THE LUNG AND HIV

Question 1

What percentage of HIV positive patients will experience at least one episode of respiratory disease over their lifetime?

Answer 1

60%

Question 2

Are HIV positive patient with a normal CD4 count any more prone to lung infections than the general population?

Answer 2

Yes - but to the same typical community-acquired infections

Question 3

What are the HIV associated respiratory tract infections?

Answer 3

Acute bronchitis

Acute sinusitis

Chronic sinusitis

Bronchiectasis

Bacterial pneumonia

Tuberculosis

Pneumocystis jirovecii pneumonia - PCP

Cryptococcus neoformans pneumonia

Histoplasma capsulatum

Influenza A

Question 4

What are the organisms that most commonly cause bronchitis?

Answer 4

Streptococcus pneumonia

Haemophilus influenzae

Question 5

What are the causative factors of bronchiectasis in an HIV positive patient?

Answer 5

Low CD4 count leads to recurrent bacterial, mycobacterial or pneumocystis infections. These eventually lead to bronchiectasis.

Question 6

What imaging technique is used to diagnose bronchiectasis?

Answer 6

High resolution CT

Question 7

How much more prone to bacterial pneumonia are HIV patients not taking cART?

Answer 7

6 - 10 times more likely

Question 8

What group of HIV positive patients are particularly prone to bacterial pneumonia?

Answer 8

IVDUs

Question 9

What is the organism most commonly responsible for bacterial pneumonia in HIV positive patients?

Answer 9

S. pneumoniae followed by H. influenzae

Question 10

What does bacterial pneumonia look like on a radiograph of someone who is HIV positive?

Answer 10

More frequently atypical, mimicking PCP in up to half of cases.

Question 11

What can we do to reduce risk of bacterial pneumonia in HIV positive patients?

Answer 11

Immunisation with 23-valent pneumococcal vaccination at diagnosis of HIV and at 5 years post diagnosis

cART to keep CD4 count high

Question 12

What type of organism is Pneumocystis jirovecii?

Answer 12

Fungus

Question 13

Which HIV positive patients are most at risk of PCP?

Answer 13

Those who are unaware of their diagnosis: it is a common presenting complaint that leads to HIV diagnosis

Those who do not tolerate or adhere to their cART

Question 14

What are the clinical features of PCP?

Answer 14

Non-productive cough

Progressive exertional breathlessness

Several days to weeks duration

With or without fever

Chest is usually clear on auscultation

End-inspiratory crackles are very occasionally heard

Question 15

What does a typical chest radiograph of someone with PCP looking like?

Answer 15

In early cases, 10% of cases will have normal looking chest x-ray

Most common features are bilateral, perihilar interstitial infiltrates - more clearly seen on CT scan

Progresses to diffuse alveolar shadowing over a period of a few days

Question 16

What are the atypical features of a chest radiograph of someone with PCP present in up to 20% of cases?

Answer 16

Upper zone infiltrates resembling TB

Hilar/mediastinal lymphadenopathy

Intrapulmonary nodules

Lobar consolidation

Question 17

How do we definitively diagnose PCP?

Answer 17

Sputum culture often reveals nothing

Bronchoalveolar lavage is needed to demonstrate PCP

However, patients are normally treated empirically especially if they have CD4 count less than 200

Question 18

How clinically stratify severity of PCP?

Answer 18

Mostly using PaO2 and SaO2

Mild:
PaO2 more than 11.0
SaO2 more than 96%

Moderate:
PaO2 between 8.1 - 11.0
SaO2 between 91 - 96%

Severe:
PaO2 less than or equal to 8.0
SaO2 less than 91

Question 19

What is the first line treatment in the management of PCP?

Answer 19

Co-trimoxazole BD or QDS for 21 days

Mild: PO

Moderate to severe: IV

Most will need admitting to ITU

Question 20

What are the two medications contained within co-trimoxazole?

Answer 20

Sulfamethoxazole 100 mg/kg/day

Trimethoprim 20 mg/kg/day

Question 21

What is the second line treatment in the management of PCP if co-trimoxazole fails?

Answer 21

MILD / MODERATE:
Clindamycin-primaquine

OR

Dapsone with trimethoprim

OR

Atovaquone

SEVERE:

Clindamycin-primaquine

OR

IV pentamidine

Question 22

What additional medication should patients with PCP who present with a PaO2 of less than 9.3 kPa be given?

Answer 22

Glucocorticoids within 72 hours of starting anti-PCP treatment

Question 23

What are the indications for prescribing prophylaxis of PCP?

Answer 23

CD4 count of less than 200 cells/microlitre

CD4 count of less than 14% of total lymphocytes

History of another AIDS defining diagnosis - eg Kaposi

All patients after an episode of PCP (secondary prophylaxis)

Question 24

What criteria must be met before a patient can come off secondary prophylaxis of PCP (ie post having the disease)?

Answer 24

Must be on cART

Have sustained increased in CD4 count over 200 cells/microlitre

Undetectable plasma HIV RNA

All for over 3 months

Question 25

What is the first choice drug and dose for PCP prophylaxis?

