Fever of Unknown Origin — MCQs
A person presents to the hospital with fever and chills. Fever profile is ordered and is found to be negative for malaria and dengue. Rk39 test is found to be positive. What is the treatment of choice?
How many blood samples should be drawn in cases of fever of unknown origin to optimize detection of intermittent bacteremia?
A patient presents with fever and a rim-enhancing lesion with an air-fluid level on brain CT. What is the most likely diagnosis?
Which of the following statements regarding classical Dengue fever is FALSE?
Fever of unknown origin in a farmer who raises goats would most likely be caused by which of the following organisms?
Katayama fever is caused by which of the following?
Major signs for AIDS case definition according to WHO is-
A 25-year-old woman presents with a sudden onset of high fever, chills, and rigors. Blood cultures are pending. What is the next appropriate step in her management?
Giemsa stained smear cannot detect:
A 6-year-old with congenital heart disease presents with fever, new-onset murmur, and petechiae. Blood cultures are pending, but initial Gram stain shows Gram-positive cocci. What is the most appropriate initial intervention?
Fever of Unknown Origin Indian Medical PG Practice Questions and MCQs
Question 1: A person presents to the hospital with fever and chills. Fever profile is ordered and is found to be negative for malaria and dengue. Rk39 test is found to be positive. What is the treatment of choice?
- A. Amphotericin B (Correct Answer)
- B. Dapsone
- C. Hydroxychloroquine
- D. Griseofulvin
Explanation: Amphotericin B - A positive RK39 test suggests visceral leishmaniasis (kala-azar), especially with fever and chills in an endemic area [1]. - Amphotericin B (specifically liposomal Amphotericin B) is a highly effective and often the drug of choice for treating visceral leishmaniasis, particularly in severe cases or regions with antimonial resistance. Dapsone - Dapsone is primarily used in the treatment of leprosy and بعض forms of dermatitis (e.g., dermatitis herpetiformis). - It has no significant role in treating leishmaniasis. Hydroxychloroquine - Hydroxychloroquine is an antimalarial drug also used for certain autoimmune diseases like lupus and rheumatoid arthritis [2]. - It is ineffective against leishmaniasis. Griseofulvin - Griseofulvin is an antifungal medication used to treat dermatophyte infections (e.g., ringworm of the skin, hair, or nails). - It has no activity against Leishmania parasites.
Question 2: How many blood samples should be drawn in cases of fever of unknown origin to optimize detection of intermittent bacteremia?
- A. 2
- B. 3 (Correct Answer)
- C. 1
- D. 4
Explanation: ***3*** - Drawing **three separate blood samples** significantly increases the likelihood of detecting intermittent bacteremia, as bacteria may not always be present in high concentrations in the bloodstream. - This practice maximizes the diagnostic yield while minimizing the risk of false positives from contamination. *1* - A single blood sample has a **low sensitivity** for detecting intermittent bacteremia, as transient presence of bacteria might be missed. - Relying on one sample increases the chance of a **false negative**, delaying appropriate treatment. *2* - While two samples are better than one, they still may not be sufficient to reliably detect **intermittent bacteremia** which can fluctuate. - This quantity might be acceptable for some conditions but is suboptimal for robust exclusion of **bacteremia in FUO** [1]. *4* - While four samples might slightly increase sensitivity over three, the **incremental benefit** in diagnostic yield is often negligible. - This approach adds to the **patient discomfort** and increases resource utilization without substantial additional diagnostic value.
Question 3: A patient presents with fever and a rim-enhancing lesion with an air-fluid level on brain CT. What is the most likely diagnosis?
