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Open access

Daphne Yau, Maria Salomon-Estebanez, Amish Chinoy, John Grainger, Ross J Craigie, Raja Padidela, Mars Skae, Mark J Dunne, Philip G Murray and Indraneel Banerjee

Summary

Congenital hyperinsulinism (CHI) is an important cause of severe hypoglycaemia in infancy. To correct hypoglycaemia, high concentrations of dextrose are often required through a central venous catheter (CVC) with consequent risk of thrombosis. We describe a series of six cases of CHI due to varying aetiologies from our centre requiring CVC for the management of hypoglycaemia, who developed thrombosis in association with CVC. We subsequently analysed the incidence and risk factors for CVC-associated thrombosis, as well as the outcomes of enoxaparin prophylaxis. The six cases occurred over a 3-year period; we identified an additional 27 patients with CHI who required CVC insertion during this period (n = 33 total), and a separate cohort of patients with CHI and CVC who received enoxaparin prophylaxis (n = 7). The incidence of CVC-associated thrombosis was 18% (6/33) over the 3 years, a rate of 4.2 thromboses/1000 CVC days. There was no difference in the frequency of genetic mutations or focal CHI in those that developed thromboses. However, compound heterozygous/homozygous potassium ATP channel mutations correlated with thrombosis (R 2 = 0.40, P = 0.001). No difference was observed in CVC duration, high concentration dextrose or glucagon infused through the CVC. In patients receiving enoxaparin prophylaxis, none developed thrombosis or bleeding complications. The characteristics of these patients did not differ significantly from those with thrombosis not on prophylaxis. We therefore conclude that CVC-associated thrombosis can occur in a significant proportion (18%) of patients with CHI, particularly in severe CHI, for which anticoagulant prophylaxis may be indicated.

Learning points:

  • CVC insertion is one of the most significant risk factors for thrombosis in the paediatric population.

  • Risk factors for CVC-associated thrombosis include increased duration of CVC placement, malpositioning and infusion of blood products.

  • To our knowledge, this is the first study to evaluate CVC-associated thrombosis in patients with congenital hyperinsulinism (CHI).

  • The incidence of CVC-associated thrombosis development is significant (18%) in CHI patients and higher compared to other neonates with CVC. CHI severity may be a risk factor for thrombosis development.

  • Although effective prophylaxis for CVC-associated thrombosis in infancy is yet to be established, our preliminary experience suggests the safety and efficacy of enoxoaparin prophylaxis in this population and requires on-going evaluation.

Open access

Ved Bhushan Arya, Jennifer Kalitsi, Ann Hickey, Sarah E Flanagan and Ritika R Kapoor

Summary

Diazoxide is the first-line treatment for patients with hyperinsulinaemic hypoglycaemia (HH). Approximately 50% of patients with HH are diazoxide resistant. However, marked diazoxide sensitivity resulting in severe hyperglycaemia is extremely uncommon and not reported previously in the context of HH due to HNF4A mutation. We report a novel observation of exceptional diazoxide sensitivity in a patient with HH due to HNF4A mutation. A female infant presented with severe persistent neonatal hypoglycaemia and was diagnosed with HH. Standard doses of diazoxide (5 mg/kg/day) resulted in marked hyperglycaemia (maximum blood glucose 21.6 mmol/L) necessitating discontinuation of diazoxide. Lower dose of diazoxide (1.5 mg/kg/day) successfully controlled HH in the proband, which was subsequently confirmed to be due to a novel HNF4A mutation. At 3 years of age, the patient maintains age appropriate fasting tolerance on low dose diazoxide (1.8 mg/kg/day) and has normal development. Diagnosis in proband’s mother and maternal aunt, both of whom carried HNF4A mutation and had been diagnosed with presumed type 1 and type 2 diabetes mellitus, respectively, was revised to maturity-onset diabetes of young (MODY). Proband’s 5-year-old maternal cousin, also carrier of HNF4A mutation, had transient neonatal hypoglycaemia. To conclude, patients with HH due to HNF4A mutation may require lower diazoxide than other group of patients with HH. Educating the families about the risk of marked hyperglycaemia with diazoxide is essential. The clinical phenotype of HNF4A mutation can be extremely variable.

Learning points:

  • Awareness of risk of severe hyperglycaemia with diazoxide is important and patients/families should be accordingly educated.

  • Some patients with HH due to HNF4A mutations may require lower than standard doses of diazoxide.

  • The clinical phenotype of HNF4A mutation can be extremely variable.

