Rare coexistence of aldosterone resistance and adrenal insufficiency in asymptomatic infant with persistent hyperkalaemia: A case report

Table 1 Serial blood investigations of this patient

Serum/plasma	Day 1	Day 3		1 month follow-up	3 months follow-up	6 months follow-up	12 months follow-up	Reference range
Sodium (mmol/L)	138	139	Patient on oral hydrocortisone, fludrocortisone and kalimate	133	135	138	136	135-145
Potassium (mmol/L)	6.9	6.5		5.9	4.8	5.1	4.9	3.5-5.5
Urea (mmol/L)	3.3	3.6		5.3	5.0	5.2	4.9	2.7-8.0
Creatinine (µmol/L)	40	28		39	35	37	38	44-80
Chloride (mmol/L)	109	110		110	105	102	101	98-107
Calcium (mmol/L)		2.53		2.29	2.30	2.31	2.30	2.25-2.75
Phosphate (mmol/L)		2.10		1.07	1.17	1.20	1.23	1.15-2.25
Random cortisol (nmol/L)		63.4		221	350	445	515	130-500
Aldosterone (pmol/L)		1825		1050	802	750	735	70-540
Plasma Renin Activity (ng/mL/hour)		< 0.02		< 0.02	< 0.02	< 0.02	< 0.02	0.5-3.3
Venous pH		7.4		7.32	-	-	-	7.35-7.45
HCO3 (mmol/L)		19		23	-	-	-	22-28

Table 2 Short synacthen test

Time (minute)	Cortisol (nmol/L)	17-OHP (nmol/L)
0	17.9	1.57
30	81.1	4.15
60	94.15	6.85

Basal (0 minute) serum cortisol was low for age and gender specific range and shows inadequate response to synacthen test (a normal response shows cortisol rise of more than 374 nmol/L based on assay specific range)[17]. Basal 17-hydroxyprogesterone (17-OHP) and its stimulated level at 60 minutes was normal (normal basal 17-OHP is < 6 nmol/L and a normal stimulated level of 17-OHP is < 30 nmol/L at 60 minutes. 17-OHP: 17-hydroxyprogesterone.

Table 3 Causes of persistent hyperkalemia in an infant

Differential diagnosis	Description	Test findings	Treatment
Congenital adrenal hyperplasia[18]	Inherited autosomal recessive disorder affecting adrenal steroidogenesis, most commonly is 21-hydroxylase deficiency	Raised serum 17-OHP, hypocortisolism, hyperkalaemia, hyponatraemia, Short synacthen test shows adrenal insufficiency, and genetic testing to proved the specific mutated gene involved	Glucocorticoids and mineralocorticoids (to also replace concurrent mineralocorticoid deficiency)
Hypoaldosteronism[19]	Insufficient aldosterone production or action, leading to hyperkalemia and metabolic acidosis. It could coexist with other conditions such as primary adrenal insufficiency or part of RTA type 4	Hyperkalemia and metabolic acidosis. Low urine pH in RTA type 4, hypocorticolism with ACTH stimulation test proved adrenal insufficiency in Addison’s disease	Fludrocortisone, salt supplementation, management of underlying conditions
AKI[20]	KDIGO defined AKI as an increase in serum creatinine (absolute increase of ≥ 0.3 mg/dL within 48 hours or relative increase of ≥ 50% from baseline within 7 days) and reduction in urine output (urine volume less than 0.5 mL/kg/hour for at least 6 hours)	Raised serum creatinine and urea, hyperkalaemia, hyponatraemia, emerging renal biomarker to detect early AKI e.g. neutrophil gelatinase-associated lipocalin	Depending on types (e.g., hydration for pre-renal AKI, renal replacement therapy for severe acute tubular necrosis), correction of electrolyte disturbances

AKI: Acute kidney injury; RTA: Renal tubular acidosis; 17-OHP: 17-hydroxyprogesterone; KDIGO: Kidney disease: Improving global outcomes; ACTH: Adrenocorticotropic hormone.