Narrow-Band UVB Therapy Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Narrow-Band UVB Therapy. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Narrow-Band UVB Therapy Indian Medical PG Question 1: A nurse got accidental prick from the HIV infected needle. Which of the following statements is false regarding the management of this nurse?
- A. Follow up viral markers of health care personnel should be measured at 6 weeks
- B. Zidovudine is used as monotherapy for post-exposure prophylaxis (Correct Answer)
- C. Baseline viral markers of health care personnel should be done at the time of presentation
- D. Washing hands with soap and water is advised
Narrow-Band UVB Therapy Explanation: **Zidovudine is used as monotherapy for post-exposure prophylaxis**
- **Monotherapy** with zidovudine is **insufficient** for effective **HIV post-exposure prophylaxis (PEP)** due to the high risk of treatment failure and development of drug resistance.
- **Current guidelines** recommend a **multi-drug regimen**, typically involving three antiretroviral drugs, for PEP to maximize efficacy against HIV transmission.
*Follow up viral markers of health care personnel should be measured at 6 weeks*
- **Follow-up viral markers** for HIV, such as **HIV RNA PCR** and **antibody tests**, are routinely measured at specific intervals (e.g., 6 weeks, 3 months, 6 months) to monitor for seroconversion [1].
- This allows for **early detection of HIV infection** if PEP fails, enabling prompt initiation of treatment.
*Baseline viral markers of health care personnel should be done at the time of presentation*
- Establishing **baseline HIV status** of the healthcare worker at the time of exposure is crucial to differentiate pre-existing infection from a new infection acquired from the needle stick [1].
- This information helps in **interpreting subsequent test results** and guiding further management.
*Washing hands with soap and water is advised*
- **Immediate washing** of the exposed area with **soap and water** is an important first step in managing a needle stick injury [1].
- This **reduces the viral load** at the site of exposure, minimizing the risk of transmission, although it does not eliminate the need for PEP.
Narrow-Band UVB Therapy Indian Medical PG Question 2: What is the optimal wavelength of light emitted by a Wood's lamp for dermatological examinations?
- A. 365 nm (Correct Answer)
- B. 400 nm
- C. 320 nm
- D. 200 nm
Narrow-Band UVB Therapy Explanation: **365 nm**
- A Wood's lamp primarily emits **long-wave UVA light** in the 320 to 400 nm range, with an optimal peak around **365 nm**.
- This specific wavelength is ideal for inducing **fluorescence** in various dermatological conditions, making them visible.
*400 nm*
- While within the UVA range, **400 nm** is at the higher end and may not provide the optimal fluorescence yield for all diagnostic purposes compared to 365 nm.
- Light at 400 nm is closer to the visible light spectrum and might offer less distinction for subtle fluorescence.
*320 nm*
- **320 nm** is at the lower end of the UVA spectrum, bordering on UVB.
- While still capable of inducing some fluorescence, it is generally less effective than 365 nm for the conditions typically examined with a Wood's lamp.
*200 nm*
- **200 nm** falls into the **UVC range** (100-280 nm), which is harmful and not used for diagnostic purposes in a Wood's lamp.
- This wavelength is absorbed by the atmosphere and epidermis and can cause significant **DNA damage**, making it unsafe for routine dermatological examination.
Narrow-Band UVB Therapy Indian Medical PG Question 3: Contraindications for skin traction: a) Dermatitis b) Vascularly compromised status of limb c) Abrasions d) Hypopigmentation (vitiligo) e) Bony deformity
- A. ab
- B. abc (Correct Answer)
- C. acd
- D. bcd
Narrow-Band UVB Therapy Explanation: ***ab***
- All conditions listed under 'a' and 'b' (Dermatitis, Vascularly compromised status of limb, Abrasions) are **absolute contraindications** for skin traction as they directly compromise skin integrity or circulation.
- Applying skin traction in these situations can lead to **skin breakdown**, infection, or further **ischemic damage**, worsening the patient's condition.
