A 65-year-old patient presents with symptoms of bone pain, anemia, hypercalcemia, and renal impairment. A bone marrow biopsy confirms the diagnosis of multiple myeloma. The patient is started on a treatment regimen. Which of the following treatments is most likely associated with the reactivation of herpes zoster?
Q2
A patient with HIV who is currently on antiretroviral therapy consisting of zidovudine, lamivudine, and nevirapine is diagnosed with tuberculosis. Considering potential drug interactions, which of the following TB drugs should be changed in this patient?
Q3
A 28-year-old primigravid woman at 38 weeks' gestation is brought to the emergency department in active labor. She has not had regular prenatal care. She has a history of HIV infection but is not currently on antiretroviral therapy. Her previous viral load is unknown. Treatment with intravenous zidovudine is begun to reduce perinatal transmission of the virus. Which of the following processes is most likely affected by this drug?
Q4
The physician recommends that the patient receive an influenza vaccine. The patient becomes nervous and reports that he has never received an influenza vaccination because of an allergy to eggs. The allergy was diagnosed many years ago, after he developed hives upon eating scrambled eggs. Which of the following is the most appropriate next step in management?
Q5
A 35-year-old male is found to be infected with an HIV strain resistant to saquinavir and zidovudine. Which of the following best explains the drug resistance observed in this patient?
Q6
A 72-year-old man presents to the emergency department with a change in his behavior. The patient is brought in by his family who state that he is not acting normally and that his responses to their questions do not make sense. The patient has a past medical history of diabetes and Alzheimer dementia. His temperature is 103°F (39.4°C), blood pressure is 157/98 mmHg, pulse is 120/min, respirations are 19/min, and oxygen saturation is 98% on room air. Physical exam reveals a systolic murmur heard along the right upper sternal border. HEENT exam reveals a normal range of motion of the neck in all 4 directions and no lymphadenopathy. A mental status exam reveals a confused patient who is unable to answer questions. Laboratory values are ordered and a lumbar puncture is performed which demonstrates elevated white blood cells with a lymphocytic predominance, a normal glucose, and an elevated protein. The patient is started on IV fluids and ibuprofen. Which of the following is the next best step in management?
Q7
A 44-year-old man comes to the physician for a follow-up examination. Ten months ago, he was diagnosed with HIV infection and appropriate antiretroviral therapy was initiated. Physical examination shows no abnormalities. Laboratory studies show increased viral load despite ongoing treatment. His pharmacotherapy is switched to a new combination drug regimen including an agent that binds to glycoprotein 41. The expected effect of this drug is most likely due to inhibition of which of the following?
Q8
A 55-year-old man with HIV on antiretroviral therapy comes to the physician for a follow-up examination. His HIV viral load is 559 copies/mL (N<49). His physician is concerned about the development of drug resistance. The result of HIV genotype testing shows reduced viral susceptibility to darunavir and ritonavir. Which of the following molecular processes is most likely affected by this mutation?
Q9
A 63-year-old HIV-positive man comes to the physician for a routine health maintenance examination. Four years ago, he was diagnosed with HIV and was started on cART therapy. He tells the physician that he has been having difficulty adhering to his medication regimen. He has been unemployed for the past couple of years and relies on unemployment benefits to cover the costs of daily living. His father died of lymphoma at the age of 60 years. He wants more information about his risk of developing DLBCL. Which of the following is the greatest risk factor for the development of DLBCL in HIV-positive patients?
Q10
A 27-year-old man is brought to the emergency department by his friends in a confused state. He was doing fine 5 days ago when he started to complain of fever and flu-like symptoms. His fever was low-grade and associated with a headache. For the past 2 days, he has become increasingly irritable, confused, and was getting angry at trivial things. Past medical history is unremarkable. He is a college student and is physically active. He smokes cigarettes occasionally. He drinks alcohol socially. He is sexually active with his girlfriend and they use condoms inconsistently. Physical examination reveals: blood pressure 120/80 mm Hg, heart rate 108/min, respiratory rate 10/min, and temperature 37.4°C (99.4°F). He is confused and disoriented. Pupils are 3 mm in diameter and respond to light sluggishly. He is moving all his limbs spontaneously. His neck is supple. MRI of the brain is shown in the picture. Cerebrospinal fluid (CSF) reveals an opening pressure of 16 cm of H20, a total leukocyte count of 112/mm3 with 85% lymphocytes, the protein of 42 mg/dL, and glucose of 58 mg/dL. What is the best treatment for this condition?
