Resp 7 lung cancer and tb Flashcards
What are the main imaging techniques used in lung cancer ?
Chest X-ray
CT scan NB staging CT = extends down to kidney region
PET - to check for distant metastases
What imaging techniques are sometimes used in lung cancer ?
MRI
Ultra sound scan
Bone scan
ECHO
Where is lung cancer likely to spread to?
Lung, pericardium, pleura, draining lymph nodes Brain Bone Liver Adrenals
What methods are used for tissue sampling of suspected metastases ?
Bronchoscopy
Ultrasound scan
CT biopsy
Thorocoscopy
List the types of lung cancer (classified histologically)
Small cell carcinoma
Non small cell carcinoma:
Squamous cell carcinoma
Adenocarcinoma
Large cell carcinoma
What treatments are indicated for each histological tumour type? Describe the prognosis
Non small cell carcinoma
- surgery - 20-25% operable - best chance of cure
- otherwise combination chemotherapy - modest survival increase, symptom control
Small cell
- chemotherapy - potentially curative in a minority
Other treatments -
Combination chemoradiotherapy - potentially curative in a minority
Palliative care - NB can have greater survival time than chemo ( rduced infection risk etc) + better quality of life
Typical pattern of symptoms in lung cancer
1. Those caused by primary tumour
Commonly no symptoms until late stage
Respiratory : Cough Dysponea Wheezing Haemoptysis - coughing blood
Chest & shoulder pain
Lethargy / Malaise
Weight loss
Typical pattern of symptoms in lung cancer
- Those caused by metastases and metabolic changes
Bloated face - SVC obstruction
Hoarseness - left recurrent laryngeal n. palsy
Dysponea - anaemia, pleural or pericardial effusions
Dysphagia - oesophageal compression
Chest pain - parietal pleural involvement
Bone pain / fractures
CNS symptoms (blurred vision, confusion, headaches etc)
Seizures (hyponatreamia)
Thirst & constipation (hyperkaleamia)
Aetiological factors in lung cancer
Smoking!! - 80% of cases Asbestos Radon Occupational carcinogens - chromium, nickel & arsenic Genetic factors
Clinical signs in lung cancer
Often no signs
Consolidation Signs of pleural effusion Cervical (neck) lymphadenopathy Liver enlargement Finger clubbing Cachexia Muffled heart sounds Pale conjunctiva Horner's syndrome Skin metastases Neurological long tract signs
What group/s have highest incidence of lung cancer ?
Not simply smokers
Least affluent socio economic groups
What is the first line treatment for TB?
Multi drug regimen : Rifampicin Isoniazid Pyrazinamide Ethambutol
What are the symptoms of pulmonary TB?
Cough Night sweats Fever Weight loss & anorexia Tiredness & malaise
Breathlessness if pleural effusion
Occasionally haemoptysis
What investigations are indicated in suspected TB?
NB notifiable disease!
Chest X-ray
Sputum - 3 early am samples, min 5ml
Or induced sputum
Or bronchoscopy - pts w/ dry cough
HIV test
What are the radiological signs of TB?
Commonly apex of lung
Patchy consolidation
Caviation (black area with white border)
May see white areas of pleural effusion
What laboratory tests are used in cases of suspected active TB?
NB notifiable disease !
Ziehl Neelsen stain - stain pink (blue background)
Auramine stain - stain yellow ( black background - fluorescent stain)
Also nucleic acid amplification test
HIV test
Describe the test used for diagnosis of latent TB
Mantoux test
Tuberculin injected intradermally
Size of induration measure 2-3 days later
NB false positives (BCG, other mycobacterium)
And false negatives (Immunosuppression)
Describe in principle the TMN staging system
T - size, location and number of nodes
N- number of lymph nodes affected
M - metastasis - local intra thoracic or disseminated
What groups are at highest risk of TB in the UK?
Non UK born
Immunocompromised
Young adults
Homeless
Drug users
Prisoners
Describe relationship between HIV and TB
HIV at risk group as immunocompromised
Also at higher risk of reactivation in latent infection
Also extra pulmonary TB more likely
All confirmed and suspected cases of TB must have HIV test
What are the side effects of the multi drug regimen for TB?
Rifampicin -
raised transaminases & induces cytochrome p450
orange secretions
Isoniazid -
peripheral neuropathy
Hepatotoxicity
Pyrazinamide -
hepatotoxicity
Ethambutol -
visual disturbances
Describe microbiology of TB
Mycobacterium tuberculosis :
Non motile & rod shaped
Cell wall contains lots of long chain fatty acids, complex waxes and glycolipids -> can replicate inside macrophages, structural rigidity, acid & alcohol fast, staining characteristics
Relatively slow growing
Describe the pathogenosis of TB from primary infection to primary disease or latent TB.
Inhaled aerosol -> engulfed by alveolar macrophages -> local lymph nodes -> forms primary complex Which generally resolves via containment of the infection by the immune system (->latent disease) but can lead to primary disease
Describe what is seen in latent TB
Not much - not a case of TB, not infectious
(Negative CXR, sputum smears & cultures, no symptoms or signs)
But usually positive TST or IFN gamma result
