Author: Kate Smith / Editor: Jason Kendall / Reviewer: Raja Shahid Ali / Codes: NeuP3, PhC2, PhC4, PhP1, SLO1 / Published: 11/05/2020

A 40-year-old man had a seizure which was witnessed by his wife; she reported that he was unresponsive and all limbs were shaking; the seizure terminated spontaneously after approximately 10 minutes. There was no incontinence.

Preceding symptoms:

He felt lightheaded and anxious, turning blue around the lips and face.
Recovery: he recovered relatively quickly over approximately 10 minutes, afterwards felt slightly tired, and his anxiousness remained.

Background:

His children have been calling him “Papa Smurf” as he periodically turns blue. He has suffered headaches, fatigue, intermittent syncope and feeling weak for the last 12-18 months.

He drinks alcohol to excess, historically consuming 2 bottles of wine a day plus 2 units of spirits, which has reduced to half a bottle of wine a day and no spirits in the last month with support of GP.
He had two recent episodes of mixed overdoses of venlafaxine and mirtazapine within the last month.
He takes no over-the-counter, internet-acquired or illicit drugs or supplements.
He has had no foreign travel in the last 2 years.

PMH: Depression
DH: Mirtazapine, venlafaxine, diazepam
SH: Unemployed, smoker, ETOH excess
FH: Nil

On examination: alert, orientated, anxious, peripheral and central cyanosis, saturations of 81% on air, high respiratory rate and tachycardic.

Venous blood gas:
PH 7.37, pC02 4.8kPa, p02 7.0kPa,
Na140mmol/l, K 4.4mmol/l, CL- 105mmol/l, Ca++ 1.17mmol/l,
Glucose 5.2,
Lactate 3.0mmoll,
tHB 168g/l, O2Hb 56.8% COHb 0.0%. MetHb 33.7%, HHb 7.5%, sO2 88.7%,
Base Excess -3.8, AG 19, HCO3- 20.7mmol/l, Hct 50%

You recognise this patient has significantly elevated Methaemoglobin levels.

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