FMGE 2025 - Pediatrics Practice Questions

Q: While evaluating a 3-year-old with short stature, height is measured at 90cm and the lower segment is 45 cm. What is the likely diagnosis?

Spondyloepiphyseal dysplasia. ***Spondyloepiphyseal dysplasia*** - This child has an **upper:lower segment ratio of 1:1** (45 cm each), which indicates **adult body proportions at age 3** - Normal U:L ratio at 3 years should be approximately **1.3:1** (relatively longer trunk than legs) - Spondyloepiphyseal dysplasia causes **short trunk dwarfism** due to vertebral and epiphyseal involvement - The **limbs are relatively preserved**, leading to a **lower U:L ratio** than expected for age (approaching adult 1:1 ratio prematurely) - This creates **disproportionate short stature** with the trunk being the primary affected segment *Congenital hypothyroidism* - Causes **proportionate short stature** with generalized growth retardation - Would maintain normal U:L ratio for age (1.3:1 at 3 years) - Associated with delayed bone age, developmental delay, and other systemic features *Rickets* - Primarily affects the **lower limbs** with bowing deformities (genu varum/valgum) - Would cause a **higher U:L ratio** (relatively shorter legs) if severe - Does not typically present with this specific 1:1 ratio pattern *Achondroplasia* - Causes **short limb dwarfism** (rhizomelic shortening) - Would result in a **high U:L ratio** (relatively longer trunk than limbs) - Opposite pattern to what is seen in this case

Q: A child presents with micrognathia and low-set ears. These clinical features are commonly associated with which type of genetic abnormality?

Deletion. ***Correct: Deletion*** - **Micrognathia** and **low-set ears** are characteristic features of many syndromes caused by chromosomal deletions, such as **DiGeorge syndrome** (22q11.2 deletion) or **Cri-du-chat syndrome** (5p deletion). - The loss of a significant segment of a chromosome leads to **haploinsufficiency** for multiple genes, severely impacting craniofacial and auricular development. *Incorrect: Translocation* - This involves the exchange of segments between non-homologous chromosomes; while it can cause genetic disorders, it is not the most common genetic mechanism leading to the specific classic combination of micrognathia and low-set ears. - **Balanced translocations** usually do not cause clinical symptoms in the carrier, but can lead to abnormal gametes and offspring with partial monosomy or trisomy. *Incorrect: Amplification* - This refers to the increase in the copy number of a gene or DNA sequence, which is primarily linked to cancer development (**oncogenesis**, e.g., *HER2* amplification), not generalized congenital dysmorphism. - While large segmental duplications (a form of gain) can cause syndromes, specific amplification events are rarely the cause of micrognathia or low-set ears. *Incorrect: Inversion* - This involves a chromosomal segment reversing its orientation; the primary concern is the formation of **unbalanced gametes** during meiosis, particularly with **pericentric inversions**. - Although offspring can inherit unbalanced chromosomes resulting in abnormalities, deletions remain the most common cause for the specific constellation of features mentioned.

Q: A child presents with a right transverse palmar crease, a cardiac defect, survival into childhood, and mild intellectual impairment. What chromosomal mechanism is most likely associated with these findings?

Mosaicism. ***Mosaicism*** - **Mosaicism** is the presence of two or more cell lines with different genetic constitutions in a single individual, allowing for a **milder phenotype** of chromosomal syndromes like Trisomy 21. - The combination of classic Down syndrome features (transverse palmar crease, cardiac defect) with relatively **mild intellectual impairment** and survival into childhood with better outcomes suggests **Mosaic Down Syndrome** (mosaic Trisomy 21). - In mosaicism, only a proportion of cells carry the extra chromosome 21, resulting in **less severe manifestations** compared to complete trisomy. *Incorrect: Trisomy* - While **complete Trisomy 21** (Down syndrome) presents with similar features, it typically causes **more severe intellectual disability** and greater phenotypic expression. - The emphasis on **"mild" intellectual impairment** in this case points toward mosaicism rather than complete trisomy. *Incorrect: Haploid* - **Haploid** refers to a cell having only one set of chromosomes (n=23), a state that is **incompatible with human survival** beyond early embryonic development. - A complete haploid individual cannot survive into **childhood**. *Incorrect: Monosomy* - **Monosomy** (loss of one chromosome, 2n-1) for autosomes is typically **lethal in utero**, making survival into childhood impossible. - The only viable monosomy is **Monosomy X** (Turner syndrome), which presents with distinct features (short stature, webbed neck, ovarian dysgenesis) without the characteristic Down syndrome features described.