Open access

Himangshu S Bose, Alan M Rice, Brendan Marshall, Fadi Gebrail, David Kupshik and Elizabeth W Perry

Summary

Steroid hormones are essential for the survival of all mammals. In adrenal glands and gonads, cytochrome P450 side chain cleavage enzyme (SCC or CYP11A1), catalyzes conversion of cholesterol to pregnenolone. We studied a patient with ambiguous genitalia by the absence of Müllerian ducts and the presence of an incompletely formed vagina, who had extremely high adrenocorticotropic hormone (ACTH) and reduced pregnenolone levels with enlarged adrenal glands. The testes revealed seminiferous tubules, stroma, rete testis with interstitial fibrosis and reduced number of germ cells. Electron microscopy showed that the patient’s testicular mitochondrial size was small with little SCC expression within the mitochondria. The mitochondria were not close to the mitochondria-associated ER membrane (MAM), and cells were filled with the microfilaments. Our result revealed that absence of pregnenolone is associated with organelle stress, leading to altered protein organization that likely created steric hindrance in testicular cells.

Learning points:

  • Testes revealed seminiferous tubules, stroma, rete testis with interstitial fibrosis and reduced number of germ cells;

  • Testicular mitochondrial size was small with little SCC expression within the mitochondria;

  • Absence of pregnenolone is associated with organelle stress.

Open access

Saurabh Uppal, James Blackburn, Mohammed Didi, Rajeev Shukla, James Hayden and Senthil Senniappan

Summary

Beckwith–Wiedemann syndrome (BWS) can be associated with embryonal tumours and congenital hyperinsulinism (CHI). We present an infant with BWS who developed congenital hepatoblastoma and Wilms’ tumour during infancy. The infant presented with recurrent hypoglycaemia requiring high intravenous glucose infusion and was biochemically confirmed to have CHI. He was resistant to diazoxide but responded well to octreotide and was switched to Lanreotide at 1 year of age. Genetic analysis for mutations of ABCC8 and KCNJ11 were negative. He had clinical features suggestive of BWS. Methylation-sensitive multiplex ligation-dependent probe amplification revealed hypomethylation at KCNQ1OT1:TSS-DMR and hypermethylation at H19 /IGF2:IG-DMR consistent with mosaic UPD(11p15). Hepatoblastoma was detected on day 4 of life, which was resistant to chemotherapy, requiring surgical resection. He developed Wilms’ tumour at 3 months of age, which also showed poor response to induction chemotherapy with vincristine and actinomycin D. Surgical resection of Wilms’ tumour was followed by post-operative chemotherapy intensified with cycles containing cyclophosphamide, doxorubicin, carboplatin and etoposide, in addition to receiving flank radiotherapy. We report, for the first time, an uncommon association of hepatoblastoma and Wilms’ tumour in BWS in early infancy. Early onset tumours may show resistance to chemotherapy. UPD(11p15) is likely associated with persistent CHI in BWS.

Learning points:

  • Long-acting somatostatin analogues are effective in managing persistent CHI in BWS.

  • UPD(11)pat genotype may be a pointer to persistent and severe CHI.

  • Hepatoblastoma and Wilms’ tumour may have an onset within early infancy and early tumour surveillance is essential.

  • Tumours associated with earlier onset may be resistant to recognised first-line chemotherapy.

Open access

Sarah Kiff, Carolyn Babb, Maria Guemes, Antonia Dastamani, Clare Gilbert, Sarah E Flanagan, Sian Ellard, John Barton, M Dattani and Pratik Shah

Summary

We report a case of partial diazoxide responsiveness in a child with severe congenital hyperinsulinaemic hypoglycaemia (CHI) due to a homozygous ABCC8 mutation. A term baby, with birth weight 3.8 kg, born to consanguineous parents presented on day 1 of life with hypoglycaemia. Hypoglycaemia screen confirmed CHI. Diazoxide was commenced on day 7 due to ongoing elevated glucose requirements (15 mg/kg/min), but despite escalation to a maximum dose (15 mg/kg/day), intravenous (i.v.) glucose requirement remained high (13 mg/kg/min). Genetic testing demonstrated a homozygous ABCC8 splicing mutation (c.2041-1G>C), consistent with a diffuse form of CHI. Diazoxide treatment was therefore stopped and subcutaneous (s.c.) octreotide infusion commenced. Despite this, s.c. glucagon and i.v. glucose were required to prevent hypoglycaemia. A trial of sirolimus and near-total pancreatectomy were considered, however due to the significant morbidity potentially associated with these, a further trial of diazoxide was commenced at 1.5 months of age. At a dose of 10 mg/kg/day of diazoxide and 40 µg/kg/day of octreotide, both i.v. glucose and s.c. glucagon were stopped as normoglycaemia was achieved. CHI due to homozygous ABCC8 mutation poses management difficulties if the somatostatin analogue octreotide is insufficient to prevent hypoglycaemia. Diazoxide unresponsiveness is often thought to be a hallmark of recessively inherited ABCC8 mutations. This patient was initially thought to be non-responsive, but this case highlights that a further trial of diazoxide is warranted, where other available treatments are associated with significant risk of morbidity.

