Viral & Fungal Infections
40 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Why are systemic fungal infections often difficult to treat?

  • Fungal cells are structurally similar to bacterial cells, making them difficult to target with existing antibiotics.
  • Fungal infections are easily eradicated with short-term treatments.
  • The medications used to treat fungal infections are easily delivered directly to the site of infection in the body without causing off-target effects .
  • Some infections resist treatment, and prolonged therapy with potentially toxic drugs may be required. (correct)

    • Which of the following is a key difference between yeast and mold?

  • Some are part of the normal flora.
  • Yeast have thick rigid cell walls and molds do not.
  • Information comparing the details of yeast and mold has not been shared. (correct)
  • Yeast are always pathogenic, while molds are always beneficial.

    • Which of the following best describes the pathogenesis of systemic fungal infections?

  • They occur when environmental fungal spores or normal flora overgrow and invade the host defenses in immunocompromised individuals. (correct)
  • They primarily affect individuals with healthy immune systems who are exposed to high concentrations of fungal spores.
  • They result from direct person-to-person transmission through close contact or contaminated surfaces.
  • They arise when antibiotics disrupt the balance of normal flora, allowing opportunistic fungi to proliferate.

    • What is the primary challenge associated with systemic antifungal drug delivery?

    <p>Systemic antifungals can cause liver damage and are difficult to deliver. (C)</p> Signup and view all the answers

    Which clinical manifestation is most closely associated with superficial fungal infections?

    <p>Localized rash or itching. (D)</p> Signup and view all the answers

    Which of the following mechanisms describes how amphotericin B exerts its antifungal effect?

    <p>Binding to ergosterol in the fungal cell membrane, increasing permeability and causing leakage of intracellular cations. (C)</p> Signup and view all the answers

    Why are azole antifungals often preferred over amphotericin B for treating systemic mycoses?

    <p>Azoles generally exhibit lower toxicity and can be administered orally. (D)</p> Signup and view all the answers

    Which of these conditions is NOT typically treated with nystatin?

    <p>Tinea pedis (athlete's foot) (D)</p> Signup and view all the answers

    What is the primary mechanism by which acyclovir combats herpes simplex virus (HSV) infections?

    <p>It inhibits viral DNA polymerase, thereby suppressing viral DNA synthesis. (D)</p> Signup and view all the answers

    A patient receiving intravenous amphotericin B develops rigors. Which medication is most appropriate to administer?

    <p>Meperidine or dantrolene (D)</p> Signup and view all the answers

    Itraconazole's mechanism of action involves:

    <p>Inhibiting the synthesis of ergosterol and fungal cytochrome P450-dependent enzymes. (A)</p> Signup and view all the answers

    What is a major disadvantage of using azole antifungals?

    <p>Inhibition of P450 drug-metabolizing enzymes, leading to potential drug interactions. (A)</p> Signup and view all the answers

    Which statement is correct regarding fluconazole?

    <p>It is a fungistatic agent with good oral absorption, and IV/PO dosages are the same. (A)</p> Signup and view all the answers

    Which adverse effect is specifically associated with ketoconazole due to its impact on steroid synthesis?

    <p>Effects on sex hormones (C)</p> Signup and view all the answers

    What is the rationale for using multiple antiretroviral drugs in the treatment of HIV?

    <p>To target multiple stages of the viral life cycle and reduce the risk of drug resistance. (B)</p> Signup and view all the answers

    Zidovudine (AZT), a nucleoside reverse transcriptase inhibitor (NRTI), is used in HIV treatment. What is its primary mechanism of action?

    <p>Inhibiting HIV replication by suppressing the synthesis of viral DNA. (B)</p> Signup and view all the answers

    Efavirenz is a preferred NNRTI for treating HIV. Which of the following is a notable adverse effect?

    <p>Transient adverse CNS effects (C)</p> Signup and view all the answers

    Which of these statements accurately describes the difference between HIV and AIDS?

