Dermatology
1 questionsA patient presents with painful vesicles as shown in the image. What is the diagnosis?
NEET-PG 2024 - Dermatology NEET-PG Practice Questions and MCQs
Question 161: A patient presents with painful vesicles as shown in the image. What is the diagnosis?
- A. Chancroid
- B. Syphilis
- C. Herpes (Correct Answer)
- D. Candidiasis
Explanation: ***Herpes*** - The image shows a cluster of **small, painful vesicles on an erythematous base**, which is highly characteristic of a herpes simplex virus (HSV) infection. - These lesions typically evolve into ulcers, crust over, and heal, and are often recurrent. *Chancroid* - Chancroid presents as **painful, soft chancres** (ulcers) with irregular, undermined borders and a gray or yellow base, often accompanied by **buboes** (enlarged, tender lymph nodes). - It does not typically manifest as clusters of small vesicles. *Syphilis* - Primary syphilis presents as a **painless chancre**—a single, firm, ulcerated lesion with a clean base and raised borders. - Secondary syphilis can cause a variety of skin manifestations, but not painful vesicles. *Candidiasis* - Cutaneous candidiasis usually appears as a **red, moist rash with satellite lesions** (smaller papules or pustules spreading from the main rash), often in skin folds. - While it can be inflammatory and itchy, it does not typically form discreet painful vesicles as seen in the image.
Internal Medicine
2 questionsA 40-year-old farmer presents with fever, calf tenderness, conjunctival suffusion, retro-orbital pain, and hypokalemia. What is the diagnosis?
Which viral infection is most likely responsible for triggering this aplastic crisis in the patient?
NEET-PG 2024 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 161: A 40-year-old farmer presents with fever, calf tenderness, conjunctival suffusion, retro-orbital pain, and hypokalemia. What is the diagnosis?
- A. Malaria
- B. Dengue
- C. Leptospira (Correct Answer)
- D. Influenza
- E. Typhoid fever
Explanation: ***Leptospira*** - The combination of **fever**, **calf tenderness**, **conjunctival suffusion** (red eyes without purulent discharge), **retro-orbital pain**, and **hypokalemia** is highly suggestive of **leptospirosis**. - A farmer's occupation increases the risk of exposure to contaminated water or soil, which is a common transmission route for Leptospira. - **Calf tenderness** and **conjunctival suffusion** are particularly characteristic features. *Malaria* - Characterized by **cyclic fevers**, **chills**, and **sweats**, often with **splenomegaly** and **anemia**. - **Calf tenderness**, **conjunctival suffusion**, and **retro-orbital pain** are not typical primary symptoms of malaria. *Dengue* - Often presents with **high fever**, **severe headache** (especially retro-orbital), **muscle and joint pain** ("breakbone fever"), and **rash**. - **Conjunctival suffusion** and significant **calf tenderness** are not classic features, and hypokalemia is less common than with leptospirosis. *Influenza* - Acute respiratory illness with **fever**, **cough**, **sore throat**, **muscle aches**, and **fatigue**. - While muscle aches can occur, **calf tenderness**, **conjunctival suffusion**, and **hypokalemia** are not characteristic of influenza. *Typhoid fever* - Presents with **sustained fever**, **relative bradycardia**, **rose spots**, and **hepatosplenomegaly**. - **Conjunctival suffusion**, **calf tenderness**, and **retro-orbital pain** are not typical features of typhoid fever.
Question 162: Which viral infection is most likely responsible for triggering this aplastic crisis in the patient?