Learning points:

  • Homozygous ABCC8 mutations are commonly thought to cause diazoxide non-responsive hyperinsulinaemic hypoglycaemia.

  • This case highlights that partial diazoxide responsiveness in homozygous ABCC8 mutations may be present.

  • Trial of diazoxide treatment in combination with octreotide is warranted prior to considering alternative treatments, such as sirolimus or near-total pancreatectomy, which are associated with more significant side effects.

Open access

Charlotte S Schömig, Marie-Ève Robinson and Julia E von Oettingen

Summary

Congenital hypothyroidism requires prompt treatment to prevent adverse health outcomes. Poor intestinal levothyroxine absorption can complicate management. We present a case of a term female newborn with necrotizing enterocolitis (NEC) requiring subtotal ileum resection. Congenital hypothyroidism was diagnosed by newborn screening. Treatment was complicated by intestinal malabsorption of levothyroxine. Intravenous levothyroxine substitution restored euthyroidism and supraphysiologic PO doses subsequently maintained a euthyroid state. After several months, the required levothyroxine dose was weaned down to typical recommended dosing. In conclusion, small bowel resection secondary to NEC may lead to malabsorption of oral levothyroxine. An intravenous levothyroxine dose of approximately 50% typical PO dosing is effective in providing rapid normalization of free T4 and TSH. High PO doses may be required to maintain euthyroidism. Close thyroid function monitoring and immediate therapy adjustment are essential as the individual absorption may vary widely. Normal absorption levels may be regained due to adaption of the neonatal intestines.

Learning points:

  • In neonates with malabsorption after ileum resection intravenous levothyroxine replacement should be used to provide normalization of free T4 and TSH.

  • Very high doses of up to 500% usual oral levothyroxine may be required to maintain euthyroidism. The estimated degree of malabsorption can be used to determine the initial dose.

  • Close thyroid function monitoring and immediate therapy adjustment are essential as the absorption and intestinal adaption may vary widely.

Open access

Nicholas R Zessis, Jennifer L Nicholas and Stephen I Stone

Summary

Bilateral adrenal hemorrhages rarely occur during the neonatal period and are often associated with traumatic vaginal deliveries. However, the adrenal gland has highly regenerative capabilities and adrenal insufficiency typically resolves over time. We evaluated a newborn female after experiencing fetal macrosomia and a traumatic vaginal delivery. She developed acidosis and acute renal injury. Large adrenal hemorrhages were noted bilaterally on ultrasound, and she was diagnosed with adrenal insufficiency based on characteristic electrolyte changes and a low cortisol (4.2 µg/dL). On follow-up testing, this patient was unable to be weaned off of hydrocortisone or fludrocortisone despite resolution of hemorrhages on ultrasound. Providers should consider bilateral adrenal hemorrhage when evaluating critically ill neonates after a traumatic delivery. In extreme cases, this may be a persistent process.

Learning points:

  • Risk factors for adrenal hemorrhage include fetal macrosomia, traumatic vaginal delivery and critical acidemia.

  • Signs of adrenal hemorrhage include jaundice, flank mass, skin discoloration or scrotal hematoma.

  • Adrenal insufficiency often is a transient process when related to adrenal hemorrhage.

  • Severe adrenal hemorrhages can occur in the absence of symptoms.

  • Though rare, persistent adrenal insufficiency may occur in extremely severe cases of bilateral adrenal hemorrhage.

  • Consider adrenal hemorrhage when evaluating a neonate for shock in the absence of an infectious etiology.

Open access

Pradeep Vasudevan, Corrina Powell, Adeline K Nicholas, Ian Scudamore, James Greening, Soo-Mi Park and Nadia Schoenmakers

Summary

In the absence of maternal thyroid disease or iodine deficiency, fetal goitre is rare and usually attributable to dyshormonogenesis, for which genetic ascertainment is not always undertaken in the UK. Mechanical complications include tracheal and oesophageal compression with resultant polyhydramnios, malpresentation at delivery and neonatal respiratory distress. We report an Indian kindred in which the proband (first-born son) had congenital hypothyroidism (CH) without obvious neonatal goitre. His mother’s second pregnancy was complicated by fetal hypothyroid goitre and polyhydramnios, prompting amniotic fluid drainage and intraamniotic therapy (with liothyronine, T3 and levothyroxine, T4). Sadly, intrauterine death occurred at 31 weeks. Genetic studies in the proband demonstrated compound heterozygous novel (c.5178delT, p.A1727Hfs*26) and previously described (c.7123G > A, p.G2375R) thyroglobulin (TG) mutations which are the likely cause of fetal goitre in the deceased sibling. TG mutations rarely cause fetal goitre, and management remains controversial due to the potential complications of intrauterine therapy however an amelioration in goitre size may be achieved with intraamniotic T4, and intraamniotic T3/T4 combination has achieved a favourable outcome in one case. A conservative approach, with surveillance, elective delivery and commencement of levothyroxine neonatally may also be justified, although intubation may be required post delivery for respiratory obstruction. Our observations highlight the lethality which may be associated with fetal goitre. Additionally, although this complication may recur in successive pregnancies, our case highlights the possibility of discordance for fetal goitre in siblings harbouring the same dyshormonogenesis-associated genetic mutations. Genetic ascertainment may facilitate prenatal diagnosis and assist management in familial cases.

