Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 951: Raspberry tongue is a feature of

A. Yellow fever
B. Mamba's disease
C. Katayama fever
D. Scarlet fever (Correct Answer)

Explanation: ***Scarlet fever*** - **Raspberry (or strawberry) tongue** is a classic sign of **scarlet fever**, characterized by an initial white coating that peels, revealing red, swollen papillae [1]. - This symptom is caused by the **erythrogenic toxins** produced by Group A Streptococcus bacteria, which are responsible for scarlet fever [1]. *Yellow fever* - Yellow fever is a **viral hemorrhagic disease** transmitted by mosquitoes, typically presenting with fever, muscle aches, and **jaundice**. - It does not present with characteristic tongue changes like a **raspberry tongue**. *Mamba's disease* - **Mamba's disease** is not a recognized medical condition; it does not exist in standard medical literature. - This option is a distractor, as such it is not associated with any specific clinical features, including tongue changes. *Katayama fever* - Katayama fever is an **acute manifestation of schistosomiasis** (snail fever) occurring shortly after exposure to contaminated water. - Symptoms usually include high fever, cough, hepatosplenomegaly, and eosinophilia, but **not a raspberry tongue**.

Question 952: All of the following are strongly associated with AIDS except:

A. Candidiasis
B. Kaposi sarcoma
C. Oral hairy leukoplakia
D. ANUG (Correct Answer)

Explanation: ***ANUG*** - **Acute necrotizing ulcerative gingivitis (ANUG)**, also known as Vincent stomatitis or "trench mouth," is a severe form of gingivitis caused by a bacterial infection. While it can occur in immunocompromised individuals, it is not considered an AIDS-defining illness [1]. - ANUG is characterized by painful, bleeding gums, foul breath, and ulceration of the interdental papillae, but its mere presence does not automatically indicate an AIDS diagnosis [1]. *Candidiasis* - **Candidiasis**, particularly **esophageal candidiasis**, is an **AIDS-defining illness** and strongly associated with advanced HIV infection [1]. - Oral candidiasis (thrush) is also very common in HIV-positive individuals and often progresses to esophageal involvement as the immune system weakens [1]. *Kaposi sarcoma* - **Kaposi sarcoma** is an **AIDS-defining cancer** caused by **human herpesvirus 8 (HHV-8)**, and its presence strongly indicates advanced HIV disease [1]. - It manifests as vascular lesions on the skin, mucous membranes, and internal organs, and its incidence has decreased with effective antiretroviral therapy [1]. *Oral hairy leukoplakia* - **Oral hairy leukoplakia (OHL)** is a benign lesion caused by the **Epstein-Barr virus (EBV)**, commonly seen in HIV-positive individuals, signaling significant immunosuppression [1]. - While not an AIDS-defining condition itself, OHL is a strong indicator of **HIV disease progression** and impaired immune function [1].

Question 953: What is the most common extra-intestinal complication of Shigellosis?

A. Pneumonia
B. Meningitis
C. HUS
D. Reactive arthritis (Correct Answer)

Explanation: ***Reactive arthritis*** - **Reactive arthritis** is triggered by a prior infection, such as *Shigellosis*, and is the most common extra-intestinal complication, especially in HLA-B27 positive individuals [1]. - It typically presents with a triad of **arthritis**, **urethritis**, and **conjunctivitis**, though not all symptoms may be present [1]. *Pneumonia* - While pneumonia can occur in severely ill patients, it is not a common nor specific extra-intestinal complication directly linked to the pathogenesis of *Shigellosis*. - Respiratory complications are rare in uncomplicated cases of shigellosis. *Meningitis* - **Meningitis** is a rare and severe complication, primarily seen in young children or immunocompromised individuals, and is not the most common extra-intestinal manifestataion. - It suggests systemic spread of the bacteria beyond the gastrointestinal tract, which is uncommon. *HUS* - **Hemolytic Uremic Syndrome (HUS)** is a well-known complication of *E. coli* O157:H7 (Shiga toxin-producing E. coli, STEC), rather than *Shigella* species. - While some *Shigella* strains produce Shiga toxin, HUS is far less common in *Shigellosis* compared to STEC infections.

Question 954: A lady presented with fever and rashes. She returned from the USA and gives a history of exposure to ticks. Most probable diagnosis is

A. Oraya fever
B. Rocky mountain fever (Correct Answer)
C. Scrub typhus
D. Epidemic typhus

Explanation: ***Rocky mountain fever*** - **Rocky Mountain spotted fever (RMSF)** is a **tick-borne disease** caused by the bacterium *Rickettsia rickettsii*, characterized by **fever and rash**. - The patient's history of returning from the **USA** and **tick exposure** in the context of fever and rash makes RMSF the most probable diagnosis, as it is endemic to many regions of the Americas. *Oraya fever* - **Oraya fever** is caused by **Bartonella bacilliformis** and is characterized by acute hemolytic anemia and fever, with a rash appearing later in some cases. - It is geographically restricted to **Andean regions of Peru, Ecuador, and Colombia**, making it unlikely for a patient returning from the USA. *Scrub typhus* - **Scrub typhus** is a **mite-borne disease** caused by *Orientia tsutsugamushi*, presenting with fever, rash, and often an **eschar** [1]. - It is endemic to **Asia, Australia, and the Pacific Islands**, not typically associated with exposure in the USA [1]. *Epidemic typhus* - **Epidemic typhus** is caused by **Rickettsia prowazekii** and is typically transmitted by the **human body louse**, occurring in crowded, unsanitary conditions. - While it presents with fever and rash, the mode of transmission and typical epidemiological context (lice, crowded living) do not fit the presented case of tick exposure in the USA.