Q: A girl presents with microcephaly and a high-pitched cry. Which of the following is the most likely chromosomal abnormality?

Deletion. ***Deletion***- The combination of **microcephaly** and a peculiar **high-pitched cry** (often described as 'cat-like') is the hallmark clinical presentation of **Cri-du-chat syndrome**.- Cri-du-chat syndrome is caused by a **deletion** of the distal part of the short arm of chromosome 5 (5p-).*Isochromosome*- An **isochromosome** is a structural chromosomal abnormality where an arm is duplicated, resulting in two copies of one arm and none of the other (e.g., often seen in X chromosome abnormalities like **Turner syndrome**).- This type of structural error does not typically result in the specific features of Cri-du-chat syndrome, which require the loss of specific genes on **chromosome 5 short arm**.*Trisomy*- **Trisomy** is the presence of an extra copy of a chromosome (47 total chromosomes, e.g., **Down syndrome - Trisomy 21**).- Syndromes resulting from autosomal trisomies (like Patau or Edwards) present with different constellations of congenital and developmental abnormalities, lacking the pathognomonic **cat-like cry**.*Mosaicism*- **Mosaicism** describes the presence of two or more populations of cells with different genotypes in one individual, often mitigating the severity of major aneuploidies.- While it can occur with some deletions, **mosaicism** is not the primary mechanism or classification for the specific **Cri-du-chat syndrome** which is defined by the **5p deletion**.

Q: A child presents with recurrent Staphylococcus infections. Laboratory examination shows very low levels of immunoglobulins (G, A, M, E), and a low quantity of B cells. There is a normal reaction to environmental antigens on the skin. What is the most likely diagnosis?

Bruton's agammaglobulinemia. ***Bruton's agammaglobulinemia***- This X-linked disease is caused by a defect in the **Bruton tyrosine kinase (BTK)** gene, which is essential for B-cell maturation.- The deficiency results in a severe block in B-cell development, leading to **near absence of mature B cells** and consequently, extremely **low levels of all immunoglobulin isotypes** (IgG, A, M, E).*DiGeorge syndrome*- Primary feature is **T-cell deficiency** due to failure of the 3rd and 4th pharyngeal pouches, leading to **thymic hypoplasia**; this would typically impair the skin test response. - Although B cell numbers can sometimes be affected, the hallmark is severe T-cell deficiency, and Ig levels are often normal or near-normal, unlike the pan-hypogammaglobulinemia seen here.*Hyper IgM syndrome*- This condition is characterized by a failure in **isotype switching** (often due to defects in **CD40L**), resulting in normal or high levels of **IgM** but very low levels of IgG, IgA, and IgE.- B cells are present in normal counts, distinguishing it from this patient who has very few B cells and very low IgM.*Common variable immunodeficiency*- CVID typically presents later, in adolescence or adulthood, and causes **hypogammaglobulinemia** (low IgG and usually low IgA/IgM).- While B-cell function is impaired, patients usually have **normal B-cell counts**, contrasting with the severe reduction in B cells seen in this child.

Q: What is the recommended treatment for nephrotic syndrome in children?

Steroids. ***Steroids***- **Corticosteroids** (typically Prednisone/Prednisolone) are the recommended **first-line therapy** for pediatric nephrotic syndrome, as *minimal change disease* (**MCD**) is the most common cause (90% of cases).- The vast majority of children with MCD are **steroid-sensitive**, exhibiting remission (proteinuria cessation) within 2-4 weeks of high-dose treatment.*Steroids and cyclophosphamide*- Combination therapy including **cyclophosphamide** is typically reserved for children who show **steroid dependence** or **frequent relapses**, not for initial therapy.- Adding cyclophosphamide as a first-line agent is unnecessary due to its potential for significant **gonadal toxicity** and other systemic side effects.*Cyclophosphamide*- **Cyclophosphamide** is a powerful **second-line immunosuppressive agent** used primarily for children who are steroid-dependent or **steroid-resistant**.- Using it as initial monotherapy is inappropriate because children with MCD usually respond well to steroids alone, avoiding risks like **myelosuppression**.*ACE inhibitors*- **Angiotensin-converting enzyme (ACE) inhibitors** are used primarily to reduce **proteinuria** by lowering **glomerular hydrostatic pressure**.- Their role is generally adjunctive management for resistant proteinuria or for treating associated **hypertension**, not as the primary agent to induce remission.

