Chronic Respiratory Infection

Question 1

describe diagnosis of chronic respiratory infection and the differential diagnosis

Answer 1

shadow on CXR
weight loss
persistent sputum production 
chest pain 
increasing shortness of breath 
low levels of albumin in liver

similar to lung cancer (shadow on CXR and weight loss)
shadow on CXR in upper quadrant indicates TB (returning travelers, immunosuppressed patients - HIV)
persistent sputum production indicates infection;
intrapulmonary abscess
empyema
bronchiectasis
cystic fibrosis

Question 2

describe symptoms of chronic respiratory infection

Answer 2

weight loss
cachexia - weakness and wasting of body due to chronic illness
clubbing
lethargy

Question 3

describe the risk factors for developing chronic pulmonary infection

Answer 3

not normal to develop chronic lung infection;
abnormal host response - immunodeficiency (congenital, acquired), immunosuppression (drugs, malignancy)
abnormal innate host defence - damaged bronchial mucosa, abnormal cilia, abnormal secretions (CF)
repeated insult - aspiration, indwelling material

Question 4

describe immunodeficiency

Answer 4

an abnormal host response
primary immunodeficiency is not common, patients present with lung infection, sinusitis

immunoglobin deficiency;
IgA deficiency - common, increased risk of acute infections but rarely chronic
hypogammaglobulinaemia - rare, increased risk of acute and chronic infections
common variable immune deficiency (CVID) - most common cause of immunodeficiency, recurrent (ear) infections
specific polysacchardie antibody defiency (SPAD) - strepococcal infections

hypo-splenism

immune paresis - most common, myeloma, lymphoma, metastatic malignancy

HIV

Question 5

describe immunosuppression

Answer 5

an abnormal host response
increasingly common therapy for more and more disease processes;
steroids
azathioprine
methotrexate
cyclophosphamide
monoclonal antibodies - TNFa, CD20, leflunamide
chemotherapy - causes neutropenia (low level of neutrophils), exposing patients to bacterial and fungal infections (especially in the lung)

Question 6

describe the defective innate host defence

Answer 6

damaged bronchial mucosa - smoking, recent pneumonia or viral infection, malignancy
abnormal cilia - Kartenager’s syndrome, Young’s syndrome
abnormal secretions - CF, channelopathies

Question 7

describe Kartenager’s syndrome

Answer 7

rare, autosomal recessive genetic ciliary disorder comprising the triad of situs inversus, chronic sinusitis, and bronchiectasis. The basic problem lies in the defective movement of cilia, leading to recurrent chest infections, ear/nose/throat symptoms, and infertility

Question 8

describe young’s syndrome

Answer 8

combination of syndromes such as bronchiectasis, rhinosinusitis and reduced fertility

Question 9

describe repeated insult

Answer 9

recurrent aspiration - NG feeding, poor swallow, pharyngeal pouch
indwelling material - NG tube in wrong place, chest drain, inhaled foreign body (e.g. peanut, chicken bone)

Question 10

describe the different forms of chronic infection

Answer 10

intrapulmonary abscess
empyema
chronic bronchial sepsis
bronchiectasis 
cystic fibrosis and other oddities

Question 11

describe intrapulmonary abscess

Answer 11

indolent presentation 
weight loss common
lethargy, tiredness, weakness
cough +/- sputum 
high mortality if not treated 
usually a preceding illness of some sort - pneumonic infection, post viral, foreign body 
mortality is 10%

multiple abscess indicates the infection is from elsewhere circulating in the blood

Question 12

describe preceding illnesses of an intrapulmonary abscess

Answer 12

pneumonia;
influenza - staph pneumonia - cavitating pneumonia - abscess

aspiration pneumonia;
vomiting, lowered conscious level, pharyngeal pouch

poor host immune response;
hypogammaglobulinaemia

Question 13

describe the pathogens of intrapulmonary abscess

Answer 13

bacteria - strepoccous, staphylococcus, E-Coli, gram negative (worst kind)
fungi - aspergillus

