A Costly Assumption: Misinterpretation of Thyroid Function Tests Delaying Guillain-Barré Syndrome Diagnosis in Pregnancy
https://doi.org/10.15605/jafes.041.S1
- Author:
Chen Huey Ng
1
;
Wei Ton Wong
2
Author Information
1. Hospital Sultan Ismail Petra
2. Hospital Besut
- Publication Type:Journal Article
- MeSH:
Female;
Pregnancy;
Thyroid Function Tests
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):108-109
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:A common diagnostic error is the tendency to attribute
new symptoms directly to the most obvious laboratory
abnormality. In pregnancy, a suppressed thyroidstimulating hormone (TSH) with elevated free T4 is
frequently presumed to indicate primary hyperthyroidism,
overlooking the possibility of benign gestational transient
thyrotoxicosis (GTT). We report a case where this pattern led
to the misattribution of acute flaccid paralysis to thyrotoxic
periodic paralysis, critically delaying the diagnosis of
Guillain-Barré syndrome (GBS).
Case:A 21-year-old female Malay primigravida at 19 weeks and
5 days presented with a 2-week history of progressive,
descending bilateral lower limb weakness culminating in
paralysis, associated with vomiting and 5 kg weight loss.
On admission, she was febrile (38.0°C) and tachycardic
(150 bpm). Neurological examination revealed proximalpredominant flaccid paralysis and hyporeflexia with intact
sensation, without thyroid eye signs or goiter. Thyroid
function tests showed profound thyrotoxicosis (TSH <0.005
mIU/L, free thyroxine 4 20.16 pmol/L) with hypokalemia
(2.9 mmol/L). A neck ultrasound was normal. A provisional
diagnosis of thyrotoxic periodic paralysis with impending
storm was made, leading to treatment with potassium
replacement, propylthiouracil, and hydrocortisone.
Despite biochemical improvement, her paralysis persisted.
On day 5, she developed acute bulbar palsy and respiratory
failure requiring intubation. A subsequent comprehensive
workup for infectious, autoimmune (including thyroid
antibodies), and nutritional causes was unremarkable.
Nerve conduction studies confirmed the acute motor axonal
neuropathy (AMAN) variant of GBS. Treatment with a
5-day course of intravenous immunoglobulin resulted in
neurological improvement and successful extubation.
Conclusion:This case highlights the critical pitfall of prematurely
attributing acute neurological deficits to abnormal thyroid
function tests in pregnancy. Biochemical thyrotoxicosis,
including GTT, should not preclude urgent evaluation
for life-threatening neurological conditions such as GBS,
particularly when weakness is progressive or refractory to
metabolic correction.
- Full text:202608050828175885EP_A160.pdf