- A. Glioblastoma
- B. Metastasis
- C. Tuberculoma
- D. Brain abscess (Correct Answer)
Explanation: ***Brain abscess*** - The presence of **fever** points towards an infectious etiology, and a **rim-enhancing lesion with an air-fluid level** on CT is highly characteristic of a brain abscess. The air-fluid level suggests gas-forming organisms or communication with an air-containing structure like a paranasal sinus. - An abscess is a collection of pus, and the "rim-enhancement" indicates the inflammatory capsule surrounding the infection, while the **air-fluid level** is virtually pathognomonic for an abscess containing gas. *Glioblastoma* - While glioblastoma can be a **rim-enhancing lesion**, it is a primary brain tumor and typically does not present with **fever** or an **air-fluid level**. - It often shows **irregular, thick enhancement** and typically causes significant surrounding edema, but the key differentiating factors here are the fever and air-fluid level. *Metastasis* - Brain metastases often present as **multiple, rim-enhancing lesions**, but they are tumors and do not typically cause **fever** (unless very large with extensive necrosis) or exhibit **air-fluid levels**. - The clinical context (e.g., history of cancer) would be important for metastasis, but the **air-fluid level** strongly differentiates this case. *Tuberculoma* - A tuberculoma is a **granulomatous lesion** that can also show **rim enhancement**, especially with central caseous necrosis. However, it typically does not present with an **air-fluid level**. - While fever can be present in tuberculosis, the **air-fluid level** is the most discriminating feature pointing away from tuberculoma and towards an abscess.
Question 4: Which of the following statements regarding classical Dengue fever is FALSE?
- A. Positive tourniquet test (Correct Answer)
- B. Low case fatality rate
- C. Self limiting disease
- D. Transmitted by Aedes aegypti
Explanation: **CRITICAL ISSUE:** This question as currently written is problematic because **all four statements are TRUE** about classical dengue fever, making it impossible to identify a FALSE statement. ***Analysis of Each Statement:*** **Positive tourniquet test** (Currently marked as answer) - This is actually a **TRUE statement** about classical dengue fever - The tourniquet test is **positive in classical dengue fever** and is used as a diagnostic criterion by WHO - A positive tourniquet test indicates capillary fragility and is seen in both classical dengue and DHF - **This should NOT be the answer** to a FALSE question **Low case fatality rate** - TRUE statement: Classical dengue fever has a very low case fatality rate (<1%) with proper supportive care - Mortality is primarily associated with severe dengue/DHF/DSS **Self limiting disease** - TRUE statement: Classical dengue is typically self-limiting, resolving within 7-10 days with symptomatic treatment - Characterized by fever, headache, retro-orbital pain, myalgia, and rash **Transmitted by Aedes aegypti** - TRUE statement: **Aedes aegypti** is the primary vector for dengue transmission - Also transmitted by Aedes albopictus in some regions - Day-biting mosquitoes found in urban/semi-urban areas **RECOMMENDATION:** This question needs revision as it currently has no correct answer. All options are true statements about classical dengue fever.
Question 5: Fever of unknown origin in a farmer who raises goats would most likely be caused by which of the following organisms?
- A. T. pallidum
- B. Histoplasma capsulatum
- C. Clostridium novyi
- D. Brucella melitensis (Correct Answer)
Explanation: ***Brucella melitensis*** - **Brucellosis** is a zoonotic infection commonly acquired through contact with infected animals or consumption of unpasteurized dairy products. - ***Brucella melitensis* is specifically associated with goats and sheep**, making it the most likely organism in this clinical scenario. - It classically presents as **fever of unknown origin (FUO)** due to its varied and non-specific clinical manifestations, including undulating fever, malaise, myalgia, arthralgia, and hepatosplenomegaly. *T. pallidum* - *Treponema pallidum* is the causative agent of **syphilis**, a sexually transmitted infection. - While syphilis can cause fever, its primary modes of transmission (sexual contact, vertical transmission) and clinical manifestations (e.g., chancres, rash, mucous patches) are distinct from the scenario described. - Not associated with occupational goat exposure. *Histoplasma capsulatum* - *Histoplasma capsulatum* causes **histoplasmosis**, a fungal infection associated with exposure to **bird or bat droppings**, particularly in endemic areas (e.g., Ohio and Mississippi River valleys). - Although it can cause disseminated disease and fever, the epidemiological context (exposure to goats, not birds/bats) makes it unlikely in this scenario. *Clostridium novyi* - *Clostridium novyi* is an anaerobic bacterium known to cause **gas gangrene** (clostridial myonecrosis) and occasionally **black disease** in livestock. - It is not typically associated with human fever of unknown origin in the context of occupational animal contact described. - More relevant to wound infections or animal disease rather than systemic FUO in farmers.