- A. Parvovirus B19 (Correct Answer)
- B. Epstein-Barr Virus (EBV)
- C. Hepatitis B Virus (HBV)
- D. Cytomegalovirus (CMV)
Explanation: ***Parvovirus B19*** - **Parvovirus B19** specifically targets and destroys **red blood cell precursors** in the bone marrow, leading to a temporary cessation of erythropoiesis [1]. - In patients with underlying hemolytic anemias (e.g., **sickle cell disease**, **hereditary spherocytosis**), this temporary aplasia can trigger a severe **aplastic crisis** due to their already shortened red blood cell lifespan [2]. *Epstein-Barr Virus (EBV)* - While EBV can cause various hematologic complications, including some myelosuppression, it is not typically associated with triggering acute **aplastic crises** due to direct erythroid precursor destruction [3]. - EBV is primarily known for causing **infectious mononucleosis** and is linked to lymphoproliferative disorders [3]. *Hepatitis B Virus (HBV)* - HBV infection primarily affects the **liver** and is not a common cause of acute **aplastic crisis** by directly targeting bone marrow hematopoietic cells. - Chronic HBV infection can rarely be associated with **aplastic anemia**, but not usually with an acute crisis. *Cytomegalovirus (CMV)* - CMV can cause myelosuppression, especially in **immunocompromised individuals**, and may lead to pancytopenia. - However, CMV does not typically induce the sudden and severe **erythroid aplasia** characteristic of an aplastic crisis in hemolytic anemia patients, as seen with Parvovirus B19 [1].
Microbiology
6 questionsA frequent traveler presented with 4 days of continuous fever, abdominal pain, and bradycardia. What is the best diagnostic test to confirm the pathogen?
An adult patient with a military background is admitted with a rash, fever, altered sensorium, and a deficiency of the membrane attack complex. What is the most likely etiological agent?
A patient was admitted with bloody diarrhea after consumption of oysters. The organism exhibits the Kanagawa phenomenon. What is the correct organism?
Desert rheumatism is caused by:
Broad-based budding yeasts are seen in:
A female patient presents with dysuria and frequency. A coagulase-negative, novobiocin-resistant Staphylococcus species (>10^4 CFU/mL) was grown in urine culture. What does this indicate?
NEET-PG 2024 - Microbiology NEET-PG Practice Questions and MCQs
Question 161: A frequent traveler presented with 4 days of continuous fever, abdominal pain, and bradycardia. What is the best diagnostic test to confirm the pathogen?
- A. Widal test
- B. Blood culture (Correct Answer)
- C. Urine culture
- D. Stool culture
Explanation: ***Blood culture*** - **Blood culture** is the most sensitive and specific test for confirming **typhoid fever** in the first week of illness. - The presence of **continuous fever** (step-ladder pattern), **abdominal pain**, and **relative bradycardia** in a traveler strongly suggests typhoid fever caused by *Salmonella Typhi*. *Widal test* - The **Widal test** detects antibodies against *Salmonella Typhi* antigens and is often positive later in the disease course. - It has **limited sensitivity and specificity**, especially in endemic areas or with prior vaccination, leading to false positives and negatives. *Urine culture* - **Urine culture** has a low yield for *Salmonella Typhi*, as bacteria are intermittently shed in urine, usually later in the disease. - It's primarily useful for diagnosing **urinary tract infections** or in chronic carriers of typhoid. *Stool culture* - **Stool culture** yield is higher in the later stages of typhoid fever, as *Salmonella Typhi* is shed in feces. - Its sensitivity is lower than blood culture in the early acute phase when bacteremia is most prominent.
Question 162: An adult patient with a military background is admitted with a rash, fever, altered sensorium, and a deficiency of the membrane attack complex. What is the most likely etiological agent?
- A. Klebsiella pneumoniae
- B. Neisseria meningitidis (Correct Answer)
- C. Haemophilus influenzae
- D. CMV
Explanation: ***Neisseria meningitidis*** - A deficiency in the **membrane attack complex (MAC)**, particularly **C5-C9 components**, predisposes individuals to recurrent infections with encapsulated bacteria, especially *N. meningitidis*. - *N. meningitidis* is a common cause of **meningitis**, presenting with **fever, altered sensorium**, and often a **petechial rash** due to disseminated intravascular coagulation (DIC), which align with the patient's symptoms. *Klebsiella pneumoniae* - While *K. pneumoniae* can cause severe infections, including pneumonia and meningitis, it is not specifically associated with **MAC deficiency**. - Its infections more commonly manifest as **severe pneumonia** or **urinary tract infections** in immunocompromised patients. *Haemophilus influenzae* - *H. influenzae* can cause meningitis and other invasive infections, especially in children, but it is not typically linked to **MAC deficiency**. - The classic presentation involving **rash** and severe systemic symptoms as described is more characteristic of **meningococcal disease**. *CMV* - **Cytomegalovirus (CMV)** is a herpesvirus that causes a wide range of diseases, particularly in immunocompromised individuals. - However, CMV infections are primarily associated with **cellular immunity defects** rather than a deficiency in the **membrane attack complex** of the complement system.
