Infectious Diseases Practice Questions

Q: A farmer presents with severe leg pain, fever, chills, retro-orbital pain, and bilateral conjunctival suffusion. What is the most likely diagnosis?

Leptospirosis. **Leptospirosis** - The combination of **leg pain**, **fever**, chills, **retro-orbital pain**, and **bilateral conjunctival suffusion** (red eyes without frank pus) in a farmer (occupational exposure to contaminated water/soil) is highly suggestive of **leptospirosis** [1]. - **Conjunctival suffusion** is a classic and distinctive sign of leptospirosis, differentiating it from many other febrile illnesses [1]. *Dengue fever* - While dengue fever can present with **fever**, **retro-orbital pain**, and **myalgia**, **conjunctival suffusion** is not a typical feature, and severe leg pain is less emphasized compared to leptospirosis [2]. - Dengue is also common in tropical/subtropical regions but the specific constellation of symptoms points away from it [2]. *Malaria* - Malaria presents with classic **cyclic fevers**, **chills**, and **sweats**, often accompanied by headache and muscle aches, and sometimes hepatosplenomegaly. - **Conjunctival suffusion** and severe leg pain are not characteristic features of uncomplicated malaria [2]. *Rickettsia infection* - Rickettsial infections (e.g., Rocky Mountain spotted fever, scrub typhus) often present with **fever**, **headache**, and a **rash**, which can be maculopapular or petechial [3]. - **Retro-orbital pain** and **conjunctival suffusion** are not typical symptoms, and a distinctive rash is generally a key diagnostic clue for rickettsial diseases [3].

Q: Abdominal TB can occur through all of the following EXCEPT

Direct contact with infected animal. ***Direct contact with infected animal*** - While animal products like **unpasteurized milk** can transmit *Mycobacterium bovis* to humans, direct contact with an infected animal is not a primary mode of transmission for **abdominal TB**. - **Abdominal TB** is usually caused by *Mycobacterium tuberculosis* which is primarily a human pathogen, not typically transmitted through direct contact with animals. *Direct spread from mesenteric lymph nodes* - **Mesenteric lymph nodes** are often involved in abdominal TB, and the infection can directly spread from these nodes to adjacent abdominal organs. - This is a common mechanism for localized propagation within the abdominal cavity. *Feco - oral route* - The **ingestion of contaminated food or milk** (from infected cattle) containing *Mycobacterium bovis* or swallowing of **infected sputum** (from pulmonary TB) containing *Mycobacterium tuberculosis* are common ways the bacteria can reach the gastrointestinal tract. - This leads to primary intestinal infection or reactivation of previously ingested bacteria. *Hematogenous spread* - **Hematogenous dissemination** from a primary pulmonary or other mycobacterial focus is a significant mode of transmission for abdominal TB. - Bacteria can travel through the bloodstream and seed distant abdominal organs, including the **peritoneum**, **intestines**, or **mesenteric lymph nodes**.

Q: What is the most common site of abdominal tuberculosis?

Ileocecal junction. ***Ileocecal junction*** - The **ileocecal junction** is the most common site for abdominal tuberculosis due to its rich lymphoid tissue (Peyer's patches) and physiological stasis. - Tuberculous infection at this site can lead to **mucosal ulceration**, stricture formation, and mass lesions. *Colon* - While the colon can be affected by abdominal tuberculosis, it is **less common** than the ileocecal region. - Colonic involvement often presents with symptoms such as abdominal pain, diarrhea, and weight loss. *Small intestine* - Though other parts of the small intestine can be involved, the **distal ileum** and its junction with the cecum are disproportionately affected. - Involvement of the jejunum and duodenum is less frequent. *Rectum* - **Rectal involvement** in abdominal tuberculosis is rare and typically occurs in conjunction with more extensive colonic or disseminated disease. - Symptoms may include tenesmus, rectal bleeding, or fistula formation.

Q: A patient, who is a known case of HIV with a CD4 count of 200 cells/cu.mm, presents with 5 days of cough and high-grade fever without chills and rigors. There is no history of diarrhoea, vomiting, or nuchal rigidity. Chest x-ray is normal. What treatment will you give?

