FMGE 2023 Practice Questions

Q: Identify the type of inhibition shown in the graph.

Noncompetitive inhibition. ***Noncompetitive inhibition***- This inhibition type is characterized by a decrease in **$V_{max}$** but no change in the **$K_m$** value, meaning the inhibitor reduces the enzyme's efficiency but not its affinity for the substrate.- The inhibitor typically binds reversibly to an **allosteric site** (not the active site), affecting the enzyme's catalytic functionality whether the substrate is bound or not.*Competitive inhibition*- Competitive inhibition is characterized by an **increased $K_m$** (decreased apparent affinity) while the **$V_{max}$** remains unchanged.- The inhibitor binds directly to the **active site**, competing with the substrate, and the effect can be overcome by increasing substrate concentration.*Allosteric Inhibition*- Allosteric inhibition is a general mechanism where a molecule binds to a site other than the active site (**allosteric site**), changing the enzyme's conformation and activity.- While noncompetitive and uncompetitive inhibitions are types of allosteric regulation, "noncompetitive inhibition" is the specific and most accurate term for the observed kinetic behavior (decreased $V_{max}$, constant $K_m$).*Uncompetitive inhibition*- This type involves the inhibitor binding only to the **enzyme-substrate complex (ES)**, resulting in a proportional decrease in both **$V_{max}$** and **$K_m$**.- On a Lineweaver-Burk plot, this is shown by parallel lines, highly distinguishing it from noncompetitive inhibition where the lines intersect on the X-axis.

Q: Which source and cell produce testosterone?

Cholesterol and Leydig cells. ***Cholesterol and Leydig cells***- **Testosterone** is a steroid hormone, and like all steroid hormones (glucocorticoids, mineralocorticoids, estrogen), it is derived from the precursor molecule, **cholesterol**.- The primary source of testosterone production in the male testes is the **Leydig cells** (interstitial cells), stimulated by **Luteinizing Hormone (LH)**.*Cholesterol and Sertoli cells*- While **cholesterol** is the accurate precursor (source), **Sertoli cells** are mainly responsible for supporting **spermatogenesis** and producing **androgen-binding protein (ABP)** and **inhibin**.- Sertoli cells regulate the testicular microenvironment and are primarily stimulated by **FSH**, not for testosterone synthesis.*Dihydrotestosterone and Leydig cells*- **Dihydrotestosterone (DHT)** is a potent *metabolite* formed from testosterone via the enzyme **5-alpha reductase**, not the precursor for testosterone synthesis itself.- Although **Leydig cells** are the site of testosterone production, the initial source must be **cholesterol**, making DHT incorrect.*FSH and Leydig cells*- **FSH** (Follicle-Stimulating Hormone) primarily targets the **Sertoli cells** to promote sperm development and inhibin production.- The pituitary hormone that stimulates **Leydig cells** to synthesize testosterone from cholesterol is **Luteinizing Hormone (LH)**.

Q: The SAFE strategy given by WHO forms the mainstream of the management of Trachoma. What does the S in the acronym represent?

Surgery. ***Surgery*** - The 'S' in the WHO's SAFE strategy for Trachoma management stands for **Surgery**, which is essential for correcting **trichiasis** (in-turned eyelashes). - Surgery prevents irreversible vision loss by stopping the eyelashes from rubbing against and scarring the **cornea**. *Symptom* - Management of specific **symptoms** is generally an element of clinical treatment but does not represent a component of the comprehensive population-level intervention strategy known as SAFE. - The SAFE approach focuses on addressing the **infectious agent** (Antibiotics) and transmission factors (Facial cleanliness, Environmental improvement) for elimination. *Spectacles* - **Spectacles** are used for correcting refractive errors (like myopia or hyperopia) and are not a therapeutic measure for active **Chlamydia trachomatis** infection or trichiasis. - The goal of SAFE is elimination of the infectious cause and treatment of the blinding sequelae, not visual **refractive correction**. *Symbol* - A **symbol** is an abstract representation and does not constitute a concrete public health or clinical intervention necessary for the elimination of trachoma. - The other components (**Antibiotics**, **Facial cleanliness**, **Environmental improvement**) are tangible actions aimed at disease control and prevention.

