Symposium 1 - HIV and respiratory infections Flashcards
State which diseases are associated with decreasing CD4 lymphocyte count?
What are the differentials for respiratory infections in patients according to CD4 lymphocyte count?
Name the HIV related respiratory infections
- PCP pneumonia
- Bacterial pneumonias (CAP and HAP)
–Pneumococcal pneumonia
–H influenza
–Staphylococcus aureus
-Atypical agents
- C pneumoniae
- M pneumoniae
- Fungal pneumonias
–Aspergillosis
–Cryptococcis
–Histoplasmosis
•Viral pneumonias
–CMV pneumonitis
–Influenza
TB
What is the Epidemiology of Pneumocystis jiroveci Pneumonia?
- P jiroveci (formerly P carinii)
- Ubiquitous in the environment
- Initial infection usually occurs in early childhood
- PCP may result from reactivation or new exposure
- In immunosuppressed patients, possible airborne spread
Before ART, which infection was seen in 70-80% of AIDS patients?
PCP
Why has there been a decline in PCP cases?
Substantial decline in incidence in high income settings, owing to prophylaxis and ART
Which patients are usually infected by PCP?
Most cases occur in patients unaware of their HIV infection, in those who are not in care, and in those with advanced AIDS (CD4 count <100 cells/µL)
What are the risk factors for PCP?
- CD4 count <200 cells/µL
- CD4 percentage <14%
- Prior PCP
Oral thrush
- Recurrent bacterial pneumonia
- Unintentional weight loss
- High HIV RNA
What are the clinical manifestations of PCP?
- Progressive exertional dyspnea, fever, nonproductive cough, chest discomfort
- Subacute onset, worsens over days-weeks (fulminant pneumonia is uncommon)
- Chest exam may be normal, or diffuse dry rales, tachypnea, tachycardia (especially with exertion)
- Extrapulmonary disease seen rarely; occurs in any organ, associated with aerosolized pentamidine prophylaxis
How is PCP diagnosed?
•Clinical presentation, blood tests, radiographs suggestive but not diagnostic
–Organism cannot be cultured
–Definitive diagnosis should be sought
- Hypoxemia: characteristic, may be mild or severe (PO2 <70 mmHg or A-a gradient >35 mmHg)
- LDH >500 mg/dL is common but nonspecific
–1,3β-D-glycan may be elevated; uncertain sensitivity and specificity
How does PCP present on a chest x-ray?
–May be normal in early disease
–Typical: diffuse bilateral, symmetrical interstitial infiltrates
–May see atypical presentations, including nodules, asymmetric disease, blebs, cysts, pneumothorax
–Cavitation, intrathoracic adenopathy, and pleural effusion are uncommon (unless caused by a second concurrent process)
What does this chest x-ray show?
Chest X ray: PCP with bilateral, diffuse granular opacities
What does this chest x-ray show?
Chest X ray: PCP with bilateral perihilar opacities, interstitial prominence, hyperlucent cystic lesions
What does this HRCT show?
High-resolution computed tomograph (HRCT) scan of the chest showing PCP. Bilateral patchy areas of ground-glass opacity are suggestive of PCP.
How is a definitive diagnosis of PCP reached?
Definitive diagnosis requires demonstrating organism:
–Induced sputum (sensitivity <50% to >90%)
•Spontaneously expectorated sputum: low sensitivity
–Bronchoscopy with bronchoalveolar lavage (sensitivity 90-99%)
–Transbronchial biopsy (sensitivity 95-100%)
–Open-lung biopsy (sensitivity 95-100%)
–PCR: high sensitivity for BAL sample; may not distinguish disease from colonization
When should PCP treatment be started?
•Treatment may be initiated before definitive diagnosis is established
–Organism persists for days/weeks after start of treatment
When should PCP prophylaxis be initiated, discontinued and reinitiated?
Initiate:
–Consider for:
- CD4% <14% or history of AIDS-defining illness
- CD4 200-250 cells/µL if Q 3-month CD4 monitoring is not possible
Discontinue:
–On ART with CD4 >200 cells/µL for >3 months
Reinitiate:
CD4 decreases to <200 cells/µL
What is the preferred PCP prophylaxis?
–Trimethoprim-sulfamethoxazole (Septrim) DS 1 tablet PO QD*
–TMP-SMX SS 1 tablet PO QD
Desensatisation or dosage reduction of PCP prophylaxis should be considered for which patients?
For patients who experience non life-threatening adverse events, consider desensitization or dosage reduction.
* Effective such as toxoplasmosis prophylaxis (for CD4 count <100 cells/µL + positive serology)
What is the treatment for PCP?
- Duration: 21 days for all treatment regimens
- Preferred: Septrin is treatment of choice
–Moderate-severe PCP
- Septrin: IV or oral in divided doses
- Mild-moderate PCP
- Oral septrin
Adjust dosage for renal insufficiency
What is the ajunctive treatment for PCP?
–Corticosteroids
- For moderate-to-severe disease (room air PO2 <70 mmHg or A-a gradient >35 mmHg)
- Give as early as possible (within 72 hours)
- Prednisone 40 mg BID days 1-5, 40 mg QD days 6-10, 20 mg QD days 11-21, or methylprednisolone at 75% of respective prednisone dosage
What are the possible respiratory infections in the cART era?
High Income settings: CD4>250
–Bacterial pneumonia
–Hospital acquired pneumonia
–Other respiratory conditions: COPD, asthma, Lung cancer
–TB
–COVID-19 pneumonitis
Low income settings and CD4<250
–All of above plus
–PCP
–Fungal pneumonias
–TB
- COVID-19 pneumonitis
What interventions are important for HIV patients?
- Seasonal flu vaccine
- Pneumovax vaccine
- COVID-19 vaccination
- Smoking cessation
- Substance abuse counselling
- cART
