Infectious Diseases Practice Questions

Q: What is the drug of choice for diarrhea in AIDS?

Loperamide. ***Loperamide*** - **Loperamide** is the **drug of choice** for symptomatic relief of **diarrhea in AIDS** due to its effectiveness in reducing stool frequency and volume. - It works as an **opioid receptor agonist** in the gut, decreasing intestinal motility and allowing for greater water and electrolyte absorption. *Lactulose* - **Lactulose** is a **laxative** used to treat constipation and **hepatic encephalopathy**, not diarrhea. - Its osmotic effect draws water into the colon, which would worsen, not alleviate, diarrhea. *Octreotide* - **Octreotide** is a **somatostatin analog** used to treat secretory diarrhea, especially in conditions like **carcinoid syndrome** or **VIPomas**. - Its use for general diarrhea in AIDS is typically reserved for cases that are refractory to conventional therapies like loperamide and other anti-motility agents. *Codeine* - **Codeine** can be used as an **antidiarrheal agent** due to its opioid effects, but it is generally **not the first-line choice** for diarrhea in AIDS. - It carries a **higher risk of side effects** such as sedation and dependency compared to loperamide, which has localized gut effects.

Q: All of the following are seen in cerebral malaria, except:

Hyperglycaemia. All of the following are seen in cerebral malaria, except: ***Hyperglycaemia*** - **Hypoglycemia**, not hyperglycemia, is a common complication of cerebral malaria, especially in children and pregnant women, due to increased glucose consumption by red blood cells with high parasitic load and quinine treatment. - While extremely rare, **hyperglycemia** is an atypical finding in severe malaria and would warrant investigation for co-existing conditions, as it is not directly caused by the disease pathophysiology. *Thrombocytopaenia* - **Thrombocytopaenia** is a very common hematologic abnormality in both uncomplicated and severe malaria, including cerebral malaria. - It is thought to occur due to increased platelet destruction, splenic sequestration, and bone marrow suppression. *Acute respiratory distress syndrome* - **Acute respiratory distress syndrome (ARDS)** is a severe pulmonary complication that can occur in cerebral malaria, particularly in adults. - It is often associated with fluid overload, inflammation, and pulmonary edema. *Heavy parasitemia* - **Heavy parasitemia** (high parasitic load) is a hallmark of severe malaria, including cerebral malaria [1]. - It involves a significant percentage of red blood cells being infected, leading to widespread microvascular obstruction and organ dysfunction [1].

Q: Which of the following infections is least likely to be associated with nephropathies?

Staphylococcus epidermidis. Staphylococcus epidermidis - While Staphylococcus epidermidis can cause infections, particularly with prosthetic devices or in immunocompromised individuals, it is least commonly associated with the development of specific nephropathies. - Unlike the other options, it does not typically trigger well-recognized immune-mediated glomerular diseases [1] or direct renal damage that would be termed a nephropathy in the same context. Salmonella enterica serotype Typhi - Typhoid fever, caused by Salmonella Typhi, can lead to various complications, including renal complications like acute kidney injury or glomerulonephritis in severe cases. - The systemic inflammatory response and potential for immune complex deposition can contribute to nephropathy. Hepatitis B - Chronic hepatitis B virus (HBV) infection is a well-established cause of various nephropathies, particularly membranous nephropathy and membranoproliferative glomerulonephritis, due to immune complex deposition. - The viral antigens and antibodies form complexes that can deposit in the glomeruli, leading to inflammation and kidney damage. Legionella pneumophila - Legionnaires' disease, caused by Legionella pneumophila, is frequently associated with acute kidney injury (AKI), often due to rhabdomyolysis, direct renal tubular injury, or systemic inflammation. - Although primarily known for its respiratory effects, severe Legionella infection can indeed lead to significant renal involvement and nephropathy.

Q: All are true about amoebic liver abscess except?