    <p>HIV is a condition with a normal CD4 count. AIDS is when the CD4 count drops below 200 and/or an opportunistic infection occurs. (A)</p> Signup and view all the answers

    Which of the following is NOT a common route of transmission for HIV?

    <p>Mosquito bites. (A)</p> Signup and view all the answers

    A patient is diagnosed with influenza and presents to the clinic 3 days after symptom onset. Which antiviral medication, if any, is most likely to be beneficial?

    <p>No antiviral medication is likely to be beneficial at this stage. (D)</p> Signup and view all the answers

    A patient presents with a suspected systemic fungal infection. Initial lab results show elevated neutrophils. What stage of infection does this most likely indicate?

    <p>Early stage, indicative of acute inflammatory response. (A)</p> Signup and view all the answers

    A patient is prescribed a systemic antifungal medication. Considering the limitations of systemic antifungal treatments, what is/are the most significant risk(s) the prescriber should consider?

    <p>Potential for liver damage and prolonged treatment duration. (D)</p> Signup and view all the answers

    Which statement best describes the challenges associated with treating systemic mycoses compared to superficial mycoses?

    <p>Systemic mycoses often require prolonged treatment with potentially toxic drugs, whereas superficial mycoses typically respond to localized treatment. (A)</p> Signup and view all the answers

    An immunocompromised patient is diagnosed with aspergillosis. Which category of antifungal drugs would be most appropriate as a first-line treatment, considering their mechanism of action and spectrum of activity?

    <p>Echinocandins, targeting the synthesis of beta-glucan in the fungal cell wall. (C)</p> Signup and view all the answers

    A patient undergoing treatment for a systemic fungal infection develops nephrotoxicity. Which class of antifungal agents is least likely to be the primary cause?

    <p>Echinocandins (D)</p> Signup and view all the answers

    Which of the following intravenous pretreatment options is LEAST likely to mitigate infusion-related reactions associated with amphotericin B, while also minimizing potential for additive adverse effects?

    <p>Aspirin + Meperidine (D)</p> Signup and view all the answers

    A patient develops a fungal infection resistant to fluconazole. Considering alternative azole antifungals, which factor would be MOST important when selecting a replacement therapy?

    <p>The potential for overlapping toxicities and drug interactions. (A)</p> Signup and view all the answers

    A patient with HIV develops oral thrush unresponsive to topical nystatin. Which systemic antifungal agent would be MOST appropriate, considering potential drug interactions with antiretroviral therapy?

    <p>Fluconazole, owing to its limited adverse effect profile (A)</p> Signup and view all the answers

    Which of the following statements BEST encapsulates the challenges in developing effective antiviral therapies, compared to antibacterial therapies?

    <p>Viruses' rapid mutation rates result in swift development of drug resistance, complicating long-term treatment strategies. (C)</p> Signup and view all the answers

    Acyclovir's mechanism of action is most directly affected by which of the following viral enzyme deficiencies?

    <p>Deficient thymidine kinase production prevents acyclovir activation (C)</p> Signup and view all the answers

    A patient receiving ganciclovir for CMV retinitis develops neutropenia. Which of the following strategies is LEAST appropriate?

    <p>Continuing ganciclovir at the same dose, while closely monitoring blood counts (D)</p> Signup and view all the answers

    What is the MOST accurate description of how HIV's reverse transcriptase contributes to the virus's ability to cause chronic infection?

    <p>It transcribes viral RNA into DNA, which can then be integrated into the host's DNA. (A)</p> Signup and view all the answers

    Why is adherence to HAART (Highly Active Antiretroviral Therapy) so critical in managing HIV infection?

    <p>To suppress viral replication, minimize drug resistance, and improve immune function. (A)</p> Signup and view all the answers

    Which antiretroviral drug class interferes with the late stages of the HIV replication cycle, specifically preventing the assembly of new viral particles?

    <p>Protease Inhibitors (D)</p> Signup and view all the answers

    A patient on efavirenz complains of vivid dreams and difficulty concentrating. What is the MOST appropriate initial intervention?

