Dermatology
5 questionsSkin scraping and KOH mounting is primarily used to diagnose which of the following conditions?
In which condition is an ulceronecrotic nodule typically observed?
Treatment of dermatitis herpetiformis:
What is the most common trigger associated with erythema multiforme?
Acantholysis is not seen in:
NEET-PG 2013 - Dermatology NEET-PG Practice Questions and MCQs
Question 1151: Skin scraping and KOH mounting is primarily used to diagnose which of the following conditions?
- A. Dermatophyte infection (Correct Answer)
- B. Bacterial infection
- C. Candidiasis
- D. Herpes Simplex Virus (HSV)
Explanation: ***Dermatophyte infection*** - Skin scraping followed by **KOH mounting** is the **primary and gold standard** diagnostic method for dermatophyte infections - **Potassium hydroxide (KOH)** dissolves keratin, making **fungal hyphae and arthroconidia** clearly visible under microscopy - This is the **most common indication** for KOH preparation in dermatology practice - Demonstrates **septate hyphae** characteristic of dermatophytes *Candidiasis* - KOH mounting can also identify *Candida* species by revealing **pseudohyphae and budding yeast cells** - While KOH can diagnose candidiasis, dermatophyte infections remain the **primary and most frequent indication** for this test in skin lesions - Candida more commonly affects mucosal surfaces where other diagnostic methods may be preferred *Bacterial infection* - Bacterial infections are diagnosed using **Gram stain, culture, and sensitivity** testing - KOH mounting is specifically for **fungal elements** and does not visualize bacteria effectively - Bacterial skin infections require different diagnostic approaches *Herpes Simplex Virus (HSV)* - HSV infections are diagnosed using **Tzanck smear** (showing multinucleated giant cells), **viral culture, or PCR** - KOH mounting is exclusively for fungal identification and **cannot detect viruses** - Viral cytopathic effects are not visible with KOH preparation
Question 1152: In which condition is an ulceronecrotic nodule typically observed?
- A. Lucio's leprosy (Correct Answer)
- B. Lepromatous leprosy
- C. Indeterminate leprosy
- D. Histoid leprosy
Explanation: ***Lucio's leprosy*** - This is a rare, diffuse variant of **lepromatous leprosy** characterized by widespread, diffuse infiltration of the skin without distinct nodules. - The distinctive feature is the occurrence of **necrotizing vasculitis**, leading to painful, irregular ulcers and scars, known as **Lucio phenomenon** or erythema necroticans. *Lepromatous leprosy* - Characterized by **multiple, symmetrical nodules**, plaques, and diffuse infiltration, but typically without the profound ulceronecrotic changes seen in Lucio's leprosy. - The immune response is weak, leading to high bacterial load and widespread involvement, but usually not spontaneous ulceration. *Indeterminate leprosy* - This is an **early, undifferentiated form** of leprosy, characterized by a single or a few hypopigmented or erythematous macules. - Distinct nodules or ulceronecrotic lesions are not a feature of indeterminate leprosy, as the disease has not yet progressed to develop specific clinical manifestations. *Histoid leprosy* - A rare variant of lepromatous leprosy that presents with **cutaneous nodules** and papules that often resemble dermatofibromas or xanthomas. - These nodules are firm, smooth, and have a unique histological appearance, but they do not typically undergo spontaneous ulceronecrotic changes like those in Lucio's leprosy.
Question 1153: Treatment of dermatitis herpetiformis:
- A. Dapsone
- B. Sulfonamide
- C. Gluten-free diet
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - **Dermatitis herpetiformis (DH)** is a chronic, intensely itchy blistering skin condition associated with **celiac disease**. - Effective management involves both a **gluten-free diet** to address the underlying autoimmune process and medications like **dapsone** or **sulfonamides** for symptomatic relief. *Gluten-free diet* - A strict **gluten-free diet** is crucial for long-term management as it addresses the underlying small intestinal enteropathy associated with **celiac disease** and **dermatitis herpetiformis**. - While it may take several months to see full skin improvement, it can eventually lead to resolution of skin lesions and reduced or eliminated need for medication. *Dapsone* - **Dapsone** is a rapidly effective medication for alleviating the intense itching and rash of **dermatitis herpetiformis**, often providing relief within 24-48 hours. - It works by inhibiting neutrophil migration and inflammation, but does not treat the underlying gluten-sensitive enteropathy. *Sulfonamide* - **Sulfonamides**, such as sulfapyridine or sulfamethoxypyridazine, can be used as an alternative for patients who cannot tolerate **dapsone** or who respond inadequately to it. - Like dapsone, these medications provide symptomatic relief by reducing inflammation and neutrophil activity in the skin, but do not address the gluten-induced intestinal damage.
Question 1154: What is the most common trigger associated with erythema multiforme?
