| Literature DB >> 24616761 |
N Amin1, N S Alvi1, J H Barth2, H P Field2, E Finlay3, K Tyerman3, S Frazer4, G Savill5, N P Wright6, T Makaya6, T Mushtaq1.
Abstract
UNLABELLED: Type 1 pseudohypoaldosteronism (PHA) is a rare heterogeneous group of disorders characterised by resistance to aldosterone action. There is resultant salt wasting in the neonatal period, with hyperkalaemia and metabolic acidosis. Only after results confirm isolated resistance to aldosterone can the diagnosis of type 1 PHA be confidently made. Type 1 PHA can be further classified into i) renal type 1 (autosomal dominant (AD)) and ii) multiple target organ defect/systemic type 1 (autosomal recessive (AR)). The aim of this case series was to characterise the mode of presentation, management and short-term clinical outcomes of patients with PHA type 1. Case notes of newly diagnosed infants presenting with PHA type 1 were reviewed over a 5-year time period. Seven patients were diagnosed with PHA type 1. Initial presentation ranged from 4 to 28 days of age. Six had weight loss as a presenting feature. All subjects had hyperkalaemia, hyponatraemia, with elevated renin and aldosterone levels. Five patients have renal PHA type 1 and two patients have systemic PHA type, of whom one has had genetic testing to confirm the AR gene mutation on the SCNN1A gene. Renal PHA type 1 responds well to salt supplementation, whereas management of patients with systemic PHA type 1 proves more difficult as they are likely to get frequent episodes of electrolyte imbalance requiring urgent correction. LEARNING POINTS: Patients with type 1 PHA are likely to present in the neonatal period with hyponatraemia, hyperkalaemia and metabolic acidosis and can be diagnosed by the significantly elevated plasma renin activity and aldosterone levels.The differential diagnosis of type 1 PHA includes adrenal disorders such as adrenal hypoplasia and congenital adrenal hyperplasia; thus, adrenal function including cortisol levels, 17-hydroxyprogesterone and a urinary steroid profile are required. Secondary (transient) causes of PHA may be due to urinary tract infections or renal anomalies; thus, urine culture and renal ultrasound scan are required respectively.A differentiation between renal and systemic PHA type 1 may be made based on sodium requirements, ease of management of electrolyte imbalance, sweat test results and genetic testing.Management of renal PHA type 1 is with sodium supplementation, and requirements often decrease with age.Systemic PHA type 1 requires aggressive and intensive fluid and electrolyte management. Securing an enteral feeding route and i.v. access are essential to facilitate ongoing therapy.In this area of the UK, the incidence of AD PHA and AR PHA was calculated to be 1:66 000 and 1:166 000 respectively.Entities:
Year: 2013 PMID: 24616761 PMCID: PMC3922296 DOI: 10.1530/EDM-13-0010
Source DB: PubMed Journal: Endocrinol Diabetes Metab Case Rep ISSN: 2052-0573
Summary of cases. Plasma results of sodium, potassium, bicarbonate and pH are from the day of presentation, unless indicated. Initial urinary electrolytes, renin and aldosterone concentrations are from the initial admission
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| Age at presentation (days) | 25 | 28 | 8 | 23 | 10 | 5 | 10 |
| Symptoms | Vomiting and weight loss | Weight loss and poor feeding | Weight loss | Vomiting and weight loss | Inpatient | Jaundice and weight loss | Weight loss and drowsiness |
| Plasma Na (mmol/l) (RR 135–145) | 119 | 126 | 118 | 118 | 109 | 142 (112 on D10) | 126 |
| Plasma K (mmol/l) (RR 3.5–5) | NA | 6.8 | 8.2 | 7.3 | 6.8 | 6.1 (11.3 on D10) | 10 |
| Plasma HCO3− (mmol/l) (RR 17–25) | 19.4 | 17.9 | 19.6 | NA | 18.6 | 19.3 (D10) | 10.4 |
| pH | 7.39 | 7.27 | NA | NA | 7.27 | 7.38 | 7.21 |
| Creatinine (μmol/l) (RR 37–89) | 67 | 61 | 29 | 48 | 96 | 74 (87 on D10) | 49 (D11) |
| Urine K (mmol/l) | 37 | 20 | NA | 19 (24) | 10 | 22 | 7 (D15) |
| Urine Na (mmol/l) | 50 | 16 | 15 | 20 (D24) | 35 | 111 | 142 (D15) |
| Serum aldosterone (pmol/l) (RR 400–3000) | 35 700 | 39 900 | 83 390 | 48 000 | 49 500 | 57 000 | 16 580 |
| PRA (nmol/l per h) (RR 1.9–29) | 41.3 | 250 | >250 | 16 | >250 | >250 | 131.5 |
| Duration of follow-up (months) | 62 | 38 | 25 | 14 | 36 | 39 | 42 |
| Weight centile at last clinic appointment | 91st–98th | 9th–25th | 25th | 50th | 91st–98th | 9th | 75th |
| Ongoing management | Initial Na supplementation 2.5 mmol/kg per day | Initial Na supplementation 1.5 mmol/kg per day | Initial Na supplementation 2 mmol/kg per day | Discharged from follow-up. Not on medication | Initial Na supplementation 4 mmol/kg per day | Initial Na supplementation 3.8 mmol/kg per day | Na supplements 8.5 mmol/kg per day |
| Now on 0.7 mmol/kg per day | Now on Na 0.7 mmol/kg per day | Now on Na 0.8 mmol/kg per day | NaHCO3 1.6 mmol/kg per day | NaHCO3 2 mmol/kg per day | |||
| Indomethacin 1.5 mg/kg b.d. | Flucloxacillin 125 mg b.d. | ||||||
| Gaviscon | Penicillin V 125 mg b.d. | ||||||
| Ranitidine | Omeprazole 0.6 mg/kg b.d. | ||||||
| Low potassium feeds | Domperidone 0.35 mg/kg b.d. | ||||||
| Intermittent requirement for i.v. 0.9% NaCl | Montelukast 4 mg o.d. | ||||||
| Beclometasone 200 μg b.d. | |||||||
| Sodium cromoglycate 5 mg q.d.s. | |||||||
| Low potassium feeds | |||||||
| PRA (nmol/l per h) after long-term management | 6.1 | 24.9 | NA | 7.4 | 1.1 | 0.3 | Not done |
| Aldosterone (pmol/l) after long-term management | 1230 | 5450 | 23.3 | 3400 | 385 | <55 | Not done |
| Renal and bladder USS | Normal | Normal | Normal | Normal | Normal | Normal | Normal |
RR, reference range (age appropriate); PRA, plasma renin activity; NA, not available; o.d., once daily; b.d., twice daily; q.d.s., four times daily; USS, ultrasound scan.
Doses subject to variation.