Infectious Diseases Overview
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Questions and Answers

Which laboratory test result is commonly associated with Brucellosis?

  • Presence of anti-Ds-DNA antibodies
  • Elevated ESR > 100 (correct)
  • Increased white blood cell count
  • Positive Widal test (correct)

    • What is a key opportunistic infection associated with HIV pathogenesis?

  • Ameobiasis
  • Brucellosis
  • Hepatitis B
  • Tuberculosis (correct)

    • When investigating a fever of unknown origin, which investigation is most relevant?

  • Cultural analysis of blood or urine (correct)
  • Serological tests like ANA
  • Bone biopsy
  • Liver function test

    • Which of the following is a common complication of AIDS?

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

    What is a typical symptom of a Brucella infection?

    <p>Night sweats and weight loss (B)</p> Signup and view all the answers

    What is the best diagnostic test for Brucellosis?

    <p>Brucella agglutination test (A)</p> Signup and view all the answers

    Which of the following are common complications associated with AIDS?

    <p>Opportunistic infections (B)</p> Signup and view all the answers

    Which symptom is NOT associated with Brucellosis?

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

    What is the initial treatment for Brucellosis?

    <p>Doxycycline or Rifampicin (B)</p> Signup and view all the answers

    Which mode of infection is primarily associated with HIV?

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

    What best characterizes Fever of Unknown Origin (FUO)?

    <p>Fever above 38.5°C for 3 weeks without a diagnosis (C)</p> Signup and view all the answers

    Which opportunistic infection is most closely related to AIDS?

    <p>Tuberculosis (TB) (B)</p> Signup and view all the answers

    What is a key feature of the clinical presentation of AIDS?

    <p>Asymptomatic phase lasting up to 10 years (C)</p> Signup and view all the answers

    Which of the following is a common mode of transmission for Brucella infections?

    <p>Direct contact with infected animals (C)</p> Signup and view all the answers

    What is a key symptom associated with acute Brucellosis?

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

    Which laboratory investigation is primarily used for diagnosing Fever of Unknown Origin?

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

    Which complication is most commonly associated with AIDS?

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

    In HIV pathogenesis, which process leads to a decrease in CD4 T-cell counts?

    <p>Direct destruction of T-cells by the virus (C)</p> Signup and view all the answers

    What is one of the main bacterial causes of fever associated with travel to endemic regions?

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

    Which of the following is NOT a symptom of acute HIV infection?

    <p>Cough (B)</p> Signup and view all the answers

    In cases of brucellosis, which of the following is an important aspect of treatment?

    <p>Long-term antibiotic therapy (B)</p> Signup and view all the answers

    Flashcards

    Brucellosis cause

    Infectious disease caused by the bacteria Brucella.

    Brucellosis transmission

    Transmission occurs through contact with contaminated milk or aborted animal products from infected animals.

    AIDS etiology

    Acquired immunodeficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV).

    AIDS pathogenesis

    HIV infects T-lymphocytes, weakens both cellular and humoral immunity; when T-cells drop low, opportunistic infections develop.

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    AIDS diagnostic test

    The best diagnostic test for AIDS is HIV RNA by PCR.

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    Brucellosis diagnostic test

    The best diagnostic test for Brucellosis is a Brucella agglutination test.

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    Fever of Unknown Origin (FUO)

    Persistent fever (over 38.5°C) for 3 weeks without a clear diagnosis after a week of observation.

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    Brucellosis treatment

    Treatment for Brucellosis usually involves doxycycline or rifampicin for 6 weeks.

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    Infectious diseases

    Illnesses caused by pathogens like bacteria, viruses, fungi, or parasites.

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    Fever (pyrexia)

    Elevated body temperature above the normal range.

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    Typhoid Fever

    Infectious disease caused by Salmonella, transmitted through contaminated food/water; characterized by fever, rash, and other symptoms.

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    Salmonella

    Bacteria that cause typhoid fever.

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    Mode of Typhoid transmission

    Feco-oral transmission meaning it's spread through contaminated food or water.

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    Symptoms of Typhoid (1st week)

    Fever (step-ladder), headache, relative bradycardia, constipation, rash.