Question 955: Most common single cause of pyrexia of unknown origin

A. Salmonella paratyphi
B. Brucella
C. Mycobacterium tuberculosis (Correct Answer)
D. Salmonella typhi

Explanation: ***Mycobacterium tuberculosis*** - **Tuberculosis** (TB) is a common cause of **Pyrexia of Unknown Origin (PUO)** [2], especially in endemic areas, often presenting with fever, weight loss, and night sweats [3], [4]. - The fever in TB can be **intermittent** and **debilitating**, making diagnosis challenging without specific investigations like cultures or biopsies [1]. *Salmonella paratyphi* - This bacterium causes **paratyphoid fever**, which can present with prolonged fever similar to typhoid, but it is less common globally as a single cause of PUO compared to TB. - While it can manifest as a persistent fever, other characteristic symptoms like rash or gastrointestinal issues might be present, making it less "unknown" in some contexts. *Brucella* - **Brucellosis** (Malta fever) is characterized by **undulating fever**, arthralgia, and fatigue, but infections are often linked to exposure to infected animals or unpasteurized dairy products, limiting its prevalence as the *most common single* PUO cause. - Diagnosis requires specific serological tests or cultures, but its geographical distribution and transmission routes make it less globally pervasive than TB. *Salmonella typhi* - **Typhoid fever**, caused by *Salmonella typhi*, is a significant cause of prolonged fever, but its typical presentation often includes specific symptoms like **relative bradycardia**, **rose spots**, and gastrointestinal symptoms, which might lead to an earlier diagnosis than a true PUO. - While it can cause prolonged, high fever, global incidence and the often-distinctive clinical picture prevent it from typically being labeled as the *most common single* cause of PUO.

Question 956: Young female with 3 days fever presents with headache, BP 90/60 mmHg, Heart rate of 114/min, and pin point spots developed distal to BP cuff. Most likely organism is:

A. Brucella suis
B. N. meningitidis (Correct Answer)
C. Staphylococcus aureus
D. Brucella abortus

Explanation: ***N. meningitidis*** - The presentation of **fever**, **headache** [1], signs of **shock** (hypotension, tachycardia), and **petechiae/purpura** (pinpoint spots distal to BP cuff, indicating a bleeding disorder such as thrombocytopenia or DIC often associated with meningococcemia) is classic for **meningococcal sepsis**. - *Neisseria meningitidis* is well-known for causing **rapidly progressive sepsis with disseminated intravascular coagulation (DIC)** and a characteristic **petechial or purpuric rash**. *Brucella suis* - *Brucella suis* causes **brucellosis**, which typically presents with **undulating fever**, **arthralgia**, fatigue, and hepatosplenomegaly. - While it can cause systemic illness, it does not typically manifest with the acute, severe presentation of **sepsis** and **hemorrhagic rash** seen in this patient. *Staphylococcus aureus* - *Staphylococcus aureus* can cause widespread infections, including sepsis characterized by **fever**, **hypotension**, and **tachycardia**, often leading to **toxic shock syndrome**. [2] - However, while *S. aureus* can cause skin manifestations like cellulitis or abscesses, it is less commonly associated with the specific **petechial rash** in the context of acute sepsis, unless it's an endocarditis with septic emboli, which would have a different clinical scenario. [2] *Brucella abortus* - Similar to *Brucella suis*, *Brucella abortus* causes **brucellosis**, a chronic zoonotic infection. - The clinical picture of **acute fulminant sepsis with hemorrhagic skin lesions** is not characteristic of *Brucella abortus* infection.

Question 957: Early sign of tetanus is locked jaw due to early involvement of:

A. Temporalis
B. Medial pterygoid
C. Lateral pterygoid
D. Masseter (Correct Answer)

Explanation: ***Masseter*** - **Trismus**, or **locked jaw**, is one of the earliest and most characteristic signs of tetanus [1]. - It results from powerful and sustained **spasms** of the **masseter muscles**, which are the primary muscles responsible for closing the jaw. *Temporalis* - The **temporalis muscle** is also involved in jaw closure, but the **masseter** is often the first and most prominently affected in early tetanus, leading to the characteristic "locked jaw." - It is a fan-shaped muscle on the side of the skull, contributing to chewing. *Medial pterygoid* - The **medial pterygoid muscle** aids in jaw closure, protrusion, and side-to-side movements but is not typically the very first muscle to manifest severe spasms in tetanus. - Spasms in this muscle would contribute to trismus but usually follow the more direct impact on the masseters. *Lateral pterygoid* - The **lateral pterygoid muscle** is primarily responsible for opening the jaw and moving it side-to-side, rather than closing it. - Spasm of this muscle would cause the jaw to involuntarily open or deviate, which is contrary to the "locked jaw" symptom of tetanus.