Q: A patient presented with unilateral nasal obstruction associated with watery nasal discharge and bleeding. A diagnosis of inverted papilloma is made. Which of the following is true about this condition?

Benign and invasive. ***Benign and invasive*** Inverted papilloma (Schneiderian papilloma) is a **benign epithelial tumor** that characteristically exhibits **locally invasive behavior**, making option D correct. **Key features of inverted papilloma:** - **Benign histology** but behaves aggressively - **Locally invasive** - grows into underlying stroma and can erode bone - Unilateral presentation (cardinal feature) - Origin from lateral nasal wall/maxillary sinus - High recurrence rate (10-30%) if incompletely excised - **Malignant transformation risk: 5-15%** (usually to squamous cell carcinoma) - Requires complete surgical excision with wide margins **Clinical presentation (as in this case):** - Unilateral nasal obstruction (most common) - Epistaxis (bleeding) - Watery rhinorrhea - Fullness/mass sensation *Incorrect: Malignant and invasive* While inverted papilloma is invasive, it is histologically benign, not malignant. However, surveillance is needed due to malignant transformation potential. *Incorrect: Benign and non-invasive* Though benign, inverted papilloma is NOT non-invasive. Its locally aggressive behavior with invasion into adjacent structures distinguishes it from simple benign polyps. *Incorrect: Malignant and non-invasive* This option is incorrect on both counts - inverted papilloma is benign (not malignant) and invasive (not non-invasive).

Q: A 5-year-old child presents with sudden severe ear pain and hearing loss. On otoscopy, you observe hemorrhagic bullae on an inflamed tympanic membrane. What is the most likely diagnosis?

Myringitis bullosa. ***Myringitis bullosa*** - This diagnosis is strongly suggested by the otoscopic image showing **hemorrhagic or serous bullae (blisters)** on an inflamed tympanic membrane, which is the pathognomonic feature of this condition. - It is an acute inflammation of the tympanic membrane, often associated with viral or bacterial infections (e.g., **Mycoplasma pneumoniae**, Influenza virus), and typically presents with sudden, severe otalgia and hearing loss. *Serous otitis media* - This condition, also known as otitis media with effusion, is characterized by the presence of fluid in the middle ear space, leading to a **dull, retracted tympanic membrane** with visible **air-fluid levels or bubbles**, not bullae on the surface. - It typically presents with conductive hearing loss and a feeling of fullness in the ear, but lacks the severe inflammation and bullae seen in the image. *Acute otitis media* - The classic sign of acute otitis media is a **bulging, erythematous, and opaque tympanic membrane** due to purulent effusion in the middle ear, with loss of normal landmarks. - While bullae can occasionally form in severe cases of AOM, the primary feature is the bulging eardrum, and the prominent, multiple vesicles seen here are more specific to myringitis bullosa. *Myringitis granulosa* - This is a chronic inflammatory condition characterized by the presence of **granulation tissue** on the lateral surface of the tympanic membrane. - It typically presents with persistent otorrhea and conductive hearing loss, and the otoscopic appearance is of a raw, granular surface, which is distinctly different from the fluid-filled bullae shown in the image.

Q: A patient presents with a thick nasal discharge and headache. Examination reveals hypertrophy of the inferior turbinate with a mulberry appearance. Which of the following is the most likely diagnosis?

Hypertrophic rhinitis. ***Hypertrophic rhinitis***- This is a form of **chronic rhinitis** where persistent inflammation leads to irreversible changes, including mucosal and sub-mucosal fibrosis and hypertrophy.- The inferior turbinate hypertrophy becomes nodular, leading to the characteristic irreversible **"mulberry appearance"** on examination, correlating with thick discharge and obstruction.*Atrophic rhinitis*- This condition involves **atrophy** (shrinking) of the nasal mucosa and associated turbinates, leading to wide nasal passages, crusting, and often a foul smell (**ozena**).- The examination would show diminished turbinate size and a patent nasal cavity, which contradicts the finding of turbinate hypertrophy.*Common cold*- While causing discharge and headache, the discharge is typically watery (**rhinorrhea**) initially, progressing to mucoid, and the illness is acute and self-limiting.- It does not cause permanent or marked **fibrotic hypertrophy** of the inferior turbinates with a mulberry appearance, which is a sign of chronic inflammation.*Nasal polyp*- Nasal polyps are pale, glistening, freely mobile, non-tender masses that typically resemble **peeled grapes** and usually arise from the middle meatus.- Polyps represent edematous mucosa and are distinct from the fixed, hyperplastic tissue constituting the hypertrophied inferior turbinate itself.