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    Symptoms of Typhoid (2nd week)

    Sustained high fever, tachycardia, diarrhea, splenomegaly (enlarged spleen).

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    Diagnosis of Typhoid (Investigations)

    Includes blood tests (CBC, Widal test), and cultures (blood, stool, urine), to confirm and monitor the infection.

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    What is the most common cause of FUO?

    The most common cause of Fever of Unknown Origin (FUO) is infections.

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    What are some examples of bacterial causes of FUO?

    Bacterial causes of FUO include tuberculosis (TB), infective endocarditis, typhoid fever, brucellosis, lung abscess, and pyelonephritis.

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    What are some examples of viral causes of FUO?

    Viral causes of FUO include Epstein-Barr virus (EBV), cytomegalovirus (CMV), HIV, and Hepatitis.

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    What is a typical lab finding in FUO?

    A high ESR (erythrocyte sedimentation rate) of over 100 mm/hr is typically seen in FUO due to infections, collagen diseases, and malignancy.

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    What are some imaging techniques used to investigate FUO?

    Imaging techniques used to investigate FUO include chest X-ray, bone X-ray, ultrasound of the heart, abdomen, and pelvis.

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    Study Notes

    Infectious Diseases Overview

    • Infectious diseases are a broad category encompassing various illnesses caused by pathogenic agents.
    • Learning objectives for this topic include understanding the pathophysiology, etiology, epidemiology, manifestations, complications, and management of key infectious diseases.
    • Knowledge of clinical manifestations and investigations is vital for reasonable diagnosis and implementing an effective management plan.

    Aetiological Classification

    • Bacterial:
      • Gram-positive: streptococci, staphylococci
      • Gram-negative: Klebsiella, Pseudomonas, Haemophilus influenza
      • Anaerobic bacteria: Bacteroides
    • Mycobacterial: Tuberculosis (TB), Leprosy
    • Spirochetal: Syphilis, Leptospirosis
    • Rickettsial: Typhus
    • Chlamydia
    • Viral: Dengue, influenza, Herpes Simplex Virus (HSV), Varicella-Zoster Virus (VZV), Cytomegalovirus (CMV), Epstein-Barr virus (EBV), Measles, Mumps, Rubella
    • Protozoal: Malaria, Amebiasis, Bilharzia, Giardiasis
    • Fungal: Candida albicans, Aspergillus niger

    Fever and its Types

    • Normal body core temperature ranges from 36.5°C to 37.2°C.
    • Fever (pyrexia): an increase in body temperature above the normal upper limit.
    • Types of fever:
      • Sustained fever: daily fluctuations of fever less than 1°C
      • Remittent fever: daily fluctuations of fever more than 1°C
      • Hectic fever: body temperature falls to normal once or more during the day.
      • Relapsing fever: days of fever interrupted by days of normal temperature
    • Hyperpyrexia: body temperature > 40°C

    Typhoid Fever

    • Aetiology: Caused by Salmonella typhi and paratyphi A & B; transmitted through feco-oral route.
    • Clinical manifestations:
      • Week 1: Step-ladder fever, headache, relative bradycardia, constipation, rash (rose spots).
      • Week 2: continuous fever, tachycardia, diarrhea, splenomegaly.
      • Week 3: convalescence begins
    • Complications: Intestinal bleeding, peritonitis, meningitis, encephalitis, convulsions, pyelonephritis.
    • Investigations: CBC (leucopenia with relative lymphocytosis), Widal test (+ve from 2nd week), blood, stool & urine cultures (+ve in week 1, 2, & 3, respectively – best diagnostic).
    • Treatment: Ciprofloxacin, co-trimoxazole (septrin), ceftriaxone.

