CRACKCast Episode 132 – HIV/AIDS

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This episode of CRACKCast covers Rosen’s Chapter 124 (9th Ed.), HIV/AIDS. Next time you look after an HIV/AIDS patient on shift, this episode will have you covered!

Shownotes – PDF Here

Rosen’s In Perspective

Box 124.2: Dermatologic and Mucocutaneous Manifestations of WHO Stage 4 HIV Disease

  1. Chronic herpes simplex virus ulcers
  2. Extrapulmonary tuberculosis
  3. Kaposi’s sarcoma
  4. Extrapulmonary cryptococcosis
  5. Disseminated mycosis
  6. Atypical disseminated leishmaniasis
  7. Disseminated nontuberculous mycobacterial infection
  8. Extrapulmonary cryptococcosis including meningitis

Box 124.3: Cutaneous Findings Highly Suggestive of HIV Disease

  1. Any WHO criteria for stage 4 HIV disease
  2. Facial molluscum in an adult
  3. Proximal subungual onychomycosis
  4. Herpes zoster scarring
  5. Oral hairy leukoplakia
  6. Bacillary angiomatosis
  7. Widespread dermatophytosis
  8. Severe seborrheic dermatitis

See Figure 124.4 for a graphic representation of the natural history of untreated HIV.

[1] Define AIDS

CDC definition:  “a CD4+ cell count below 200 cells/μL or the presence of an AIDS-defining condition.”

At this level, immune dysfunction is severe and, without ART, survival is short. Those with a CD4+ cell count below 50 cells/μL have advanced AIDS and are at much higher risk for death and development of opportunistic infections. Some infections are so common in patients with AIDS that primary prophylaxis is indicated and is cost-effective. Prophylaxis is started for PCP when CD4+ counts are less than 200 cells/μL, for toxoplasmosis, when CD4+ counts are less than 100 cells/μL and, for Mycobacterium avium complex (MAC) infection, when CD4+ counts are less than 50 cells/μL (Table 124.2).

[2] List 5 risk factors for HIV / AIDS

  • Contact with semen, blood, vaginal secretions, and breast milk of viremic individuals
  • These fluids must come into contact with damaged tissue / mucous membrane / entry into bloodstream.
  • HIV-positive blood transfusion MOST COMMON
  • exposure to serum with a high viral load
  • lack of male circumcision
  • presence of an ulcerative, sexually transmitted infection.
  • Type of sexual contact:
    • 1% to 30% for receptive anal intercourse
    • 0.1% to 10% for receptive vaginal and insertive anal intercourse
    • 0.1% to 1% for insertive vaginal intercourse.

After transmission, the virus replicates in the mucosal surface or lymphoid tissue at the site of entry in lymphocytes and macrophages. If enough cells are infected, the virus spreads to draining lymph nodes and infection is established, usually within 48 to 72 hours.

[3] List 10 AIDS defining conditions

Box 124.1 – AIDS-Defining Conditions

  1. Bacterial infections, multiple or recurrent
  2. Candidiasis of bronchi, trachea, or lungs
  3. Candidiasis of esophagus
  4. Cervical cancer, invasive
  5. Coccidioidomycosis, disseminated or extrapulmonary
  6. Cryptococcosis, extrapulmonary
  7. Cryptosporidiosis, chronic intestinal (>1 mo duration)
  8. Cytomegalovirus disease (other than liver, spleen, or nodes), onset at age >1 mo
  9. Cytomegalovirus retinitis (with loss of vision)
  10. Encephalopathy, HIV related
  11. Herpes simplex: chronic ulcers (>1 mo duration) or bronchitis, pneumonitis, or esophagitis (onset at age >1 mo)
  12. Histoplasmosis, disseminated or extrapulmonary
  13. Isosporiasis, chronic intestinal (>1 mo duration)
  14. Lymphoma, Burkitt’s (or equivalent term)
  15. Kaposi’s sarcoma
  16. Lymphoma, immunoblastic (or equivalent term)
  17. Lymphoma, primary, of brain
  18. Mycobacterium avium complex or Mycobacterium kansasii,disseminated or extrapulmonary
  19. Mycobacterium tuberculosis of any site, pulmonary, disseminated, or extrapulmonary
  20. Mycobacterium, other species or unidentified species, disseminated or extrapulmonary
  21. Pneumocystis jiroveci pneumonia
  22. Pneumonia, recurrent
  23. Progressive multifocal leukoencephalopathy
  24. Salmonella septicemia, recurrent
  25. Toxoplasmosis of brain, onset at age >1 mo
  26. Wasting syndrome attributed to HIV

Think head to toe and start listing conditions

[4] Describe 3 serum tests for HIV

  • HIV Serology. A screening CBC and CD4 count are the place to start, but you still need to send for serology!!!
  • Absolute lymphocyte count between 1000 and 2000 cells/µL appears to correlate with immunosuppression
  • CD4 count below 200!