Antivirals US Medical PG Practice Questions and MCQs
Question 1: A 65-year-old patient presents with symptoms of bone pain, anemia, hypercalcemia, and renal impairment. A bone marrow biopsy confirms the diagnosis of multiple myeloma. The patient is started on a treatment regimen. Which of the following treatments is most likely associated with the reactivation of herpes zoster?
A. Bortezomib (Correct Answer)
B. Lenalidomide
C. Daratumumab
D. Melphalan
E. Dexamethasone
Explanation: ***Bortezomib***
- **Bortezomib**, a **proteasome inhibitor**, is known to increase the risk of herpes zoster reactivation in patients with multiple myeloma due to its immunosuppressive effects.
- Prophylaxis with antiviral agents (e.g., acyclovir) is often recommended during bortezomib treatment to prevent this complication.
- Studies show herpes zoster incidence of 10-15% in bortezomib-treated patients without prophylaxis.
*Lenalidomide*
- While lenalidomide is an **immunomodulatory drug** used in multiple myeloma, it is generally associated with a lower risk of herpes zoster reactivation compared to proteasome inhibitors.
- It primarily acts by inhibiting angiogenesis and stimulating T-cell and natural killer cell activity.
*Daratumumab*
- **Daratumumab** is a **monoclonal antibody** targeting CD38 on myeloma cells, leading to their destruction.
- Although it has immunosuppressive effects, it is less commonly associated with herpes zoster reactivation than bortezomib.
*Melphalan*
- **Melphalan** is an **alkylating agent** used in chemotherapy for multiple myeloma, particularly in conditioning regimens for stem cell transplantation.
- While it causes myelosuppression and general immunosuppression, the direct association with herpes zoster reactivation is not as prominent or specific as with bortezomib.
*Dexamethasone*
- **Dexamethasone** is a **corticosteroid** commonly used in combination regimens for multiple myeloma (e.g., RVD, VCD).
- While corticosteroids cause immunosuppression and can increase infection risk, the specific association with herpes zoster reactivation is less pronounced than with bortezomib.
Question 2: A patient with HIV who is currently on antiretroviral therapy consisting of zidovudine, lamivudine, and nevirapine is diagnosed with tuberculosis. Considering potential drug interactions, which of the following TB drugs should be changed in this patient?
A. Isoniazid
B. Rifampicin (Correct Answer)
C. Ethambutol
D. Streptomycin
E. Pyrazinamide
Explanation: **Rifampicin**
- **Rifampicin** is a potent **CYP450 enzyme inducer**, which significantly increases the metabolism of **nevirapine**, a non-nucleoside reverse transcriptase inhibitor (NNRTI), leading to subtherapeutic levels and potential treatment failure.
- In patients on **nevirapine-based ART**, **rifampicin** is typically avoided or replaced with other rifamycins (like **rifabutin**), or the antiretroviral regimen is switched to one that is less affected by enzyme induction.
*Isoniazid*
- **Isoniazid** does not have significant, clinically problematic interactions with the antiretroviral regimen mentioned (zidovudine, lamivudine, nevirapine), and is generally well-tolerated.
- It is a cornerstone of TB treatment and is usually continued without dose adjustment or substitution in this scenario.
*Pyrazinamide*
- **Pyrazinamide** is part of the standard first-line TB treatment regimen and does not have clinically significant drug interactions with zidovudine, lamivudine, or nevirapine.
- It can be safely continued without dose adjustment in patients on this ART regimen.
*Ethambutol*
- **Ethambutol** primarily causes **optic neuritis** as a side effect and does not have significant pharmacokinetic interactions with the antiretroviral drugs listed.
- Its use in TB treatment alongside this ART regimen is generally safe and does not require a change.
*Streptomycin*
- **Streptomycin** is an **aminoglycoside antibiotic** primarily used for multi-drug resistant TB or in specific situations, and its main toxicity is **ototoxicity** and **nephrotoxicity**.
- It does not have known significant drug interactions with zidovudine, lamivudine, or nevirapine that would necessitate a change.
Question 3: A 28-year-old primigravid woman at 38 weeks' gestation is brought to the emergency department in active labor. She has not had regular prenatal care. She has a history of HIV infection but is not currently on antiretroviral therapy. Her previous viral load is unknown. Treatment with intravenous zidovudine is begun to reduce perinatal transmission of the virus. Which of the following processes is most likely affected by this drug?