*ab*
- While **dermatitis**, **vascular compromise**, and **abrasions** are indeed contraindications, the option for 'abc' implies there might be other correct choices included, which is not the case for this option.
- This option is incomplete as it misses 'c' (Abrasions) which is also a significant contraindication.
*acd*
- This option incorrectly includes **hypopigmentation (vitiligo)** as a contraindication, which does not inherently prevent skin traction.
- It also omits **vascularly compromised status of limb**, a critical contraindication, while including 'a', 'c', and 'd'.
*bcd*
- This option incorrectly includes **hypopigmentation (vitiligo)** as a contraindication for skin traction.
- It also omits **dermatitis**, a key contraindication, while including 'b', 'c', and 'd'.
Narrow-Band UVB Therapy Indian Medical PG Question 4: PUVA therapy is used in all except:
- A. Psoriasis
- B. Vitiligo
- C. Mycosis fungoides
- D. Melasma (Correct Answer)
Narrow-Band UVB Therapy Explanation: ***Melasma***
- **PUVA (Psoralen plus UVA) therapy** is contraindicated in melasma due to its potential to worsen hyperpigmentation and cause paradoxical darkening.
- Melasma is best managed with topical agents like **hydroquinone**, **tretinoin**, and chemical peels, along with strict **sun protection**.
*Psoriasis*
- **PUVA therapy** is a well-established and effective treatment for moderate to severe psoriasis, especially for patients with widespread plaques.
- It works by inhibiting DNA synthesis and cell proliferation in rapidly dividing keratinocytes, leading to a reduction in psoriatic lesions.
*Vitiligo*
- **PUVA therapy** is a common treatment for vitiligo, stimulating melanocyte activity and promoting repigmentation in affected areas.
- Psoralen sensitizes melanocytes to UVA light, which then encourages melanin production.
*Mycosis fungoides*
- In its early stages, **mycosis fungoides**, a cutaneous T-cell lymphoma, can be effectively treated with **PUVA therapy**.
- PUVA induces apoptosis of malignant T-cells in the skin, leading to remission of skin lesions.
Narrow-Band UVB Therapy Indian Medical PG Question 5: Treatment of choice for Pustular psoriasis is:
- A. Methotrexate (Correct Answer)
- B. Psoralen - UV therapy
- C. Systemic steroid
- D. Estrogen
Narrow-Band UVB Therapy Explanation: ***Methotrexate***
- **Methotrexate** is a systemic immunosuppressant often considered the first-line treatment for severe forms of **pustular psoriasis** due to its efficacy in reducing inflammation and hyperproliferation of skin cells.
- It works by inhibiting **dihydrofolate reductase**, thereby interfering with DNA synthesis and cell division, which is crucial in rapidly dividing cells like those found in psoriasis.
*Psoralen - UV therapy*
- **Psoralen and ultraviolet A (PUVA)** therapy can be used for chronic plaque psoriasis, but it is generally **contraindicated or used with extreme caution** in pustular psoriasis due to the risk of exacerbating the disease or causing irritation.
- **UV light therapy** can sometimes trigger or worsen pustular flares, especially in acute generalized pustular psoriasis.
*Systemic steroid*
- While systemic steroids can provide temporary relief by addressing inflammation, their use in pustular psoriasis is generally **not recommended for long-term management** due to the high risk of severe rebound flares upon withdrawal.
- Withdrawal of **systemic corticosteroids** can precipitate or worsen generalized pustular psoriasis, making them a less desirable long-term treatment option.
*Estrogen*
- **Estrogen** has no direct role in the treatment of psoriasis. Psoriasis is an inflammatory skin condition, and its pathophysiology is not directly influenced by estrogen levels.
- Hormonal therapies are not indicated for the management of psoriasis, including its pustular forms.
Narrow-Band UVB Therapy Indian Medical PG Question 6: Which of the following is the most common side effect of Isotretinoin used for acne vulgaris?
