FMGE 2018 Practice Questions

Q: Most medial nucleus of cerebellum is:

Fastigial. ***Fastigial*** - The **fastigial nucleus** is located most **medially** within the cerebellum, closest to the midline in the roof of the fourth ventricle [1]. - It is the most medial of the four deep cerebellar nuclei and is primarily associated with the **vestibulocerebellum** (flocculonodular lobe) [1]. - Functions: Maintains **balance, posture, and coordinated eye movements** via connections to vestibular nuclei and reticular formation [1]. *Dentate* - The **dentate nucleus** is the **largest and most lateral** of the cerebellar nuclei, with a characteristic crumpled sac-like appearance (resembling an olive). - Located deep within the **lateral cerebellar hemisphere** white matter [1]. - Associated with the **neocerebellum** (cerebrocerebellum) and involved in **planning and initiating voluntary movements** via the ventrolateral thalamus to motor cortex [1]. *Emboliform* - The **emboliform nucleus** is elongated and located **medial to the dentate** but **lateral to the globose** nucleus. - Together with the globose nucleus, forms the **interposed nuclei**. - Associated with the **spinocerebellum** and involved in **modulating limb movements** and adjusting ongoing motor activity [1]. *Globose* - The **globose nucleus** consists of rounded cell masses located **medial to emboliform** and **lateral to fastigial** nucleus. - Part of the **interposed nuclei** along with emboliform nucleus. - Functions in **fine-tuning and coordinating ongoing movements**, particularly of distal limbs.

Q: Most Common enzyme deficient in galactosemics:

Galactose-1-phosphate uridyl transferase/GALT. ***Galactose-1-phosphate uridyl transferase/GALT*** - **GALT deficiency** is the most common cause of **classic galactosemia** (Type I), a severe inherited metabolic disorder. - This enzyme is crucial for converting **galactose-1-phosphate** to **glucose-1-phosphate** in the main pathway of galactose metabolism. - Accounts for approximately **95%** of all galactosemia cases. *Galactosidase* - **Galactosidase** enzymes are involved in the hydrolysis of galactose-containing oligosaccharides or glycoconjugates but are not the primary enzymes deficient in classic galactosemia. - This enzyme is not part of the Leloir pathway of galactose metabolism, which is the pathway affected in galactosemia. *UDP galactose epimerase* - Deficiency of **UDP galactose epimerase** (GALE) causes a milder form of galactosemia (Type III), but it is much less common than GALT deficiency. - GALE is involved in the interconversion of UDP-galactose and UDP-glucose. - This is the rarest form of galactosemia. *Galactokinase* - **Galactokinase deficiency** (GALK) causes a different, milder form of galactosemia (Type II), characterized by **cataracts** as the primary symptom. - It prevents the initial phosphorylation of galactose to galactose-1-phosphate. - This accounts for less than 5% of galactosemia cases.

Q: Highest Contraceptive failure is reported in

Spermicidal methods. ***Spermicidal methods*** - **Spermicides** have a significantly higher failure rate compared to other contraceptive methods because their effectiveness relies heavily on **correct and consistent application** before each act of intercourse. - Their efficacy is often compromised by improper use, short duration of action, or failure to adequately kill sperm, leading to a higher chance of **unintended pregnancy**. *Implant* - Contraceptive **implants** (e.g., etonogestrel implant) are among the most effective contraceptive methods, with a very low failure rate due to **continuous hormone release**. - They offer **long-acting reversible contraception (LARC)**, eliminating user error upon insertion. *IUD* - **Intrauterine devices (IUDs)**, both hormonal and copper, are highly effective LARC methods with very low failure rates. - Their effectiveness is independent of user adherence after insertion, making them **highly reliable**. *Oral contraceptive pills* - **Oral contraceptive pills** are effective when used perfectly, but their typical use effectiveness is lower than implants or IUDs due to the possibility of **user error**, such as missing pills. - **Adherence** to a daily regimen is crucial for their efficacy.