    <p>Reassure the patient that these effects are usually transient and advise monitoring. (A)</p> Signup and view all the answers

    Which mechanism differentiates NNRTIs from NRTIs in their action against HIV reverse transcriptase?

    <p>NNRTIs bind directly to the reverse transcriptase enzyme, causing a conformational change that inhibits its activity. (D)</p> Signup and view all the answers

    A patient tests positive for HIV but has a high CD4 count and no symptoms. What stage of HIV infection are they in?

    <p>Chronic HIV Infection (Stage 2) (A)</p> Signup and view all the answers

    What is the primary reason HIV requires lifelong treatment?

    <p>HIV integrates into the host DNA. (D)</p> Signup and view all the answers

    Which of the following infections is LEAST likely to be considered an 'opportunistic infection' in the context of HIV/AIDS?

    <p>Influenza (A)</p> Signup and view all the answers

    A patient with a known history of valvular heart disease is prescribed itraconazole for onychomycosis. What specific risk should be MOST carefully monitored?

    <p>Cardiosuppression (A)</p> Signup and view all the answers

    Flashcards

    Fungal Infection

    Infection caused by fungus, affecting skin or systemic areas.

    Immunocompromised Host

    A person with a weakened immune system, vulnerable to infections.

    Systemic Fungal Infection Symptoms

    Can include pain, malaise, fever, and increased neutrophils.

    Antifungal Treatment Difficulty

    Antifungal drugs can be hard to deliver and toxic, especially systemically.

    Signup and view all the flashcards

    Four Classes of Antifungal Drugs

    Includes Polyene, Azoles, Echinocandins, and more.

    Signup and view all the flashcards

    Amphotericin B

    A broad-spectrum antifungal agent used primarily for systemic mycoses.

    Signup and view all the flashcards

    Ergosterol

    A sterol component of fungal cell membranes that amphotericin B binds to.

    Signup and view all the flashcards

    Nephrotoxicity

    Kidney damage resulting from some medications like amphotericin B.

    Signup and view all the flashcards

    Infusion reaction

    Reactions like fever and chills occurring after administering amphotericin B.

    Signup and view all the flashcards

    Azoles

    A class of broad-spectrum antifungal drugs that inhibit ergosterol synthesis.

    Signup and view all the flashcards

    Itraconazole

    An azole antifungal effective against systemic mycoses with low toxicity.

    Signup and view all the flashcards

    Fluconazole

    An azole antifungal with good oral absorption and fungistatic properties.

    Signup and view all the flashcards

    Ketoconazole

    An azole used for systemic mycoses, lower effective but less toxic.

    Signup and view all the flashcards

    Candidiasis

    A fungal infection caused by Candida species, often treated with antifungals.

    Signup and view all the flashcards

    Acyclovir

    An antiviral medication used primarily for herpes virus infections.

    Signup and view all the flashcards

    HIV Pathogenesis

    The process by which HIV infects and destroys CD4 T cells.

    Signup and view all the flashcards

    NRTIs

    Nucleoside Reverse Transcriptase Inhibitors that inhibit viral DNA synthesis.

    Signup and view all the flashcards

    NNRTIs

    Non-nucleoside Reverse Transcriptase Inhibitors that directly inhibit reverse transcriptase.

    Signup and view all the flashcards

    Opportunistic Infections

    Infections that occur frequently in immunocompromised patients, like those with HIV/AIDS.

    Signup and view all the flashcards

    ART

    Antiretroviral therapy that reduces AIDS deaths and viral load.

    Signup and view all the flashcards

    Fungal Infection Etiology

    Caused by fungi, which have thick, rigid cell walls.

    Signup and view all the flashcards

    Superficial Fungal Symptoms

    Includes localized inflammation and itching.

    Signup and view all the flashcards

    Opportunistic Fungal Infections

    Infections that occur mainly in immunocompromised hosts, like candidiasis.