Co-trimoxazole only. ***Co-trimoxazole only*** - The patient has a CD4 count of 200 cells/cu.mm with cough and fever and a normal chest X-ray, all of which are highly suggestive of **Pneumocystis jirovecii pneumonia (PJP)**, even without classic infiltrates. Therefore, **co-trimoxazole** (trimethoprim-sulfamethoxazole) is the first-line treatment [1]. - In a patient with HIV and a CD4 count below 200, **PJP prophylaxis** with co-trimoxazole should also be considered [2], and its empirical treatment is indicated in this scenario. *Co-trimoxazole + steroids* - While co-trimoxazole is the correct treatment for PJP, **steroids** are typically reserved for patients with more severe disease, indicated by **hypoxia** (PaO2 35 mmHg) or diffuse interstitial infiltrates on chest imaging, neither of which are described here [1]. - Adding steroids without clear indications could increase the risk of side effects in an immunocompromised patient. *Amoxicillin-clavulanic acid + Azithromycin* - This combination targets typical **bacterial community-acquired pneumonia**, which is less likely given the patient's HIV status, low CD4 count, and normal chest X-ray. - This regimen would not effectively treat **PJP**, which is the most probable diagnosis in this immunocompromised setting. *Antitubercular treatment* - While tuberculosis is common in HIV patients, the normal chest X-ray makes pulmonary tuberculosis less likely, especially without other classic symptoms like night sweats, weight loss, or hemoptysis. In patients with CD4 counts below 200, the clinical presentation of TB differences substantially from those without HIV [1]. - **Antitubercular treatment** would not address the immediate concern of possible PJP, which can rapidly progress if untreated.

Q: 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?

Amphotericin B. 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.

Q: A 35-year-old patient with a history of dysentery for 6 weeks complains of pain in the right upper abdomen. Entamoeba histolytica serology is positive. On ultrasound, a hypoechoic lesion with internal echoes is seen in the liver. Identify the condition based on the given image?

Amoebic liver abscess. ***Amoebic liver abscess*** - The history of **dysentery** (often caused by *Entamoeba histolytica*) 6 weeks prior strongly points to an amoebic infection. - The presence of a **hypoechoic lesion with internal echoes** in the liver on ultrasound is characteristic of an amoebic liver abscess, which is a common extraintestinal manifestation of amoebiasis. *Hemangioma* - A hemangioma is a **benign vascular tumor** of the liver, typically asymptomatic and discovered incidentally. - It would not be causally linked to a recent history of dysentery. *Pyogenic liver abscess* - While a pyogenic (bacterial) liver abscess can also present as an abscess on imaging, a **clear history of dysentery** strongly favors an amoebic cause. - Pyogenic abscesses are often associated with other sources of infection like biliary obstruction or diverticulitis. *Hydatid cyst* - A hydatid cyst is caused by the parasite **_Echinococcus granulosus_** and is more common in endemic regions. - Although it appears as a cystic lesion, it is not directly linked to a history of dysentery as its mode of transmission differs.

Q: A 35-year-old patient with a history of dysentery for 6 weeks complains of pain in the right upper abdomen. Entamoeba histolytica serology is positive. On ultrasound, a hypoechoic lesion is seen in the liver. Identify the condition based on the given image?

Amoebic liver abscess. ***Amoebic liver abscess*** - The patient's history of **dysentery** 6 weeks prior, combined with **positive *Entamoeba histolytica* serology**, strongly points to an amoebic infection, as *Entamoeba histolytica* can spread from the colon to the liver via the portal vein. - The ultrasound finding of a **hypoechoic lesion** in the liver is characteristic of an abscess, and in the context of confirmed *Entamoeba histolytica* infection, it is highly suggestive of an amoebic liver abscess. *Hydatid cyst* - Hydatid cysts are caused by *Echinococcus granulosus* and are typically seen in patients with a history of **sheep herding** or exposure to dogs. - Ultrasound findings often show **daughter cysts** or a "water lily" sign, which are not described here or evident in the image. *Hemangioma* - Hemangiomas are the **most common benign liver tumors** and are typically **hyperechoic** on ultrasound, unlike the hypoechoic lesion described. - They are usually **asymptomatic** and not associated with a history of dysentery or acute pain. *Pyogenic liver abscess* - While a pyogenic liver abscess can present as a hypoechoic lesion on ultrasound and cause pain, it is typically associated with **biliary tract infection**, diverticulitis, or other sources of bacterial infection, not usually dysentery alone. - Pyogenic abscesses are often **multiple** and frequently occur in the setting of conditions like cholangitis or appendicitis.

Q: An ICU patient is suffering from Rhinovirus infection. How do we treat the patient?

Supportive care only. ***Supportive care only*** - **Rhinovirus** is a common cause of the **common cold**, and there is no specific antiviral treatment available for it. [1] - Management focuses on alleviating symptoms such as fever, congestion, and cough to ensure patient comfort and prevent secondary complications, especially in an ICU setting. *Piperacillin + Tazobactam + Azithromycin* - This combination is a broad-spectrum antibiotic regimen (piperacillin/tazobactam is an extended-spectrum penicillin, and azithromycin is a macrolide) targeting bacterial infections. [2] - **Rhinovirus is a virus**, and antibiotics are ineffective against viral infections, making this an inappropriate treatment. *Clarithromycin* - **Clarithromycin** is a macrolide antibiotic primarily used to treat bacterial infections, such as respiratory tract infections caused by **atypical bacteria** or community-acquired pneumonia. [2] - It has no activity against **Rhinovirus**, a common cold virus. *Cephalosporin + Ganciclovir* - **Cephalosporins** are a class of beta-lactam antibiotics used for various bacterial infections. [2] - **Ganciclovir** is an antiviral agent specifically used to treat **cytomegalovirus (CMV)** infections, not Rhinovirus.

Q: During the discharge of a COVID patient treated with steroids and remdesivir, which of the following will you inform him about? 1. Repeat RT-PCR after 7 days of discharge 2. Watch for the persistence of Anosmia 3. Watch for headache and nasal discharge 4. Monitor glucose levels 5. Watch for Sinusitis symptoms

3,4 and 5. **3, 4, and 5** - For patients treated with **steroids**, it is crucial to monitor **glucose levels** due to the potential for steroid-induced hyperglycemia [1]. - Symptoms like **headache** and **nasal discharge** (and by extension **sinusitis symptoms**) could indicate conditions like **mucormycosis**, a serious fungal infection seen in immunocompromised COVID-19 patients, especially those having received steroids. *1, 3, and 4* - A **repeat RT-PCR after 7 days** of discharge is generally not recommended as per current guidelines, as viral shedding can persist without infectivity. - While monitoring for headache, nasal discharge, and glucose levels is appropriate, omitting the direct vigilance for **sinusitis symptoms** is less comprehensive. *2, 3, and 4* - While **anosmia** (loss of smell) can persist post-COVID, it is primarily a lingering symptom of the infection itself and typically resolves spontaneously, not usually requiring specific discharge instructions for monitoring its persistence to prevent complications. - The focus should be on new or worsening symptoms that might indicate post-COVID complications or secondary infections. *1, 2, 3, 4, and 5* - Including **repeat RT-PCR** and solely "watch for the persistence of Anosmia" without emphasizing resolution or specific actions makes this option less pertinent for discharge advice. - The priority for discharge instructions should be preventable complications and warning signs of serious conditions.

Q: A forest officer from a scrub-vegetation region of South/Southeast Asia develops the lesion as shown in the image. Which of the following is not a differential to consider?

KFD. **KFD** - **Kyasanur Forest disease (KFD)** is a tick-borne viral hemorrhagic fever characterized by acute fever, headache, myalgia, gastrointestinal symptoms, and, in severe cases, hemorrhagic manifestations. - It does not characteristically produce a primary necrotic skin lesion or inoculation eschar like the one shown. Therefore, it is not an appropriate differential diagnosis for this lesion. **Cutaneous anthrax** - Cutaneous anthrax typically progresses from a painless papule to vesiculation and then a black eschar, often with prominent surrounding edema. - Exposure to infected animals, contaminated animal products, or contaminated soil can occur in people working outdoors, so it is a plausible differential. **Scrub typhus** - Scrub typhus is an infection caused by *Orientia tsutsugamushi* and transmitted by trombiculid mite larvae (chiggers), particularly in scrub-vegetation regions of South and Southeast Asia. - It commonly produces an inoculation eschar at the bite site, making it a leading differential in this geographic and occupational setting. **Healing necrotic arthropod bite** - Some arthropod bites can produce localized tissue necrosis and a central dark crust or eschar during healing. - A healing necrotic arthropod bite is therefore a reasonable clinical differential for the pictured lesion.

Question 1

A farmer presents with severe leg pain, fever, chills, retro-orbital pain, and bilateral conjunctival suffusion. What is the most likely diagnosis?

Accepted Answer

Leptospirosis

Answer

Dengue fever

Answer

Malaria

Answer

Rickettsia infection

Question 2

Abdominal TB can occur through all of the following EXCEPT

Accepted Answer

Direct contact with infected animal

Answer

Direct spread from mesenteric lymph nodes

Answer

Feco - oral route

Answer

Hematogenous spread

Question 3

What is the most common site of abdominal tuberculosis?

Accepted Answer

Ileocecal junction

Answer

Colon

Answer

Small intestine

Answer

Rectum

Question 4

A patient, who is a known case of HIV with a CD4 count of 200 cells/cu.mm, presents with 5 days of cough and high-grade fever without chills and rigors. There is no history of diarrhoea, vomiting, or nuchal rigidity. Chest x-ray is normal. What treatment will you give?

Accepted Answer

Co-trimoxazole only

Answer

Co-trimoxazole + steroids

Answer

Amoxicillin-clavulanic acid + Azithromycin

Answer

Antitubercular treatment

Question 5

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?

Accepted Answer

Amphotericin B

Answer

Dapsone

Answer

Hydroxychloroquine

Answer

Griseofulvin

Question 6

A 35-year-old patient with a history of dysentery for 6 weeks complains of pain in the right upper abdomen. Entamoeba histolytica serology is positive. On ultrasound, a hypoechoic lesion with internal echoes is seen in the liver. Identify the condition based on the given image?

Accepted Answer

Amoebic liver abscess

Answer

Hemangioma

Answer

Pyogenic liver abscess

Answer

Hydatid cyst

Question 7

A 35-year-old patient with a history of dysentery for 6 weeks complains of pain in the right upper abdomen. Entamoeba histolytica serology is positive. On ultrasound, a hypoechoic lesion is seen in the liver. Identify the condition based on the given image?

Accepted Answer

Amoebic liver abscess

Answer

Pyogenic liver abscess

Answer

Hydatid cyst

Answer

Hemangioma

Question 8

An ICU patient is suffering from Rhinovirus infection. How do we treat the patient?

Accepted Answer

Supportive care only

Answer

Piperacillin + Tazobactam + Azithromycin

Answer

Clarithromycin

Answer

Cephalosporin + Ganciclovir

Question 9

During the discharge of a COVID patient treated with steroids and remdesivir, which of the following will you inform him about?

1. Repeat RT-PCR after 7 days of discharge
2. Watch for the persistence of Anosmia
3. Watch for headache and nasal discharge
4. Monitor glucose levels
5. Watch for Sinusitis symptoms

Accepted Answer

3,4 and 5

Answer

1,3 and 4

Answer

2,3 and 4

Answer

1,2,3,4 and 5

Question 10

A forest officer from a scrub-vegetation region of South/Southeast Asia develops the lesion as shown in the image. Which of the following is not a differential to consider?

Accepted Answer

KFD

Answer

Cutaneous anthrax

Answer

Scrub typhus

Answer

Healing necrotic arthropod bite

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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