Q: Classical complement is activated by:

Ag-Ab complex. ***Ag-Ab complex*** - The **classical complement pathway** is initiated by the binding of **C1q** to an antigen-antibody complex, specifically involving **IgM** or certain subclasses of **IgG**. - This binding triggers a cascade of events leading to the activation of the complement system, ultimately resulting in the **lysis of target cells**, **opsonization**, and **inflammation**. *C3 Convertase* - **C3 convertase** is an enzyme complex formed later in the complement cascade, responsible for cleaving C3 into C3a and C3b. - While essential for all complement pathways, it is a **downstream effector** and not the initial activator of the classical pathway. *C1* - **C1** is a complex protein that includes C1q, C1r, and C1s. While C1 plays a crucial role in the classical pathway, it is **activated by** the antigen-antibody complex, not an independent activator. - The activation sequence is: **Ag-Ab complex → C1q binding → C1 activation → cascade initiation**. Thus, the Ag-Ab complex is the primary trigger, and C1 is the responder. *IgA* - **IgA** primarily functions in mucosal immunity and is generally **not an activator** of the classical complement pathway. - Instead, IgA can activate the **alternative complement pathway** under specific circumstances, but not the classical pathway through direct binding to C1q.

Q: In Plasmodium vivax malaria, relapse is caused by:

Hypnozoite. ***Hypnozoite*** - **Hypnozoites** are dormant forms of *Plasmodium vivax* and *P. ovale* that persist in the liver for months to years after initial infection. - These dormant hepatic stages can later reactivate, develop into merozoites, and cause a **relapse** of malaria symptoms even after successful treatment of the blood-stage infection. - Relapses are a defining feature of *P. vivax* malaria and require treatment with **primaquine** or **tafenoquine** for radical cure to eliminate hypnozoites. *Incorrect: Schizont* - **Schizonts** are stages where asexual reproduction occurs, either in liver cells (hepatic schizonts) or red blood cells (erythrocytic schizonts). - Erythrocytic schizonts cause acute malaria symptoms but do not cause delayed relapses as they are cleared by standard antimalarial treatments. - Hepatic schizonts complete their cycle within 1-2 weeks and do not remain dormant. *Incorrect: Sporozoite* - **Sporozoites** are the infective stage injected by the mosquito that travel to the liver to initiate infection. - They differentiate into either developing schizonts or dormant hypnozoites but do not directly cause relapses. - Sporozoites represent the initial infection, not the mechanism of relapse. *Incorrect: Gametocyte* - **Gametocytes** are the sexual stage found in human blood that are ingested by mosquitoes to continue the parasite lifecycle. - They are responsible for transmission to mosquitoes but do not cause human symptoms or relapses in the host. - Gametocytes do not remain dormant in the liver.

Q: Most common site of osteomyelitis in children

Metaphysis. ***Metaphysis*** - The **metaphysis** is the most common site for osteomyelitis in children due to its rich, **slow-flowing sinusoidal blood supply**, which facilitates bacterial seeding. - The **nutrient arteries** in the metaphysis make sharp loops, creating a turbulent flow that slows circulation and allows bacteria to lodge more easily. *Epiphysis* - The **epiphysis** is less commonly affected in children because its separate blood supply is not as prone to bacterial seeding as the metaphysis. - In infants, however, infection can spread from the metaphysis to the epiphysis and joint space due to **transphyseal vessels**. *Growth plate* - The **growth plate** itself is generally resistant to infection due to its avascular nature. - However, infection in the adjacent metaphysis or epiphysis can potentially disrupt its function. *Diaphysis* - While the **diaphysis** has a blood supply, it is less common for osteomyelitis to originate here compared to the metaphysis. - It usually occurs as a secondary spread from a metaphyseal infection or in specific scenarios like in **sickle cell disease**.

Q: Marble bone disease is:

Osteopetrosis. ***Osteopetrosis*** - **Osteopetrosis**, also known as **marble bone disease**, is a rare genetic disorder characterized by abnormally dense bones due to a defect in **osteoclast function** [1]. - Impaired bone resorption leads to an accumulation of woven bone, causing bones to be fragile despite their density [1]. *Osteosclerosis* - **Osteosclerosis** is a general term for increased bone density and can be a feature of various conditions, including osteopetrosis. - However, it is a descriptive term rather than a specific disease diagnosis equivalent to marble bone disease. *Histiocytosis X* - **Histiocytosis X**, also known as **Langerhans cell histiocytosis**, is a rare disorder involving the proliferation of Langerhans cells. - It primarily affects bone but can also involve other organs, presenting with lytic lesions rather than increased bone density. *Osteomalacia* - **Osteomalacia** is a condition characterized by inadequate mineralization of bone tissue, leading to soft and weakened bones. - It is typically caused by **vitamin D deficiency** and is the opposite of increased bone density. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1188-1189.