    Signup and view all the flashcards

    Difficulties with Antifungal Treatment

    Antifungal drugs can be hard to deliver and can damage the liver.

    Signup and view all the flashcards

    Ergosterol Binding

    Amphotericin B binds to ergosterol in fungal membranes, increasing permeability.

    Signup and view all the flashcards

    Cytomegalovirus (CMV)

    Herpesvirus transmitted through body fluids, can remain dormant.

    Signup and view all the flashcards

    Ganciclovir

    Synthetic antiviral for treating CMV infections, especially in immunocompromised.

    Signup and view all the flashcards

    Protease Inhibitors

    Effective antiretroviral drugs that reduce viral load, used with NRTIs.

    Signup and view all the flashcards

    HIV Integration

    Process where HIV integrates its DNA into the host's DNA with integrase.

    Signup and view all the flashcards

    Study Notes

    Fungal Infections

    • Fungal infections are caused by a thick-walled fungus.
    • Some fungi are part of the normal human flora.
    • Fungal infections can be superficial, subcutaneous, or systemic.
    • Superficial infections cause localized inflammation and itching.
    • Subcutaneous infections cause widespread inflammation, ulcers, and abscesses.
    • Systemic infections involve pain, discomfort, malaise, and possible fever.
    • Elevated neutrophils are often seen in early fungal infections.

    Systemic Fungal Infection Pathogenesis

    • Immunocompromised hosts are at increased risk for systemic fungal infections.
    • Environmental fungal spores or normal flora can overgrow and invade the host's defenses, leading to systemic infection.

    Treatment Implications

    • Antifungal treatments are often difficult to deliver effectively.
    • Topical antifungal use is sometimes possible.
    • Systemic antifungals can potentially stress or damage the liver.

    Antifungal Agents

    • Systemic mycoses/infections require antifungal drugs.
    • Superficial mycoses/infections require antifungals.
    • Some drugs treat both types.

    Systemic Mycoses

    • Immunocompromised hosts may develop opportunistic infections like candidiasis, aspergillosis, cryptococcosis, or mucormycosis.
    • Non-opportunistic infections, like Farmer's Lung Disease, can affect any host.
    • Fungal diseases include sporotrichosis, blastomycosis, histoplasmosis, and coccidioidomycosis.
    • Candida species often cause infections in mucous membranes and moist skin.
    • Chronic infections frequently affect the scalp, skin, and nails.
    • Examples of specific infections, include tinea pedis (feet), tinea corporis (body), tinea cruris (groin), and tinea capitis (scalp).
    • Oral candidiasis (thrush) and vulvovaginal candidiasis are common. Pregnancy, diabetes, debilitation, HIV, and certain medications are risk factors for vulvovaginal candidiasis.
    • Onychomycosis are fungal nail infections.

    Four Classes of Antifungal Drugs

    • Polyenes, Azoles, Echinocandins, and Pyrimidine analogs are four main classes of antifungal drugs.

    Amphotericin B

    • Amphotericin B is a broad-spectrum antifungal agent, sometimes used against protozoa.
    • It's highly toxic and often given intravenously.
    • It can cause infusion reactions, renal damage, and hypokalemia.
    • It works by binding to ergosterol in the fungal cell membrane.
    • Before amphotericin B, systemic fungal infections were often fatal.

    Amphotericin B: Adverse Effects

    • Infusion reactions include fever, chills, rigors, nausea, and headache.
    • Nephrotoxicity, hypokalemia, and bone marrow suppression are also possible side effects directly from the drug.

    Amphotericin B: Infusion Reaction (Cont.)

    • Pretreatment with diphenhydramine or acetaminophen is common.
    • Aspirin may increase renal damage.
    • IV meperidine or dantrolene may be required for severe reactions.

    Azoles

    • Azoles are broad-spectrum antifungals, often used as an alternative to amphotericin B for systemic mycoses.
    • They are generally less toxic and sometimes given orally, making them more convenient.
    • Azoles inhibit P450 drug-metabolizing enzymes, which can affect other medications.