More common in left side. Amoebic liver abscesses are much more common in the right lobe of the liver (>80-90%) due to the portal venous flow from the colon predominantly going to the right lobe [1]. The left lobe is rarely affected, and multifocal abscesses are also less common than a single right-sided lesion. Metronidazole is indeed the drug of choice for treating amoebic liver abscesses due to its excellent tissue penetration and efficacy against Entamoeba histolytica. Treatment for 7-10 days typically eradicates the trophozoites in the abscess and in the intestinal tract. While single, large abscesses often benefit from aspiration, multifocal abscesses are generally not amenable to aspiration due to their diffuse nature and numerous locations. Medical treatment with metronidazole is the primary approach for multifocal amoebic liver abscesses. Amoebic liver abscesses are actually more common in males than females, with a male-to-female ratio typically ranging from 7:1 to 10:1. This predisposition in males is not fully understood but may be related to hormonal factors or lifestyle differences.

Q: An abattoir worker presented with a lesion on his hand that progressed to form an ulcer. A smear was taken from the ulcer and sent to the laboratory for investigation. What is the diagnosis?

Cutaneous anthrax. ***Cutaneous anthrax*** - The patient's occupation as an **abattoir worker** places him at high risk for exposure to *Bacillus anthracis* from infected animal products [1]. - Cutaneous anthrax typically presents as a small **papule** that progresses to a **vesicle**, then to a characteristic **painless ulcer with a black eschar** (malignant pustule), fitting the description [1]. *Ulcerating melanoma (irregular pigmentation)* - While melanomas can ulcerate, they typically present with **irregular pigmentation**, **asymmetry**, and **border irregularity**, which are not mentioned. - There is no specific occupational link to abattoir work for melanoma, unlike anthrax. *Infected rodent ulcer* - A "rodent ulcer" is a lay term for a **basal cell carcinoma**, which is a type of skin cancer. - These typically grow slowly and may ulcerate, but they are not acutely infectious and lack the direct occupational exposure context. *Carbuncle (ulceration possible)* - A carbuncle is a **deep-seated skin infection** involving multiple hair follicles, often caused by *Staphylococcus aureus*. - While it can ulcerate and be painful, it's less likely in an abattoir worker context for a singular lesion without systemic signs of severe staphylococcal infection.

Q: Round worms cause all of the following conditions, except:

Intestinal perforation. ***Intestinal perforation*** - While **Ascaris lumbricoides** can cause obstructions, migration, and inflammation, **bowel perforation** is an extremely rare complication, usually associated with massive worm burdens or pre-existing bowel damage. - The thick cuticle of the adult worm is not typically capable of directly perforating healthy intestinal wall tissue. *Obstructive jaundice* - **Ascaris worms** can migrate into the **biliary tree**, especially the common bile duct, leading to its obstruction. - This obstruction can cause symptoms and signs of **obstructive jaundice**, such as yellowing of skin and eyes, dark urine, and pale stools. *Pancreatitis* - Migrating adult **Ascaris worms** can enter the **pancreatic duct** via the ampulla of Vater. - This can obstruct the duct and lead to **acute pancreatitis**, characterized by severe abdominal pain and elevated pancreatic enzymes. *Intestinal obstruction* - A large number of **adult Ascaris worms** can form a tightly packed bolus within the lumen of the small intestine. - This **worm bolus** can cause a mechanical blockage, leading to **intestinal obstruction**, which is a common and serious complication.

Q: A patient from Himachal Pradesh presents with fever for 5 days, altered sensorium, increased jugular venous pressure, maculopapular rash, and erythema on the back with black necrotic tissue. What is the most appropriate treatment option?

Doxycycline. ***Doxycycline*** - The clinical picture strongly suggests **scrub typhus**, an endemic illness in Himachal Pradesh, characterized by fever, altered sensorium, rash, and an **eschar** (black necrotic tissue) [1]. - **Doxycycline** is the first-line treatment for scrub typhus, effectively targeting *Orientia tsutsugamushi*. *Aminoglycosides* - These antibiotics primarily target **gram-negative bacteria** and **tuberculosis**, which do not fit the clinical presentation of scrub typhus. - Aminoglycosides are **ineffective** against *Orientia tsutsugamushi*, the causative agent of scrub typhus. *Chloramphenicol* - While historically used for scrub typhus, **chloramphenicol** is now a second-line option due to potential severe side effects like reversible bone marrow suppression and **aplastic anemia**. - **Doxycycline** is preferred due to its superior safety profile and equivalent efficacy. *Tetracycline* - **Tetracycline** is a broad-spectrum antibiotic that could be effective, but **doxycycline** is a more potent and better-tolerated tetracycline derivative. - **Doxycycline** offers better pharmacokinetic properties, allowing for once-daily dosing in most cases.

Q: Which of the following is not a common complication of tubercular meningitis?

Sinovenous thrombosis. ***Sinovenous thrombosis*** - While possible in severe inflammatory states, **sinovenous thrombosis** is not considered a common or characteristic complication of tubercular meningitis, unlike the other mentioned complications. - The inflammatory exudates in TB meningitis primarily affect the base of the brain, leading to complications related to CSF flow and arterial compromise rather than venous sinus obstruction [1]. *Hydrocephalus* - **Hydrocephalus** is a very common complication of tubercular meningitis, resulting from obstruction of CSF flow by thick inflammatory exudates, particularly at the base of the brain [1], [2]. - The blockage can occur at various points, leading to accumulation of cerebrospinal fluid and increased intracranial pressure [2]. *Infarction* - **Infarction** (stroke) is a frequent and serious complication, caused by **vasculitis** and narrowing or occlusion of intracranial blood vessels, particularly the basal arteries [1]. - This is secondary to the extensive inflammatory exudate that surrounds and infiltrates the vessels, leading to **ischemia** and tissue death. *Obliterative endarteritis* - **Obliterative endarteritis** is the underlying pathological process leading to infarction in tubercular meningitis, involving inflammation and fibrosis of the arterial walls. - This inflammation of the small and medium-sized arteries, especially at the base of the brain, causes luminal narrowing and eventual occlusion.

Q: A febrile 23-year-old college student presents with fatigue and difficulty swallowing. Physical examination reveals exudative tonsillitis, palatal petechiae, cervical lymphadenopathy, and tender hepatosplenomegaly. A complete blood count shows mild anemia, lymphocytosis with approximately 30% of the lymphocytes exhibiting atypical features, and mild thrombocytopenia. The Coombs' test is positive. Which of the following is the most likely complication of this syndrome?

Splenic rupture. **Splenic rupture** - The patient's symptoms (fatigue, difficulty swallowing, exudative tonsillitis, palatal petechiae, cervical lymphadenopathy, hepatosplenomegaly, atypical lymphocytosis, and positive Coombs' test) are highly suggestive of **infectious mononucleosis** [1]. - **Splenic enlargement** (splenomegaly) is common in infectious mononucleosis, making the spleen vulnerable to rupture, especially with trauma or increased abdominal pressure [2]. *Acute cholecystitis* - Not a typical complication of infectious mononucleosis, which primarily affects lymphoid tissues and can involve the liver and spleen [3]. - Usually caused by **gallstone obstruction** of the cystic duct, leading to gallbladder inflammation. *Diarrhea* - Not a characteristic symptom or complication of infectious mononucleosis. - More commonly associated with **gastrointestinal infections**. *Ascending cholangitis* - An infection of the bile ducts, usually due to **biliary obstruction** by stones or strictures, not a known complication of infectious mononucleosis. - Symptoms include Charcot's triad (fever, right upper quadrant pain, jaundice).

Q: Amoebic liver abscess most commonly affects which part of the liver?