Question 14

describe septic emboli

Answer 14

type of embolism that is infected with bacteria, resulting in the formation of pus
causes;
right sided endocardits (infection in endocardium)
infected DVT
septicaemia
intravenous drug users;
inject into groin
DVT
infection 
PE and abscesses

Question 15

describe empyema

Answer 15

pus in the pleural space
57% of all patients with pneumonia develop pleural fluid, the remainder are primary empyema - often iatrogenic, many idiopathic
high mortality - as high as severe pneumonia, >20% of all patients with empyema die

Question 16

describe the progression of pleural effusion to empyema

Answer 16

simple parapneumonic effusion;
clear fluid 
pH>7.2
LDH<1000
glucose>2.2

complicated parapneumonic effusion;
pH<7.2
LDH>1000
glucose<2.2
requires chest tube drainage 

empyema
frank pus
no other tests required
requires chest tube drainage

Question 17

describe bacteriology of empyema

Answer 17

aerobic organisms most frequently 
gram positive;
step milleri
staph aureus (usually post operative, or nosocomial)
immunocompromised
gram negative;
E-Coli
psedudomonas
haemophilus influenzae
kelbsiellae
anaerobes in 13% of cases ln
severe pneumonia or door dental hygiene

Question 18

describe diagnosis of empyema

Answer 18

clinical suspicion;
slow to resolve pneumonia
lateral chest film
CXR;
persisting effusion, particularly if loculations visible 
'D' sign
USS;
preferred investigation, bed side test
targeted sampling 
CT;
differentiation between empyema and abscess

Question 19

describe treatment of empyema

Answer 19

IV antibiotics;
broad spectrum 
amoxicillin and metronidazole initially 
oral antibiotics;
directly towards cultured bacteria 
co-amoxiclav

Question 20

describe bronchiectasis

Answer 20

(wide airway) localised, irreversible dilation of the bronchial tree
involved bronchi are dilated, inflamed and easily collapsible
airflow obstruction
impaired clearance of secretions - cilia does not work properly, failure of muscociliary escalator

Question 21

describe presentation of bronchiectasis

Answer 21

recurrent chest infections
recurrent antibiotic prescriptions
no response to antibiotics
short lived response to antibiotics

Question 22

describe diagnosis of bronchiectasis

Answer 22

radiological;
CT - dilation of airways, thickening of bronchial walls,, tapering of airways
in normal lung, the artery should be bigger than airway (other way round in bronchiectasis)

Question 23

describe pathophysiology of bronchiectasis

Answer 23

bronchial obstruction 
CF
young's syndrome 
kartanager's syndrome 
ABPA
immunodeficiency 
rheumatoid arthitis 
bronchopulmonary sequestration 
mounier-khun syndrome 
yellow nail syndrome 
traction bronchiectasis associated with pulmonary fibrosis

Question 24

describe chronic bronchial sepsis

Answer 24

all hallmarks of bronchiectasis but no bronchiectasis on the high resolution CT
confirmed positive sputum results
common in younger patients, mainly woman, involved in childcare
others are older, with COPD, or airways disease
same work up as bronchiectasis
sinuses - reservoir of infection

Question 25

describe treatment options for chronic bronchial sepsis

Answer 25

stop smoking 
influenza vaccine 
pneumococcal vaccine
reactive antibiotics;
send sputum sample
give antibiotics appropriate to most recent positive culture

if colonised with persistent bacteria;
oral macrolide antibiotics
nebulised gentamicin, colomycin
pulsed IV abx
alternating oral antibiotics

anti-inflammatory;
low dose macrolide antibiotics reduce exacerbation rates in bronchiectasis - clarithromysin, azithromycin
not effective in current smokers

Question 26

describe treatment of acute exacerbations of chronic bronchial sepsis

Answer 26

2 weeks of antibiotics appropriate to most recent positive sputum sample
send sputum every time
alter antibiotics if the sputum culture shows resistant organisms
aggressively eradicate pseudomonas aeriginosa