus can be diagnosed in first trimester by ultrasound?

 A

Anencephaly

 B

Inencephaly

 C

Microcephaly

 D

Holoprosencephaly

Ans. A

Explanation:

A i.e. Anencephaly


Q. 17

Neural tube defect is best detected by

 A

USG

 B

Chromosomal analysis

 C

Amniocentesis

 D

Placentography

Q. 17

Neural tube defect is best detected by

 A

USG

 B

Chromosomal analysis

 C

Amniocentesis

 D

Placentography

Ans. C

Explanation:

C i.e. Amniocentesis


Q. 18

Commonest site of meningocele is –

 A

Lumbosacral

 B

Occipital

 C

Frontal

 D

Thoracic

Q. 18

Commonest site of meningocele is –

 A

Lumbosacral

 B

Occipital

 C

Frontal

 D

Thoracic

Ans. A

Explanation:

Ans. is ‘a’ i.e., Lumbosacral 


Q. 19

Accurate diagnosis of anencephaly on ultrasound can be done at:      

September 2005

 A

5 weeks of gestation

 B

8 weeks of gestation

 C

10 weeks of gestation

 D

14 weeks of gestation

Q. 19

Accurate diagnosis of anencephaly on ultrasound can be done at:      

September 2005

 A

5 weeks of gestation

 B

8 weeks of gestation

 C

10 weeks of gestation

 D

14 weeks of gestation

Ans. C

Explanation:

Ans. C: 10 weeks of gestation

In the first half of the pregnancy, the diagnosis is made by the elevated alfa-fetoprotein in amniotic fluid and confirmed by sonography.

The findings at 13 weeks are:

  1. Absence of cranial vault
  2. Angiomatous brain tissue

In the later half of the pregnancy the diagnosis is difficult specially when associated with hydramnios.


Q. 20

Shoulder dystocia is seen predominantly in:

March 2007

 A

Transverse lie

 B

Cord around neck

 C

Anencephaly

 D

Hand prolapse

Q. 20

Shoulder dystocia is seen predominantly in:

March 2007

 A

Transverse lie

 B

Cord around neck

 C

Anencephaly

 D

Hand prolapse

Ans. C

Explanation:

Ans. C: Anencephaly

There are well-recognised risk factors, such as diabetes, fetal macrosomia,post maturity, multiparity, anencephaly, fetal ascites and maternal obesity, but it is often difficult to predict.

A number of obstetrical maneuvers are sequentially performed in attempt to facilitate delivery at this point,including :

  • Gaskin maneuver involves moving the mother to an all fours position with the back arched, widening the pelvic outlet.
  • McRobert’s maneuver;
  • Woods’ screw maneuver which leads to turning the anterior shoulder to the posterior and vice versa.
  • Jacquemier’s maneuver, or delivery of the posterior shoulder first, in which the forearm and hand are identified in the birth canal, and gently pulled.

More drastic maneuvers include

  • Zavanelli’s maneuver involves pushing the fetal head back in with performing a cesarean section.
  • Intentional clavicular fracture, which reduces the diameter of the shoulder girdle that requires to pass through the birth canal.
  • Symphisiotomy, which makes the opening of the birth canal laxer by breaking the connective tissue between the two pubes bones facilitating the passage of the shoulders.

Don’ts in shoulder dystocia:

  • Do not give traction over baby’s head
  • Do not apply fundal pressure.



Q. 21

The earliest congenital malformation that can he detected on USG:

 A

Anencephaly

 B

Hydrocephalus

 C

Sacral agenesis

 D

Down’s syndrome

Q. 21

The earliest congenital malformation that can he detected on USG:

 A

Anencephaly

 B

Hydrocephalus

 C

Sacral agenesis

 D

Down’s syndrome

Ans. A

Explanation:

Ans. Anencephaly



Leave a Reply

%d bloggers like this:
Malcare WordPress Security