- A. Xerosis
- B. Hair loss
- C. Facial erythema
- D. Cheilitis (Correct Answer)
Narrow-Band UVB Therapy Explanation: ***Cheilitis***
- **Cheilitis** (dry, cracked lips) is the most frequently reported side effect due to the drug's effect on sebaceous glands and subsequent reduction in sebum production.
- This symptom affects nearly all patients on isotretinoin therapy.
*Xerosis*
- While **xerosis** (dry skin) is a common side effect of isotretinoin, it is typically less pervasive and severe than cheilitis.
- Patients often experience generalized skin dryness, but it usually doesn't affect all patients to the same degree as labial dryness.
*Hair loss*
- **Hair loss** (alopecia) is a known but less common side effect, usually mild and reversible upon discontinuation of the drug.
- It does not affect the majority of patients undergoing isotretinoin treatment.
*Facial erythema*
- **Facial erythema** (redness) can occur due to skin sensitivity and dryness, but it's not as universal or prominent as cheilitis.
- It is more of an indirect effect of the drug, rather than a direct and universal consequence of its mechanism of action.
Narrow-Band UVB Therapy Indian Medical PG Question 7: A patient presents with a skin rash that is exaggerated on sun exposure. What is the repair mechanism involved in this condition?
- A. Nucleotide excision repair (Correct Answer)
- B. Base excision repair
- C. Mismatch repair
- D. Double stranded DNA break repair
Narrow-Band UVB Therapy Explanation: ***Nucleotide excision repair***
- This mechanism is responsible for repairing **bulky lesions** in DNA, such as **pyrimidine dimers** caused by **UV radiation** from sun exposure.
- Patients with defects in nucleotide excision repair (e.g., **xeroderma pigmentosum**) are highly sensitive to sunlight and develop skin rashes, pigment changes, and skin cancers.
*Base excision repair*
- This pathway primarily corrects **small damaged bases** that do not cause significant distortion of the DNA helix, such as deaminated, oxidized, or alkylated bases.
- It does not primarily address the bulky lesions induced by UV light that cause exaggerated sun sensitivity.
*Mismatch repair*
- This system corrects errors, like **mismatched base pairs**, that are incorporated during DNA replication.
- It is not directly involved in repairing DNA damage caused by environmental factors like UV radiation.
*Double stranded DNA break repair*
- This mechanism repairs **double-strand breaks** in DNA, which are highly deleterious lesions caused by ionizing radiation or oxidative stress.
- While critical for genome stability, it is not the primary repair pathway for UV-induced DNA lesions or the direct cause of sun sensitivity.
Narrow-Band UVB Therapy Indian Medical PG Question 8: Wood's lamp has a wavelength of –
- A. 320 nm
- B. 300 nm
- C. 360 nm (Correct Answer)
- D. 250 nm
Narrow-Band UVB Therapy Explanation: ***360 nm***
- A **Wood's lamp** emits **long-wave ultraviolet (UV-A) light**, which is typically in the range of 320 to 450 nm.
- The precise wavelength of **360 nm** is the most common and effective for dermatological diagnostic applications, allowing visualization of specific fluorescence patterns.
*320 nm*
- While 320 nm falls within the UV-A spectrum, it is at the lower end and less characteristic of the peak emission wavelength used in Wood's lamps for diagnostic purposes.
- Using this lower wavelength might result in less pronounced or absent fluorescence for some conditions.
*300 nm*
- A wavelength of 300 nm is in the **UV-B spectrum** which is primarily used for therapeutic purposes like **phototherapy for psoriasis**, not for diagnostic fluorescence with a Wood's lamp.
- UV-B light has different biological effects and is too short to elicit the characteristic fluorescence observed with a Wood's lamp.
*250 nm*
- This wavelength falls into the **UV-C spectrum**, which is **germicidal** and harmful to human tissue.
- UV-C light is not used in Wood's lamps for diagnostic purposes due to its damaging properties and inability to produce the desired fluorescence.
Narrow-Band UVB Therapy Indian Medical PG Question 9: An 8-year-old girl has extreme photosensitivity since birth. She has recently been diagnosed with skin cancer. What is the diagnosis?
