Neurology Practice Questions

Q: A child with low IQ, poor communication, presented with loss of bladder control/urinary incontinence. Which of the following is the most likely diagnosis?

Heller’s disease. ***Heller’s disease*** - Also known as **Childhood Disintegrative Disorder**, it is characterized by a marked regression in multiple areas of development, such as language, social skills, and bladder/bowel control, following a period of normal development for at least two years. - Diagnosis is often suspected when a child demonstrates a significant loss of previously acquired skills, often accompanied by global developmental delays (low IQ) and communication deficits. *Refsum’s disease* - This is a rare autosomal recessive metabolic disorder characterized by **phytanic acid accumulation** due to a deficiency in phytanoyl-CoA hydroxylase. - Clinical presentation typically includes **retinitis pigmentosa**, peripheral neuropathy, and cerebellar ataxia rather than developmental regression and urinary incontinence. *ADHD* - ADHD is a neurodevelopmental disorder marked by persistent patterns of **inattention**, **hyperactivity**, and **impulsivity** that interfere with functioning or development. - It does not involve the loss of previously acquired milestones or bladder control typically seen in degenerative or disintegrative disorders. *Weil’s disease* - This is the severe form of **Leptospirosis**, caused by infection with *Leptospira* bacteria, and presents with jaundice, acute kidney injury, and hemorrhage. - It is an acute infectious process, not a developmental disorder, and does not cause a loss of communication skills or developmental regression.

Q: A female child had normal developmental milestones until 6-8 months of age, after which she developed progressive regression in language, social interaction, and adaptive behavior. The regression was accompanied by loss of purposeful hand use replaced by stereotyped repetitive hand-wringing or clapping movements, and deceleration of head circumference growth. Which of the following is the most likely diagnosis?

Rett syndrome. ***Rett syndrome*** - This condition is characterized by **normal development** until 6-18 months, followed by characteristic **regression** that includes loss of purposeful hand skills and the development of **stereotyped hand movements** like wringing or clapping. - It is classically associated with **deceleration of head growth** (acquired microcephaly) and is most commonly caused by **MECP2 gene mutations** on the X chromosome. *Childhood disintegrative disorder* - This disorder requires a period of **normal development for at least 2 years** followed by the loss of previously acquired skills. - It involves a more profound regression in multiple areas (social, communication, play) than is typically seen in the early phases of Rett syndrome. *Down syndrome* - This is a chromosomal disorder caused by **trisomy 21**, typically presenting with **intellectual disability** and characteristic dysmorphic facial features from **birth**. - Developmental delays are usually present early, rather than characterized by a distinct period of normal development followed by regression. *Asperger syndrome* - Historically defined as a high-functioning form of autism, it is characterized by social impairment and repetitive behaviors but **lacks the loss of acquired skills** or motor regression seen in Rett syndrome. - There is typically no associated **deceleration in head circumference** or specific hand stereotypies characteristic of Rett syndrome.

Q: A child presents with a history of hypopigmented macules on the back, infantile spasms, and delayed milestones. What is the most likely diagnosis?

Tuberous sclerosis. ### Explanation **Correct Answer: C. Tuberous Sclerosis (TSC)** The clinical triad of **hypopigmented macules (Ash-leaf spots)**, **infantile spasms** (West Syndrome), and **delayed milestones** is classic for Tuberous Sclerosis Complex. * **Pathophysiology:** TSC is an autosomal dominant neurocutaneous syndrome caused by mutations in the *TSC1* (Hamartin) or *TSC2* (Tuberin) genes, leading to the overactivation of the mTOR pathway and the formation of hamartomas in multiple organs. * **Dermatological markers:** Ash-leaf spots are often the earliest sign. Other features include Adenoma sebaceum (angiofibromas), Shagreen patches (connective tissue nevi), and periungual fibromas (Koenen tumors). * **Neurological markers:** Cortical tubers and subependymal nodules lead to seizures (infantile spasms) and intellectual disability. **Why Incorrect Options are Wrong:** * **A. Neurofibromatosis:** Characterized by *hyperpigmented* Café-au-lait macules, Lisch nodules, and neurofibromas, rather than hypopigmentation and infantile spasms. * **B. Sturge-Weber Syndrome:** Presents with a Port-wine stain (Nevus Flammeus) in the V1/V2 distribution of the trigeminal nerve, glaucoma, and leptomeningeal angiomas. * **C. Nevus Anemicus:** A localized vascular anomaly presenting as a pale patch due to catecholamine sensitivity. It does not cause systemic neurological symptoms or developmental delay. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign:** Ash-leaf spots (best seen under **Wood’s lamp**). * **Most common heart lesion:** Rhabdomyoma (often regresses spontaneously). * **Most common kidney lesion:** Angiomyolipoma. * **Drug of choice for Infantile Spasms in TSC:** Vigabatrin. * **Pathognomonic sign:** Koenen tumors (Periungual fibromas).

