WEEK 9 Flashcards
What is the terminology used to describe a part of a CXR that is too black/black in the wrong place? What pathology does this suggest?
Increased translucency
- air (gas)
- loss of tissue density
What is the terminology used to describe a part of a CXR that is too white/white in the wrong place? What pathology does this suggest?
Opacification
- fluid
- increased tissue e.g. lymphadenopathy (at hilum)
If part of a CXR is really, really white or very radio opaque, what could this suggest?
Think HARDWARE
- pacemaker
- endotracheal tube
- nasogastric tube
- sternal wiring
- prosthetic heart valves
- CVP line
- chest drain
When describing any abnormality, how do you explain WHERE said abnormality is?
Using ZONES (upper, middle and lower) Also specify if left or right sided abnormality
What is consolidation?
Replacement of normal air space gas with fluid/solid material
If a normal airspace is filled with (i) pus (ii) blood (iii) fluid (iv) cells (v) protein, what disease(s) could this suggest?
(i) infection (pneumonia)
(ii) pulmonary haemorrhage
(iii) pulmonary oedema, drowned lung
(iv) lung cancer
(v) alveolar proteinosis
What is atelectasis? (also can be referred to as collapse but the former is preferred)
Reduction in inflation of all or part of the lung
What on a CXR would make you suspect atelectasis? (HINT: there’s 6 things)
Volume loss Displacement of trachea Displacement of diaphragm Displacement of lung fissures Compensatory over inflation of non collapsed lung Crowding of vessels and bronchi
What are the causes of a deviated trachea (i) towards pathology (ii) away from pathology?
(i) pneumonectomy/lobectomy, lobar collapse
(ii) tension pneumothorax, (massive) pleural effusion, or any mass effect.
What does the ABCDE mneumonic stand for with regards to abnormalities seen on a CXR of a pt with pulmonary oedema?
A - alveolar oedema (bat wings) B - kerley B lines C - cardiomegaly D - upper lobe diversion E - pleural effusions
What is pneumoperitoneum?
When there is significant air underneath the peritoneum of the diaphragm
What does air in the soft tissues suggest?
Subcutaneous emphysema
What are the hidden areas when examining a CXR?
Apices
Behind the heart
Mediastinum: widening, adenopathy, mediastinal emphysema
But remember the hilum too!
What condition pushes the trachea away, has increased opacity, is dull to percuss on examination and decreases vocal resonance?
Pleural effusion
What is the pKa for carbonic acid/bicarbonate?
6.1
Describe a Davenport Diagram
pH<7.35 = acidosis
pH>7.45 = alkalosis
AB shows plasma pH changes as CO2 changes
CD shows plasma pH change when non-volatile acid (lactic acid, those derived from phosphate etc) is added/removed (static PCO2)
NOTE: volatile acid = CO2 based
What are the causes fo acid base disturbances?
increased CO2
Decreased CO2
Increased non-volatile acid/decreased base
Decreased non-volatile acid/increased base
What type of disorder is it if the primary change is to (i) CO2 levels (ii) bicarbonate?
(i) respiratory disorders
(ii) metabolic disorders
What is (i) acidosis (ii) alkalosis caused by?
(i) rise in PCO2, fall in HCO3-
(ii) fall in PCO2, rise in HCO3-
What are the 2 ways the lungs and kidneys try to return any disturbances to normal (i.e. compensation)?
- Respiratory system alters ventilation - immediate response
- Kidneys alter excretion of bicarbonate - takes 2-3 days
What are the various causes of respiratory acidosis?
COPD Blocked airway - foreign body/tumour Lung collapse Injury to chest wall Drugs reducing respirator y drive e.g. morphine, general anaesthetics, barbituates
What is the 2 compensations done for respiratory acidosis?
An increase in PCO2 causes increase in H+ so plasma HCO3- levels increase to compensate for increased H+
Renal - increased HCO3- reabsorption and increased HCO3- production, raising pH to normal
Respiratory acidosis results form an increase in PCO2 which is caused by what 2 things?
- Hypoventilation (less CO2 being blown away)
2. V/Q mismatch
Respiratory alkalosis results from a decrease in PCO2 generally caused by what?
Alveolar hyperventilation
- more CO2 being blown away
Decrease in H+ and therefore rise in pH