Question 163: A patient was admitted with bloody diarrhea after consumption of oysters. The organism exhibits the Kanagawa phenomenon. What is the correct organism?
- A. Staphylococcus aureus
- B. Vibrio parahaemolyticus (Correct Answer)
- C. Campylobacter jejuni
- D. Salmonella typhi
Explanation: ***Vibrio parahaemolyticus*** - This organism is a common cause of **gastroenteritis** linked to consumption of **raw or undercooked seafood**, especially oysters, and is known for causing **bloody diarrhea**. - The **Kanagawa phenomenon** refers to the production of **thermostable direct hemolysin (TDH)** by *V. parahaemolyticus*, which is a key virulence factor causing hemolysis and is detectable by a specific agar assay. *Staphylococcus aureus* - While *S. aureus* can cause **food poisoning** through its toxins, it typically presents with **nausea, vomiting**, and **abdominal cramps**, not bloody diarrhea. - Food poisoning from *S. aureus* is usually rapid-onset (within hours) and is associated with **improperly handled foods**, particularly those requiring no cooking after preparation (e.g., salads, custards). *Campylobacter jejuni* - This bacterium is a common cause of **bacterial gastroenteritis** and can lead to **bloody diarrhea**, but it's typically acquired from **poultry** or contaminated water, not specifically oysters. - **Guillain-Barré syndrome** is a serious complication that can follow *C. jejuni* infection, which is not characteristic of *Vibrio* infections. *Salmonella typhi* - *Salmonella typhi* causes **typhoid fever**, a systemic illness characterized by **sustained fever, headache, malaise**, and can lead to a "rose spot" rash. - While it can cause gastrointestinal symptoms, **bloody diarrhea is not the predominant symptom**, and raw oyster consumption is not its typical mode of transmission; it's usually spread through contaminated food or water by asymptomatic carriers.
Question 164: Desert rheumatism is caused by:
- A. Paracoccidioides brasiliensis
- B. Candida albicans
- C. Cryptococcus neoformans
- D. Coccidioides immitis (Correct Answer)
Explanation: ***Coccidioides immitis*** - This fungus is the causative agent of **coccidioidomycosis**, also known as **Valley fever** or **desert rheumatism**, due to its prevalence in arid regions. - Infection most commonly occurs through inhalation of **arthroconidia** from disturbed soil in endemic areas. *Paracoccidioides brasiliensis* - This fungus causes **paracoccidioidomycosis** (South American blastomycosis), which is endemic to Latin America. - It typically manifests as chronic granulomatous disease affecting the lungs, skin, mucous membranes, lymph nodes, and internal organs. *Candida albicans* - This is a common opportunistic yeast responsible for various infections, from **superficial mucocutaneous candidiasis** (e.g., thrush, vaginal yeast infections) to severe invasive candidemia. - It is not associated with "desert rheumatism." *Cryptococcus neoformans* - This encapsulated yeast is a major cause of **cryptococcosis**, particularly in immunocompromised individuals. - It commonly causes **meningoencephalitis** and pulmonary disease, and is associated with bird droppings, but not "desert rheumatism."