A. Cleavage of viral polypeptides
B. Elongation of viral DNA (Correct Answer)
C. Fusion of virus with T cells
D. Integration of viral genome
E. Action of viral RNA polymerase
Explanation: ***Elongation of viral DNA***
- **Zidovudine (AZT)** is a **nucleoside reverse transcriptase inhibitor (NRTI)** that mimics thymidine and gets incorporated into the growing viral DNA strand by HIV reverse transcriptase.
- Its incorporation causes **chain termination** because it lacks a 3'-hydroxyl group, preventing further phosphodiester bond formation and thus inhibiting the elongation of viral DNA.
*Cleavage of viral polypeptides*
- This process is targeted by **protease inhibitors**, which prevent the HIV protease enzyme from cleaving large precursor polypeptides into functional proteins.
- Zidovudine's mechanism of action is distinct from protease inhibition.
*Fusion of virus with T cells*
- This step is inhibited by **fusion inhibitors**, which block the interaction between the viral envelope glycoprotein (gp120/gp41) and the host cell receptors (CD4 and co-receptors like CCR5 or CXCR4).
- Zidovudine does not interfere with viral entry into the host cell.
*Integration of viral genome*
- This process is targeted by **integrase inhibitors**, which prevent the HIV integrase enzyme from inserting the viral DNA into the host cell's genome.
- Zidovudine acts earlier in the viral life cycle by inhibiting reverse transcription, before integration occurs.
*Action of viral RNA polymerase*
- HIV is a retrovirus and uses **reverse transcriptase** to convert its RNA genome into DNA, not a viral RNA polymerase for genome replication.
- While host RNA polymerase II is used to transcribe viral DNA into mRNA, zidovudine specifically targets reverse transcriptase, not RNA polymerase.
Question 4: The physician recommends that the patient receive an influenza vaccine. The patient becomes nervous and reports that he has never received an influenza vaccination because of an allergy to eggs. The allergy was diagnosed many years ago, after he developed hives upon eating scrambled eggs. Which of the following is the most appropriate next step in management?
A. Administer oseltamivir
B. Prescribe oseltamivir for standby emergency treatment
C. Administer influenza immunoglobulins
D. Administer inactivated influenza vaccine (Correct Answer)
E. End the examination without additional measures
Explanation: ***Administer inactivated influenza vaccine***
- The patient's reported allergy to eggs (hives after eating scrambled eggs) is a **mild allergic reaction** and does not contraindicate receiving an inactivated influenza vaccine.
- The **ACIP guidelines** state that individuals with a history of **mild egg allergy** can safely receive any FDA-approved influenza vaccine suitable for their age and health status.
*Administer oseltamivir*
- **Oseltamivir** is an antiviral medication used for the treatment or prevention of influenza, not for vaccination.
- Administering oseltamivir before potential exposure or as a treatment is not the same as providing the patient with the recommended influenza vaccine.
*Prescribe oseltamivir for standby emergency treatment*
- This option involves prescribing an antiviral for potential future use, which is not the primary goal of vaccinating against influenza and does not address the patient's need for immunization.
- Standby treatment does not provide the **prophylactic benefits** of vaccination.
*Administer influenza immunoglobulins*
- **Influenza immunoglobulins** are not a standard or routine method for providing protection against seasonal influenza in healthy individuals.
- They are typically reserved for specific situations involving severe immunocompromised patients or high-risk exposures.
*End the examination without additional measures*
- This would mean neglecting the recommendation for influenza vaccination and not addressing the patient's misconception about egg allergy.
- Healthcare providers should take steps to ensure patients receive recommended vaccinations, especially when the perceived contraindication is manageable.
Question 5: A 35-year-old male is found to be infected with an HIV strain resistant to saquinavir and zidovudine. Which of the following best explains the drug resistance observed in this patient?
A. HBV co-infection
B. env mutation
C. pol mutation (Correct Answer)
D. HIV evasion of host response
E. CCR5 mutation
Explanation: ***Correct: pol mutation***
- Saquinavir is a **protease inhibitor** and zidovudine is a **reverse transcriptase inhibitor (NRTI)**. Both target enzymes encoded by the **pol gene** in HIV.
- Mutations in the **pol gene** alter the structure of protease and reverse transcriptase enzymes, preventing drug binding and leading to resistance.
