Diagnosis and Patch Testing Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Diagnosis and Patch Testing. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Diagnosis and Patch Testing Indian Medical PG Question 1: A child has a rash. His family history is positive for asthma. What could be the most probable diagnosis?
- A. Seborrheic dermatitis
- B. Atopic dermatitis (Correct Answer)
- C. Allergic contact dermatitis
- D. Erysipelas
Diagnosis and Patch Testing Explanation: ***Atopic dermatitis***
- The presence of a rash in a child with a family history of **asthma** strongly suggests atopic dermatitis, as it is part of the **atopic triad** (eczema, asthma, allergic rhinitis).
- Atopic dermatitis often presents with **erythematous, pruritic patches** and plaques, commonly affecting flexural areas like the antecubital and popliteal fossae, as well as the face and neck in younger children.
*Seborrheic dermatitis*
- This condition typically presents with **greasy, yellowish scales** on an erythematous base, often affecting areas rich in sebaceous glands such as the scalp, face (nasolabial folds), and chest.
- While it can occur in infants, it does not have the strong association with a family history of asthma seen in atopic dermatitis.
*Allergic contact dermatitis*
- This rash results from an **exposure to an allergen**, leading to a localized, erythematous, and pruritic eruption, often with vesicles or bullae, at the site of contact.
- The history does not provide information about a specific allergen exposure, and while it could produce a similar-looking rash, the family history of asthma points more strongly to atopic diathesis.
*Erysipelas*
- Erysipelas is a superficial skin infection, usually caused by *Streptococcus pyogenes*, presenting as a **well-demarcated, intensely erythematous, warm, and painful rash** with a raised border.
- This is an **acute bacterial infection** and would typically be accompanied by systemic symptoms like fever and chills, which are not mentioned in the child's presentation.
Diagnosis and Patch Testing Indian Medical PG Question 2: A patient comes to you with skin reactions after visiting the hair dresser. What will you do to confirm the diagnosis of contact dermatitis?
- A. S IgE
- B. Allergy Test
- C. Patch Test (Correct Answer)
- D. VDRL
Diagnosis and Patch Testing Explanation: ***Patch Test***
- A **patch test** is the gold standard for diagnosing **allergic contact dermatitis** by directly applying suspected allergens to the skin.
- This test identifies specific substances that cause a delayed hypersensitivity reaction, which is characteristic of contact dermatitis.
*S IgE*
- **Serum IgE** levels are primarily indicative of **Type I hypersensitivity** reactions, such as allergic rhinitis or asthma.
- Contact dermatitis is a **Type IV delayed hypersensitivity reaction**, not mediated by IgE antibodies.
*Allergy Test*
- The term "allergy test" is broad and can refer to various methods including skin prick tests, IgE blood tests, or patch tests.
- Without specifying **patch testing**, other forms of allergy tests are less appropriate for diagnosing contact dermatitis, as they target different immune mechanisms.
*VDRL*
- **VDRL (Venereal Disease Research Laboratory)** test is used to screen for **syphilis**, a sexually transmitted infection.
- It has no relevance to the diagnosis of contact dermatitis, which is an inflammatory skin condition caused by contact with an allergen or irritant.
Diagnosis and Patch Testing Indian Medical PG Question 3: What is the diagnosis if a patient can only see 3 green dots on the Worth 4 Dot test?
- A. Right eye suppression (Correct Answer)
- B. Crossed diplopia
- C. Uncrossed diplopia
- D. Left eye suppression
Diagnosis and Patch Testing Explanation: ***Right eye suppression***
- Seeing **three green dots** exclusively indicates that the patient is only perceiving input from the **left eye**.
- In the Worth 4 Dot test, the **left eye** (viewing through a green filter) sees **three green dots**: the white dot at the top (which appears green through the filter) plus the two lateral green dots.
- The **right eye** (viewing through a red filter) normally sees **two red dots**: the white dot at the top (which appears red) plus the red dot at the bottom.