Learning points:

  • CH due to biallelic, loss-of-function TG mutations is well-described and readily treatable in childhood however mechanical complications from associated fetal goitre may include polyhydramnios, neonatal respiratory compromise and neck hyperextension with dystocia complicating delivery.

  • CH due to TG mutations may manifest with variable phenotypes, even within the same kindred.

  • Treatment options for hypothyroid dyshormogenic fetal goitre in a euthyroid mother include intraamniotic thyroid hormone replacement in cases with polyhydramnios or significant tracheal obstruction. Alternatively, cases may be managed conservatively with radiological surveillance, elective delivery and neonatal levothyroxine treatment, although intubation and ventilation may be required to support neonatal respiratory compromise.

  • Genetic ascertainment in such kindreds may enable prenatal diagnosis and anticipatory planning for antenatal management of further affected offspring.

Open access

Bronwen E Warner, Carol D Inward and Christine P Burren

Summary

This case, presenting with bilateral impalpable testes, illustrates the relevance of a broad differential disorders of sex development case management. It provides new insights on hypothalamic–pituitary–gonadal (HPG) axis and testicular function abnormalities in the multisystem disorder of Lowe syndrome. Lowe syndrome, also known as oculocerebrorenal syndrome, is a rare disorder characterised by eye abnormalities, central nervous system involvement and proximal renal tubular acidosis. There are a handful of reports of pubertal delay, infertility and cryptorchidism in Lowe syndrome. Biochemistry aged 72 h: testosterone 6.4 nmol/L, LH <0.5 IU/L and FSH <0.5 IU/L. Gonadotropin-releasing hormone stimulation test identified significantly raised baseline LH = 45.4 IU/L (contrasts with earlier undetectable LH), with a 20% increase on stimulation, while baseline FSH = 4.3 IU/L with no increase on stimulation. Day 14 HCG stimulation test produced an acceptable 50% increase in testosterone. The constellation of further abnormalities suggested Lowe syndrome: hypotonia, bilateral cataracts (surgical extraction and intraocular lens implantation) and renal tubular acidosis (microscopic haematuria, hypercalciuria, proteinuria, generalised aminoaciduria, hypophosphataemia and metabolic acidosis). DNA sequencing identified de novo hemizygous frameshift mutation OCRL c.2409_2410delCT in exon 22. Interpretation of initial and repeat GnRH and HCG testing indicates the likelihood of testicular failure. Partial testicular descent occurred but left orchidopexy was required. Improving long-term gonadal function in Lowe syndrome assumes increased importance for current cohorts as advances in renal replacement therapy have greatly improved life expectancy. Noting HPG axis abnormalities in Lowe syndrome in infancy can identify cases requiring increased surveillance of pubertal progress for earlier detection and management.

Learning points:

  • Clinical endocrine problems in Lowe syndrome has been reported, but has focused on abnormalities in adolescence and young adulthood: pubertal delay and infertility.

  • We present an infant with isolated LH elevation at baseline and on GnRH stimulation testing who also had bilateral impalpable testes.

  • Early testing of the HPG axis in patients with Lowe syndrome may help predict gonadal abnormalities from a younger age, which will enhance the overall case management into adolescence.

Open access

María Clemente, Alejandro Vargas, Gema Ariceta, Rosa Martínez, Ariadna Campos and Diego Yeste

Summary

HNF4A gene mutations have been reported in cases of transient and persistent hyperinsulinaemic hypoglycaemia of infancy (HHI), particularly in families with adulthood diabetes. The case of a patient with HHI, liver impairment and renal tubulopathy due to a mutation in HNF4A is reported.

Learning points:

  • Urine specimen study in cases of HHI with diazoxide response is necessary to rule out specific metabolic conditions (l-3-hydroxyacyl-coenzyme A dehydrogenase deficiency) or tubular renal involvement.

  • Hyperinsulinaemic hypoglycaemia due to the heterozygous mutation (p.Arg63Trp, c. 187C > T) in the HNF4A gene is associated with renal tubulopathy and liver involvement.

  • Follow-up of patients diagnosed of HHI is mandatory to detect associated conditions.