Anti-glutamic acid decarboxylase autoimmunity presenting as chronic intestinal pseudo-obstruction with dysautonomia and late-onset autoimmune diabetes: A case report

Table 1 Laboratory results

Test	May 2023	September 2025	Units	Reference range
Urea	4.8	6.3	mmol/L	2.5-7.8
Sodium	138	139	mmol/L	135-145
Potassium	3.1 (decline)	4.5	mmol/L	3.5-5.3
Creatinine	103	62	μmol/L	59-104
eGFR	64.4	> 90	mL/minute/1.73 m²	-
ALT	38	30	U/L	5-41
Total bilirubin	8.3	7.9	μmol/L	2-21
ALP	268 (increase)	105	U/L	5-41
GGT	182 (increase)	15	U/L	10-71
Total protein	74	66	g/L	60-80
Albumin	32 (decline)	45	g/L	35-50
CRP	72.6 (increase)	3.8	mg/L	0-5
TSH	1.910	-	mIU/L	0.27-4.2
WBC	10.0	6.2	× 109/L	4.0-10.0
RBC	3.64 (decline)	5.07	× 109/L	4.50-5.50
Hb	10.8 (decline)	15.2	g/dL	13-17
HCT	0.32	0.46	L/L	0.40-0.50
MCV	86.5	91.3	fL	83-101
Platelets	189	191	× 109/L	150-400
INR	1.0	1.0	-	-
HbA1c	90	-	mmol/mol	-

ALP: Alkaline phosphatase; ALT: Alanine aminotransferase; CRP: C-reactive protein; eGFR: Estimated glomerular filtration rate; GGT: Gamma-glutamyl transferase; Hb: Hemoglobin; HbA1c: Glycated hemoglobin; HCT: Hematocrit; INR: International normalized ratio; MCV: Mean corpuscular volume; RBC: Red blood cells; TSH: Thyroid-stimulating hormone; WBC: White blood cells.

Table 2 Anti-glutamic acid decarboxylase antibody levels

Antibodies	April 2023	August 2023	March 2024	March 2025
Anti-GAD antibodies (IU/mL)	255	44.0	16.0	9.0
Anti-neutrophil antibodies	Negative	Not tested	Not tested	Not tested

Anti-GAD: Anti-glutamic acid decarboxylase.