Q: A mother has a child diagnosed with Duchenne's muscular dystrophy. What is the risk that her next male child will suffer from this illness?

50%. ### Explanation **Concept:** Duchenne Muscular Dystrophy (DMD) follows an **X-linked recessive (XLR)** inheritance pattern. In this scenario, since the mother has already given birth to an affected child, she is an obligate carrier (genotype: $X^D X^d$). When a carrier mother ($X^D X^d$) conceives with an unaffected father ($X^D Y$): * **Male offspring:** There is a **50% chance** the son will inherit the mutated X chromosome ($X^d Y$) and be **affected**, and a 50% chance he will inherit the normal X ($X^D Y$) and be healthy. * **Female offspring:** There is a 50% chance the daughter will be a carrier ($X^D X^d$) and a 50% chance she will be genetically normal ($X^D X^D$). **Analysis of Options:** * **B (50%) is Correct:** This represents the probability specifically for **male** children of a carrier mother. * **A (25%):** This is the risk that any *random* future pregnancy (regardless of sex) will result in an affected child (1 in 4). * **C (100%):** This would only occur if the mother was homozygous for the mutation (extremely rare) or if the father had the disease and the mother was a carrier. * **D (0%):** This is incorrect as the mother is a confirmed carrier. **High-Yield Clinical Pearls for NEET-PG:** * **Gene Mutation:** Deletion of the **Dystrophin gene** (the largest known human gene) located on **Xp21**. * **Clinical Signs:** Gower’s sign (using hands to "climb up" the body to stand) and **pseudohypertrophy** of calves (fatty replacement of muscle). * **Diagnosis:** Gold standard is **Genetic testing** (MLPA); Screening shows massively elevated **Serum Creatine Kinase (CK)**. * **Cause of Death:** Usually respiratory failure or dilated cardiomyopathy in the late teens or early twenties.

Question 1

A child with low IQ, poor communication, presented with loss of bladder control/urinary incontinence. Which of the following is the most likely diagnosis?

Accepted Answer

Heller’s disease

Answer

Refsum’s disease

Answer

ADHD

Answer

Weil’s disease

Question 2

A female child had normal developmental milestones until 6-8 months of age, after which she
developed progressive regression in language, social interaction, and adaptive behavior. The
regression was accompanied by loss of purposeful hand use replaced by stereotyped repetitive
hand-wringing or clapping movements, and deceleration of head circumference growth. Which of
the following is the most likely diagnosis?

Accepted Answer

Rett syndrome

Answer

Childhood disintegrative disorder

Answer

Down syndrome

Answer

Asperger syndrome

Question 3

A child diagnosed with Dravet syndrome is receiving multi-drug anti-seizure therapy and is being
considered for add-on treatment with fenfluramine. Which of the following monitoring strategies is
most critical before initiating and during the course of this therapy, given the known
pharmacological adverse-effect profile of fenfluramine?

Accepted Answer

Serial echocardiography to evaluate for cardiac valvular disease and pulmonary hypertension

Answer

Monthly complete blood count to monitor for agranulocytosis and aplastic anemia

Answer

Baseline and periodic ophthalmic examinations to monitor for visual field defects

Answer

Serial liver function tests and serum ammonia levels to monitor for hepatotoxicity

Question 4

A child presents with a history of hypopigmented macules on the back, infantile spasms, and delayed milestones. What is the most likely diagnosis?

Accepted Answer

Tuberous sclerosis

Answer

Neurofibromatosis

Answer

Sturge-Weber syndrome

Answer

Nevus anemicus

Question 5

A mother has a child diagnosed with Duchenne's muscular dystrophy. What is the risk that her next male child will suffer from this illness?

Accepted Answer

50%

Answer

25%

Answer

100%

Answer

0%

Neurology — MCQs

Neurology — MCQs

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