- A. Herpes simplex (Correct Answer)
- B. Mycoplasma pneumoniae
- C. TB
- D. Drugs
Explanation: ***Herpes simplex*** - **Herpes simplex virus (HSV)** is the most common precipitating factor for **erythema multiforme**, accounting for **50-60% of identifiable cases**, particularly the recurrent form. - The rash typically appears **10-14 days after an HSV outbreak**, suggesting an immune-mediated reaction. - **HSV-1** is more commonly implicated than HSV-2. *Mycoplasma pneumoniae* - **Mycoplasma pneumoniae** is the **second most common infectious trigger** for erythema multiforme, especially in children and young adults. - EM associated with Mycoplasma typically occurs during or after respiratory infection. - However, it is still less common than HSV as a trigger. *TB* - **Tuberculosis (TB)** is not typically associated with erythema multiforme. - While other infections can trigger erythema multiforme, TB is rarely implicated. *Drugs* - **Drug reactions** are a recognized cause of erythema multiforme, but they are less common than HSV infection as a trigger. - Certain medications like **sulfonamides, anticonvulsants, NSAIDs, and penicillins** are among the drugs that can induce erythema multiforme.
Question 1155: Acantholysis is not seen in:
- A. Lichen planus (Correct Answer)
- B. Dermatitis herpetiformis
- C. Hailey-Hailey disease
- D. Bullous pemphigoid
Explanation: ***Lichen planus*** - **Lichen planus** is a **non-blistering inflammatory dermatosis** where **acantholysis is completely absent** as it is not a blistering disorder. - Characterized by **acanthosis** (epidermal thickening), **hyperkeratosis**, **wedge-shaped hypergranulosis**, and a **band-like lymphocytic infiltrate** at the dermo-epidermal junction. - The pathology involves **basal cell liquefaction** and inflammation, not loss of keratinocyte cohesion. - **Most appropriate answer** as lichen planus is fundamentally a non-blistering condition, unlike the other options which are blistering diseases. *Bullous pemphigoid* - A **subepidermal bullous disease** where blister formation occurs *below* the epidermis at the **dermo-epidermal junction**. - Autoantibodies target **BP180 and BP230** antigens in **hemidesmosomes**, causing separation between epidermis and dermis. - **No acantholysis** is present as keratinocytes within the epidermis remain cohesive; the split is subepidermal. - Also a correct answer, but less optimal than lichen planus as it is still a blistering disease. *Dermatitis herpetiformis* - A **subepidermal blistering disease** associated with **celiac disease** and characterized by intensely pruritic papulovesicles. - Features **neutrophilic microabscesses** in dermal papillae and granular **IgA deposits** at the dermo-epidermal junction. - **No acantholysis** as blister formation is subepidermal due to immune complex deposition, not loss of keratinocyte adhesion. - Also technically correct, but lichen planus remains the best answer. *Hailey-Hailey disease* - **INCORRECT:** This condition is characterized by **suprabasal acantholysis**, making it a classic example where acantholysis IS present. - Also known as **familial benign chronic pemphigus**, caused by mutation in **ATP2C1 gene** affecting calcium regulation. - Leads to chronic, relapsing blistering and erosions in **intertriginous areas** (axillae, groin). - **Acantholysis is the defining histological feature**, producing a "dilapidated brick wall" appearance.
Internal Medicine
4 questionsMatch stick test is positive in ?
Which type of leprosy does not involve nerve damage?
A man with pain during defecation, no gastrointestinal symptoms, and ulcers extending into the anal canal. Diagnosis?
Which of the following is a characteristic feature of Granulomatosis with polyangiitis?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 1151: Match stick test is positive in ?
- A. Rhinophyma
- B. P. versicolor
- C. Leprosy (Correct Answer)
- D. Rhinoscleroma
Explanation: ***Leprosy*** - The **matchstick test** is a simple neurological examination used to detect **nerve damage** in leprosy, specifically **sensory loss** [1]. - A positive test indicates the patient cannot perceive the touch or pain from a matchstick, commonly due to damage to superficial nerves caused by *Mycobacterium leprae* [1]. *Rhinophyma* - This condition is characterized by **sebaceous gland hypertrophy** and **fibrosis** of the nose, often associated with rosacea. - It does not involve nerve damage or sensory loss that would be assessed by a matchstick test. *Rhinoscleroma* - Rhinoscleroma is a **chronic granulomatous bacterial infection** of the upper respiratory tract. - While it causes significant tissue destruction and structural changes, it is not primarily associated with the sensory neuropathies that the matchstick test evaluates. *P. vesticolor* - *Pityriasis versicolor* is a **superficial fungal infection** of the skin, causing discolored patches. - This condition is a dermatological issue and does not involve nerve damage or sensory deficits, making the matchstick test irrelevant.
Question 1152: Which type of leprosy does not involve nerve damage?