- Since the patient sees only **three green dots**, the visual input from the **right eye is being suppressed**.
*Crossed diplopia*
- **Crossed diplopia** (heteronymous diplopia) occurs when the image from the right eye is perceived to the left of the image from the left eye.
- This typically occurs with **exotropia** (divergent strabismus) and would result in seeing **five or more dots** (patient perceives both eyes' images but misaligned), not just three green.
*Uncrossed diplopia*
- **Uncrossed diplopia** (homonymous diplopia) occurs when the image from the right eye is perceived to the right of the image from the left eye.
- This is usually associated with **esotropia** (convergent strabismus) and would also lead to the perception of **five or more dots** (both eyes' images perceived but misaligned), not only three green dots.
*Left eye suppression*
- If there were **left eye suppression**, the patient would see **two red dots** from the right eye only (the white dot appearing red plus the red dot at the bottom).
- Seeing **three green dots** confirms the **left eye input is dominant** and the **right eye is suppressed**.
Diagnosis and Patch Testing Indian Medical PG Question 4: Cover test and prism testing are used to diagnose which ocular condition?
- A. Strabismus
- B. Both A & B (Correct Answer)
- C. Heterophoria
- D. None of the options
Diagnosis and Patch Testing Explanation: ***Both A & B***
- The **cover test** and **prism testing** are fundamental diagnostic tools used to detect and quantify **both manifest and latent ocular deviations**.
- **Cover-uncover test** detects **strabismus (heterotropia)** - a manifest deviation present even with both eyes open.
- **Alternate cover test** reveals the **total deviation**, including both manifest strabismus and latent heterophoria.
- **Prism testing** is used to **quantify both conditions** - measuring the angle of deviation in both tropias and phorias.
- These tests work together to diagnose the full spectrum of ocular misalignment disorders.
*Strabismus (alone)*
- While partially correct, this option is incomplete.
- Cover test and prism testing are indeed used for strabismus, but they also diagnose heterophoria.
- Selecting only strabismus ignores the heterophoria component.
*Heterophoria (alone)*
- While partially correct, this option is incomplete.
- Cover test (especially alternate cover test) and prism testing do diagnose heterophoria, but they equally diagnose manifest strabismus.
- The cover-uncover test is the **primary clinical test for detecting manifest strabismus**.
- Selecting only heterophoria ignores the strabismus component.
*None of the options*
- Incorrect, as both strabismus and heterophoria are correctly diagnosed using these tests.
Diagnosis and Patch Testing Indian Medical PG Question 5: Which test is essential in a patient with suspected Cushing's syndrome for diagnosis confirmation?
- A. 24-hour urine cortisol (Correct Answer)
- B. Plasma ACTH
- C. Serum aldosterone
- D. Serum renin
Diagnosis and Patch Testing Explanation: ***24-hour urine cortisol***
- This test directly measures the total amount of **free cortisol excreted over a 24-hour period**, reflecting the body's overall cortisol production [1].
- An elevated **24-hour urine free cortisol** is a primary diagnostic test used to confirm the presence of **hypercortisolism**, a hallmark of Cushing's syndrome [1].
*Plasma ACTH*
- While important for determining the **etiology of Cushing's syndrome** (ACTH-dependent vs. ACTH-independent), it does not confirm the diagnosis of Cushing's syndrome itself [1].
- A normal or high ACTH would suggest an ACTH-dependent cause (e.g., pituitary adenoma or ectopic ACTH production), whereas a low ACTH would suggest an ACTH-independent cause (e.g., adrenal adenoma) [1].
*Serum aldosterone*
- This hormone is primarily involved in **fluid and electrolyte balance** and is relevant in diagnosing conditions like primary aldosteronism, not Cushing's syndrome.
- Cushing's syndrome is characterized by **excess cortisol**, not typically by primary abnormalities in aldosterone secretion.
*Serum renin*
- **Renin** is an enzyme released by the kidneys that plays a crucial role in the **renin-angiotensin-aldosterone system**, regulating blood pressure.