    Brucellosis

    • Etiology: Caused by Brucella (melitensis, abortus, or suis)
    • Mode of infection: Contaminated milk or remnants of aborted animals
    • Clinical picture: Bone & muscle pain, vomiting, constipation, relapsing fever (days of fever alternating with fever-free periods).
    • Complications: Relapse, infective endocarditis, orchitis, paraplegia from transverse myelitis, abortion
    • Investigations: CBC (lymphocytosis during fever spike), Blood Culture (+ve during fever), Serological tests (Brucella agglutination test - best diagnostic test)
    • Treatment: Doxycycline or rifampicin for 6 weeks

    Acquired Immunodeficiency Syndrome (AIDS)

    • Aetiology: Infection with Human Immunodeficiency Virus (HIV).
    • Modes of infection: Parenteral, sexual, vertical
    • Clinical picture: Asymptomatic (lasting up to 10 years), Acute HIV syndrome (fever, rigors, arthralgia, rash for 2 weeks), symptomatic syndromes, and generalized lymphadenopathy.
    • Opportunistic Infections: Cytomegalovirus (CMV), Herpes Simplex Virus (HSV), Tuberculosis (TB), Pneumocystis carinii Pneumonia.
    • Secondary Neoplasms: Kaposi sarcoma, Non-Hodgkin's lymphoma.
    • Investigations: HIV antibodies (screening), HIV-RNA by PCR (diagnostic).
    • Treatment: Antiretroviral therapies (HAART), Zidovudine 600 mg/day orally.

    Fever of Unknown Origin (FUO)

    • Definition: Persistent elevation of body temperature over 38.5°C for 3 weeks, without a specific diagnosis after at least one week of inpatient investigations.
    • Causes: Infections (bacterial, viral, protozoal), Malignancy (hematologic or non-hematologic), Collagen disease, other conditions.

    Pulmonary Tuberculosis (TB)

    • Definition: Chronic infection of the lung caused by Mycobacterium tuberculosis, aerobic, non-motile, acid-fast bacillus.
    • Aetiology: M. Tuberculosis. Predisposing factors include children under 5, contacts with open TB patients, and immunocompromised individuals (e.g., AIDS, diabetes, leukemia, steroid use).
    • Mode of transmission: Droplet infection.
    • Symptoms: Toxic manifestations (night fever, sweating, weight loss), cough with sputum (mucoid, mucopurulent, sometimes blood-tinged), and chest signs.
    • Clinical features: Consolidation to cavitation and fibrosis, possible CNS involvement.
    • Investigations: Chest X-ray, ESR, C-reactive protein (CRP), sputum microscopy and culture, PCR, tuberculin skin test, and serological tests (Quantiferon Gold, anti-deaminase antibody (ADA)).
    • Treatment: First-line drugs (isoniazid (INH), rifampicin, pyrazinamide, ethambutol, streptomycin) combined for a long period, standard regimen for 6 months.

    Dengue Fever

    • Definition: A viral disease caused by the dengue virus.
    • Aetiology: RNA virus (Flavivirus, arbovirus).
    • Vector: Mosquito Aedes aegypti
    • Pathogenesis: Virus inoculated by mosquito bite, replication in reticuloendothelial system, leads to immune response, causing lymphocytic vasculitis and capillary leakage, resulting in possible complications.
    • Clinical features: Incubation period (5-9 days), fever, rapid defervescence, headache, mouth/nose bleeding, muscle pain, vomiting, rash, photophobia, eye pain, and various others, depending on the stage and type of dengue infection.
    • Complications: Dengue Shock Syndrome (DSS) and Dengue Hemorrhagic Fever (DHF).
    • Investigations: Elevated hematocrit, leucopaenia, low platelets, elevated liver enzymes, and serological tests (dengue antibody IgM and IgG ELISA), and PCR.
    • Management: Supportive, including intravenous crystalloids, paracetamol, platelet infusion and FFP.

    Prevention

    • Hand hygiene: 5 moments approach for hand hygiene, alcohol-based hand sanitizers, and use of appropriate personal protective equipment (PPE).
    • Respiratory precautions: Report symptoms of acute respiratory illness, covering mouth, proper hand hygiene, and tissue disposal, and provision of protective measures in specific cases.

    Other information

    • The presentation includes references.

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    Description

    Explore the vast field of infectious diseases, focusing on their pathophysiology, etiology, and epidemiology. This quiz will test your knowledge on various classifications of infectious agents, including bacteria, viruses, and protozoa, along with their clinical manifestations and management strategies.

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