Respiratory System

Question 1

What is pleural effusion

Answer 1

Collection of serous fluid in pleural space
Hemo thorax
Chylothroax
Empyema

Question 2

Causes of pleural effusion

Answer 2

Caused due to increased hydrostatic pressure,decreased osmotic pressure(cardiac,liver,renal failure) or increased microvascular pressure due to disease of pleura or adjacent lung(exudative effusion)
Pneumonia (parapneuminic effusion)
Tuberculosis
Pulmonary infarction
Malignant disease
Cardiac failure
Subdiaphragmatic disorders(subphrenic abscess,pancreatitis)
Hypoproteinemia (liver failure nephoritc syndrome, malnutrition)
Meigs syndrome(ovarian tumour and effusion)

Question 3

Investigations for effusion

Answer 3

Radiological
. Chest xray
PA view,blunting of costophrenic angle,curved shadow at lung base tracking along lateral chest wall
200 ml fluid required to detect in xray
. USG
More accurate
Transudate and exudate
. CT scan
For malignancy

Aspiration
Colour and texture of fluid
Transudate or exudate
Gram stain

Question 4

Management of pleural effusion

Answer 4

Therapeutic aspiration
Not more than 1.5 l otherwise risk of re expansion pulm edema
Treatment of underlying cause

Question 5

Lights criteria

Answer 5

For distinguishing pleural transudate and exudate

Exudate is likely if one or more foll criteria is met
. Pleural fluid protein: serum protein ratio> 0.5
. Pleural fluid LDH: serum LDH ratio> 0.6
. Pleural fluid LDH >two thirds of upper limit of normal serum LDH

Question 6

Causes of dyspnea/ DD

Answer 6

Cardiovascular
. Acute
Pulmonary edema
. Chronic dyspnea
Chronic heart failure
Myocardial ischemia
Respiratory
. Acute
Acute severe asthma
Acute exc of COPD
pneumothorax
Pneumonia
Pulmonary embolus
ARDS
Inhaled foreign body
Lobar collapse
Laryngeal edema
. Chronic
COPD
chronic asthma
Lung cancer
Interstitial lung disease(sarcoidosis,pneumoconiosis)
Chronic pulm thromboembolism
Large pleural effusion
Others
. Acute
Metabolic acidosis(diabetic,lactic)
Hyperventilation
. Chronic
Anemia
Obesity

Question 7

What is asthma

Answer 7

Chronic inflammatory disorder of airway,associated with hyper responsiveness that leads to recurrent episodes of wheezing,cough,chest tightness, breathlessness particularly in night and early morning,airflow obstruction within lung is reversible,either spontaneously or with treatment.

Question 8

Pathophysiology of asthma

Answer 8

AHR-tendency of airways to narrow excessively in response to triggers
Atopy-propensity to produce igE

Aspirin sensitive asthma-ingestion of salicylates results in inhibition of cyclo-oxygenase enzymes shunting the metabolism of arachidonic acid through lipoxygenase pathway with resultant production of asthomgenic cysteinyl leukotreines.

Exercise induced asthma- hyperventilation results in water loss from pericellular lining or resp mucosa,which triggers mediator release. Also heat loss.

Question 9

Medication that triggers asthma

Answer 9

Beta blockers
Aspirin
NSAIDS
OCP
cholinergic agenst
Prostaglandin

Question 10

How to diagnose asthma

Answer 10

Compatible clinical history plus either/or
. FEV1 >=12% increase following adminstration of bronchodilator or glucocorticoid
. >20% diurnal variation on more than 3 days a week for two weeks
. FEV1>=15% decrease after six minutes of exercise

Question 11

Approach to mngmnt of asthma

Answer 11

1. Occasional use of short acting beta2 agonists (salbutamol,terbutalin)
2. Introduction of regular precentor therapy
   Beclamethasone,budasumide for patients who
   . Has exacerbation of asthma in last two yrs
   . Uses beta two agonists three times a week
   .reports symptoms three times a week
   .awakened by asthma one night a week
3. Add on therapy
   Long acting beta two agonist along with glucocorticoid (budesomide and formoterol)
4. Poor control of moderate dose of glucocorticoid and add on therapy:addition of fourth drug
5. Continuous or frequent use of glucocorticoid
   (Risk of systemic side effects,bisphosphonates to prevent osteoporosis,omalizumab,mepolizumab)
6. Step down therapy

Question 12

Immediate assessment of acute severe asthma

Answer 12

Acute severe asthma
.PEF 33-50%
.Heart rate >=110
Resp rate>=25
. inability to complete sentences in one breath
Life threatening features
.PEF<33%
.Pao2<8kPa
.normal or raised PaCo2
.silent chest
.cyanosis
.feeble resp effort
.bradycardia
.hypotension
.exhaustion
.delirium
.coma
Near fatal asthma
.raised PaCo2 requiring mech ventilation

Question 13

Indication for assisted ventilation in ASA

Answer 13

Coma
Resp arrest
Arterial blood gases(PaO2 <8;PaCo2>6; pH low and falling)
Exhaustion,delirium,drowsiness