Acid Base Disorders

Question 1

What are the causes of Respiratory Acidosis?

Answer 1

Caused by hypoventilation

Type 2 respiratory failure 
Respiratory Depression
Neuromuscular disease limiting ventilaiton  e.g. Scoliosis or Myastenia Gravis 
Very late stage Asthma
COPD Exacerbation

Question 2

What are the causes of Respiratory Alkalosis ?

Answer 2

Caused by hyperventilation

Anxiety Attack
Type 1 respiratory failure - PE or Asthma
CNS problems can cause abnormal breathing

Question 3

What are the causes of Metabolic Alkalosis?

Answer 3

Excessive Vomiting
Hypokalaemia
Loss through kidneys e.g. In Hyponatremia – Kidneys persevere Na and lose K+ in process

Question 4

What are the causes of Metabolic Acidosis?

Answer 4

Normal Anion Gap
Renal Tubular Acidosis
Diarrhoea
Addisons disease

Large Anion Gap
DKA
Methanol Poisoning 
Renal Failure - Urate build up
Lactic Acidosis - Shock/infection/ischamiea

Question 5

pH - Low
O2 - Low 
CO2 - High 
HC03 - Low 
Base Excess - Large anion gap

Answer 5

Mixed respiratory/metabolic acidosis
Causes:
Infective exacerbation of COPD - Reduced perfusion causes lactic acidosis on top of a type 2 respiratory failure

Question 6

pH - High
O2 - Normal
Co2 - Normal
HC03- High
Base Excess

Answer 6

Metabolic Alkalosis
Causes: - Vomiting
Children think Pyloric Stenosis
Adults think Peptic Ulcer
Elderly think Oesophageal/gastric Malignancy
Could be an Alkali overdose - E.g. Too much milk
Hypokalaemia

Question 7

pH - Low 
O2 - High
CO2 - Low
HCO3 - Low
Base Excess - Large anion gap

Answer 7

Partially compensated Metabolic Acidosis
Causes:
DKA
Aspirin Overdose
Methanol Poisoning
Look for Kussmaul’s Breathing -  deep and laboured breathing pattern to try and blow off CO2

Question 8

pH - Normal
O2 - High
CO2 - High
HCO3 - High
Base Excess  - Large anion gap

Answer 8

Compensated metabolic alkalosis or compensated respiratory acidosis
Compensated respiratory acidosis is the most likely
Causes:
Normal COPD - Not in exacerbation
Neuromuscular disease causing an inability to ventilate e.g. Scoliosis or Myasthenia Gravis

Question 9

pH - High
O2 - High
CO2 - Low 
HCO3 - Normal
Base Excess

Answer 9

Respiratory Alkalosis
Causes:
Hyperventilation due to panic attack etc

Question 10

pH -High 
O2 - Low 
CO2 - Low
HCO3 - Normal
Base Excess

Answer 10

Respiratory Alkalosis
Causes:
Type 1 respiratory failure