Porphyria MCQ

Question 1

Question 1

Appropriate statements regarding labour and acute hepatic porphyria (AHP) include:
a) Regional anaesthesia is unsafe and should be avoided.
b) Clonidine cannot be used safely as an adjunct to bupivacaine when administering an epidural for labour analgesia.
c) Dimophine is considered to be safe and can be given during labour.
e)Routine drugs for labour such as ergometrine do not need to be avoided.

Oxytocin can be used for the induction and augmentation of labour.

Answer 1

a) False. Regional anaesthesia has been safely used in patients with AHP.
b) False. Clonidine is considered safe as it does not induce an acute porphyric crisis.
c) True. Diamorphine is considered to be safe as it does not induce an acute porphyric crisis.
d) False. Drugs known to be unsafe should be avoided, particularly as there are already other possible triggers (e.g. pregnancy, stress). ‘Unsafe’ drugs have been shown to be porphrynogenic in animals or in vitro. However, medicines including ergometrine can be used if required to treat a serious or life-threatening complication.
e) True. Oxytocin is considered safe as it does not induce an acute porphyric crisis.

Question 2

Question 2

You are consulted about a 34-yr-old woman with acute intermittent porphyria (AIP) who, 48 h ago, underwent surgery under general anaesthesia. Preoperatively, the serum sodium was 138 mmol L–1. She has deteriorated, and the treating team suspect an acute attack. After clinical review and discussion with the clinical team, which of the following would be an indication for requesting haem arginate for immediate treatment of an acute attack?

Nausea and vomiting.

Severe abdominal pain requiring intravenous morphine.

Serum sodium of 125 mmol L–1.

Hypertension and tachycardia.

enew proximal muscle weakness.

Answer 2

Rationale

a) False. Nausea and vomiting can be effectively managed by symptomatic measures.
b) False. Pain can be effectively managed by symptomatic measures.
c) True. Severe hyponatraemia during an acute attack can be difficult to manage, and haem arginate is indicated to terminate the attack.
d) False. Hypertension and tachycardia can be effectively managed with medication that is known to be safe.
e) True. Evolving motor neuropathy is an indication for urgent haem arginate therapy to prevent further deterioration.

Question 3

Question 3

A 30-yr-old man was admitted to the emergency department with weakness, fever, and generalised tonic clonic seizures. He was initially treated with intravenous phenytoin, ceftriaxone, and acyclovir. Despite optimal treatment he continued to have seizures. As his Glasgow Coma Score was 7 (Eye 1, Verbal 2, Motor 4), he underwent rapid sequence induction of anaesthesia with propofol 200 mg, fentanyl 100 µg, and rocuronium 80 mg. He was transferred to the ICU, where sedation was maintained with propofol and alfentanil. The results of most of the investigations were within normal limits. However, his urine has demonstrated a porphobilinogen (PBG)/creatinine ratio of 49 µmol mmol–1(reference interval <1.5 µmol mmol–1), and a diagnosis of acute porphyria has been made. Medicines considered to be safe in this patient include:
Rocuronium
Propofol
Phenytoin
Ceftriaxone

Answer 3

a) True. Alfentanil is considered safe to use in acute porphyria.
b) True. Rocuronium is considered safe to use in acute porphyria.
c) True. Propofol is considered safe to use in acute porphyria.
d) False. There is extensive evidence indicating that phenytoin has previously triggered acute attacks and is therefore considered unsafe to use in acute porphyria.
e) True. Ceftriaxone is considered safe to use in acute porphyria