Q: In a child presenting with a beaded appearance in the chest with the following X-ray, what is the diagnosis? ![img-94.jpeg](img-94.jpeg)

Rickets. ***Rickets*** - The clinical finding of a "beaded appearance" in the chest refers to **rachitic rosary**, which is a classic sign of rickets caused by the enlargement of the costochondral junctions. - The wrist X-ray confirms the diagnosis by showing characteristic features of defective bone mineralization, including **cupping**, **fraying**, and widening of the distal metaphysis of the radius and ulna. *Scurvy* - Scurvy, caused by **vitamin C deficiency**, typically presents with **bleeding gums**, poor wound healing, and perifollicular hemorrhage, not skeletal deformities like a rachitic rosary. - Radiographic findings in scurvy include a **white line of Fraenkel** (a dense metaphyseal line) and subperiosteal hemorrhages, which are absent in the provided X-ray. *Beri Beri* - Beri Beri is a result of **thiamine (vitamin B1) deficiency** and primarily manifests with neurological (dry beriberi) or cardiovascular (wet beriberi) symptoms. - This condition does not cause the characteristic skeletal abnormalities or radiographic changes seen in rickets. *Pellagra* - Pellagra is caused by **niacin (vitamin B3) deficiency** and is characterized by the classic triad of **dermatitis**, **diarrhea**, and **dementia** (the "3 Ds"). - It is a systemic illness that does not involve the skeletal system in the manner described or shown in the X-ray.

Q: A newborn male presents with urinary retention, lethargy and a distended bladder. Antenatal ultrasound showed a "keyhole sign" with a thickened bladder wall. Which of the following is the most likely diagnosis?

Posterior urethral valves. ***Posterior urethral valves***- The **"keyhole sign"** seen on antenatal ultrasound, characterized by a dilated posterior urethra and a thickened, distended bladder, is highly specific for **posterior urethral valves (PUV)**.- PUV is the most common cause of severe **lower urinary tract obstruction** in male newborns, leading directly to symptoms like lethargy, a palpable **distended bladder**, and urinary retention.*Hypospadias*- *Hypospadias* is an abnormal location of the **urethral meatus** on the ventral aspect of the penis.- It does not cause the severe **obstructive uropathy** (like urinary retention and bladder distension) or the **keyhole sign** observed in this patient.*Vesicoureteral reflux*- *Vesicoureteral reflux* (VUR) involves the reflux of urine from the bladder back up to the ureters and is typically a **non-obstructive** cause of hydronephrosis and UTIs.- While VUR can coexist with PUV, it is the secondary phenomenon, and VUR itself does not cause the primary **urethral obstruction** or the characteristic **keyhole appearance**.*Neurogenic bladder*- A *neurogenic bladder* results from impaired nerve supply, often due to conditions like **spina bifida**, leading to poor bladder emptying.- While it can cause retention, the unique finding of the **keyhole sign** points specifically to a fixed, **anatomical obstruction** in the posterior urethra, which is not characteristic of neurological issues.

Q: A child with progressive pallor and bone pain has an elevated HbS based on the HPLC report. Which is the best treatment to manage hemolysis in this patient?

Voxelotor. ***Voxelotor*** - It is a **hemoglobin polymerization inhibitor** that stabilizes the oxygenated form of red blood cells, preventing **sickling** and subsequent hemolytic anemia, thereby directly managing the hemolysis. - It significantly improves **hemoglobin levels** and reduces markers of hemolysis, such as **indirect bilirubin** and **reticulocyte count**. *Hydroxyurea* - Its primary mechanism is inducing the production of **fetal hemoglobin (HbF)**, thereby diluting the concentration of HbS and *indirectly* reducing hemolysis over time. - Although crucial for managing **vaso-occlusive crises** (VOCs), it is not as direct an anti-hemolytic agent as Voxelotor. *Azacytidine* - This is a **DNA methyltransferase inhibitor**, primarily used in high-risk **Myelodysplastic Syndrome (MDS)** and Acute Myeloid Leukemia (AML). - While it can induce HbF like Hydroxyurea, it is not a standard or approved frontline treatment for the routine management of Sickle Cell Disease (SCD). *Bortezomib* - This drug is a **proteasome inhibitor** used exclusively in the treatment of **Multiple Myeloma** and certain related plasma cell dyscrasias. - It has no therapeutic role or clinical indication in the specific management of hemolysis or the underlying pathophysiology of SCD.