- It is not directly involved in the diagnosis or confirmation of **Cushing's syndrome**, which concerns cortisol excess.
Diagnosis and Patch Testing Indian Medical PG Question 6: Most sensitive test for carpal tunnel syndrome -
- A. Tinel's sign
- B. Tourniquet test
- C. Phalen's test (Correct Answer)
- D. None of the options
Diagnosis and Patch Testing Explanation: ***Phalen's test***
- **Phalen's test** is performed by having the patient forcefully flex their wrists together for 60 seconds.
- The appearance of **paresthesias** (tingling or numbness) in the median nerve distribution is considered a positive and highly **sensitive** result for carpal tunnel syndrome.
*Tinel's sign*
- **Tinel's sign** involves gently tapping over the median nerve at the wrist.
- While it can reveal a positive result in some cases, its **sensitivity** for carpal tunnel syndrome is generally **lower** than Phalen's test.
*Tourniquet test*
- The **tourniquet test** (or **pressure provocation test**) involves applying a blood pressure cuff to the arm and inflating it above systolic pressure.
- This test is designed to reproduce symptoms by increasing pressure within the carpal tunnel, but it is **less sensitive** compared to Phalen's test for initial screening.
*None of the options*
- This option is incorrect, as **Phalen's test** is widely recognized as having the highest sensitivity among the listed clinical tests for carpal tunnel syndrome.
- While **nerve conduction studies** are the gold standard for definitive diagnosis, among the physical examination tests, Phalen's is most sensitive.
Diagnosis and Patch Testing Indian Medical PG Question 7: A 52 year old lady presents with constant leakage of urine and dysuria two weeks after a complicated total abdominal hysterectomy. A diagnosis of Vesicovaginal fistula is suspected. The most important test for the diagnosis is:
- A. Urine culture
- B. Cystoscopy
- C. Triple Swab Test (Correct Answer)
- D. IVP
Diagnosis and Patch Testing Explanation: ***Triple Swab Test***
- The **Triple Swab Test** (also known as the **dye test** or **tampon test**) is the **gold standard diagnostic test** for confirming vesicovaginal fistula.
- **Methylene blue** or indigo carmine dye is instilled into the bladder via a catheter, and tampons are placed in the vagina.
- If the tampon stains blue, it **confirms the diagnosis** of vesicovaginal fistula by demonstrating direct communication between bladder and vagina.
- This is a **simple, non-invasive, and definitive diagnostic test** that directly proves the presence of a fistula.
*Cystoscopy*
- **Cystoscopy** is important for **evaluation and surgical planning** rather than initial diagnosis.
- It allows direct visualization of the **fistula site, size, and proximity to ureteral orifices**, which is crucial for planning repair.
- While it can identify the fistula, it is an **invasive procedure** and is typically performed after diagnosis is confirmed, to characterize the fistula before surgical intervention.
*Urine culture*
- A **urine culture** identifies bacterial infections and guides antibiotic treatment for urinary tract infections.
- While UTIs commonly accompany vesicovaginal fistula and cause dysuria, urine culture **does not diagnose the fistula itself**.
- It is useful for managing concurrent infection but not for confirming the anatomical defect.
*IVP*
- **Intravenous Pyelogram (IVP)** is primarily used to assess **upper urinary tract pathology** and ureteral integrity.
- It may show contrast leakage but is **not specific for vesicovaginal fistula** and does not provide direct confirmation.
- IVP is more useful for ruling out ureteral injury or ureterovaginal fistula rather than diagnosing vesicovaginal fistula.
Diagnosis and Patch Testing Indian Medical PG Question 8: Most sensitive test for myaesthenia gravis
- A. Edrophonium test (Tensilon test)
- B. Single fibre Electromyography (EMG) (Correct Answer)
- C. Multiple fibre EMG
- D. Repetitive nerve stimulation
Diagnosis and Patch Testing Explanation: ***Single fibre Electromyography (EMG)***
- This is the **most sensitive test** for myasthenia gravis, detecting abnormalities in neuromuscular transmission even in subclinical cases [1].