Question 6: Katayama fever is caused by which of the following?
- A. F. hepatica
- B. C. sinensis
- C. A. lumbricoides
- D. S. japonicum (Correct Answer)
Explanation: ***Correct: S. japonicum*** - Katayama fever, also known as **acute schistosomiasis**, is a systemic hypersensitivity reaction to the migrating schistosomula and oviposition of eggs that primarily occurs in infections with **_Schistosoma japonicum_** or _S. mansoni_. - It presents with fever, chills, cough, diarrhea, abdominal pain, hepatosplenomegaly, and eosinophilia, typically 2-8 weeks after exposure to contaminated water. - S. japonicum tends to cause the most severe form of Katayama fever. *Incorrect: F. hepatica* - **_Fasciola hepatica_** causes fascioliasis, an infection of the bile ducts and liver, which can present with fever and eosinophilia, but it does not typically cause the acute systemic reaction known as Katayama fever. - The disease is usually acquired by ingesting **metacercariae** on aquatic vegetation or in contaminated water. *Incorrect: C. sinensis* - **_Clonorchis sinensis_** is the Chinese liver fluke, causing clonorchiasis, an infection primarily of the bile ducts. - Symptoms are often mild or asymptomatic but can include abdominal pain, indigestion, diarrhea, and jaundice in heavy infections, without the distinct acute systemic syndrome of Katayama fever. *Incorrect: A. lumbricoides* - **_Ascaris lumbricoides_** is a roundworm that causes ascariasis, primarily affecting the gastrointestinal tract. - While it can cause pulmonary symptoms during larval migration (Löffler's syndrome), it does not cause Katayama fever, which is specific to schistosomiasis.
Question 7: Major signs for AIDS case definition according to WHO is-
- A. Prolonged fever more than 1 month (Correct Answer)
- B. Prolonged cough for > 1 month
- C. Generalized lymphadenopathy
- D. Generalized pruritic dermatitis
Explanation: Prolonged fever more than 1 month - Prolonged unexplained fever (intermittent or constant) lasting for more than 1 month is a major clinical sign for AIDS case definition according to the WHO clinical staging system for adults and adolescents. - This symptom reflects the chronic systemic inflammation and immune dysregulation characteristic of advanced HIV infection [1]. Prolonged cough for > 1 month - While chronic cough can be a minor sign or an indicator of opportunistic infections like tuberculosis or Pneumocystis pneumonia in HIV-positive individuals, it is not listed as a major sign for the WHO AIDS case definition [1], [2]. - Major signs are those considered to be strong indicators of severe immunodeficiency. Generalized lymphadenopathy - Persistent generalized lymphadenopathy (PGL) is a common finding in early and mid-stage HIV infection, often indicating viral replication but not necessarily advanced immunodeficiency [1]. - It is classified as an HIV clinical stage 1 condition by the WHO, meaning it’s not a major sign for AIDS [1]. Generalized pruritic dermatitis - Generalized pruritic papular eruptions or severe pruritic dermatitis are considered clinical conditions defining WHO clinical stage 2 or stage 3 HIV disease, respectively [1]. - While these can be prominent symptoms, they are not categorized as the primary "major signs" used for the fundamental AIDS case definition as fever or severe weight loss.
Question 8: A 25-year-old woman presents with a sudden onset of high fever, chills, and rigors. Blood cultures are pending. What is the next appropriate step in her management?