- This is the direct molecular mechanism explaining resistance to both drugs in this patient.
*Incorrect: HBV co-infection*
- **HBV co-infection** can complicate HIV treatment and lead to liver damage, but it does not directly cause resistance to antiretroviral drugs.
- While it may influence overall treatment strategy (e.g., choosing drugs active against both viruses), it does not explain the specific drug resistance mechanism observed.
*Incorrect: env mutation*
- The **env gene** encodes HIV **envelope proteins (gp120 and gp41)**, which are crucial for viral entry into host cells.
- Mutations in env typically affect **viral tropism** (CCR5 vs CXCR4 usage) or immune evasion, not resistance to protease or reverse transcriptase inhibitors.
*Incorrect: HIV evasion of host response*
- HIV's ability to evade the **host immune response** (through high mutation rate, latency, and immune cell destruction) is a general mechanism for chronic infection.
- This does not specifically explain resistance to particular antiretroviral drugs, which results from mutations in the viral proteins that drugs target.
*Incorrect: CCR5 mutation*
- **CCR5** is a host coreceptor that HIV uses to enter cells; a mutation in this gene (e.g., CCR5-Δ32 deletion) can confer natural resistance to HIV infection.
- However, **host** CCR5 mutations do not cause resistance to HIV drugs like saquinavir or zidovudine, which target **viral enzymes**, not host entry receptors.
Question 6: A 72-year-old man presents to the emergency department with a change in his behavior. The patient is brought in by his family who state that he is not acting normally and that his responses to their questions do not make sense. The patient has a past medical history of diabetes and Alzheimer dementia. His temperature is 103°F (39.4°C), blood pressure is 157/98 mmHg, pulse is 120/min, respirations are 19/min, and oxygen saturation is 98% on room air. Physical exam reveals a systolic murmur heard along the right upper sternal border. HEENT exam reveals a normal range of motion of the neck in all 4 directions and no lymphadenopathy. A mental status exam reveals a confused patient who is unable to answer questions. Laboratory values are ordered and a lumbar puncture is performed which demonstrates elevated white blood cells with a lymphocytic predominance, a normal glucose, and an elevated protein. The patient is started on IV fluids and ibuprofen. Which of the following is the next best step in management?
A. Acyclovir (Correct Answer)
B. MRI
C. CSF culture
D. CSF polymerase chain reaction
E. Ceftriaxone, vancomycin, and ampicillin
Explanation: ***Acyclovir***
- The patient's presentation with **fever**, **altered mental status**, and **lymphocytic pleocytosis** in the CSF strongly suggests **viral encephalitis**, particularly **herpes simplex virus (HSV) encephalitis**, given the elderly age and rapid deterioration.
- **Empiric acyclovir** treatment should be initiated immediately for suspected HSV encephalitis because delayed treatment significantly increases morbidity and mortality.
*MRI*
- While an **MRI of the brain** would be helpful in confirming the diagnosis, showing characteristic temporal lobe abnormalities, it should not delay the empirical treatment with acyclovir.
- Doing an MRI first could waste precious time, especially in a potentially life-threatening condition like HSV encephalitis.
*CSF culture*
- A **CSF culture** is useful for identifying **bacterial pathogens**, but the CSF analysis shows a **lymphocytic predominance** and **normal glucose**, which are more consistent with viral infection rather than bacterial meningitis.
- This test would be critical in bacterial meningitis, but less so as a *next best step* for this specific presentation.
*CSF polymerase chain reaction*
- **CSF PCR** for HSV is the **gold standard** for diagnosing HSV encephalitis and should be performed.
- However, the results take time, and treatment should not be delayed while awaiting these results due to the urgency of management for HSV encephalitis.
*Ceftriaxone, vancomycin, and ampicillin*
- This combination of **antibiotics** is used for **empiric treatment of bacterial meningitis**, which typically presents with **neutrophilic pleocytosis**, **low CSF glucose**, and **elevated protein**.
- Given the **lymphocytic predominance** and **normal glucose** in the CSF, bacterial meningitis is less likely, making these antibiotics not the most appropriate *next best step*.
Question 7: A 44-year-old man comes to the physician for a follow-up examination. Ten months ago, he was diagnosed with HIV infection and appropriate antiretroviral therapy was initiated. Physical examination shows no abnormalities. Laboratory studies show increased viral load despite ongoing treatment. His pharmacotherapy is switched to a new combination drug regimen including an agent that binds to glycoprotein 41. The expected effect of this drug is most likely due to inhibition of which of the following?