- It measures the variability in the **inter-potential interval** (jitter) between two muscle fibers innervated by the same motor neuron, showing increased jitter or blocking in affected individuals [1].
*Edrophonium test (Tensilon test)*
- While historically used, its sensitivity is lower than SFEMG, and it carries risks of **cholinergic crisis** or bradycardia.
- It involves administering a short-acting **acetylcholinesterase inhibitor** and observing for temporary improvement in muscle weakness.
*Multiple fibre EMG*
- This technique samples multiple muscle fibers but is less precise than single fiber EMG and may not detect subtle neuromuscular transmission defects.
- It is more commonly used to assess the **architecture of motor units** in neuropathic or myopathic conditions [1].
*Repetitive nerve stimulation*
- This test involves stimulating a nerve at low frequencies (2-3 Hz) and looking for a **decremental response** (a >10% drop in amplitude) in the compound muscle action potential.
- Its sensitivity is good for generalized myasthenia gravis but lower for ocular or mild forms, making it less sensitive overall than SFEMG.
Diagnosis and Patch Testing Indian Medical PG Question 9: A patient presents with fever and retro-orbital pain. Which investigation should be conducted next for confirmation of dengue fever?
- A. Viral culture
- B. NS1 antigen test (Correct Answer)
- C. IgM ELISA
- D. PCR
Diagnosis and Patch Testing Explanation: ***NS1 antigen test***
- The **NS1 antigen test** is highly sensitive and specific for dengue in the **early stages** of infection (typically 0-7 days after symptom onset), which is when a patient with fever and retro-orbital pain would likely present.
- It detects a non-structural protein of the dengue virus, indicating **active viral replication**.
*Viral culture*
- **Viral culture** for dengue is time-consuming and technically demanding, making it impractical for rapid diagnosis in clinical settings, especially when an urgent confirmation is needed for patient management.
- It is primarily used for research purposes rather than routine clinical diagnosis [2].
*IgM ELISA*
- **IgM ELISA** detects antibodies produced in response to dengue infection, which typically become detectable **5-7 days after symptom onset**.
- While useful for confirming dengue in later stages of illness, it may yield a **false negative** result if performed too early in the course of the disease [2].
*PCR*
- **PCR (Polymerase Chain Reaction)** detects dengue viral RNA and is highly sensitive and specific in the **early acute phase** of infection (first 5 days) [1].
- However, it is generally more expensive, requires specialized laboratory equipment, and has a longer turnaround time compared to the NS1 antigen test, making NS1 a more accessible initial diagnostic choice.
Diagnosis and Patch Testing Indian Medical PG Question 10: Best provocative test for diagnosis of Gastrinoma is:
- A. Ca++ infusion test
- B. Secretin injection test (Correct Answer)
- C. ACTH stimulation test
- D. Steroid assay
Diagnosis and Patch Testing Explanation: ***Secretin injection test***
- The **secretin injection test** is the most reliable provocative test for gastrinoma, leading to a paradoxical increase in gastrin levels [1].
- In normal individuals, secretin suppresses gastrin release, but in gastrinoma, it stimulates **gastrin secretion** [1].
*Ca++ infusion test*
- The **calcium infusion test** can also stimulate gastrin release in gastrinoma patients, but it is less specific and potentially more risky than the secretin test due to potential side effects like cardiac arrhythmias.
- It involves infusing calcium gluconate to observe any uncharacteristic rise in gastrin.
*ACTH stimulation test*
- The **ACTH stimulation test** is used to evaluate adrenal gland function, particularly in suspected cases of adrenal insufficiency or hypercortisolism [2].
- It does not have any direct relevance to the diagnosis of **gastrinoma**.
*Steroid assay*
- **Steroid assays** measure levels of various steroid hormones (e.g., cortisol, aldosterone) in the body to assess adrenal or gonadal function.
- This test is not used for diagnosing **gastrinoma**.
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