Q: A child presents with kawasaki disease with multiple small coronary artery aneurysms. Treatment is?

Aspirin for 6 weeks. ***Aspirin for 6 weeks*** - After the acute phase is treated with **IVIG** and high-dose aspirin, the regimen is switched to low-dose aspirin for its **antiplatelet** effects to prevent thrombosis in the affected coronary arteries. - This low-dose therapy is typically continued for 6-8 weeks, at which point a follow-up **echocardiogram** is performed and inflammatory markers (like **ESR** and **CRP**) should have normalized. *Aspirin lifelong* - Lifelong antiplatelet therapy is generally reserved for patients with **large** or **giant** coronary artery aneurysms due to a high risk of **thrombosis** and stenosis. - For small aneurysms, which often resolve, therapy is guided by serial echocardiograms and is not typically lifelong from the outset. *Aspirin for 4 weeks* - A 4-week duration is insufficient, as it may not cover the entire period of coronary wall inflammation and thrombocytosis, which usually peaks in the subacute phase. - The standard follow-up interval for re-evaluation with an **echocardiogram** is at 6-8 weeks, making it logical to continue therapy at least until that point. *Aspirin and clopidogrel for 6 weeks* - **Dual antiplatelet therapy** with aspirin and clopidogrel is recommended for patients with **medium-sized** or **giant** coronary artery aneurysms, not for small aneurysms. - The flowchart provided indicates that for small aneurysms (Z score ≥2.5 to <5), **single antiplatelet therapy** with low-dose aspirin is the appropriate treatment.

Question 1

While evaluating a 3-year-old with short stature, height is measured at 90cm and the lower segment is 45 cm. What is the likely diagnosis?

Accepted Answer

Spondyloepiphyseal dysplasia

Answer

Congenital hypothyroidism

Answer

Rickets

Answer

Achondroplasia

Question 2

A child presents with micrognathia and low-set ears. These clinical features are commonly associated with which type of genetic abnormality?

Accepted Answer

Deletion

Answer

Amplification

Answer

Inversion

Answer

Translocation

Question 3

A child presents with a right transverse palmar crease, a cardiac defect, survival into childhood, and mild intellectual impairment. What chromosomal mechanism is most likely associated with these findings?

Accepted Answer

Mosaicism

Answer

Haploid

Answer

Monosomy

Answer

Trisomy

Question 4

A girl presents with microcephaly and a high-pitched cry. Which of the following is the most likely chromosomal abnormality?

Accepted Answer

Deletion

Answer

Mosaicism

Answer

Trisomy

Answer

Isochromosome

Question 5

A child presents with recurrent Staphylococcus infections. Laboratory examination shows very low levels of immunoglobulins (G, A, M, E), and a low quantity of B cells. There is a normal reaction to environmental antigens on the skin. What is the most likely diagnosis?

Accepted Answer

Bruton's agammaglobulinemia

Answer

Common variable immunodeficiency

Answer

Hyper IgM syndrome

Answer

DiGeorge syndrome

Question 6

What is the recommended treatment for nephrotic syndrome in children?

Accepted Answer

Steroids

Answer

ACE inhibitors

Answer

Cyclophosphamide

Answer

Steroids and cyclophosphamide

Question 7

In a child presenting with a beaded appearance in the chest with the following X-ray, what is the diagnosis? ![img-94.jpeg](img-94.jpeg)

Accepted Answer

Rickets

Answer

Beri Beri

Answer

Pellagra

Answer

Scurvy

Question 8

A newborn male presents with urinary retention, lethargy and a distended bladder. Antenatal ultrasound showed a "keyhole sign" with a thickened bladder wall. Which of the following is the most likely diagnosis?

Accepted Answer

Posterior urethral valves

Answer

Hypospadias

Answer

Vesicoureteral reflux

Answer

Neurogenic bladder

Question 9

A child with progressive pallor and bone pain has an elevated HbS based on the HPLC report. Which is the best treatment to manage hemolysis in this patient?

Accepted Answer

Voxelotor

Answer

Azacytidine

Answer

Hydroxyurea

Answer

Bortezomib

Question 10

A child presents with kawasaki disease with multiple small coronary artery aneurysms. Treatment is?

Accepted Answer

Aspirin for 6 weeks

Answer

Aspirin for 4 weeks

Answer

Aspirin lifelong

Answer

Aspirin and clopidogrel for 6 weeks

FMGE 2025 — Pediatrics