Table 124.1: HIV Testing by Laboratory Stage

STAGE LABORATORY MARKER HIV STAGE
RNA p24 Antigen Third-Generation Antibody (EIA) Western Blot
1 + Acute HIV infection
2 +++ + Acute HIV infection
3 +++ +/− + Seroconversion
4 +++ +/− + Intermediate Seroconversion
5 ++ +/− + + Seroconversion
6 +–+++ +/− + + Chronic HIV infection (all Western blot bands are positive, older antibody tests react)
EIA, Enzyme immunoassay.

[5] List 6 causes of respiratory infection in HIV?

TABLE124.3 Differential Diagnosis of Respiratory Infections in HIV-Infected Patients by CD4+ Count

CD4+ COUNT AND STAGE DIFFERENTIAL DIAGNOSIS
Present at any stage Acute bronchitis
Bacterial pneumonia
Tuberculosis
>500 cells/µL Bacterial pneumoniaa
Early HIV infection PCPa
HHV-8–related Kaposi’s sarcoma
200–500 cells/µL Bacterial pneumoniaa
PCPa
<200 cells/µL Bacterial pneumoniaa (consider bacteremia)
AIDS PCPa
Histoplasma capsulatum or Coccidioides immitispneumonia
Cryptococcus neoformans pneumonia
Extrapulmonary or disseminated tuberculosisa
≤50 cells/µL Bacterial pneumoniaa
Advanced HIV infection PCPa
Toxoplasma gondii pneumonia
Pulmonary Kaposi’s sarcoma
Histoplasma capsulatum or Coccidioides immitispneumonia
Mycobacterium avium complex pneumonia
HHV-8, Human herpesvirus 8; PCP, Pneumocystis jiroveci pneumonia.

See Table 124.4 for the pulmonary manifestations of disease in HIV patients.

[6] Describe the presentation and treatment of PCP pneumonia

Presentation:

  • Gradual onset  non productive cough / dyspnea / fever  >2weeks
  • Typical CD4 < 200

Diagnosis:

  • Hypoxia w/ exercise (walk test)
  • Elevated LDH
  • CXR – bilateral retic / intersitial pattern (aka bat wing)
  • CT Chest – ground glass

See figures 124.5 and 124.6 for x-ray and CT images of Pneumocystis pneumonia.

TABLE124.5 Treatment of Pneumocystis jiroveci Pneumonia in Patients with HIV Infection

SEVERITY OF ILLNESS PREFERRED THERAPY ALTERNATIVE THERAPY
Moderate to severe TMP-SMX, IV; switch to oral administration after clinical improvement
21-day therapy
Pentamidine
or
Primaquine + clindamycin
Mild to moderate TMP-SMX Dapsone + trimethoprim
or
Primaquine + clindamycin
or
Atovaquone

[7] Describe an approach to diagnosis and management of CNS infection in AIDS

Any HIV/AIDS patient w/ headaches, abnormal neuro exam, change in mental status needs labs, cultures, imaging and CSF sampling.

Imaging: CT with Contrast

Common problems:

  • cryptococcal meningitis
  • Toxoplasmosis
  • primary central nervous system (CNS) lymphoma
  • progressive multifocal leukoencephalopathy
  • Neurosyphilis
  • Cryptococcal meningitis

See Table 124.6 for an extended list of causes.

Treatment:

  • ART is first line!
  • Chemo for lymphoma
  • amphotericin B and flucytosine for Crypto
  • pyrimethamine and sulfadiazine for toxoplasma
  • Careful with steroid use and false negatives for CNS lymphoma

[8] List 5 causes of odynophagia in HIV

Esophagitis is common in HIV/AIDS, think about it especially in patients with CD4 <100

  1. CANDIDA
  2. Herpes simplex virus
  3. CMV
  4. Deep aphthous ulcers
  5. Kaposi Sarcoma

[9] List 6 causes of diarrhea in the HIV patient

Bacteria

  • Clostridium difficile
  • Salmonella
  • Shigella
  • Campylobacter
  • Yersinia spp

Parasites

  • Cryptosporidium
  • Isospora
  • microsporidia

Virus

  • CMV

[10] Describe HAART therapy

Taken from UpToDate

“OVERVIEW OF HIV REPLICATION — The life cycle of HIV can be broken down into 6 steps: (1) entry (binding and fusion), (2) reverse transcription, (3) integration, (4) replication (transcription and translation), (5) assembly, and (6) budding and maturation. The identification and understanding of these processes have provided the basis for antiretroviral drug discovery.