Right lobe of liver. ***Right lobe of liver*** - The **right lobe** of the liver [1] is supplied by a larger proportion of blood from the superior mesenteric and splenic veins, making it more susceptible to parasitic emboli from the bowel. - Due to its larger size and more direct blood supply from the **portal vein**, the right lobe is the most common site (approximately 80-90%) for amoebic liver abscess formation [1]. *Left lobe of liver* - While it can be affected, the **left lobe** is less commonly involved in amoebic liver abscesses compared to the right lobe. - Its blood supply directly from the **portal vein** is less direct and abundant for parasitic entry than that of the right lobe. *Portal vein* - The **portal vein** is the route of entry for *Entamoeba histolytica* cysts from the intestines to the liver, but it is not the site where an abscess forms. - Abscesses form in the **liver parenchyma** [1] after the trophozoites travel via the portal venules and elicit an inflammatory response. *Right pleural cavity* - The **right pleural cavity** is a potential site for complications of a ruptured amoebic liver abscess, leading to **pleural effusion** or **empyema**. - However, it is not the primary site where the amoebic liver abscess itself develops, as it is outside the liver.

Question 1

What is the drug of choice for diarrhea in AIDS?

Accepted Answer

Loperamide

Answer

Lactulose

Answer

Codeine

Answer

Octreotide

Question 2

All of the following are seen in cerebral malaria, except:

Accepted Answer

Hyperglycaemia

Answer

Acute respiratory distress syndrome

Answer

Heavy parasitemia

Answer

Thrombocytopaenia

Question 3

Which of the following infections is least likely to be associated with nephropathies?

Accepted Answer

Staphylococcus epidermidis

Answer

Salmonella enterica serotype Typhi

Answer

Hepatitis B

Answer

Legionella pneumophila

Question 4

All are true about amoebic liver abscess except?

Accepted Answer

More common in left side

Answer

Multifocal abscess cannot be treated by aspiration

Answer

More common in female

Answer

Metronidazole is mainstay of treatment

Question 5

An abattoir worker presented with a lesion on his hand that progressed to form an ulcer. A smear was taken from the ulcer and sent to the laboratory for investigation. What is the diagnosis?

Accepted Answer

Cutaneous anthrax

Answer

Infected rodent ulcer

Answer

Ulcerating melanoma (irregular pigmentation)

Answer

Carbuncle (ulceration possible)

Question 6

Round worms cause all of the following conditions, except:

Accepted Answer

Intestinal perforation

Answer

Intestinal obstruction

Answer

Obstructive jaundice

Answer

Pancreatitis

Question 7

A patient from Himachal Pradesh presents with fever for 5 days, altered sensorium, increased jugular venous pressure, maculopapular rash, and erythema on the back with black necrotic tissue. What is the most appropriate treatment option?

Accepted Answer

Doxycycline

Answer

Aminoglycosides

Answer

Chloramphenicol

Answer

Tetracycline

Question 8

Which of the following is not a common complication of tubercular meningitis?

Accepted Answer

Sinovenous thrombosis

Answer

Hydrocephalus

Answer

Infarction

Answer

Obliterative endarteritis

Question 9

A febrile 23-year-old college student presents with fatigue and difficulty swallowing. Physical examination reveals exudative tonsillitis, palatal petechiae, cervical lymphadenopathy, and tender hepatosplenomegaly. A complete blood count shows mild anemia, lymphocytosis with approximately 30% of the lymphocytes exhibiting atypical features, and mild thrombocytopenia. The Coombs' test is positive. Which of the following is the most likely complication of this syndrome?

Accepted Answer

Splenic rupture

Answer

Diarrhea

Answer

Acute cholecystitis

Answer

Ascending cholangitis

Question 10

Amoebic liver abscess most commonly affects which part of the liver?

Accepted Answer

Right lobe of liver

Answer

Left lobe of liver

Answer

Portal vein

Answer

Right pleural cavity

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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