- A. Indeterminate leprosy (Correct Answer)
- B. Borderline tuberculoid leprosy
- C. Tuberculoid leprosy
- D. Lepromatous leprosy
Explanation: ***Indeterminate leprosy*** - This is the earliest form of leprosy and often presents with only a **single skin lesion** and no demonstrable nerve damage. - Due to the minimal immune response, it can be difficult to classify and may progress to other forms if left untreated. *Tuberculoid leprosy* - Characterized by a **strong cell-mediated immune response** to *Mycobacterium leprae*, leading to significant nerve involvement [1]. - Patients typically present with well-demarcated, **hypopigmented patches** with definite **sensory loss** due to nerve damage [1]. *Borderline tuberculoid leprosy* - This form sits between tuberculoid and borderline lepromatous leprosy, showing features of both, including **nerve involvement** [2]. - It presents with a few to several skin lesions that are usually smaller and less clearly defined than tuberculoid lesions, often with **palpable nerves** and mild sensory loss [2]. *Lepromatous leprosy* - Characterized by a **weak or absent cell-mediated immune response**, leading to widespread bacterial proliferation and extensive nerve damage, often symmetrical [1]. - Patients show numerous, poorly defined skin lesions, nodules, and severe nerve involvement, which can result in significant **deformities** [2].
Question 1153: A man with pain during defecation, no gastrointestinal symptoms, and ulcers extending into the anal canal. Diagnosis?
- A. Cytomegalovirus (CMV)
- B. Gonococcal infection
- C. Genital herpes (Correct Answer)
- D. HIV infection
Explanation: Herpes simplex virus (HSV) infection of the anal canal is characterized by lesions that present as painful ulcers [1]. Direct extension into the anal canal is common in individuals with receptive anal intercourse or autoinoculation, often causing symptoms such as anal or rectal pain [1]. CMV proctitis typically causes more diffuse inflammation, often with bloody stools, diarrhea, and abdominal pain, which are not described in this case. While CMV can cause ulcers, they are usually shallow and often associated with immunocompromised states. Gonococcal proctitis often presents with purulent anal discharge, rectal pain, itching, and tenesmus, but typically without deep ulcerations. HIV infection can cause various anorectal complications, including aphthous ulcers, but isolated anal ulcers and defecation pain would prompt investigation into sexually transmitted infections like herpes as a more direct cause.
Question 1154: Which of the following is a characteristic feature of Granulomatosis with polyangiitis?
- A. Nasal polyp
- B. Perforated nasal septum (Correct Answer)
- C. Persistent sinusitis
- D. Collapse of nasal bridge
Explanation: ***Perforated nasal septum*** - **Granulomatosis with polyangiitis (GPA)**, previously known as **Wegener's granulomatosis**, is characterized by **granulomatous inflammation** and **vasculitis** of small to medium-sized vessels, particularly affecting the upper and lower respiratory tracts, and the kidneys [1]. - Damage to the nasal cartilage and bone due to inflammation and vasculitis can lead to a **perforation of the nasal septum**, which is a classic feature. *Nasal polyp* - While nasal polyps can occur in inflammatory conditions, they are **not a specific or highly characteristic feature** of Granulomatosis with polyangiitis compared to septal perforation. - **Allergic rhinitis** or **chronic rhinosinusitis** are more commonly associated with nasal polyps. *Persistent sinusitis* - **Persistent sinusitis** (rhinosinusitis) is a very common initial manifestation of Granulomatosis with polyangiitis due to upper airway inflammation. - However, it's a **less specific finding** than a perforated septum, as sinusitis can be caused by many other conditions. *Collapse of nasal bridge* - **Collapse of the nasal bridge**, also known as a **saddle nose deformity**, can occur in advanced or destructive cases of Granulomatosis with polyangiitis due to extensive cartilage and bone destruction. - While possible, a **perforated nasal septum often precedes** or is a more direct, earlier indicator of the destructive process in the nose.
Pharmacology
1 questionsWhich drug would be most appropriate for treating a patient with suspected chlamydia-gonorrhea coinfection?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 1151: Which drug would be most appropriate for treating a patient with suspected chlamydia-gonorrhea coinfection?
- A. Ciprofloxacin
- B. Nalidixic acid
- C. Doxycycline (Correct Answer)
- D. Norfloxacin
Explanation: ***Doxycycline*** - **Doxycycline** is a highly effective treatment for **chlamydia**, and its broad-spectrum activity also covers potential **gonorrhea coinfection** when used as part of a dual therapy regimen. - It is often prescribed alongside a **single dose of ceftriaxone** for presumed gonorrhea coinfection, as ceftriaxone targets gonorrhea while doxycycline targets chlamydia. *Ciprofloxacin* - **Ciprofloxacin** is a **fluoroquinolone** antibiotic, which is generally not recommended as first-line treatment for uncomplicated **gonorrhea** or **chlamydia** due to increasing resistance. - It has activity against *Neisseria gonorrhoeae*, but its effectiveness against *Chlamydia trachomatis* is suboptimal compared to macrolides or tetracyclines. *Norfloxacin* - **Norfloxacin** is another **fluoroquinolone** with a narrower spectrum of activity than ciprofloxacin and is primarily used for **urinary tract infections**. - It has **poor efficacy against chlamydia** and is not a recommended treatment for either organism in this context. *Nalidixic acid* - **Nalidixic acid** is a first-generation **quinolone** with a very limited spectrum, used mainly for **gram-negative urinary tract infections**. - It has **no significant activity against chlamydia** or gonorrhea and is therefore inappropriate for treating this suspected coinfection.