Infectious Diseases Practice Questions

Q: Exanthems are caused by all except which of the following?

Malaria. ***Malaria*** - **Malaria** is a parasitic disease that affects red blood cells and typically causes symptoms like **fever, chills, and headache**, but does not present with a characteristic skin rash or exanthem [3]. - While skin manifestations like **petechiae or jaundice** can occur in severe cases, a widespread rash defining an exanthem is not typical [3]. *Typhoid* - **Typhoid fever**, caused by *Salmonella Typhi*, can present with a characteristic exanthem known as **"rose spots"** on the trunk and abdomen [3]. - These are small, erythematous macules that blanch on pressure and are an important diagnostic clue. *Measles* - **Measles**, caused by the measles virus, is well-known for its characteristic **maculopapular rash** (exanthem) that typically starts on the face and spreads downwards [1]. - This rash is often preceded by **Koplik spots** in the mouth [1]. *Rubella* - **Rubella** (German measles), caused by the rubella virus, also presents with a classic exanthem, which is a **fine, pinkish-red maculopapular rash** that begins on the face and neck and spreads to the trunk and extremities [2]. - The rash is typically milder and resolves more quickly than measles.

Q: Procalcitonin is considered a marker for:

Sepsis. **Sepsis** - **Procalcitonin** (PCT) levels significantly rise in response to bacterial infections and **sepsis**, making it a useful diagnostic and prognostic marker. - Its levels correlate with the severity of bacterial infection and can help differentiate bacterial from viral etiologies. *Medullary thyroid carcinoma* - **Medullary thyroid carcinoma** (MTC) is characterized by the production of **calcitonin**, a different hormone from procalcitonin, by the parafollicular C cells of the thyroid. - While calcitonin is a tumor marker for MTC, **procalcitonin** is not. *Vitamin D resistant rickets* - **Vitamin D resistant rickets** (also known as X-linked hypophosphatemia) is a genetic disorder characterized by impaired phosphate reabsorption in the kidneys [1]. - It is associated with low phosphate levels and bone deformities, but not with elevated procalcitonin [1]. *Parathyroid adenoma* - A **parathyroid adenoma** leads to primary hyperparathyroidism, characterized by excessive production of **parathyroid hormone (PTH)** [1]. - This results in hypercalcemia and hypophosphatemia, with no direct link to procalcitonin levels [1].

Q: Commonest cause for acute sinusitis is:

Acute rhinitis. **Acute rhinitis** - **Acute rhinitis**, commonly known as the common cold, is the most frequent precursor to acute sinusitis due to inflammation and obstruction of the ostia. - The **inflammation** and **edema** of the nasal passages in rhinitis can block the sinus drainage pathways, leading to fluid accumulation and secondary bacterial infection within the sinuses. *Swimming/Diving* - While **swimming** and **diving** can introduce water and pathogens into the sinuses, leading to sinusitis, they are not the most common cause overall. - **Pressure changes** and chemical irritants like chlorine can also contribute, but usually as an exacerbating factor rather than the primary etiology. *Nasal tumours* - **Nasal tumors** can cause chronic sinusitis by physically obstructing sinus drainage, but they are relatively rare and not the most common cause of acute sinusitis. - Symptoms typically develop **gradually** and may include unilateral nasal obstruction, epistaxis, or facial pain, which are distinct from acute inflammatory onset. *Deviated nasal septum* - A **deviated nasal septum** can predispose individuals to sinusitis by impairing mucociliary clearance and ventilation of the sinuses, but it is a predisposing factor rather than the direct cause of acute sinusitis itself. - Often contributes to **recurrent** or **chronic sinusitis** by creating anatomical blockages, but an acute infectious trigger is usually necessary for an acute episode.

Q: What should you do next for a 35-year-old man who is positive for HBsAg and HBeAg, discovered incidentally during blood donation screening, with normal SGOT and SGPT laboratory values?

HBV-DNA estimation. ***HBV-DNA estimation*** - The presence of **HBsAg** and **HBeAg** indicates **active viral replication**, necessitating quantification of HBV-DNA to assess viral load [1]. - Normal SGOT and SGPT suggest compensated liver function, but **viral load** is crucial for staging the disease and guiding future management [1]. *Observation* - While liver enzymes are normal, the presence of **HBsAg** and **HBeAg** indicates active hepatitis B infection, which warrants further investigation, not just observation [1]. - Undiagnosed and untreated chronic hepatitis B can lead to serious complications such as **cirrhosis** and **hepatocellular carcinoma** [1]. *Liver biopsy* - **Liver biopsy** is an invasive procedure typically reserved for cases where histological assessment is required to confirm **fibrosis** or **inflammation severity**, or when there's discordance between viral markers and clinical presentation. - It's not the initial step for a patient with normal transaminases and clear serological markers of active infection; **HBV-DNA estimation** is generally performed first [1]. *Interferon therapy* - **Interferon therapy** is a treatment for chronic hepatitis B, but initiating treatment requires a comprehensive assessment including **HBV-DNA levels**, in addition to liver enzyme levels and evaluation of liver damage [2]. - It would be premature to consider treatment without a **viral load** measurement and a full workup to determine the phase of infection and the need for therapy [2].