    Itracaonazole [Sporanox]

    • Itraconazole is an azole antifungal.
    • It's used for systemic mycoses (alternative to amphotericin B).
    • It works by inhibiting ergosterol synthesis and fungal cytochrome P450 enzymes.
    • Common side effects include cardiosuppression, transient decrease in ventricular ejection fraction, and hepatotoxicity.
    • It's generally well-tolerated at standard doses.

    Fluconazole [Diflucan]

    • Fluconazole is a fungistatic azole antifungal.
    • It has a similar mechanism of action to itraconazole.
    • It's well absorbed orally and has the same IV and oral dosages.
    • Common side effects are nausea, headache, vomiting, abdominal pain, and diarrhea.

    Ketoconazole

    • Another azole antifungal, ketoconazole.
    • It's an alternative to amphotericin B, often used for chronic fungal infections.
    • It is generally less toxic than amphotericin B but has a slower effect.
    • Common side effects include GI issues (reduced with food), hepatotoxicity, and interactions with sex hormones.

    Viral Infections

    • Viruses are composed of a small capsid containing DNA or RNA, potentially with a protective envelope.
    • Examples include HIV, coronavirus, and adenovirus.
    • Viral infections involve penetration of host defenses, creation of viral RNA from the host cell DNA, and production (via host cell machinery) of viral proteins that form new virus cells. Release of the new viral bodies ends the infection cycle.
    • Immunization confers immunity by exposing hosts to pathogens and decreasing the number of susceptible hosts in the population.

    Antiviral Therapy

    • Treatment of viral infections is limited.
    • Viruses use host cell machinery to replicate.
    • Antivirals work by targeting unique processes in viral reproduction.

    Acyclovir [Zovirax]

    • Acyclovir specifically targets herpesvirus family viruses.
    • It's used to treat Herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections.
    • Some herpesviruses (like HSV) may develop resistance to acyclovir.
    • Possible side effects include phlebitis, reversible nephropathy, neurotoxicity, gastrointestinal issues, vertigo, and stinging sensations on topical use.

    Cytomegalovirus Infection

    • Cytomegalovirus (CMV) is a member of the herpesvirus family.
    • It's transmitted by direct contact with body fluids.
    • Most individuals show no obvious symptoms but the virus can remain dormant for life.
    • Immunocompromised patients are at high risk for reactivation.

    Ganciclovir [Cytovene, Vitrasert, Zirgan]

    • Ganciclovir is a synthetic antiviral agent used to treat or prevent CMV infections in immunocompromised individuals.
    • Possible side effects include granulocytopenia, thrombocytopenia, reproductive toxicity, nausea, fever, rash, anemia, liver issues, and central nervous system symptoms.

    Influenza Virus

    • Droplet precaution and the Tamiflu (Oseltamivir) vaccine are used for influenza treatment.
    • Treatment must begin within 48 hours of symptom onset.

    HIV Transmission

    • HIV can be transmitted through blood contact (needles, infected products), sexual contact, perinatal exposure (in utero, during delivery), and breast milk.

    HIV Pathogenesis & Treatment Implications

    • HIV targets T-helper cells and replicates by using the host's cellular machinery.
    • HIV's life cycle involves reverse transcription from RNA to DNA and integration into the host DNA. This sets the stage for replication, leading to proliferation and spread of HIV.

    HIV/AIDS Pathogenesis

    • HIV infection progresses through stages: acute infection, chronic HIV infection, and AIDS.
    • Acute HIV involves rapid viral replication, resulting in seroconversion—developing antibodies to the virus.
    • Chronic HIV has a clinical latency period, with the virus remaining (often with low replication levels).
    • AIDS emerges when CD4 T-cell counts fall below 200, setting the patient up for opportunistic infections.

    HIV/AIDS Clinical Manifestations

    • The clinical manifestations vary dependent on the stage of the infection, but symptomatic flu-like episodes in the first stage can be followed by a period of latency with no apparent or few symptoms, culminating in opportunistic infections in the later stages.