Q: Most common benign breast tumour:

Fibroadenoma. ***Fibroadenoma*** - **Fibroadenomas** are the **most common benign breast tumors**, typically presenting as mobile, firm, and non-tender masses [1]. - They are composed of both **glandular and stromal tissue** and are more prevalent in younger women [1]. *Phyllodes tumour* - **Phyllodes tumors** are much **rarer** than fibroadenomas and can be benign, borderline, or malignant [3]. - They tend to grow **rapidly** and are characterized by a leaf-like stromal pattern [3]. *Fibroadenosis* - **Fibroadenosis** (or fibrocystic changes) refers to a collection of **benign changes** in the breast tissue, including cysts, fibrosis, and epithelial hyperplasia, rather than a single tumor [2]. - It is a common condition causing lumpy and painful breasts, especially before menstruation [4]. *DCIS* - **Ductal Carcinoma In Situ (DCIS)** is a **non-invasive form of breast cancer** where abnormal cells are confined to the milk ducts. - It is not a benign tumor and carries a risk of progression to invasive breast cancer. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 448-449. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 445-446. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, p. 1074. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, p. 1052.

Q: Comment on the diagnosis of a film shown of a 65-year-old man with acute abdomen:

Colocolic intussusception. ***Colocolic intussusception*** - This is a rare form of intussusception where a **proximal segment of the colon telescopes into a distal segment** within the colon itself. - In adults, it is often associated with a **lead point**, such as a tumor, polyp, or lipoma, which can be visualized on imaging. *Sigmoid volvulus* - Characterized by the **twisting of the sigmoid colon** around its mesentery, often presenting with a characteristic "coffee bean" sign on abdominal X-ray. - While it causes acute abdomen, it is distinguishable from intussusception by its specific radiological appearance and underlying mechanism of obstruction. *Ileocolic intussusception* - This involves the **terminal ileum telescoping into the cecum**, and it is the most common type of intussusception in children. - In adults, it is also typically associated with a lead point but the segment of bowel involved is different from colocolic intussusception. *Toxic megacolon* - This is a severe complication of inflammatory bowel disease or infectious colitis, characterized by **non-obstructive colonic dilation** and signs of systemic toxicity. - Imaging would reveal a dilated colon, often with loss of haustra, but without the specific "target sign" or "pseudokidney sign" indicative of intussusception.

Question 1

Most medial nucleus of cerebellum is:

Accepted Answer

Fastigial

Answer

Dentate

Answer

Emboliform

Answer

Globose

Question 2

Most Common enzyme deficient in galactosemics:

Accepted Answer

Galactose-1-phosphate uridyl transferase/GALT

Answer

Galactosidase

Answer

UDP galactose epimerase

Answer

Galactokinase

Question 3

Chaperones are:

Accepted Answer

Mediators of post-translational assembly of protein complexes

Answer

Antigen presenting cells

Answer

Purine metabolism mediators

Answer

None of the above

Question 4

Highest Contraceptive failure is reported in

Accepted Answer

Spermicidal methods

Answer

Implant

Answer

IUD

Answer

Oral contraceptive pills

Question 5

Classical complement is activated by:

Accepted Answer

Ag-Ab complex

Answer

C3 Convertase

Answer

C1

Answer

IgA

Question 6

In Plasmodium vivax malaria, relapse is caused by:

Accepted Answer

Hypnozoite

Answer

Schizont

Answer

Sporozoite

Answer

Gametocyte

Question 7

Most common site of osteomyelitis in children

Accepted Answer

Metaphysis

Answer

Epiphysis

Answer

Growth plate

Answer

Diaphysis

Question 8

Marble bone disease is:

Accepted Answer

Osteopetrosis

Answer

Osteosclerosis

Answer

Histiocytosis X

Answer

Osteomalacia

Question 9

Most common benign breast tumour:

Accepted Answer

Fibroadenoma

Answer

Phyllodes tumour

Answer

Fibroadenosis

Answer

DCIS

Question 10

Comment on the diagnosis of a film shown of a 65-year-old man with acute abdomen:

Accepted Answer

Colocolic intussusception

Answer

Sigmoid volvulus

Answer

Toxic megacolon

Answer

Ileocolic intussusception

FMGE 2018

Anatomy

Biochemistry

Community Medicine

Microbiology

Orthopaedics

Pathology

Surgery