A. Viral genome transcription
B. Viral fusion and entry into host cells (Correct Answer)
C. Viral docking and attachment to host cells
D. Viral genome integration into host cells
E. Viral particle assembly
Explanation: ***Viral fusion and entry into host cells***
- The drug described binds to **glycoprotein 41 (gp41)**, a transmembrane protein on the HIV envelope critical for **viral fusion** with the host cell membrane.
- By binding to gp41, the drug prevents the conformational changes necessary for the virus to complete the fusion process, thereby **inhibiting its entry** into the host cell.
*Viral genome transcription*
- This process is primarily targeted by **reverse transcriptase inhibitors**, which prevent the conversion of viral RNA into DNA.
- Drugs affecting gp41 do not directly interfere with the transcription of the viral genome once inside the host cell.
*Viral docking and attachment to host cells*
- **Docking and attachment** are primarily mediated by **glycoprotein 120 (gp120)** on the viral surface binding to CD4 receptors and co-receptors (CCR5 or CXCR4) on the host cell.
- While gp41 is part of the same envelope protein complex, drugs targeting gp41 act subsequent to attachment, specifically during the fusion step.
*Viral genome integration into host cells*
- **Integration** of the viral DNA into the host cell genome is catalyzed by the **integrase enzyme**.
- Drugs targeting integrase prevent the irreversible insertion of viral DNA, which is a much later step in the viral life cycle than fusion.
*Viral particle assembly*
- **Viral assembly** involves the collection of viral components and their packaging into new virions, a process often targeted by **protease inhibitors**.
- Drugs acting on gp41 prevent the virus from entering the cell in the first place, thus not affecting the later stages of viral particle assembly.
Question 8: A 55-year-old man with HIV on antiretroviral therapy comes to the physician for a follow-up examination. His HIV viral load is 559 copies/mL (N<49). His physician is concerned about the development of drug resistance. The result of HIV genotype testing shows reduced viral susceptibility to darunavir and ritonavir. Which of the following molecular processes is most likely affected by this mutation?
A. Binding of aminoacyl-tRNA to ribosomes
B. Synthesis of DNA from an RNA template
C. Binding of glycoproteins to T-cell receptors
D. Integration of DNA into the host genome
E. Modification of translated proteins (Correct Answer)
Explanation: ***Modification of translated proteins***
- **Darunavir** and **ritonavir** are both **protease inhibitors**, which act by blocking the HIV protease enzyme.
- The protease enzyme is crucial for cleaving long polypeptide chains into functional proteins needed for viral assembly and maturation. A mutation leading to reduced susceptibility to these drugs implies an altered protease that is less inhibited, thus continuing to modify translated proteins.
*Binding of aminoacyl-tRNA to ribosomes*
- This process is primarily involved in **bacterial protein synthesis** and is the target of various antibiotics.
- It is not directly related to the mechanism of action of HIV protease inhibitors or HIV replication.
*Synthesis of DNA from an RNA template*
- This process is catalyzed by **reverse transcriptase**, which is targeted by nucleoside and non-nucleoside reverse transcriptase inhibitors.
- The patient's drugs, darunavir and ritonavir, are protease inhibitors, not reverse transcriptase inhibitors.
*Binding of glycoproteins to T-cell receptors*
- This step is part of the **viral entry mechanism**, where HIV's envelope glycoproteins (e.g., gp120) bind to CD4 receptors and co-receptors on host T-cells.
- This process is targeted by entry inhibitors, not protease inhibitors.
*Integration of DNA into the host genome*
- This step is mediated by the **HIV integrase enzyme**, which is targeted by integrase inhibitors (e.g., raltegravir, dolutegravir).
- The drugs mentioned, darunavir and ritonavir, do not inhibit integrase.
Question 9: A 63-year-old HIV-positive man comes to the physician for a routine health maintenance examination. Four years ago, he was diagnosed with HIV and was started on cART therapy. He tells the physician that he has been having difficulty adhering to his medication regimen. He has been unemployed for the past couple of years and relies on unemployment benefits to cover the costs of daily living. His father died of lymphoma at the age of 60 years. He wants more information about his risk of developing DLBCL. Which of the following is the greatest risk factor for the development of DLBCL in HIV-positive patients?
