Acute Respiratory Distress Syndrome

Question 1

What is it?

Answer 1

Increased permeability of the alveolar capillaries - fluid accumulation in alveoli- NON CARDIOGENIC PO

Question 2

Causes of ARDS

Answer 2

infection: sepsis, pneumonia
massive blood transfusion
trauma
smoke inhalation
acute pancreatitis
cardio-pulmonary bypass

Question 3

Clinical features of ARDS

Answer 3

dyspnoea
elevated respiratory rate
bilateral lung crackles
low oxygen saturations

Question 4

Key investigations

Answer 4

Chest X-ray

Arterial blood gases

Question 5

Criteria for ARDS

Answer 5

Acute onset- within 1 week of a known risk factor
Pulmonary oedema- bilateral infiltrates on Chest x-ray- not fully explained
pO2/FiO2

Question 6

Management for ARDS

Answer 6

Management
due to the severity of the condition patients are generally managed in ITU
oxygenation/ventilation to treat the hypoxaemia
general organ support e.g. vasopressors as needed
treatment of the underlying cause e.g. antibiotics for sepsis
certain strategies such as prone positioning and muscle relaxation have been shown to improve outcome in ARDS

Question 7

What is LEMS?

Answer 7

Lambert-Eaton syndrome
seen in association with small cell lung cancer and to a lesser extent breast and ovarian cancer.

• Caused by an antibody directed presynaptic voltae-gated calcium channel in the peripheral nervous sytem

Question 8

Features of LEMS

Answer 8

Repeated muscle contractions lead to increased muscle strength ( in contrast to myasthenia gravis) 
Limb-girdle weakness 
Hyporeflexia 
Autonomic symptoms 
Othalmoplegia

Question 9

Management of LEMS

Answer 9

Treatment of underlying cancer
Immunosuppression- prednisolone and/ or azothiprine
3,4-diaminopyridine trialled by blocking potassium channel efflux in the nerve terminal
Calcium channels can then be open for a longer time and allow greater acetylcholine release to stimulate muscle at end place
IV immunoglobulin and plasma exchange

Question 10

Features of small cell: lung cancer

Answer 10

• Usually central
  Arise from APUD cells
  Associated with ectopic ADH, ACT secretion
  ADH- hyponatraemia
  ACTH- Cushing’s syndrine
  ACTH secretion- bilateral adrenal hyperplasia- hypokalaemic alkalosis

Question 11

What is Ipratropium

Answer 11

A SAMA