Intersitital lung disease Flashcards
Compare and contrast interstitial vs alveolar pattern of lung disease on CXR and list the dominant cause of each pattern
Alveolar pattern - fluffy or blobby, ill defined margins, coalescing mergin, segmental lobar
-additional features include air brochagram
Dominant alveolar patterns
- pulmonary oedema
- lobar pneumonia
- haemorrhage
- lymphoma
- bronchioalveolar cell carcinoma
- ARDS
- aspiration pneumonia
Intersitial pattern - nodules, linear/reticular, reticulo nodular,
-Additional features - reduced lung volumes, honeycomb pattern
Dominant interstitial patterns
- TB
- Sarcoidosis
- idiopathic pulmonary fibrosis
- Rheumatoid lung
- scleroderma
- lymphangitis carcinomatosa
Discuss sarcoidosis and its epidemiology
Multi-system granylomatous disorder of unknown aetiology - characterised by noncaseating granulomas
Typically affects young person and presents with one or more fo the following
1) bilateral hilar adenopathy
2) pulmonary reticular opacities
3) skin, joint and/or lesions
Typicaly seen in patients between the age of 20-60 years of age
30% of patient are diganosed by characteristic CXR with hilar lymphadenopathy and reticular opacification
Diffuse interstitial lung disease is the most common presnetation with, pneumothorax, pleural thickening, chylothorax and pulmonary HTN being less common.
Discuss evaluation of sarcoid
History including occupational and environmental exposure
Full physical examination
●Laboratory testing (Serum ACE)
●Tuberculin skin test
●Posteroanterior chest radiograph and often high resolution computed tomography (HRCT)
●Pulmonary function tests
●Electrocardiogram
●Ophthalmologic examination
Discuss laboratory investigation (serum markers)
Ace level – elevated in 75% of untreated patients - however serum ACE has limited utility as a diagnostic test due to poor sensitivity and specificity
Elevated adenosine deaminase again low spec and sens
Discuss idiopathic pulmonary fibrosis
Idiopathic pulmonary fibrosis is defined as a spontaneously occurring specific form of chronic fibrosing interstitial pneumonia
Patient typically present at age 60 years or older- most patients have a history of smoking
Discuss TB pathophys
Mycobacterium tuberculosis causes human TB in nearly all cases
Two other mycobacterium havfe on rare occasion been implicated in TB M bovis and africanum
MTB is an intracellular aerobic nonmotile non spore forming bacillus with a waxy lipid coat. This coat is what make it acid fast
TB is spread via the respiratory route with droplet or aerosolization being the main vehicle - Risk of TB transmission increases when source patietns have airway and cavitary disease
Discuss clinical features of TB
High index of suspicion should be maintained for TB with poresentation such as isolated fever, chronic weakness, weight loss, failure to thrive and night sweats
Cough is the most common symptom of pulmonary TB patients presenting to the ED. It is more commonly a dry nonproductive cough
Many asymptomatic MTB patients present for medical attention because they are alarmed by haemoptysis
Clinical manifestation of TB in patients presenting to the ED may be especially challenging- 1/3 of ED patient wtih active pulmonary TB had a pulmonary chief complaint
Clinical manifestation of TB in patient co-infected wtih HIC are even more subtle and nonspecific
Describe population with the greatest risk for TB
- Close contacts of a known case
- persons with HIV infection
- foreign-born from Asia, Africa, Latin America
- Medically underserved, low income populations
- Older Adults
- Residents of long term care facilities
- Injection drug users
- Groups identified locally
Discuss complications of pulmonary TB
Haemoptysis – minor haemoptysis is a common complication of acute infection - the destruction of lung parenchyma leads to the rupture of blood vessels - an uncommon complications is the erosion of TB lesions or cavity into a pulmonary artery leading to pseudoaneurysm formation and potentially fatal haemoptysis
Pneumo thorax
Pleural effusion
Empyema
Aiway TB
Superinfection with fungi
Primary TB pericarditis
Discuss DDX of TB
Bacterial Pneumonia
Fungal and nontuberculous mycobacterial infection
Pneumonias in patient with HIV - PJP and rarely norcardia infection mimic HIV
Cavitary lesions
-Lung abcess or cavitating pneumonia caused by klebsiella, staph or aspiration may appear similar to cavitary TB on chest x-ray
Mediastinal lymphadenotpathy
The main ddx for mediastinal lymphadenopathy is lymphoma and sarcoidosis – sarcoid and lymphadenopathy tend to symmetical and bilateral as apposed to unilateral hylar adenopathy
Discuss extrapulmonary TB
Lymphadenitis
-most common form of extrapulmonary TB
Bone an joint infection
- Disease of older children and young adults
- Spinal TB (potts) accounts for 50-70% of the reported cases
- patients with pots may simply complain of backbain or stiffness
Renal disease
- the kidney is highly vascularized and haematgenous dissemination to that organ is fairly common
- Tuberculous granulomas, scarring and obstruction can occur anywhere along the urinary tract
Genital disease
Multisystem disease
- The term acute disseminated TB refers to active haematogenous spread of MTB to several organs in the body
- Milary TB refers to the massive dissemenation that leads to systemic disease
- SIADH is common and often associated with menigitis
CNS
-Approximatley 6% of extrapulmonary TB invovle the CNS
-peak incidence of TB occurs in newborns to 4 years
-
GIT
-usually secondary to haematogenous or lymphatic spread but also may result from swallowed bronchial secretions or direct spread
Discuss diagnosis of TB
WBC stimulation test – the patients blood can be tested for sensitivty of its t cells to tuberculin antigens – these test are called interferon gamma release assays
- the quantiferon gold and t-spot test are widley available
CXR - Primary
- TB infiltrates can occur in any lobe – usually limited to one lobe
- enlarged unilateral hilar or mediastinal nodes
- moderate to large pleural effusions
- if milary TB the presence of unnumberable 1-3mm nonclacified nodules
CXR - Postprimarry
- appears as a upper lung infiltrate or consolidation with or without cavitation
- can have multiopel lobes
- patient with bilateral upper lobe infiltrates are likley to have TB
- Fibrosis and cavitation are hallmark of post primary disease
Sputum test
Direct microscopy - acid fast - zeil nielson
Culture
TB skin test
- The tuberculin test is based on the principle that MTB infection induces sensitivity to certain antigens of the bacillus - these antigens are contained in the TB preparation called PPD
- in an affected patient the PPD test usually turns postive 3-8 weeks after infection when the immune response is developed
- Test results are read 48-72 hours after administration
- the largest area of palpable induration is measured and recorded in mm erythema by itself is not measured
Discuss ddx of interstitial lung disease
Upper zone predominant fibrosis (SCAT)
- silicosis, sarcoid
- pneumoconiosis
- aspergillosis
- TB
Lower zone - (BRASH)
- bronchiectasis
- rheumatoid arthritis
- asbestosis
- scleroderms
- idiopathic pulmonary fibrosis (hamman rich syndrome )
Either
- Radiation
- smoke inhlation
- ARDS
- drug induced (methrotrexate, hydralazine, nitrofurantoin, amioderone, busuplhan, cyclophosphamide, paraquat)
What are the four most commonly used first line agents for TB
RICE R- rifampin, I- isoniozide P-pyrazinamide E-ethambutol
Contact trace all jabronis