Question 165: Broad-based budding yeasts are seen in:
- A. Histoplasmosis
- B. Blastomycosis (Correct Answer)
- C. Candidiasis
- D. Coccidioidomycosis
Explanation: ***Blastomycosis*** - This fungal infection is classically characterized by **broad-based budding yeasts** seen on microscopic examination. - The yeast cells are typically large and have a characteristic wide connection between the mother and daughter cells during budding. *Histoplasmosis* - Characterized by **small, intracellular yeasts** often seen within macrophages. - These yeasts do **not exhibit broad-based budding**. *Candidiasis* - Primarily presents as **pseudohyphae** (elongated yeast cells resembling hyphae) and budding yeasts (blastoconidia) with **narrow bases**. - **True hyphae** may also be present depending on the species and growth conditions. *Coccidioidomycosis* - In tissue, it is characterized by **spherules** containing **endospores**, not budding yeasts. - The mycelial form is found in culture or environmental samples.
Question 166: A female patient presents with dysuria and frequency. A coagulase-negative, novobiocin-resistant Staphylococcus species (>10^4 CFU/mL) was grown in urine culture. What does this indicate?
- A. UTI (Correct Answer)
- B. Commensal
- C. Contamination
- D. Repeat culture needed
Explanation: ***UTI*** - The isolation of a **coagulase-negative, novobiocin-resistant Staphylococcus** in a patient with UTI symptoms suggests **_Staphylococcus saprophyticus_**, a common cause of UTIs in young women. - A bacterial count of **>10^4 CFU/mL** is generally considered significant for diagnosing a UTI, indicating active infection rather than contamination. - _S. saprophyticus_ accounts for 10-20% of UTIs in sexually active young women and is the second most common cause after _E. coli_. *Commensal* - While some coagulase-negative staphylococci can be commensals, **_S. saprophyticus_** is an important pathogen, especially in UTIs. - The combination of **novobiocin resistance** and a significant bacterial count in a symptomatic patient strongly points away from a commensal role. *Contamination* - **Contamination** usually involves lower bacterial counts (<10^4 CFU/mL) or the isolation of multiple different organisms. - The presence of **>10^4 CFU/mL** of a pure culture of a known urinary pathogen (_S. saprophyticus_) in a symptomatic patient makes contamination unlikely. *Repeat culture needed* - Repeat cultures are indicated when initial results are equivocal (e.g., low counts, mixed flora, or asymptomatic bacteriuria). - For symptomatic UTI with **>10^4 CFU/mL** of a known pathogen, a single culture is sufficient for diagnosis and treatment initiation. - Multiple consecutive samples are primarily used for diagnosing **bacteremia** or **endocarditis**, not routine UTI.
Pediatrics
1 questionsA child presented with perianal itching. The swab specimen is shown in the image. What is the diagnosis?
NEET-PG 2024 - Pediatrics NEET-PG Practice Questions and MCQs
Question 161: A child presented with perianal itching. The swab specimen is shown in the image. What is the diagnosis?
- A. Enterobius (Correct Answer)
- B. Ascaris
- C. Trichiura
- D. Ancylostoma
Explanation: ***Enterobius*** - The image shows **D-shaped** (plano-convex) and **transparent eggs**, which are characteristic of *Enterobius vermicularis* (**pinworm** or **threadworm**). - **Perianal itching**, especially at night, is the hallmark symptom due to the female worm migrating to the perianal region to lay eggs. *Ascaris* - *Ascaris lumbricoides* eggs are typically **round to oval**, with a thick, mamillated (bumpy) outer shell, or smooth in the case of decorticated eggs, which is different from the eggs pictured. - Infection with *Ascaris* can cause pulmonary symptoms (Loeffler's syndrome) and intestinal obstruction, but not typically perianal itching. *Trichiura* - *Trichuris trichiura* (**whipworm**) eggs are distinctly **barrel-shaped** with prominent **polar plugs** at each end, which is not seen in the image. - Whipworm infection is often associated with bloody diarrhea, rectal prolapse, and growth retardation, not primarily perianal itching. *Ancylostoma* - *Ancylostoma duodenale* and *Necator americanus* (hookworms) eggs are typically **oval** with a **thin shell** and segmented embryo (morula stage) within, which lacks the distinct D-shape and transparency of the pictured eggs. - Hookworm infection primarily causes iron-deficiency anemia and can lead to cutaneous larva migrans, not perianal itching as a primary symptom.