    Opportunistic Infections

    • Opportunistic infections occur more frequently in individuals with suppressed immune systems (like AIDS patients).
    • Examples include cryptosporidium (diarrhea), candida albicans (thrush), pneumocystis carinii pneumonia (PCP), mycobacterium avium complex (MAC), and Kaposi sarcoma.

    HIV/AIDS Treatment Implications

    • Antiretroviral therapy (ART) is essential.
    • Supportive care and treatment of opportunistic infections are crucial.
    • HIV is a retrovirus, with RNA as genetic material.
    • HIV uses reverse transcriptase to convert RNA into DNA and integrase to insert it into host DNA.
    • Principal target cells are CD4 T cells.
    • HIV is found in all body fluids.

    Human Immunodeficiency Virus

    • HIV causes immunodeficiency by killing CD4 T lymphocytes.
    • Standard antiretroviral therapy (ART) has greatly reduced AIDS deaths.
    • Highly active antiretroviral therapy (HAART) is a more advanced ART option.

    Classification of Antiretroviral Drugs

    • Five main classes of antiretroviral drugs include reverse transcriptase inhibitors, integrase strand transfer inhibitors, protease inhibitors, fusion inhibitors, and CCR5 antagonists.

    Nucleoside Reverse Transcriptase Inhibitors (NRTIs)

    • NRTIs inhibit HIV replication by suppressing viral DNA synthesis.
    • Common side effects include hematoxicity, lactic acidosis, myopathy, gastrointestinal issues, CNS reactions, and drug interactions.

    Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

    • NNRTIs directly inhibit reverse transcriptase and are active upon administration.

    Protease Inhibitors

    • Protease inhibitors are among the most effective antiretroviral drugs.
    • They're used in combination with NRTIs to reduce viral loads to undetectable levels.
    • Common side effects include hyperglycemia/diabetes, fat redistribution/hyperlipidemia, reduced bone density, increased bleeding in hemophiliacs, and drug interactions (particularly with other medications).

    HIV Integrase Strand Transfer Inhibitors (INSTIs)

    • INSTIs are indicated for combined use with other antiretroviral agents to treat HIV-1 infected patients.
    • Common side effects include insomnia, headache, and rare hypersensitivity reactions. FDA pregnancy risk is Category C.

    Enfuvirtide [Fuzeon]

    • Enfuvirtide is an HIV fusion inhibitor widely known as T-20.
    • It blocks HIV from entering CD4 T cells.
    • Common side effects include injection site reactions, pneumonia, and hypersensitivity reactions.

    Maraviroc [Selzentry]

    • Maraviroc is an CCR5 antagonist.
    • It's used in combination to treat CCR5-tropic HIV-1 patients.
    • Common side effects include drug interactions.

    Combination HIV Medications

    • Several combination medications are available to treat HIV.

    Principal Laboratory Tests Used to Guide Therapy

    • CD4 T-cell counts are a key measure of remaining immunocompetence.
    • Plasma HIV RNA (viral load) assays help guide treatment by monitoring viral levels.

    HIV Drug Resistance

    • In most cases, drug resistance emerges due to non-adherence to treatment regimens.
    • Some resistance can be caused by primary infections with drug-resistant HIV variants.

    HIV Treatment in Pregnancy

    • The same antiretroviral therapy principles that apply to nonpregnant adults also apply to pregnant women.
    • Mother-to-child transmission risk can be significantly reduced through ART.
    • HIV treatment principles apply to children in much the same way as they do for adults and pregnant women.

    HIV Treatment

    • Treatment strategies include young and older patient care, preventing HIV infection with drugs (both pre- and post-exposure prophylaxis), preventing perinatal transmission, and managing opportunistic infections.

    HIV Vaccines

    • Development of an effective HIV vaccine is challenging.
    • Current vaccine development efforts face various obstacles.

    .

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Viral and Fungal Diseases and Treatments PDF

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser