FMGE 2024 Practice Questions

Q: Which nerve defect causes lagophthalmos?

7th nerve. ***7th nerve***- The **Facial nerve (CN VII)** is crucial for eyelid closure as it innervates the **orbicularis oculi** muscle, one of the muscles of facial expression.- Paralysis of the 7th nerve prevents the eye from closing fully, leading to the condition known as **lagophthalmos** and subsequent exposure keratopathy.*6th nerve*- The **Abducens nerve (CN VI)** innervates the **lateral rectus** muscle, which is responsible for abducting (moving outward) the eye.- A defect results in **esotropia** (inward turning of the eye) and horizontal diplopia, unrelated to eyelid function.*4th nerve*- The **Trochlear nerve (CN IV)** innervates the **superior oblique** muscle, assisting in depression and intorsion of the eye.- Defect typically causes characteristic vertical and torsional **diplopia**, often worse when looking down and in, and does not cause lagophthalmos.*5th nerve*- The **Trigeminal nerve (CN V)** is primarily the sensory nerve of the face, with the **ophthalmic division (V1)** providing sensation to the cornea.- While a V1 defect abolishes the **afferent limb of the corneal reflex** and can lead to neurotrophic keratopathy, it does not supply the motor function required for eyelid closure.

Q: Which nerve innervates the lateral rectus muscle?

A. Sixth nerve. ***A. Sixth nerve***- Also known as the **abducens nerve**, the sixth cranial nerve is solely responsible for innervating the **lateral rectus muscle**.- The lateral rectus muscle's action is **abduction** (moving the eye laterally), which is why paralysis of the sixth nerve causes the eye to turn medially (**medial strabismus**) [1], [2].- *B. Seventh nerve*- The seventh cranial nerve (**facial nerve**) is primarily responsible for **facial expression muscles** and relays taste sensation from the anterior two-thirds of the tongue.- It has no role in the motor innervation of the **extraocular muscles**.- *C. Third nerve*- The third cranial nerve (**oculomotor nerve**) innervates most of the extraocular muscles, including the **superior, inferior, and medial recti**, and the **inferior oblique** [1].- Paralysis results in the classic **"down and out"** gaze due to the unopposed action of the abducens and trochlear nerves.- *D. Fourth nerve*- The fourth cranial nerve (**trochlear nerve**) innervates only the **superior oblique muscle** [1].- The action of the superior oblique muscle is primary **intorsion**, depression, and abduction.

Q: How does the World Health Organization (WHO) define blindness?

VA < 3/60. ***VA < 3/60*** - This visual acuity (VA) level in the better eye, with the best possible correction, meets the World Health Organization (WHO) definition of **blindness** (Visual Impairment Category 3 or worse). - It signifies that the patient cannot count fingers at a distance of 3 meters (CF 3/60* - Visual acuity *greater* than 3/60 (e.g., 6/60, 6/18) indicates better visual function and therefore does not satisfy the criteria for WHO **blindness**. - Depending on the exact VA, this level of vision may fall into the categories of **moderate** or **mild visual impairment**. *VA > 6/60* - Visual acuity greater than 6/60 (e.g., 6/12) is well above the threshold defined for both **severe visual impairment** and blindness. - An acuity of 6/60 is often the benchmark for severe impairment; vision better than this suggests residual useful vision.

Q: In the context of a new onset of a morbid disease, how does the change in incidence affect the prevalence of the disease?

Incidence and prevalence will increase. ***Incidence and prevalence will increase*** - **Incidence** is the rate of new cases arising in a population; a "new onset" inherently implies that the occurrence of **new cases** is rising or starting. - Since **prevalence** is the total number of existing cases (P ≈ I × D, where D is duration), a rise in new cases (**incidence**) directly contributes to and increases the total existing burden of the disease. *Prevalence is not related to incidence* - This is incorrect because **incidence** (the inflow of new cases) is the primary determinant, along with duration and mortality/cure, of the overall total number of existing cases (**prevalence**). - Prevalence is mathematically linked to incidence; if incidence rises, prevalence typically rises, and if incidence approaches zero, prevalence will eventually fall (assuming cases are cleared). *Incidence will increase, and prevalence will decrease* - When **incidence** increases (more new cases), it leads to an increased rate of accumulation of cases, which consequently increases **prevalence**. - Prevalence only decreases despite increasing incidence if the removal rate (due to death or cure) drastically exceeds the rate of new cases, which is highly unlikely in a scenario described as a "new onset" morbid disease. *Prevalence will increase with a decrease in the incidence* - A decrease in **incidence** (fewer new cases) leads to a decrease in **prevalence** over time, assuming the duration of the disease remains stable. - Prevalence can increase with decreasing incidence only if the **duration** of the disease or survival time increases significantly (e.g., effective palliative treatment without cure), trapping existing cases in the prevalent pool.

Q: Calculate the relative risk for the given situation: | | Developed Malaria | Did Not Develop Malaria | Total | |---|:---:|:---:|:---:| | **Vaccinated** | 6 | 94 | 100 | | **Non-vaccinated** | 12 | 88 | 100 |

0.5. ***Correct: 0.5*** **Relative Risk (RR)** is calculated as: RR = Risk in exposed group / Risk in unexposed group **Step-by-step calculation:** - Risk in **vaccinated group** = 6/100 = 0.06 - Risk in **non-vaccinated group** = 12/100 = 0.12 - **RR = 0.06 / 0.12 = 0.5** **Interpretation:** An RR of **0.5 indicates a protective effect** of vaccination. Vaccinated individuals have **half the risk** (50% reduced risk) of developing malaria compared to non-vaccinated individuals. *Incorrect: 2* This is the **inverse** of the correct RR, calculated as 0.12/0.06 = 2 (risk in non-vaccinated / risk in vaccinated). This would incorrectly suggest vaccination **doubles the risk** of malaria, which contradicts the data showing vaccination is protective. *Incorrect: 1.5* This value does not result from the correct RR formula using the given incidence rates (0.06 vs 0.12). This may arise from incorrect formula application or confusion with other epidemiological measures like the **Odds Ratio**. *Incorrect: 1.7* This is not the result of standard RR calculation based on the incidence rates of 0.06 and 0.12. It represents a **calculation error** and has no epidemiological meaning in this context.

Q: Which of the following is the diagnostic test for carcinoid tumors?

Urinary 5-hydroxyindoleacetic acid. ***Urinary 5-hydroxyindoleacetic acid***- Carcinoid tumors actively produce **serotonin**, which is rapidly metabolized by **monoamine oxidase** into the inactive metabolite **5-hydroxyindoleacetic acid (5-HIAA)**.- A **24-hour urinary collection** for 5-HIAA is the most specific and confirms the functional diagnosis of **carcinoid syndrome** [1].*24-hour urinary catecholamines*- This test is primarily used for the diagnosis of **pheochromocytoma**, which secretes excess **norepinephrine** and **epinephrine**.- High levels of catecholamine metabolites, such as **metanephrines** and **vanillylmandelic acid (VMA)**, are diagnostic for pheochromocytoma, not carcinoid tumors, which primarily produce serotonin.*Serum calcitonin levels*- **Calcitonin** secretion is the key diagnostic and monitoring marker for **medullary thyroid carcinoma (MTC)**, a non-related neuroendocrine tumor originating from C-cells.- This marker is not specific or elevated in typical **carcinoid tumors** originating from the small bowel or lungs.*Serum chromogranin A*- **Chromogranin A (CgA)** is a general biomarker for **neuroendocrine tumors (NETs)** and is useful for screening and monitoring disease burden [2].- While sensitive for carcinoid tumors, it lacks the specificity of **5-HIAA** for diagnosing **carcinoid syndrome** and can be falsely elevated in conditions like PPI use or renal failure.

Q: Which of the following microorganisms is likely responsible for causing bilateral infiltrates in an HIV-positive patient?

Pneumocystis Jirovecii. ***Pneumocystis Jirovecii***- **Pneumocystis Pneumonia (PCP)** is the most common AIDS-defining infection affecting the lungs, typically presenting with **diffuse, bilateral, perihilar interstitial infiltrates** in HIV patients [1]. - This infection is strongly associated with a **CD4 cell count below 200 cells/mm³** and often manifests clinically with gradual onset of dyspnea, fever, and a non-productive cough [1].*Cryptococcus*- Although *Cryptococcus neoformans* is a common opportunistic infection in HIV, it predominantly causes **meningitis** or **meningoencephalitis**. - Pulmonary involvement usually presents as **nodules** or localized consolidations, not the classic diffuse bilateral interstitial pattern seen with PCP.*Histoplasmosis*- *Histoplasma capsulatum* is an endemic pathogen (e.g., Ohio and Mississippi River Valleys) that typically causes **disseminated disease** in advanced HIV. - While pulmonary infection may occur, it often presents with **hilar/mediastinal lymphadenopathy** [2] or a miliary pattern, rather than isolated bilateral interstitial infiltrates.*Aspergillus*- **Invasive Aspergillosis** generally occurs in patients with profound and prolonged **neutropenia** (e.g., following chemotherapy or transplantation), which is less common in typical AIDS patients with low CD4 counts. - Pulmonary findings usually involve localized **cavities** or **nodules with a halo sign** (angioinvasive disease), contrasting with the diffuse bilateral infiltrates of PCP.

Q: A patient presents with a history of watery diarrhea and vomiting. The pathogen exhibited darting motility. Which is the best selective media for the involved pathogen?

TCBS. ***Correct: TCBS*** - **Thiosulfate Citrate Bile Salts Sucrose (TCBS) agar** is the most widely used selective medium for isolating *Vibrio cholerae* and other *Vibrio* species from clinical and environmental samples - The clinical presentation of **watery diarrhea and vomiting** with **darting motility** is characteristic of *Vibrio cholerae* - *Vibrio cholerae* ferments **sucrose** in TCBS medium, producing **yellow colonies**, contrasting with the blue-green colonies of non-sucrose fermenters like *Vibrio parahaemolyticus* - The medium contains **bile salts** that inhibit most Gram-positive bacteria while allowing Vibrio species to grow *Incorrect: Nutrient media* - Nutrient media is a **general-purpose** medium that supports the growth of a wide variety of non-fastidious organisms, making it **non-selective** for *Vibrio* - It lacks the inhibitory agents (bile salts) and specific markers (sucrose) necessary for selective isolation and differentiation of *Vibrio* species *Incorrect: Cetrimide agar* - This medium is specifically selective for **Pseudomonas aeruginosa**, as cetrimide (a quaternary ammonium compound) inhibits the growth of most other bacteria - *Vibrio cholerae* would likely be inhibited or overgrown by other organisms on this medium, making it unsuitable for isolation *Incorrect: Potassium Tellurite Agar* - Potassium Tellurite Agar (McLeod's medium) is a selective medium primarily used for the isolation of **Corynebacterium diphtheriae** - The tellurite salt inhibits most other respiratory flora but does not specifically enhance or select for the growth of *Vibrio* species

Q: The diagnosis in a patient who is unable to perform internal and external rotation of the hip is?

Dislocation of hip. ***Dislocation of hip***- Inability to perform **internal and external rotation** (both active and passive) is a hallmark sign of a **dislocated joint**, indicating mechanical blockage due to the displacement of the **femoral head** from the acetabulum.- Hip dislocations (especially posterior) present with severe pain and a **fixed deformity** (usually internal rotation, adduction, and mild flexion), which mechanically prevents any rotary movement.*Femur head fracture*- While a **femur head fracture** causes severe pain and guarded movement, it typically allows some rotation, provided the displacement is not severe enough to cause mechanical locking within the joint.- Differentiating features usually include shortening and **external rotation** of the limb (in displaced fractures), but complete mechanical block of all rotation is less specific than in frank dislocation.*Acetabular fractures*- These fractures cause gross instability and pain, but motion may still be present unless the fracture fragments are severely displaced or impinging on the **femoral head**.- The primary focus of a symptomatic acetabular fracture is significant pain, often exacerbated by axial loading, rather than a total mechanical block of rotation.*Pelvis fracture*- **Pelvis fractures** (especially stable types) cause severe pain and limit weight-bearing, but the hip joint often retains some range of motion, particularly passive rotation, if the acetabulum is intact.- Unstable pelvic ring injuries (e.g., Malgaigne fracture) are defined by instability of the bony ring and potential for hemorrhage, not by complete mechanical inability to rotate the hip joint itself.

Q: Which blood is transfused in a patient with a Bombay blood group?

Bombay (Oh) blood. ***Bombay (Oh) blood*** - Patients with Bombay phenotype lack the **H antigen** due to deficiency of **fucosyltransferase enzyme** and can only receive Bombay (Oh) blood safely. - They produce potent **anti-H, anti-A, and anti-B antibodies**, making them compatible only with other Bombay donors who also lack the H antigen. *A* - Contains both **A antigen and H antigen**, causing severe hemolytic transfusion reaction due to anti-A and anti-H antibodies. - The presence of **H antigen** makes it completely incompatible with Bombay phenotype patients. *B* - Contains both **B antigen and H antigen**, leading to rapid hemolysis from anti-B and anti-H antibodies. - Like all standard ABO blood types, the **H antigen presence** makes transfusion dangerous and contraindicated. *AB* - Contains **A antigen, B antigen, and H antigen**, causing the most severe hemolytic reaction from all three antibodies. - This is the most incompatible blood type for Bombay patients due to multiple antigen incompatibilities. *O negative* - Though lacking A and B antigens, **O negative still contains the H antigen** present in all standard ABO blood groups. - Transfusing O negative to Bombay patients causes **severe acute hemolytic transfusion reaction** due to anti-H antibodies, making it unsafe despite being the universal donor for standard ABO types.

Question 1

Which nerve defect causes lagophthalmos?

Accepted Answer

7th nerve

Answer

5th nerve

Answer

4th nerve

Answer

6th nerve

Question 2

Which nerve innervates the lateral rectus muscle?

Accepted Answer

A. Sixth nerve

Answer

B. Seventh nerve

Answer

C. Third nerve

Answer

D. Fourth nerve

Question 3

How does the World Health Organization (WHO) define blindness?

Accepted Answer

VA < 3/60

Answer

VA < 6/60

Answer

VA > 3/60

Answer

VA > 6/60

Question 4

In the context of a new onset of a morbid disease, how does the change in incidence affect the prevalence of the disease?

Accepted Answer

Incidence and prevalence will increase

Answer

Prevalence is not related to incidence

Answer

Incidence will increase, and prevalence will decrease

Answer

Prevalence will increase with a decrease in the incidence

Question 5

Calculate the relative risk for the given situation:

| | Developed Malaria | Did Not Develop Malaria | Total |
|---|:---:|:---:|:---:|
| **Vaccinated** | 6 | 94 | 100 |
| **Non-vaccinated** | 12 | 88 | 100 |

Accepted Answer

0.5

Answer

1.5

Answer

2

Answer

1.7

Question 6

Which of the following is the diagnostic test for carcinoid tumors?

Accepted Answer

Urinary 5-hydroxyindoleacetic acid

Answer

Serum chromogranin A

Answer

Serum calcitonin levels

Answer

24-hour urinary catecholamines

Question 7

Which of the following microorganisms is likely responsible for causing bilateral infiltrates in an HIV-positive patient?

Accepted Answer

Pneumocystis Jirovecii

Answer

Histoplasma

Answer

Aspergillus

Answer

Cryptococcus

Question 8

A patient presents with a history of watery diarrhea and vomiting. The pathogen exhibited darting motility. Which is the best selective media for the involved pathogen?

Accepted Answer

TCBS

Answer

Potassium Tellurite Agar

Answer

Cetrimide agar

Answer

Nutrient media

Question 9

The diagnosis in a patient who is unable to perform internal and external rotation of the hip is?

Accepted Answer

Dislocation of hip

Answer

Pelvis fracture

Answer

Acetabular fractures

Answer

Femur head fracture

Question 10

Which blood is transfused in a patient with a Bombay blood group?

Accepted Answer

Bombay (Oh) blood

Answer

A

Answer

O negative

Answer

AB

Answer

B

FMGE 2024

Anatomy

Community Medicine

Internal Medicine

Microbiology

Orthopaedics

Pathology