Infectious Diseases Practice Questions

Q: A sewerage worker presents to OPD with acute febrile illness alongwith jaundice and conjunctivitis. His blood sample was taken and sent to lab . Lab findings are suggestive of kidney failure and elevated hepatic enzymes. Which of following is likely diagnosis ?

Leptospirosis. ***Leptospirosis*** - The patient's occupation as a **sewerage worker** points to potential exposure to contaminated water, a known risk factor for leptospirosis [1]. - The classic triad of **febrile illness**, **jaundice**, and **conjunctivitis**, combined with **kidney failure** and **elevated hepatic enzymes**, is highly characteristic of severe leptospirosis (Weil's disease) [1], [2]. *Typhoid* - While typhoid can cause fever and, in severe cases, liver dysfunction, it is typically associated with **gastrointestinal symptoms** like abdominal pain and constipation/diarrhea [2]. - **Conjunctivitis** and significant **jaundice** with acute kidney failure are not typical presenting features of typhoid [2]. *Malaria* - Malaria presents with **cyclical fevers**, **chills**, and **sweats**, and can cause jaundice and kidney injury in severe cases [2]. - However, **conjunctivitis** as a prominent symptom is less common, and the distinct occupational exposure makes leptospirosis more likely [1], [2]. *Hepatitis A* - Hepatitis A causes **jaundice** and **elevated hepatic enzymes**, but it is primarily a liver infection and does not typically lead to acute **kidney failure** [3]. - While fever can be present, **conjunctivitis** and rapid progression to kidney failure are not characteristic of Hepatitis A [3].

Q: What does Legionnaire's disease cause?

Respiratory disease. Respiratory disease - **Legionnaire's disease** is a severe form of **pneumonia** caused by the bacterium *Legionella pneumophila* [1]. - It primarily affects the **lungs**, leading to symptoms such as cough, shortness of breath, fever, and muscle aches [1]. *U.T.I* - **Urinary tract infections (UTIs)** are typically caused by bacteria like *E. coli* affecting the bladder or kidneys. - Legionella does not commonly cause UTIs; its primary target organ is the **lung**. *Acute gastroenteritis* - **Acute gastroenteritis** is an inflammation of the stomach and intestines, usually caused by viruses or bacteria, leading to symptoms like diarrhea and vomiting. - While *Legionella* infection can sometimes cause gastrointestinal symptoms, its defining characteristic and primary pathology is **pneumonia** [1]. *Retroperitoneal fibrosis* - **Retroperitoneal fibrosis** is a rare disorder characterized by the formation of fibrous tissue in the retroperitoneum, often encasing the ureters and great vessels. - This condition is not related to **Legionnaire's disease**; *Legionella* infection does not cause fibrotic changes in the retroperitoneal space.

Q: Which of the following may be prodromal symptoms of tetanus except:

Urinary incontinence. ***Urinary incontinence*** - **Urinary incontinence** is not a typical prodromal symptom of tetanus; it develops later in severe cases due to autonomic dysfunction or muscle spasms affecting the bladder [1]. - Prodromal symptoms usually involve **neuromuscular excitability** (e.g., stiffness, spasms) and general discomfort or anxiety. *Anxious expression* - **Anxious expression** is a common prodromal symptom of tetanus, as patients often feel a sense of unease or apprehension before more severe symptoms develop [1]. - This symptom reflects the early effects of the **tetanospasmin toxin** on the central nervous system. *Sleeplessness* - **Sleeplessness** is a frequent prodromal symptom, often due to the increasing muscle stiffness, general discomfort, and anxiety associated with the onset of tetanus [1]. - The heightened neuromuscular excitability can make it difficult for patients to relax and sleep. *Headache* - **Headache** is a general prodromal symptom that can occur early in tetanus, indicative of the systemic effects of the bacterial infection and the body's response to the toxin [1]. - It often accompanies other non-specific symptoms like irritability and general malaise before the characteristic spasms appear.

Q: The common causative agent in diarrhea in AIDS patients is -

Cryptosporidium. ***Cryptosporidium*** - **Cryptosporidium parvum** is a common parasitic cause of severe and **chronic diarrhea** in AIDS patients due to their compromised immune systems [1]. - It leads to **profuse watery diarrhea**, abdominal cramps, nausea, and weight loss, and can be life-threatening in severely immunocompromised individuals [1]. *Mycobacteria* - While various species of **Mycobacteria**, especially **Mycobacterium avium complex (MAC)**, can cause disseminated infection in AIDS patients, diarrhea is typically a less specific or severe symptom compared to Cryptosporidium [1]. - MAC usually presents with systemic symptoms like fever, weight loss, and abdominal pain, but **diarrhea is not its primary or most common manifestation** in the context of causative agents for diarrhea [1]. *Toxoplasma* - **Toxoplasma gondii** primarily causes **cerebral toxoplasmosis** in AIDS patients, presenting as focal neurological deficits, seizures, and altered mental status. - While gastrointestinal involvement can occur, it is **rarely the primary or most common cause of diarrhea** in AIDS patients. *Salmonellae* - **Salmonella species** can cause diarrheal disease in AIDS patients, often leading to bacteremia and recurrent infections due to impaired cell-mediated immunity. - However, it is **less common overall** as a causative agent of chronic, severe diarrhea in this population compared to opportunistic parasites like Cryptosporidium.

Q: Treatment of choice for sputum positive pulmonary tuberculosis detected in 1st trimester of pregnancy-

Sta cat. I immediately. ***Sta cat. I immediately*** - All pregnant women with **active tuberculosis (TB)**, regardless of the trimester, should receive treatment immediately to prevent disease progression and transmission [1]. - **Category I treatment** includes a 6-month regimen with **isoniazid (INH), rifampicin (RIF), ethambutol (EMB), and pyrazinamide (PZA)** for the initial phase, which is generally considered safe during pregnancy [1]. *Sta cat. III immediately* - **Category III** refers to treatment for new patients with **smear-negative pulmonary TB** or **extrapulmonary TB** with severe forms, which does not fit the description of sputum-positive pulmonary TB. - While it's important to start treatment immediately, using the incorrect category would lead to an inappropriate drug regimen. *Sta cat. II immediately* - **Category II** is reserved for **retreatment cases** such as relapses, treatment failures, or treatment after default, which is not indicated for a newly diagnosed sputum-positive case. - Starting Category II treatment would involve a different, often more complex, drug regimen not appropriate for a new case. *Defer till second trimester* - **Delaying treatment** for sputum-positive pulmonary TB, even in the first trimester, increases the risk of maternal and fetal complications, including **disease progression**, **maternal mortality**, and congenital TB if the mother transmits the infection to the fetus [1]. - The benefits of immediate treatment outweigh the theoretical risks of medications during the first trimester, as key anti-TB drugs are considered relatively safe. - Pyridoxine should be prescribed in pregnant women to reduce the risk of peripheral neuropathy with isoniazid [1].

Q: Period of onset in tetanus refers to the time between:

First symptom to spasm. ***First symptom to spasm*** - The **period of onset** in tetanus specifically refers to the time elapsed from the first noticeable symptom of tetanus to the development of the first generalized **spasm** [1]. - A shorter period of onset is generally associated with a **more severe prognosis** as it indicates rapid progression of toxin effects [1]. *First spasm to death* - This timeframe describes the **duration of illness** following the onset of generalized spasms but does not define the period of onset. - It is more relevant for gauging the overall severity and **outcome** of the disease course. *First injury to spasm* - This interval is known as the **incubation period** for tetanus, which is the time from the injury (when *Clostridium tetani* spores enter the body) to the first symptom [1]. - It reflects the time required for bacterial multiplication and **toxin production** but is distinct from the period of onset [1]. *Trismus to laryngeal spasm* - Both **trismus** (lockjaw) and **laryngeal spasm** are symptoms of tetanus; however, this specific interval does not define the widely accepted "period of onset." - The period of onset refers to the time from the very **first symptom** (which might be trismus) to the *first generalized spasm*, not just between two specific types of spasms.

Q: AIDS, secondary infection will be all except

Kaposi's sarcoma. ***Kaposi's sarcoma*** - Kaposi's sarcoma is a **cancer** caused by human herpesvirus 8 (HHV-8) [2] that is common in patients with AIDS, but it is a **malignancy**, not a secondary infection [2],[3]. - While it arises due to immune suppression, it represents abnormal cell proliferation rather than direct microbial invasion. *Candida* - **Candidiasis** (e.g., oral thrush, esophageal candidiasis) is a common opportunistic fungal infection in AIDS patients due to their **impaired cellular immunity** [1]. - It often presents as **white plaques** on mucous membranes and is a clear example of a secondary infection. *HSV* - **Herpes Simplex Virus (HSV)** infections, including oral and genital herpes, are common and often severe in AIDS patients. - Due to immunocompromise, these infections can be **more widespread**, chronic, or recur frequently, qualifying as secondary infections. *Rubella* - **Rubella (German measles)** is a viral infection that is generally mild and self-limiting in immunocompetent individuals. - It is **not considered an opportunistic infection** or a common secondary infection specifically associated with AIDS; rather, it is listed as a differential diagnosis for the primary HIV infection rash [1].

Q: Immune reconstitution inflammatory syndrome typically occurs following anti retroviral therapy after a duration of:

2-6 weeks. ***2-6 weeks*** - **Immune reconstitution inflammatory syndrome (IRIS)** typically occurs within the first 2-6 weeks of initiating antiretroviral therapy (ART) in HIV-infected individuals [1]. - This time frame represents the period when the **recovering immune system** begins to mount an inflammatory response against previously subclinical or treated opportunistic infections [1]. *6-12 months* - This duration is generally too long for the typical presentation of IRIS, which is characterized by a rapid immune response shortly after ART initiation. - While immune changes continue over months, the acute inflammatory reactions defining IRIS usually manifest much earlier. *1-2 years* - This period is well beyond the typical window for IRIS onset, as the initial profound immune recovery triggering the syndrome would have already occurred. - At this stage, the immune system is usually much more stable and controlled. *1-2 weeks* - While some very rapid forms of IRIS can occur within this timeframe, the 2-6 week window is more broadly representative of the typical onset [1]. - The immune system often needs a slightly longer period to mount a sufficient inflammatory response to trigger overt IRIS symptoms.

Q: False negative Mantoux test is seen in all EXCEPT:

Chicken pox. ***Chicken pox*** - While other viral infections like measles can cause temporary **anergy** leading to a false negative Mantoux, chickenpox (varicella) is less commonly cited as a direct cause of false negative results. - The immunocompromised state or severe illness associated with widespread viral infections is more likely to cause anergy rather than the specific virus itself in immunocompetent individuals. *Measles* - **Measles virus infection** is known to cause a transient suppression of cell-mediated immunity, leading to a state of **anergy** [2]. - This anergy can result in a **false negative Mantoux test** as the body's immune response to tuberculin is temporarily blunted [2]. *Malnourished* - **Severe malnutrition**, especially protein-energy malnutrition, significantly impairs the immune system, including **cell-mediated immunity** [2]. - A compromised immune response due to malnutrition can prevent the proper reaction to tuberculin, leading to a **false negative Mantoux test** [2]. *Immunocompromised* - Individuals who are **immunocompromised** (e.g., HIV infection, organ transplant recipients on immunosuppressants, certain cancers) have a diminished or absent cell-mediated immune response [1]. - This inability to mount an adequate immune reaction to tuberculin results in a **false negative Mantoux test**, even if they have latent tuberculosis [1].

Question 1

A sewerage worker presents to OPD with acute febrile illness alongwith jaundice and conjunctivitis. His blood sample was taken and sent to lab . Lab findings are suggestive of kidney failure and elevated hepatic enzymes. Which of following is likely diagnosis ?

Accepted Answer

Leptospirosis

Answer

Typhoid

Answer

Malaria

Answer

Hepatitis A

Question 2

What does Legionnaire's disease cause?

Accepted Answer

Respiratory disease

Answer

U.T.I

Answer

Acute gastroenteritis

Answer

Retroperitoneal fibrosis

Question 3

Which of the following may be prodromal symptoms of tetanus except:

Accepted Answer

Urinary incontinence

Answer

Anxious expression

Answer

Sleeplessness

Answer

Headache

Question 4

The common causative agent in diarrhea in AIDS patients is -

Accepted Answer

Cryptosporidium

Answer

Mycobacteria

Answer

Toxoplasma

Answer

Salmonellae

Question 5

FALSE about lepromin test is:

Accepted Answer

The test is of great value in estimating prognosis in leprosy cases of all types

Answer

It is performed by injecting 0.1 ml of lepromin intradermally

Answer

It is a diagnostic test

Answer

If diameter of redness >10 mm, test is positive

Question 6

Treatment of choice for sputum positive pulmonary tuberculosis detected in 1st trimester of pregnancy-

Accepted Answer

Sta cat. I immediately

Answer

Sta cat. III immediately

Answer

Sta cat. II immediately

Answer

Defer till second trimester

Question 7

Period of onset in tetanus refers to the time between:

Accepted Answer

First symptom to spasm

Answer

First spasm to death

Answer

First injury to spasm

Answer

Trismus to laryngeal spasm

Question 8

AIDS, secondary infection will be all except

Accepted Answer

Kaposi's sarcoma

Answer

Candida

Answer

HSV

Answer

Rubella

Question 9

Immune reconstitution inflammatory syndrome typically occurs following anti retroviral therapy after a duration of:

Accepted Answer

2-6 weeks

Answer

6-12 months

Answer

1-2 years

Answer

1-2 weeks

Question 10

False negative Mantoux test is seen in all EXCEPT:

Accepted Answer

Chicken pox

Answer

Malnourished

Answer

Measles

Answer

Immunocompromised

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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