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Flashcards in respiratory infections and HIV Deck (22)
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1
Q

When was HIV identified

A

1984 HIV identified as a retrovirus and the cause of AIDS

Thought to have been transmitted from monkeys in the 1960s

2
Q

what is the natural history of HIV

A

Primary infection - dec CD4 over weeks, slight inc and then a gradual dec over years
sharp inc in HIV RNA, peak at acute HIV syndrome, drop and slow inc over years (clinical latency) and sharp inc at constitutional symptoms, opportunistic diseases and death

3
Q

what opportunistic infections are associated with a low CD4 count

A

Shingles <400
TB
oral thrush
PCP
Fungal meningitis and cerebral toxoplasmosis
CMV retinitis, MAI PML, cryptosporidosis <50

4
Q

how has HIV treatment progressed over the years

A

rapidly lethal then via incremental therapeutic advances to a manageable long term condition
ART (antiviral therapies) means that life expectancy is almost normal and quality of life in far improved

5
Q

what are comorbidities of HIV

A
CVD
chronic kidney disease
chronic liver disease
cancer
frailty
COPD
cognitive decline
polypharmacy
diabetes mellitus
6
Q

how can HIV be tested for

A

Rapid HIV test – finger prick

Confirmatory HIV test

7
Q

what respiratory infections are associated with chronic HIV CD4 count

A

Linked to
On effective cART
CD4 count
Other comorbidities
>500 - community acquired pneumonia, other URTI and TB
>350 - PCP, other HIV related pneumonia (fungal, viral, CMV, bacterial), TB

8
Q

types of HIV related respiratory infections

A

PCP pneumonia
Bacterial pneumonias (CAP and HAP)
Pneumococcal pneumonia, H influenza, staph aureus and atypical agents (C and M pneumoniae)
Fungal pneumonias
Aspergillosis, cryptococcis, histoplasmosis
Viral pneumonias
Influenza, CMV pneumonitis, TB

9
Q

what is PCP

A

Ubiquitous in the environment
Initial infection usually occurs in early childhood.
May result from reactivation or new exposure
In immunosuppressed patients it can possibly spread airborne

10
Q

who often has PCP

A

Before ART 70-80% AIDS patients with PCP
In advanced immunosuppression, treated PCP associated with 20-40% mortality
Substantial decline in high income settings – prophylaxis and ART
Most causes patients unaware of HIV infection eg not in care or advanced AIDS (CD4 <100)

11
Q

PCP risk factors

A

CD4 <200
CD4 <14%
Prior PCP
Oral thrush

12
Q

PCP symptoms

A

Recurrent bacterial pneumonia
Unintentional weight loss
High HIV RNA

13
Q

clinical manifestations of PCP

A

Progressional exertional dyspnoea, fever, non productive cough and chest discomfort
Subacute onset, worsens over days-weeks (fulminant pneumonia is uncommon)
Chest exam may be normal or diffuse dry rales, tachypnoea, tachycardia (esp exertion)
Extrapulmonary disease seen rarely, occurs in any organ, associated with aerosolized pentamidine prophylaxis

14
Q

How is PCP diagnosed

A

Clinical presentation, blood tests, radiographs suggestive but not diagnostic
Organism cannot be cultured, definitive diagnosis should be sought
Hypoxaemia: characteristics mild or severe
Low LDH uncommon but non specific
1,8B-D-glycan may be elevated, uncertain sensitivity and specificity
HRCT scan of chest showing PCP. Bilateral patchy areas of ground-glass opacity are suggestive of PCP

15
Q

can PCP be seen on X-ray

A

Normal in early disease
Typical diffuse bilateral, symmetrical interstitial infiltrates
Atypical including nodules, asymmetric disease, blebs, cysts, pneumothorax
Cavitations, intrathoracic adenopathy and pleural effusion uncommon (unless second concurrent process)

16
Q

how is PCP diagnosed definitively

A

Induced sputum - spontaneously expectorated sputum
Bronchoscopy with bronchoalveolar lavage
Transbronchial biopsy
Open-lung biopsy
PCR: high sensitivity for BAL sample; may not distinguish disease from colonization

17
Q

when is treatment for PCP initiated

A

be initiated before definitive diagnosis is established

Organism persists for days/weeks after start of treatment

18
Q

what is the primary prophylaxis of PCP

A
Initiate
Consider CD4% <14%, AIDS illness history, CD4 200-250 if cannot monitor for 3 months
Discontinue 
On ART CD4>200 for >3 months 
Reinitiate
CD4 decreases to <200
19
Q

How is PCP treated

A

preferred Septrim although there are alternatives

21 day regimen for all treatments

20
Q

what are PCP risk factors

A
Age
cART
HIV
Pollution?
Recreational drug use 
Comorbidities
Smoking
21
Q

what respiratory infections are seen in the cART era

A
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
22
Q

how can respiratory infections be prevented in HIV+

A
  • Seasonal flu vaccine
  • Pneumovax vaccine
  • COVID-19 vaccination
  • Smoking cessation
  • Substance abuse counselling
  • cART