Opioid Overdose case

Question 1

What is the key diagnostic factor in a history of opioid overdose

What other signs may point to opioid overdose

Answer 1

Low RR
Pinpoint pupils
Signs of respiratory depression

Central cyanosis, low SO2

Question 2

What may the ABG show

What may the Aa gradient be

Answer 2

pH
-low => acidotic
PO2
-low due to low resp rate
PCO2
-high due to low resp rate
HCO3
-unlikely to be chronic CO2 retainer, may be normal

Aa gradient likely to be normal assuming this patient has no other underlying conditions => no issues with the alveolar capillary exchange surface

Type 2 resp failure

Question 3

What may a CXR show

Answer 3

NAD

Question 4

What are the possible other differentials for type 2 respiratory failure
Issue with the pump function
-VITAMIN CDEF

Answer 4

Iatrogenic/idiopathic
-Opioids, sedatives

Trauma

• head trauma
• surgery
• spinal cord, nerve injury

Autoimmune
-Myasthenia gravis

Metabolic
-Pompes

Inflammatory/infective
-Late stage COPD exacerbation

Neoplastic
-Malignant compression of the phrenic

Congenital
-DMD

Degenerative

• Disc prolapse
• MND

Question 5

How would you manage opioid overdose

Why does opioid overdose result in pinpoint pupils

Answer 5

Naloxone

Opiates block the inhibition of the oculomotor pupillary reflex at the Edinger Westphal nucleus