Question 958: Early treatment failure in malaria is indicated by all, EXCEPT:

A. Parasitemia on day 3 >50% of day 1 count
B. Parasitemia on day 3 with temperature >37.5°C
C. Development of danger signs or severe malaria on days 1, 2, 3 in presence of parasitemia
D. None of the options (Correct Answer)

Explanation: Early treatment failure suggests the antimalarial regimen is ineffective and requires a change in therapy or further investigation into drug resistance, which has historically affected drugs like chloroquine and sulfadoxine-pyrimethamine [1]. *Parasitemia on day 3 >50% of day 1 count* - This criterion indicates inadequate clearance of parasites by the third day of treatment. - A significant reduction in parasite count is expected by day 3; if the count remains high (over 50% of the initial count), it suggests treatment failure. *Parasitemia on day 3 with temperature >37.5°C* - The persistence of fever along with parasitemia on day 3 signifies ongoing infection and a poor clinical response to treatment. - Effective antimalarial therapy should lead to a resolution of fever and a substantial decrease in parasite load by this time. *Development of danger signs or severe malaria on days 1, 2, 3 in presence of parasitemia* - The worsening of clinical condition to include danger signs or criteria for severe malaria within the first three days of treatment, in the presence of parasites, is a clear sign of treatment failure. - This indicates that the chosen therapy is not preventing disease progression and severe complications.

Question 959: Most common extra pulmonary involvement of TB ?

A. Bone
B. Ileocecal
C. Lymph nodes (Correct Answer)
D. Pleura

Explanation: ***Bone*** - While **skeletal tuberculosis** can occur, particularly in the spine (**Pott's disease**), it is not the most common extrapulmonary manifestation [2]. - Bone involvement typically presents with localized pain, swelling, and sometimes neurological deficits [2]. *Ileocecal* - **Gastrointestinal TB**, especially involving the **ileocecal region**, is a significant form of extrapulmonary TB. - It often leads to abdominal pain, weight loss, and malabsorption, but it is less common than lymph node involvement. *Lymph nodes* - **Tuberculous lymphadenitis** (scrofula) is the **most common extrapulmonary manifestation of TB**, especially in immunocompetent individuals and children [1]. - Typically presents as painless, slowly enlarging lymph nodes, most often in the cervical region [1]. *Pleura* - **Pleural effusion** (tuberculous pleurisy) is a common manifestation of TB and involves the lining of the lungs. - Although frequent, it is generally considered a **pulmonary complication** or a contiguous spread from the lung rather than a distinctly extrapulmonary site like the lymph nodes.

Question 960: The classic opportunistic infection in acquired immune deficiency syndrome is:

A. Aphthous stomatitis
B. Tuberculosis
C. Pneumocystis jirovecii pneumonia (Correct Answer)
D. Herpetic gingivostomatitis

Explanation: ***Pneumocystis jirovecii pneumonia*** - **Pneumocystis jirovecii pneumonia (PJP)** is a classic and common opportunistic infection in individuals with **AIDS**, especially when the **CD4 count drops below 200 cells/mm³** [1]. - It presents with fever, dyspnea, non-productive cough, and hypoxia, and is a major cause of morbidity and mortality in untreated HIV. *Aphthous stomatitis* - While common in HIV-positive individuals, **aphthous stomatitis** is not typically considered an **opportunistic infection** or an **AIDS-defining illness** [2]. - It represents a painful inflammation of the oral mucosa, often recurring due to local irritants or systemic factors, rather than a pathogen exploiting immunodeficiency. *Tuberculosis* - **Tuberculosis (TB)** is an opportunistic infection and a serious concern in HIV-infected individuals, but the question asks for the **classic** opportunistic infection in AIDS [1]. - While TB incidence is significantly higher in HIV-positive patients, **Pneumocystis jirovecii pneumonia** is historically and clinically more often cited as the classic infection associated with the initial presentation or diagnosis of AIDS. *Herpetic gingivostomatitis* - **Herpes simplex virus (HSV)** infections, including gingivostomatitis, are more frequent and severe in immunocompromised individuals. - However, **herpetic gingivostomatitis** is a specific manifestation that doesn't usually define AIDS as readily as **Pneumocystis jirovecii pneumonia**.

Practice by Chapter

Principles of Antimicrobial Therapy

Practice Questions

Fever of Unknown Origin

Practice Questions

HIV/AIDS and Related Infections

Practice Questions

Tuberculosis and Mycobacterial Diseases

Practice Questions

Tropical and Parasitic Infections

Practice Questions

Viral Infections (Hepatitis, Herpes, etc.)

Practice Questions

Healthcare-Associated Infections

Practice Questions

Fungal Infections

Practice Questions

Sepsis and Septic Shock

Practice Questions

Infection in Immunocompromised Hosts

Practice Questions

Emerging and Re-emerging Infections

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Antimicrobial Resistance

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Vaccination Principles

Practice Questions

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