Respiratory system: High-yield review quiz #5

1. HIV/AIDS (www.medbullets.com)

Random notes:

– seeing someone with oral thrush, candida is a RED FLAG
– could be – pneumocystis jirovecii (fungus)
– if there are also bacterial infections, more destruction!
– know the HIV/AIDS drugs & MOA e.g., cytokine inbititors, protease inhib., intergrase inhib.
– (primary prophylaxis) Trimethoprim-sulfamethoxazole-induced Steven Johnson syndrome in an HIV-infected patient. Trimethoprim-sulfamethoxazole (TMP/SMX) is a widely prescribed antimicrobial.
– In the early stages, you might see acterial pneumonia, TB, or oral thrush and others..
– In the late stage where CD4 < 200 there maybe pneumocystis pneumonia, disseminated TB, atypical mycobacteria, cryptococcus, toxoplamosis.
(Pneumocystis pneumonia (PCP) is a form of pneumonia, caused by the yeast-like fungus, Pneumocystis jirovecii. Pneumocystis pneumonia is not commonly found in the lungs of healthy people, but, being a source of opportunistic infection, it can cause a lung infection in people with a weak immune system).
– when there is sustained CD4 >200, discontinuation of antibiotic prophylaxis is possible
– remember that with ACE inhib. (- pril), there is an increase in bradykinin which may lead to dry cough, so replace the ACE if causing a dry cough
– think about the reasons for hypoxemia (see ABG lecture)
– watch out for V/Q mismatch/hypoventilation, if you see a pt with sats of 89% on room air, and corrects to 94% on 4L 02…something is not right, think of the cause

WEBMD:

Nucleoside/Nucleotide Reverse Transcriptase Inhibitors (NRTIs)

NRTIs force the HIV virus to use faulty versions of building blocks so infected cells can’t make more HIV.

Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

These are also called “non-nukes.” NNRTIs bind to a specific protein so the HIV virus can’t make copies of itself, similar to jamming a zipper.

Protease Inhibitors (PIs)

These drugs block a protein that infected cells need to put together new copies of the HIV virus.

Cobicistat (Tybost) is a drug that helps atazanavir and darunavir work better, but it can cause life-threatening kidney problems if you take it with certain other medicines.

  • Atazanavir + cobicistat, or ATV/COBI (Evotaz)
  • Darunavir + cobicistat, or DRV/COBI (Prezcobix)

Fusion Inhibitors

Unlike NRTIs, NNRTIs, and PIs — which work on infected cells — these drugs help block HIV from getting inside healthy cells in the first place.

Enfuvirtide, or ENF or T-20 (Fuzeon), has been approved by the FDA. Fostemsavir, ibalizumab, PRO 140, and others are being tested for approval.

CCR5 Antagonist

Maraviroc, or MVC (Selzentry), also stops HIV before it gets inside a healthy cell, but in a different way than fusion inhibitors. It blocks a specific kind of “hook” on the outside of certain cells so the virus can’t plug in.

Integrase Inhibitors

These stop HIV from making copies of itself by blocking a key protein that allows the virus to put its DNA into the healthy cell’s DNA. They’re also called integrase strand transfer inhibitors (INSTIs).

Fixed-Dose Combinations

Some drug manufacturers put together specific medicines into a single pill so they’re easier to take, including:

  • Abacavir + dolutegravir + lamivudine, or ABC/DTG/3TC (Triumeq)
  • Abacavir + lamivudine, or ABC/3TC (Epzicom)
  • Abacavir + lamivudine + zidovudine, or ABC/3TC/ZDV (Trizivir)
  • Efavirenz + emtricitabine + tenofovir, or EFV/FTC/TDF (Atripla, Tribuss)
  • Elvitegravir + cobicistat + emtricitabine + tenofovir, or EVG/COBI/FTC/TAF or ECF/TAF (Genvoya)
  • Elvitegravir + cobicistat + emtricitabine + tenofovir, or EVG/COBI/FTC/TDF or ECF/TDF (Stribild)
  • Emtricitabine + rilpivirine + tenofovir, or FTC/RPV/TAF (Odefsey)
  • Emtricitabine + rilpivirine + tenofovir, or FTC/RPV/TDF (Complera)
  • Emtricitabine + tenofovir, or TAF/FTC (Descovy)
  • Emtricitabine + tenofovir, or TDF/FTC (Truvada)
  • Lamivudine + zidovudine, or 3TC/ZDV (Combivir)

Truvada has also been approved as a way to prevent HIV infection for people who are at high risk. Even if you take it, you have to practice safe sex, too.