  • Entry – Entry inhibitors: Maraviroc and enfuvirtide are antiretroviral agents that inhibit binding and fusion, respectively. However, these agents are not commonly used for the treatment of HIV infection.
  • Reverse transcriptionNucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs) inhibit the process of reverse transcription. There are several agents in each of these classes that are widely used for the treatment of HIV.
  • IntegrationIntegrase strand transfer inhibitors (INSTIs) inhibit the process of integration. In many countries, INSTIs are considered the preferred third agent (in combination with two nucleoside analogues) for treatment-naïve individuals.
  • ReplicationThere are no antiretroviral agents that inhibit this step of the replication cycle.
  • AssemblyThere are no antiretroviral agents that inhibit this step of the replication cycle.
  • Budding and maturationProtease inhibitors are antiretroviral agents that inhibit the HIV protease enzyme, and therefore, prevent this final step in the replication cycle.

See figure 124.3 for a visual representation of the HIV replication cycle.

[11] Describe prophylaxis of opportunistic infections

CD4 count Opportunistic Infection Treatment
<200 PCP / PJP Trimethoprim-Sulfamethoxazole DS x 1 tab daily
<100 Toxoplasmosis Trimethoprim-Sulfamethoxazole DS x 1 tab daily
<50 Mycobacterium Avium Complex Azithromycin / other macrolides

Wisecracks

[1] Risk stratify exposure to healthcare associated HIV and non-healthcare associated HIV.

Healthcare Associated Exposures

Needle stick injuries less than 1/300 get HIV. No recorded cases from intact skin.

Look at MDCalc Needle Stick

Factors increasing risk for needlestick injuries:

  • depth of injury
  • injury from a device visibly contaminated with the patient’s blood
  • needle stick into a vein or artery

Bodily fluids of concern include –

  • Semen / vaginal secretion / any fluid contaminated with visible blood
  • Potentially infectious body fluids include CSF / synovial / pleural / peritoneal / pericardial / amniotic
  • NO CONCERN: vomitus, feces, nasal secretions, saliva, sputum, sweat, tears, and urine

Low-risk injuries:

  • solid needles (eg, suture needles)
  • Superficial injuries
  • low-risk source patient or body fluid
  • mucocutaneous exposures

High-risk injuries: include those involving

  • hollow bore needles with visible blood
  • percutaneous injury from a needle that was in an artery or vein of the source patient
  • Mucocutaneous exposure involves large volumes of blood from a source patient with a plasma HIV viral load more than 1500 copies/µL,. Transmission is estimated to be as low as 0.09% (1/1000) for a splash of infectious body fluid to mucous membranes or broken skin.

Non-Healthcare Associated Exposures

Possible exposure include

  1. sexual contact
  2. injection drug use,
  3. body fluids contact through broken skin or mucous membranes.

High risk exposures:

  1. receptive anal intercourse
  2. presence of genital ulcerative disease
  3. receptive vaginal intercourse and insertive vaginal intercourse
  4. IVDU w/ contaminated needle

*See shownotes for additional notes on PEP (post-exposure prophylaxis)

[2] What is Coccidiomycosis?

  • Valley Fever!!! Fungal infection usually causing respiratory illness, possible extra-pulmonary disease as well
  • Think about in HIV/AIDS snowbirds (traveling patients) that visit the southwestern USA

[3] Name common ART agents and their adverse effects

Source: UpToDate

ART Drug Class Adverse effects
ENTRY INHIBITORS

Eg enfuvirtide

local cutaneous reactions
NUCLEOSIDE/NUCLEOTIDE REVERSE TRANSCRIPTASE INHIBITORS (NRTIS)

Eg Tenofovir disoproxil fumarate

Mitochondrial toxicity: manifest as peripheral neuropathy, pancreatitis, lipoatrophy, and/or hepatic steatosis. “black box” warnings for lactic acidosis
NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS (NNRTIS) (efavirenz and rilpivirine) can result in neurologic and psychiatric side effects.
INTEGRASE STRAND TRANSFER INHIBITORS (INSTIS)

Eg Raltegravir

insomnia and dizziness / depression / suicide
PROTEASE INHIBITORS (PIS)

Eg Darunavir

insulin resistance, hyperglycemia, diabetes, hyperlipidemia, lipodystrophy, hepatotoxicity, bleeding in patients with hemophilia, and PR interval prolongation

This post was uploaded and copyedited by Owen Scheirer (@OwenGregg1)

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Adam Thomas

Adam Thomas

Adam Thomas is a MedEd re-purpose-r. He cofounded the CrackCast project to fill the obvious gap in current FOAMed. He is a true podcasting supporter, and finds it to be the best way he learns. Currently a resident in the FRCP program at the University of British Columbia.
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Chris Lipp
Chris Lipp is one of the founding Fathers for CrackCast and an EM Resident in Victoria, BC. His interests are in sports, exercise, and wilderness medicine. When he isn’t out on one of his accidental 20km trail runs, you can find him jamming with friends, or outdoors, and reading Rosen’s…..
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