Q: In which of the following conditions is glucocorticoid used?

Severe typhoid. ***Severe typhoid*** * **Glucocorticoids** (e.g., **dexamethasone**) are indicated in **severe typhoid fever** with altered mental status, delirium, stupor, coma, or shock, as they can reduce inflammation and improve neurological outcomes. * Their use in severe typhoid can decrease mortality by attenuating the systemic inflammatory response induced by *Salmonella Typhi*. *E. coli septicemia* * The use of **glucocorticoids** in **bacterial sepsis**, including *E. coli* septicemia, is generally controversial and not recommended unless there is confirmed or suspected **adrenal insufficiency**. * Routine use can increase the risk of secondary infections and other adverse effects without clear mortality benefit in immunocompetent patients. *Cerebral malaria* * **Glucocorticoids** are **contraindicated** in **cerebral malaria** because studies have shown they increase the risk of complications (e.g., gastrointestinal bleeding, seizures, hyperglycemia, infections) without improving neurological outcomes or survival. * Their use can worsen immune suppression in a disease already characterized by significant immune dysregulation. *Leishmaniasis* * **Glucocorticoids** are **not a primary treatment** for **leishmaniasis**, which is caused by a protozoan parasite and requires specific antileishmanial drugs. * While they might be used to manage severe inflammatory reactions in specific forms (e.g., post-kala-azar dermal leishmaniasis), they are not a standard therapeutic intervention and can even exacerbate the infection by suppressing the immune response.

Q: What is a condition directly associated with HIV/AIDS?

Enteropathy. ***Enteropathy*** - **HIV enteropathy** is a condition characterized by chronic diarrhea, malabsorption, and weight loss, frequently seen in HIV/AIDS patients [1]. - It results from the direct effects of HIV on the **gastrointestinal tract**, leading to mucosal damage and immune dysfunction [1]. *Hypertrophic cardiomyopathy* - While cardiac complications can occur in HIV/AIDS, **hypertrophic cardiomyopathy** is not a direct or defining association. - HIV-associated cardiac disease typically manifests as **dilated cardiomyopathy** or myocarditis, rather than hypertrophy. *Bronchial asthma* - **Bronchial asthma** is a chronic inflammatory airway disease that is not directly increased or caused by HIV infection. - Its prevalence in HIV-positive individuals is similar to the general population, without a causal link. *Peptic ulcer disease* - **Peptic ulcer disease** is primarily caused by *Helicobacter pylori* infection or NSAID use and is not a direct consequence of HIV/AIDS [1]. - Although immunosuppression might alter its presentation, HIV does not directly lead to ulcer formation.

Q: A 65-year-old male presents with fever, chills, and a productive cough with rust-colored sputum. What is the most likely diagnosis?

Pneumococcal Pneumonia. Pneumococcal Pneumonia - This presentation with fever, chills, and rust-colored sputum is classic for pneumococcal pneumonia, caused by Streptococcus pneumoniae [1]. [2] - The rust color results from the presence of hemolyzed red blood cells from the inflamed alveoli [3]. TB - While TB can cause fever and cough, the sputum is typically mucoid or purulent, and sometimes hemoptysis (frank blood) is seen, but not usually rust-colored [4]. - TB symptoms tend to be more chronic, including night sweats and weight loss, which are not mentioned here. Klebsiella pneumonia - Klebsiella pneumoniae typically causes severe pneumonia, often in individuals with alcoholism or diabetes [1]. - It classically presents with currant jelly sputum, which is distinct from rust-colored sputum [2]. Pneumocystis pneumonia - Pneumocystis jirovecii pneumonia (PCP) primarily affects immunocompromised individuals, particularly those with HIV [4]. - Symptoms are usually more insidious, involving dyspnea, non-productive cough, and hypoxia, and sputum is not typically rust-colored [4].

Q: Which of the following is a chronic complication of malaria?

Splenomegaly. Splenomegaly - Chronic malaria, especially Plasmodium falciparum infections, leads to persistent erythrocytic sequestration in the spleen. - This prolonged immune response and destruction of infected red blood cells contribute to significant and often palpable enlargement of the spleen [1]. Nephrotic syndrome - While malaria can cause kidney complications, nephrotic syndrome is more commonly associated with specific types of malaria, particularly Plasmodium malariae, and is often considered a direct acute or subacute complication rather than a widespread chronic sequela of all malaria types. - The primary chronic complication that affects a broader range of malaria cases is splenomegaly. Pneumonia - Pneumonia is an acute respiratory infection that can occur as a co-infection or complication in severely ill malaria patients. - It is not considered a chronic complication of malaria itself, but rather an acute opportunistic infection or secondary issue. Hodgkin's disease - There is no direct, established link between chronic malaria infection and the development of Hodgkin's disease [2]. - While other infections (e.g., EBV) are associated with certain lymphomas, malaria is not known to be a direct causative agent or chronic complication leading to Hodgkin's lymphoma [2].

Q: Fever and haemorrhagic rash are seen in all except which of the following?