- A. Administer broad-spectrum antibiotics (Correct Answer)
- B. Wait for blood culture results
- C. Start antipyretic therapy only
- D. Order a CT scan
Explanation: ***Administer broad-spectrum antibiotics*** - The patient presents with classic signs of **sepsis** (high fever, chills, rigors), which is a medical emergency requiring prompt intervention [2]. - **Early administration of broad-spectrum antibiotics** is crucial to improve outcomes and reduce mortality in suspected sepsis, even before culture results are available [1]. *Wait for blood culture results* - Delaying antibiotic treatment in a patient with suspected sepsis can lead to rapid clinical deterioration and increased mortality [1]. - While blood cultures are essential to guide definitive therapy, initial empiric broad-spectrum antibiotics should not be withheld [3]. *Start antipyretic therapy only* - Antipyretics only address the symptom of fever and do not treat the underlying infection causing the fever and chills. - This approach would leave the potentially life-threatening infection untreated, leading to worsening patient condition. *Order a CT scan* - A CT scan is not the immediate priority in a patient presenting with acute signs of systemic infection and suspected sepsis. - While it may be useful later to identify a source of infection, controlling the infection with antibiotics is the most urgent step.
Question 9: Giemsa stained smear cannot detect:
- A. Coxiella burnetii (Correct Answer)
- B. Bartonella
- C. E. chaffeensis
- D. Toxoplasmosis
Explanation: ***Coxiella burnetii*** - **Coxiella burnetii** is an **obligate intracellular bacterium** that **does not stain well with Giemsa stain**. - It is typically detected using specific immunofluorescence assays or molecular methods like PCR. *Bartonella* - **Bartonella species** are **Gram-negative bacteria** that can be visualized using Giemsa stain, especially in tissue sections or smears from infected patients. - They are known to cause diseases like **cat scratch disease** and **bacillary angiomatosis**. *E. chaffeensis* - **Ehlichia chaffeensis** is an **obligate intracellular bacterium** that infects monocytes and can form characteristic intracellular inclusions called **morulae**, which are visible with Giemsa stain. - This bacterium causes **human monocytic ehrlichiosis**. *Toxoplasmosis* - **Toxoplasma gondii** is an **obligate intracellular protozoan parasite** whose **tachyzoites** and **cyst forms** can be identified in tissue and fluid smears stained with Giemsa stain. - Detection with Giemsa staining is a common method for diagnosing **toxoplasmosis**.
Question 10: A 6-year-old with congenital heart disease presents with fever, new-onset murmur, and petechiae. Blood cultures are pending, but initial Gram stain shows Gram-positive cocci. What is the most appropriate initial intervention?
- A. Schedule for urgent valve replacement
- B. Administer high-dose steroids
- C. Start broad-spectrum antibiotics (Correct Answer)
- D. Wait for susceptibility testing
Explanation: ***Start broad-spectrum antibiotics*** - The presentation of **fever**, **new-onset murmur**, **petechiae**, and **Gram-positive cocci** in a patient with **congenital heart disease** is highly suggestive of **infective endocarditis**. - Prompt initiation of **broad-spectrum antibiotics** is crucial to prevent further damage to the heart valves and systemic complications while awaiting definitive culture results. *Schedule for urgent valve replacement* - **Valve replacement** is a definitive treatment for severe valvular damage but is typically considered after initial medical management has failed or in cases of severe complications like heart failure or recurrent emboli. - It is not the initial intervention for suspected infective endocarditis. *Administer high-dose steroids* - **Steroids** are anti-inflammatory but are not indicated in the treatment of active bacterial infections like endocarditis. - Administering steroids could potentially worsen the infection by suppressing the immune response. *Wait for susceptibility testing* - **Waiting for susceptibility testing** to initiate treatment would delay critical care, allowing the infection to progress and increasing morbidity and mortality. - Initial treatment should be empiric, and antibiotics can be narrowed once susceptibility results are available.
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