Q: Which of the following hepatitis viruses is likely to get transmitted via fecal-oral route?

Hepatitis A. ***Hepatitis A***- Hepatitis A virus (HAV) is primarily spread through the **fecal-oral route**, typically via consumption of food or water contaminated with feces.- It causes an **acute**, self-limiting infection that rarely results in chronic liver disease.*Hepatitis B*- Hepatitis B virus (HBV) is transmitted mainly through **parenteral** (exposure to infected blood), sexual contact, or perinatal (mother-to-child) routes.- Unlike HAV, HBV is a major cause of **chronic hepatitis**, cirrhosis, and hepatocellular carcinoma.*Hepatitis C*- Hepatitis C virus (HCV) transmission is predominantly **parenteral**, most commonly associated with intravenous drug use, blood transfusions (historically), and shared needles.- HCV is the leading cause of chronic viral hepatitis globally and frequently establishes persistent infection.*Hepatitis D*- Hepatitis D virus (HDV) is a defective RNA virus that requires **Hepatitis B surface antigen (HBsAg)** for its replication and assembly.- HDV is transmitted parenterally (same routes as HBV) and not via the fecal-oral route.

Q: What is the cause of LH (Luteinizing Hormone) surge?

Estradiol. ***Estradiol*** - The cause of LH surge- During the late follicular phase, the dominant follicle secretes increasingly high levels of **Estradiol** (a potent estrogen). When these levels remain high for a prolonged period (typically 48–50 hours) above a critical threshold, it switches from exerting negative feedback to **positive feedback** on the hypothalamus and anterior pituitary. - This positive feedback stimulates a massive release of **GnRH** and, subsequently, a sudden, sharp, increase in **LH** secretion, known as the LH surge, which prepares the dominant follicle for ovulation. *FSH* - FSH is essential for initiating the **follicular development** (growth and maturation of ovarian follicles) preceding the surge, but it is not the direct trigger for the LH surge. - Although FSH levels also rise slightly during the surge (known as the **FSH surge**), this rise is secondary to the primary positive feedback mechanism driven by Estradiol. *Progesterone* - Progesterone levels are typically low during the late follicular phase when the LH surge occurs; its primary rise happens **after ovulation** during the luteal phase. - While Progesterone contributes to the total feedback loop around the surge, it cannot initiate the surge itself, and its main role is preparing the **endometrium** and supporting a potential pregnancy. *LH* - LH (*Luteinizing hormone*) is the hormone whose concentration surges; it is the **effect** of the positive feedback loop, not the underlying cause. - The rise in LH concentration is a direct response of the **anterior pituitary** to the high levels of Estradiol acting upon it.

Q: A 2-year-old was brought to the emergency department with difficulty swallowing for the last few hours. The X-ray is given below. Which is the next best step to manage this patient?

Esophagoscopy. ***Esophagoscopy*** - The X-ray shows a circular radiopaque object, the classic **"coin sign"** on an anteroposterior view, which is characteristic of a foreign body lodged in the **esophagus**. - **Esophagoscopy** is the definitive procedure for both visualizing and safely removing the foreign object, especially important if it is a button battery which can cause rapid mucosal injury. *Bronchoscopy* - This procedure is indicated for the removal of foreign bodies from the **airways** (trachea or bronchi), not the esophagus. - A tracheal foreign body would typically present with **respiratory distress** (stridor, wheezing) and would appear as a thin line on an AP X-ray because it would be oriented in the sagittal plane. *Tracheostomy* - A tracheostomy is a surgical procedure to create an alternative airway and is reserved for severe **upper airway obstruction** or the need for long-term mechanical ventilation. - This patient's primary problem is **dysphagia** (difficulty swallowing) due to an esophageal obstruction, not an airway emergency requiring a surgical airway. *Heimlich's manoeuvre* - This is an emergency first-aid procedure used for acute **choking** caused by a foreign body obstructing the airway, leading to an inability to breathe or speak. - The patient is not described as actively choking and has a stable airway; therefore, this maneuver is inappropriate and could cause harm.

Q: Which of the following is associated with CSF otorrhea?

Battle sign. ***Battle sign***- **Battle sign** (ecchymosis over the mastoid process) is highly indicative of a **basilar skull fracture**, specifically involving the **temporal bone**.- Fractures of the petrous portion of the temporal bone often breach the **dura mater** and middle ear cavity, leading directly to leakage of cerebrospinal fluid (**CSF otorrhea**).*Traumatic rupture of the tympanic membrane*- While rupture of the **tympanic membrane (TM)** is often present, it is usually a consequence of the underlying **temporal bone fracture**, not the primary source of the CSF leak.- CSF otorrhea fundamentally requires a fracture allowing communication between the **subarachnoid space** and the middle ear; TM rupture solely allows fluid egress.*Penetrating injury to the eye*- These injuries involve the orbit and structures of the eye, typically causing orbital trauma, globe rupture, or associated **facial fractures**.- They are not the usual mechanism for basilar skull fractures involving the **middle cranial fossa** or temporal bone, which are necessary for CSF otorrhea.*Fracture of the roof of the nose*- Fractures of the skull base involving the anterior cranial fossa, such as the **cribriform plate** (roof of the nose), classically cause **CSF rhinorrhea** (CSF leakage through the nose).- This anatomical location is functionally separate from the temporal bone pathology required to produce **CSF otorrhea**.

Question 1

Identify the type of inhibition shown in the graph.

Accepted Answer

Noncompetitive inhibition

Answer

Competitive inhibition

Answer

Allosteric Inhibition

Answer

Uncompetitive inhibition

Question 2

Which source and cell produce testosterone?

Accepted Answer

Cholesterol and Leydig cells

Answer

Dihydrotestosterone and Leydig cells

Answer

FSH and Leydig cells

Answer

Cholesterol and Sertoli cells

Question 3

The SAFE strategy given by WHO forms the mainstream of the management of Trachoma. What does the S in the acronym represent?

Accepted Answer

Surgery

Answer

Spectacles

Answer

Symbol

Answer

Symptom

Question 4

A patient presented with unilateral nasal obstruction associated with watery nasal discharge and bleeding. A diagnosis of inverted papilloma is made. Which of the following is true about this condition?

Accepted Answer

Benign and invasive

Answer

Malignant and invasive

Answer

Benign and non-invasive

Answer

Malignant and non-invasive

Question 5

A 5-year-old child presents with sudden severe ear pain and hearing loss. On otoscopy, you observe hemorrhagic bullae on an inflamed tympanic membrane. What is the most likely diagnosis?

Accepted Answer

Myringitis bullosa

Answer

Serous otitis media

Answer

Acute otitis media

Answer

Myringitis granulosa

Question 6

A patient presents with a thick nasal discharge and headache. Examination reveals hypertrophy of the inferior turbinate with a mulberry appearance. Which of the following is the most likely diagnosis?

Accepted Answer

Hypertrophic rhinitis

Answer

Common cold

Answer

Nasal polyp

Answer

Atrophic rhinitis

Question 7

Which of the following hepatitis viruses is likely to get transmitted via fecal-oral route?

Accepted Answer

Hepatitis A

Answer

Hepatitis B

Answer

Hepatitis C

Answer

Hepatitis D

Question 8

What is the cause of LH (Luteinizing Hormone) surge?

Accepted Answer

Estradiol

Answer

LH

Answer

Progesterone

Answer

FSH

Question 9

A 2-year-old was brought to the emergency department with difficulty swallowing for the last few hours. The X-ray is given below. Which is the next best step to manage this patient?

Accepted Answer

Esophagoscopy

Answer

Bronchoscopy

Answer

Heimlich's manoeuvre

Answer

Tracheostomy

Question 10

Which of the following is associated with CSF otorrhea?

Accepted Answer

Battle sign

Answer

Traumatic rupture of the tympanic membrane

Answer

Penetrating injury to the eye

Answer

Fracture of the roof of the nose

FMGE 2023

Biochemistry

Community Medicine

ENT

Microbiology

Physiology

Surgery