 HIV Diagnostic tests:

From medbullets.com:

4 stages of infection
– flu-like illness (acute stage)
– feeling fine (latent stage)
– virus replicates in lymph nodes
– falling CD4 count
– final crisis

IRIS

Immune reconstitution inflammatory syndrome (IRIS) (also known as immune recovery syndrome[1]) is a condition seen in some cases of AIDS or immunosuppression, in which the immune system begins to recover, but then responds to a previously acquired opportunistic infection with an overwhelming inflammatory response that paradoxically makes the symptoms of infection worse.[2]

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2. Goodpasture Syndrome (scroll down)

From medbullets.com:

apidly progressive glomerulonephritis
  •  Goodpasture syndrome  
    • type II hypersensitivity
    • anti-GBM antibodies against α3-chain of collagen type IV
       

      • antibodies to the alveolar basement membrane result in hemoptysis and lung disease
  • Pauci-immune processes
    • granulomatosis with polyangiitis
    • microscopic polyangiitis
  • Light microscopy and immunofluorescence
    • crescent-shaped deposition of fibrin, C3b, glomerular parietal cells, monocytes, and macrophages 
    • Granulomatosis with polyangiitis
      • PR3-ANCA/c-ANCA positive 

       

 

  • Microscopic polyangiitis
    • MPO-ANCA/p-ANCA
  • Corticosteroids and cyclophosphamide

 

– Alpha3 chain of type 4 collagen
– HLA – DR2, youg women, old men
– plasmaporesis, cyclophosphamide, corticisteroids (e.g., prednisone)
– deposits of IgG in basement membranes of glomerulus and alveolar BM.
– azithroprine
– HLA DR2, DR4, DR15
– hemoptysis, low-grade fever, myalgias…
– Dx, anti-GBM antibodies, ELISA
– atypical pneumnia, dark urine, could be dehydration
– NC domain, non-collagnous portion
– Type 2 antibody reaction (immune complex membrane attack)
– unmasking hidded epitopes
– DDx, IgA nephropathy, vasculitis (ANCAS)
– act fast as rapidly fatal!

==============================

Q: what organisms would you see in bacterial tracheitis?
A: Bacterial tracheitis is usually caused by Staphylococcus aureus bacteria. Other bacteria can also cause it, including:

Streptococcus pneumonia
Hemophilic influenza
Moraxella catarrhalis

==============================

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3. Influenza

– hemagglutinin (binds virus to cells, viral entry)
– neuroamidase (virus replication and translation)
– Drift (small change, slow) vs shift Major change (rapid, pandemic), Only influenza A can do this

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4. Pertussis

– gram neg, bortatella pertussis
– 7 to 9 yrs old
– toxin causes damage, inhibits macs, polys
– affects cilliated epithelial cells
– neutrophils cause damage too
– DDx PAH for older pts.

STAGES: (medbullets.com)

Whooping cough has 4 stages

  • incubation (7-10 days)
    • no symptoms
  • catarrhal (1-2 wks)
    • most contagious phase
    • similar to mild upper respiratory infection
    • low grade fever
  • paroxysmal (2-4 wks)
    • characteristic bursts of nonproductive cough with “whoops”
    • vomiting
    • leukocytosis
  • convalescent
    • attacks become less frequent
    • complications may develop (pneumonia, seizures, encephalopathy)

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5. Croup / epiglottitis / tracheitis

Croup link

‘Steeple sign’
PARAINFLUENZA

– laryngotracheobronchitis
– INSPIRATORY STRIDOR
– VIRAL, RSV, Influenza, admission, adenovirus, mycoplasma pneumonia
– laryngitis
– 3rd generation cephalosporin g.neg and g.pos
– normal diameter of the throat is 6-7 cm for kids, 15 cm for adults, so lower radius leads to incre. in resistance

EPIDEMIOLOGY

– kids, 3-5

  • parainfluenza virus is most common cause of croup (#2 RSV) (diagnose with PCR)

Epiglottitis link (scroll down a bit)

‘thumb sign’

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