Sand fly fever. ***Sand fly fever*** - **Sand fly fever**, also known as phlebotomus fever, is typically characterized by an acute onset of fever, headache, myalgia, and malaise. - While it can cause a rash, it is generally **non-hemorrhagic** and petechiae or purpura are uncommon. *Dengue fever* - **Dengue fever** is well-known for causing **hemorrhagic manifestations**, ranging from petechiae and purpura to severe bleeding [1]. - The classic presentation includes high fever, severe headache, retro-orbital pain, and a generalized rash which can become hemorrhagic [1]. *Lassa fever* - **Lassa fever** is a severe viral hemorrhagic fever caused by the Lassa virus [2]. - It often progresses to include a **hemorrhagic rash** along with organ damage and generalized bleeding tendencies [2]. *Rift Valley fever* - **Rift Valley fever** is another viral hemorrhagic fever that can cause a spectrum of symptoms including fever and, in severe cases, **hemorrhagic manifestations** such as petechiae, ecchymoses, and epistaxis. - Ocular and neurological complications are also characteristic of severe disease.

Q: An 34-year-old male HIV patient on c-A presents with seizures and a unilateral facial nerve palsy. The CT scan shows a ring-enhancing lesion. What is the best treatment?

Sulphadiazine, pyrimethamine and Leucovorin. ***Sulphadiazine, pyrimethamine and Leucovorin*** - This combination is the standard **first-line treatment for cerebral toxoplasmosis**, which is strongly suggested by the clinical presentation (HIV patient, seizures, facial nerve palsy) and the imaging findings of **multiple ring-enhancing lesions**. - **Leucovorin** is added to prevent bone marrow suppression caused by pyrimethamine. *Albendazole with dexamethasone* - **Albendazole** is primarily used for **neurocysticercosis**, which typically presents with cystic lesions, not necessarily ring-enhancing, and the patient's HIV status makes toxoplasmosis more likely. - While **dexamethasone** may be used to reduce brain edema, it's adjunctive and not the primary antimicrobial treatment for toxoplasmosis. *Amphotericin B* - **Amphotericin B** is the mainstay treatment for **cryptococcal meningitis** and other severe fungal infections, which usually present with symptoms of meningitis and different imaging findings (e.g., hydrocephalus, gelatinous pseudocysts). - It is not effective against **Toxoplasma gondii**. *ATT with steroids* - **ATT (Anti-Tubercular Therapy)** with steroids is the treatment for **CNS tuberculosis**, which can present with ring-enhancing lesions. - However, the typical presentation for CNS tuberculosis in HIV patients often includes basilar meningitis, multiple tuberculomas, or abscesses, and toxoplasmosis is a far more common cause of ring-enhancing lesions in HIV patients with CD4 counts < 100 cells/µL.

Question 1

Exanthems are caused by all except which of the following?

Accepted Answer

Malaria

Answer

Typhoid

Answer

Rubella

Answer

Measles

Question 2

Procalcitonin is considered a marker for:

Accepted Answer

Sepsis

Answer

Medullary thyroid carcinoma

Answer

Parathyroid adenoma

Answer

Vitamin D resistant rickets

Question 3

Commonest cause for acute sinusitis is:

Accepted Answer

Acute rhinitis

Answer

Swimming/Diving

Answer

Nasal tumours

Answer

Deviated nasal septum

Question 4

What should you do next for a 35-year-old man who is positive for HBsAg and HBeAg, discovered incidentally during blood donation screening, with normal SGOT and SGPT laboratory values?

Accepted Answer

HBV-DNA estimation

Answer

Observation

Answer

Liver biopsy

Answer

Interferon therapy

Question 5

In which of the following conditions is glucocorticoid used?

Accepted Answer

Severe typhoid

Answer

E. coli septicemia

Answer

Cerebral malaria

Answer

Leishmaniasis

Question 6

What is a condition directly associated with HIV/AIDS?

Accepted Answer

Enteropathy

Answer

Hypertrophic cardiomyopathy

Answer

Bronchial asthma

Answer

Peptic ulcer disease

Question 7

A 65-year-old male presents with fever, chills, and a productive cough with rust-colored sputum. What is the most likely diagnosis?

Accepted Answer

Pneumococcal Pneumonia

Answer

TB

Answer

Klebsiella pneumonia

Answer

Pneumocystis pneumonia

Question 8

Which of the following is a chronic complication of malaria?

Accepted Answer

Splenomegaly

Answer

Nephrotic syndrome

Answer

Pneumonia

Answer

Hodgkin's disease

Question 9

Fever and haemorrhagic rash are seen in all except which of the following?

Accepted Answer

Sand fly fever

Answer

Dengue fever

Answer

Rift Valley fever

Answer

Lassa fever

Question 10

An 34-year-old male HIV patient on c-A presents with seizures and a unilateral facial nerve palsy. The CT scan shows a ring-enhancing lesion. What is the best treatment?

Accepted Answer

Sulphadiazine, pyrimethamine and Leucovorin

Answer

Albendazole with dexamethasone

Answer

Amphotericin B

Answer

ATT with steroids

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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