INI-CET 2024 Practice Questions

Q: Which is not a product of heme catabolism?

Aminolevulinic acid. ***Aminolevulinic acid*** - **Aminolevulinic acid (ALA)** is a precursor in the **heme biosynthetic pathway**, not a product of its degradation. - The formation of ALA is the **rate-limiting step** in heme synthesis, catalyzed by ALA synthase. *Ferrous ion* - During heme catabolism, the **iron atom (Fe2+)** is released from the porphyrin ring. - This **ferrous ion** is then recycled or stored, as it is a product of heme degradation. *Biliverdin* - **Biliverdin** is the first green-colored product formed when heme oxygenase cleaves the **porphyrin ring** of heme. - It is an intermediate in the conversion of heme to **bilirubin**, making it a direct product of heme catabolism. *Carbon monoxide* - The oxidative cleavage of the heme ring by **heme oxygenase** liberates one molecule of **carbon monoxide (CO)**. - This CO is an important signaling molecule and has vasodilatory effects, making it a product of heme degradation.

Q: A 13-year-old boy presents with right-sided nasal obstruction and recurrent epistaxis for the past 6 months. What is the most likely diagnosis?

JNA. ***JNA (Juvenile Nasopharyngeal Angiofibroma)*** - **Classic presentation**: Adolescent male with **unilateral nasal obstruction** and **recurrent, often profuse epistaxis** - JNA is a **highly vascular benign tumor** that predominantly affects males aged 10-18 years - Though benign, it is **locally aggressive** and can extend into adjacent structures (orbit, skull base) - The combination of age, gender, unilateral symptoms, and recurrent epistaxis makes this the most likely diagnosis *Coagulation disorder* - Would cause **generalized bleeding tendencies**, not localized unilateral nasal obstruction - Epistaxis would typically be **bilateral** and associated with other bleeding manifestations (easy bruising, gum bleeding, prolonged bleeding from cuts) - No mass effect or persistent obstruction would be expected - Other systemic bleeding signs are absent in this presentation *Antrochoanal polyp* - **Benign inflammatory lesion** originating from maxillary sinus, extending through ostium into choana - Can cause nasal obstruction but epistaxis is **much less common and less severe** than in JNA - More commonly associated with **chronic sinusitis symptoms** (rhinorrhea, postnasal drip, facial pressure) - Less vascular than JNA, so recurrent profuse epistaxis would be unusual *Allergic rhinitis* - Characterized by **bilateral symptoms**: nasal obstruction, sneezing, rhinorrhea, and nasal itching - Often has **seasonal pattern** or clear allergen triggers - May cause minor epistaxis from mucosal irritation, but not the **severe recurrent epistaxis** seen here - **Unilateral** persistent obstruction would be atypical for allergic rhinitis

Q: In folate deficiency, which of the following statements is true?

Elevated homocysteine & normal methylmalonic acid. ***Elevated homocysteine & normal methylmalonic acid*** - In **folate deficiency**, the conversion of homocysteine to methionine is impaired, leading to **elevated homocysteine** levels. - Unlike vitamin B12 deficiency, **methylmalonic acid (MMA)** levels remain normal in folate deficiency because folate is not involved in its metabolism. *B12 supplementation is recommended along with folate* - Supplementation with B12 alongside folate is crucial when **macrocytic anemia** is diagnosed, as it can mask a coexisting **B12 deficiency**, potentially worsening neurological symptoms if only folate is given. - However, in confirmed isolated folate deficiency, B12 supplementation is not strictly necessary unless there is suspicion or diagnosis of co-existing B12 deficiency. *Purine and pyrimidine synthesis are affected* - While folate is essential for **DNA synthesis**, indirectly affecting purine and pyrimidine production, this statement is a consequence rather than the primary diagnostic or distinguishing feature of folate deficiency. - **Folate** acts as a coenzyme in transferring one-carbon units, vital for the synthesis of **thymidylate** (a pyrimidine base) and **purine precursors**. *Hemolytic anemia is not a feature* - **Hemolytic anemia** is not typically a feature of folate deficiency; instead, it is characterized by **macrocytic, megaloblastic anemia**. - Conditions like **glucose-6-phosphate dehydrogenase (G6PD) deficiency** or **autoimmune disorders** are commonly associated with hemolytic anemia.

Q: A male patient with purple striae, thin skin, non-healing wound, and pedunculated abdomen, most probable cause?

Hypercortisolism. Hypercortisolism - **Purple striae** are characteristic due to the breakdown of collagen and elastic fibers from excessive **cortisol**. - **Thin skin**, **non-healing wounds**, and a **pedunculated abdomen** (central obesity) are all classic signs of chronic high cortisol levels, as seen in **Cushing's syndrome** [1]. *Insulin resistance* - While insulin resistance can lead to conditions like **acanthosis nigricans** and **obesity**, it typically does not cause purple striae or thin skin directly. - It's often associated with **type 2 diabetes**, polycystic ovary syndrome, but not the specific dermatological features presented. *Hypothyroidism* - Hypothyroidism symptoms include **dry skin**, **coarse hair**, **fatigue**, and **weight gain**, but not typically purple striae or thin skin. - It can cause **non-pitting edema** (myxedema), which is distinct from the described skin changes. *Genetic connective tissue disorder* - Genetic connective tissue disorders like **Ehlers-Danlos syndrome** can cause thin, fragile skin and poor wound healing. - However, they do not typically present with the characteristic **purple striae** or **pedunculated abdomen** that point specifically to hypercortisolism.

Q: What is the correct dosing regimen of Dexamethasone for promoting fetal lung maturity in preterm infants?

Dexamethasone 6 mg - 4 doses every 12 hrly. **Dexamethasone 6 mg - 4 doses every 12 hrly** - The standard recommended dosing for **Dexamethasone** to promote fetal lung maturity is **6 mg intramuscularly every 12 hours for a total of four doses.** - This regimen ensures adequate **antenatal corticosteroid** exposure to enhance surfactant production and reduce the incidence and severity of **respiratory distress syndrome** in preterm infants. *Dexamethasone 6 mg - 2 doses every 12 hrly* - This regimen administers only **half the recommended total dose** of Dexamethasone. - It is **insufficient** to achieve the full benefits of antenatal corticosteroids for fetal lung maturity. *Betamethasone 12 mg - 2 doses every 24 hrly* - This is the correct dosing regimen for **Betamethasone**, not Dexamethasone. - While both are antenatal corticosteroids, their dosages and administration schedules differ. *Betamethasone 6 mg - 4 doses every 12 hrly* - This option uses an **incorrect total dose and frequency** for **Betamethasone**. - The standard Betamethasone regimen is 12 mg every 24 hours for two doses.

Q: ER positivity is used as which of the following in the context of breast carcinoma?

Prognostic marker. ***Prognostic marker*** - **ER positivity** in **breast carcinoma** is primarily used as a **prognostic marker** indicating more favorable disease outcome [1]. - ER-positive tumors generally **grow more slowly**, are **less aggressive**, and have **better overall survival** compared to ER-negative tumors [2]. - While ER status also has **predictive value** for endocrine therapy response, its classification as a prognostic indicator reflects its association with inherently better tumor biology and patient outcomes [1]. - ER positivity correlates with **well-differentiated tumors** and **lower grade** malignancies. *Treatment option* - ER positivity is not a treatment itself, but rather a **biomarker** that guides treatment selection. - It identifies patients who may benefit from **endocrine therapy** (tamoxifen, aromatase inhibitors) [1]. *Molecular marker* - While ER is indeed a molecular marker (receptor protein detected by immunohistochemistry), this term is too **broad and non-specific**. - The question asks for the **specific clinical utility** of ER positivity, not its general classification. *Diagnostic marker* - ER status is **not used for initial diagnosis** of breast carcinoma. - Diagnosis requires **histopathological examination** of tissue biopsy. - ER testing is performed **after diagnosis** to characterize the tumor and guide management. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1059-1060. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1064-1066.

Q: A 30-year-old woman has experienced the loss of her newborn. She is currently producing breast milk leading to discomfort and the risk of developing a breast abscess due to milk stasis and incomplete emptying. Which of the following drugs can be used to prevent this complication?

Cabergoline. ***Cabergoline*** - **Cabergoline** is a dopamine agonist that inhibits prolactin secretion, thereby suppressing lactation and preventing breast engorgement and its complications after childbirth. - It has a longer duration of action compared to bromocriptine, allowing for less frequent dosing and better patient compliance in lactation suppression. *Chlorpromazine* - **Chlorpromazine** is an antipsychotic medication primarily used to treat psychotic disorders; it doesn't suppress lactation. - While it can cause hyperprolactinemia as a side effect due to its antidopaminergic action, it is not used to manage lactation or its complications. *Metoclopramide* - **Metoclopramide** is a dopamine receptor antagonist that *increases* prolactin levels, and is sometimes used to *stimulate* lactation, not suppress it. - It enhances gastrointestinal motility and is primarily used as an antiemetic or for gastric emptying disorders. *Mifepristone* - **Mifepristone** is a progesterone receptor antagonist primarily used for medical abortion and induction of labor. - It is not indicated for the suppression of lactation or the prevention of breast engorgement.

Q: Erythropoietin is secreted by which of the following organs?

Kidney. ***Kidney*** - The **kidneys** are the primary site of erythropoietin production in adults, particularly the **peritubular interstitial cells**. - Erythropoietin's main function is to stimulate **red blood cell production** in the bone marrow in response to hypoxia. *Muscle* - Muscles are involved in movement and metabolism but do not produce **erythropoietin**. - They primarily store glycogen and generate force through contraction. *Liver* - The liver produces erythropoietin during **fetal development** but contributes minimally to its production in adulthood. - Its main functions include metabolism, detoxification, and protein synthesis. *Heart* - The heart is responsible for **pumping blood** throughout the body and does not produce **erythropoietin**. - It primarily consists of cardiac muscle tissue.

Q: Which of the following neurotransmitters is primarily released from the sympathetic nervous system to increase heart rate in response to a DECREASE in blood pressure?

Norepinephrine. ***Norepinephrine*** - **Norepinephrine** is the primary neurotransmitter released by **postganglionic sympathetic neurons** directly onto the heart to increase heart rate and contractility in response to a drop in blood pressure. - It acts on **beta-1 adrenergic receptors** in the sinoatrial (SA) node, atria, and ventricles, leading to increased chronotropy (heart rate) and inotropy (contractility). *Dopamine* - While **dopamine** can have cardiovascular effects, particularly at high doses, it is not the primary neurotransmitter released by the sympathetic nervous system for direct heart rate regulation. - Dopamine is a precursor to norepinephrine and epinephrine, but its main physiological roles involve **renal blood flow regulation** and central nervous system functions. *Acetylcholine* - **Acetylcholine** is the primary neurotransmitter of the **parasympathetic nervous system**, which generally acts to **decrease heart rate** (bradycardia) through muscarinic receptors. - It is also released by **preganglionic sympathetic fibers**, but these do not directly innervate the heart to produce the desired effect of increasing heart rate. *Epinephrine* - **Epinephrine** (adrenaline) is primarily a **hormone** released from the **adrenal medulla** into the bloodstream, not directly from postganglionic sympathetic nerve terminals to the heart. - Although it has strong effects on beta-1 receptors in the heart, its release is more generalized and slower than the direct neuronal release of norepinephrine.

Question 1

Which is not a product of heme catabolism?

Accepted Answer

Aminolevulinic acid

Answer

Ferrous ion

Answer

Biliverdin

Answer

Carbon monoxide

Question 2

A 13-year-old boy presents with right-sided nasal obstruction and recurrent epistaxis for the past 6 months. What is the most likely diagnosis?

Accepted Answer

JNA

Answer

Coagulation disorder

Answer

Antrochoanal polyp

Answer

Allergic rhinitis

Question 3

During autopsy of a fetal death case, what is the correct order of examination to differentiate between live birth and stillbirth?

Accepted Answer

Head > thorax > abdomen

Answer

Thorax > head > abdomen

Answer

Abdomen > thorax > head

Answer

Thorax > abdomen > head

Question 4

In folate deficiency, which of the following statements is true?

Accepted Answer

Elevated homocysteine & normal methylmalonic acid

Answer

B12 supplementation is recommended along with folate

Answer

Purine and pyrimidine synthesis are affected

Answer

Hemolytic anemia is not a feature

Question 5

A male patient with purple striae, thin skin, non-healing wound, and pedunculated abdomen, most probable cause?

Accepted Answer

Hypercortisolism

Answer

Insulin resistance

Answer

Hypothyroidism

Answer

Genetic connective tissue disorder

Question 6

What is the correct dosing regimen of Dexamethasone for promoting fetal lung maturity in preterm infants?

Accepted Answer

Dexamethasone 6 mg - 4 doses every 12 hrly

Answer

Dexamethasone 6 mg - 2 doses every 12 hrly

Answer

Betamethasone 12 mg - 2 doses every 24 hrly

Answer

Betamethasone 6 mg - 4 doses every 12 hrly

Question 7

ER positivity is used as which of the following in the context of breast carcinoma?

Accepted Answer

Prognostic marker

Answer

Treatment option

Answer

Molecular marker

Answer

Diagnostic marker

Question 8

A 30-year-old woman has experienced the loss of her newborn. She is currently producing breast milk leading to discomfort and the risk of developing a breast abscess due to milk stasis and incomplete emptying. Which of the following drugs can be used to prevent this complication?

Accepted Answer

Cabergoline

Answer

Chlorpromazine

Answer

Metoclopramide

Answer

Mifepristone

Question 9

Erythropoietin is secreted by which of the following organs?

Accepted Answer

Kidney

Answer

Muscle

Answer

Liver

Answer

Heart

Question 10

Which of the following neurotransmitters is primarily released from the sympathetic nervous system to increase heart rate in response to a DECREASE in blood pressure?

Accepted Answer

Norepinephrine

Answer

Dopamine

Answer

Acetylcholine

Answer

Epinephrine

INI-CET 2024

Biochemistry

ENT

Forensic Medicine

Internal Medicine

Obstetrics and Gynecology

Pathology

Pharmacology

Physiology