- A. Xeroderma Pigmentosum (Correct Answer)
- B. Bloom syndrome
- C. Griscelli syndrome
- D. Chediak Higashi syndrome
Narrow-Band UVB Therapy Explanation: ***Xeroderma Pigmentosum***
- This condition is characterized by an extreme sensitivity to **ultraviolet (UV) light** from birth due to defects in **DNA repair mechanisms**, leading to severe sunburns, pigmentary changes (freckles, hypopigmented macules), and a high risk of developing **skin cancers** at a young age.
- The history of extreme photosensitivity since birth and the diagnosis of skin cancer in an 8-year-old girl is highly indicative of Xeroderma Pigmentosum.
*Bloom syndrome*
- Bloom syndrome is an inherited disorder characterized by **stunted growth**, a **photosensitive facial rash (telangiectatic erythema)**, and a predisposition to **various cancers**, including leukemia and lymphomas.
- While photosensitivity and cancer risk are present, the extreme skin damage and early onset of specific skin cancers (as opposed to leukemias/lymphomas often seen in Bloom) make Xeroderma Pigmentosum a more fitting diagnosis.
*Griscelli syndrome*
- Griscelli syndrome is a rare autosomal recessive disorder characterized by **partial albinism**, immunodeficiency, and neurological impairment.
- While it involves pigmentary abnormalities, it does not typically present with the extreme photosensitivity or the very early skin cancer development described in the patient.
*Chediak Higashi syndrome*
- Chediak-Higashi syndrome is an autosomal recessive disorder characterized by **partial albinism**, recurrent pyogenic infections, and neurological abnormalities, due to defective lysosomal trafficking.
- This syndrome is not primarily associated with extreme photosensitivity leading to early skin cancers but rather with immunodeficiency and neurological issues.
Narrow-Band UVB Therapy Indian Medical PG Question 10: Which of the following is NOT a complication of PUVA therapy?
- A. Premature aging of the skin
- B. Cataracts
- C. Skin cancers
- D. Exfoliative dermatitis (Correct Answer)
Narrow-Band UVB Therapy Explanation: **Explanation:**
PUVA (Psoralen + Ultraviolet A) therapy involves the administration of a photosensitizer (8-methoxypsoralen) followed by exposure to UVA radiation. While it is an effective treatment for conditions like psoriasis and vitiligo, it carries specific long-term and short-term risks.
**Why Exfoliative Dermatitis is the correct answer:**
Exfoliative dermatitis (Erythroderma) is **not** a direct complication of PUVA. In fact, PUVA is often used as a *treatment* modality for certain types of exfoliative dermatitis, such as those caused by Mycosis Fungoides or Psoriasis. While PUVA can cause a "PUVA itch" or a phototoxic burn (erythema), it does not typically trigger generalized exfoliation.
**Analysis of Incorrect Options:**
* **Premature aging of the skin (Dermatoheliosis):** Chronic UVA exposure leads to the degradation of collagen and elastin fibers, resulting in wrinkles, lentigines, and telangiectasia.
* **Cataracts:** Psoralens distribute to the lens of the eye. If the eyes are not protected with UVA-blocking sunglasses for 24 hours post-ingestion, UVA exposure can lead to lens opacification.
* **Skin cancers:** PUVA is mutagenic. Long-term therapy significantly increases the risk of Non-Melanoma Skin Cancers (NMSC), particularly **Squamous Cell Carcinoma (SCC)**.
**High-Yield Clinical Pearls for NEET-PG:**
* **Most common acute side effect:** Erythema (phototoxicity) and pruritus.
* **Most common long-term risk:** Squamous Cell Carcinoma (SCC) is more common than Basal Cell Carcinoma (BCC) in PUVA patients (reversing the usual ratio).
* **PUVA Lentigines:** Distinctive, irregular pigmented macules that appear after chronic therapy.
* **Contraindications:** Pregnancy, lactation, history of skin cancer (Xeroderma Pigmentosum), and severe hepatic/renal failure.
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