Answer 25

Co-trimoxazole - 480 mg OD or 960 mg 3 times weekly

Question 26

What are the second choice drugs that can be used for PCP prophylaxis?

Answer 26

Nebulized pentamidine Dapsone and pyrimethamine Atovaquone

Question 27

What are the two ways that pulmonary cryptococcal infection can present?

Answer 27

Either as a primary infection of lung OR As part of disseminated infection with meningitis with/without crytococcaemia

Question 28

What are the clinical features of pulmonary cryptococcal infection?

Answer 28

Chest is often clear May reveal some crackles Signs of disseminated cryptococcosis including diarrhoea, meningism and cutaneous lesions.

Question 29

What are the radiographic features of pulmonary cryptococcal infection?

Answer 29

Focal or diffuse interstitial infiltrates Focal masses Mediastinal or hilar lymphadenopathy Nodules or effusion

Question 30

How do we diagnose pulmonary cryptococcal infection?

Answer 30

Find cryptococcus neoformans in respiratory secretions or lung tissue (bronchoalveolar lavage)

Question 31

How do we treat pulmonary cryptococcal infection?

Answer 31

Fluconazole OR Liposomal amphotericin and flucytosine

Question 32

How frequent is primary pulmonary histoplasmosis?

Answer 32

Not at all. It almost invariably occurs as part of a disseminated infection.

Question 33

What are the typical features of histoplasmosis in an HIV patient?

Answer 33

Typically subacute presentation of weight loss and fever Non-productive cough Dyspnoea Hepatosplenomegaly

Question 34

What will a chest radiograph of someone with pulmonary histoplasmosis show?

Answer 34

Often normal Widespread small nodules (less than 4mm) in 1/3rd of cases

Question 35

How do we diagnose pulmonary histoplasmosis?

Answer 35

Bronchoalveolar lavage or lung tissue Serum 1-3 Beta D glucan levels may be elevated

Question 36

How do we treat mild histoplasmosis?

Answer 36

Itraconazole

Question 37

How do we treat more severe histoplasmosis?

Answer 37

Liposomal anphotericin

Question 38

What are the risk factors for aspergillus infection?

Answer 38

Neutropenia (therefore not that common in HIV) Corticosteroid therapy

Question 39

What are the clinical features of aspergillus infection?

Answer 39

Non-specific Cough Fever Dyspnoea Pleuritic chest pain can occur Haemoptysis can occur

Question 40

How do we diagnose aspergillus infection?

Answer 40

Identification in sputum or lung tissue Serum 1-3 Beta D glucan levels may be elevated

Question 41

How do we treat aspergillus infection?

Answer 41

Voriconazole OR Liposomal amphotericin

Question 42

How much more common is influenza A in HIV positive patients?

Answer 42

It isn't more common but there is a greater risk of more severe disease

Question 43

What are the typical features of influenza A in HIV positive patients?

Answer 43

Coryzal symptoms Fever Headache Myalgia

Question 44

How is influenza A diagnosed?

Answer 44

Detection of viral antigen or RNA is nasopharyngeal aspirate or nasal swab

Question 45

What treatment can be given to HIV positive patients diagnosed with influenza A?

Answer 45

Oseltamivir (Tamiflu) PO - neuraminidase inhibitor Zanamivir (Relenza) INH / IV - neuraminidase inhibitor

Question 46

Which HIV patients are most at risk of developing pulmonary CMV infection?

Answer 46

Those with CD4 count less than 100 Those with another diagnosis such as PCP

Question 47

How do we diagnose pulmonary CMV infection?

Answer 47

Characteristic intranuclear and intracytoplasmic inclusions in bronchoalveolar lavage fluid or lung tissue

Question 48

What are the non-malignant, non-infectious pulmonary conditions that HIV positive patients are at an increased risk of developing?

Answer 48

Non-specific pneumonitis Lymphocytic interstitial pneumonitis COPD Pulmonary arterial hypertension Pneumothorax

Question 49

What is non-specific pneumonitis?

Answer 49

Mimics PCP but often at higher blood CD4 counts

Question 50

How is non-specific pneumonitis diagnosed?

Answer 50

Biopsy: Transbronchial, Video assisted thoracoscopic surgery or open lung

Question 51

How do we treat non-specific pneumonitis?

Answer 51

Most episodes are self limiting Prednisolone may be beneficial

Question 52

Which group of HIV positive patients are most commonly affected by lymphocytic interstitial pneumonitis?

Answer 52

Children

Question 53

What are the clinical features of lymphocytic interstitial pneumonitis?

Answer 53

Clinically resembles idiopathic pulmonary fibrosis Slowly progressive dyspnoea Cough

Question 54

What does a typical chest radiograph of a patient with lymphocytic interstitial pneumonitis look like?

Answer 54

Bilateral reticulonodular infiltrates

Question 55

How do we definitively diagnose lymphocytic interstitial pneumonitis?

Answer 55

Biopsy

Question 56

How do we treat lymphocytic interstitial pneumonitis?

Answer 56

cART

Question 57

How much more common is pulmonary arterial hypertension in HIV positive patients?

Answer 57

6 - 12 times more common

Question 58

What should be excluded in all HIV positive patients who present with pneumothorax?

Answer 58

PCP