A. Poor adherence to cART (Correct Answer)
B. Income below $30,000 per year
C. Male sex
D. Positive family history of cancer
E. Age over 55 years
Explanation: **Poor adherence to cART**
- **Poor adherence** to cART leads to **uncontrolled HIV replication** and persistent **immunosuppression**, which significantly increases the risk of developing **DLBCL**.
- **Immune dysregulation** caused by HIV directly contributes to a higher incidence of **AIDS-defining malignancies**, including DLBCL.
*Income below $30,000 per year*
- While **socioeconomic factors** can impact access to care and medication adherence, low income itself is not a direct biological risk factor for DLBCL.
- Its influence is secondary to its effect on adherence and overall health status, rather than a primary risk factor for the malignancy.
*Positive family history of cancer*
- Although a family history of cancer can increase the risk for some malignancies, it is generally **not a significant risk factor** for **HIV-associated DLBCL**.
- The primary drivers of HIV-associated DLBCL are linked to HIV-induced immunodeficiency, not specific inherited genetic predispositions for lymphoma.
*Age over 55 years*
- While the incidence of many cancers increases with **age**, for **HIV-associated DLBCL**, age is less prominent than the degree of **immunodeficiency** caused by HIV.
- The stronger prognostic factor remains the state of the immune system, particularly a **low CD4 count**, which is often exacerbated by poor cART adherence.
*Male sex*
- While there are minor differences in cancer incidence between sexes, **male sex** is not a primary or significant independent risk factor for **HIV-associated DLBCL**.
- The risk is predominantly driven by factors related to HIV infection itself and the resulting immune dysfunction.
Question 10: A 27-year-old man is brought to the emergency department by his friends in a confused state. He was doing fine 5 days ago when he started to complain of fever and flu-like symptoms. His fever was low-grade and associated with a headache. For the past 2 days, he has become increasingly irritable, confused, and was getting angry at trivial things. Past medical history is unremarkable. He is a college student and is physically active. He smokes cigarettes occasionally. He drinks alcohol socially. He is sexually active with his girlfriend and they use condoms inconsistently. Physical examination reveals: blood pressure 120/80 mm Hg, heart rate 108/min, respiratory rate 10/min, and temperature 37.4°C (99.4°F). He is confused and disoriented. Pupils are 3 mm in diameter and respond to light sluggishly. He is moving all his limbs spontaneously. His neck is supple. MRI of the brain is shown in the picture. Cerebrospinal fluid (CSF) reveals an opening pressure of 16 cm of H20, a total leukocyte count of 112/mm3 with 85% lymphocytes, the protein of 42 mg/dL, and glucose of 58 mg/dL. What is the best treatment for this condition?
A. Intravenous immunoglobulin
B. High-dose steroids
C. Rituximab
D. Acyclovir (Correct Answer)
E. Ceftriaxone
Explanation: ***Acyclovir***
- The patient's presentation with **fever**, **flu-like symptoms** followed by **irritability**, **confusion**, and **MRI findings** suggestive of temporal lobe involvement, along with **lymphocytic pleocytosis** in CSF, is highly indicative of **herpes simplex encephalitis (HSE)**.
- **Acyclovir** is the treatment of choice for HSE, as it is an antiviral drug effective against the **herpes simplex virus (HSV)**. Prompt administration significantly improves outcomes.
*Intravenous immunoglobulin*
- **Intravenous immunoglobulin (IVIG)** is generally used for certain **immunodeficiencies** or **autoimmune conditions**, not for acute viral encephalitis like HSE.
- There is no evidence to support the use of IVIG as a primary treatment for HSV encephalitis.
*High-dose steroids*
- While steroids can reduce cerebral edema and inflammation, their routine use in **viral encephalitis** like HSE is **controversial** and not a first-line treatment.
- Steroids might be considered in specific cases of severe cerebral edema, but not as the primary antiviral therapy.
*Rituximab*
- **Rituximab** is a **monoclonal antibody** targeting **CD20-positive B cells**, primarily used in certain **lymphomas** and **autoimmune diseases** like **rheumatoid arthritis** or **multiple sclerosis**.
- It has no role in the treatment of acute viral encephalitis.
*Ceftriaxone*
- **Ceftriaxone** is a broad-spectrum **antibiotic** used to treat **bacterial meningitis** or other bacterial infections.
- It is ineffective against viral infections such as HSV encephalitis.
