Minor Procedures in Patients with Congenital Bleeding Disorders - One Centre Experience

Introduction: Patients with congenital bleeding disorders (CBD) have an increased bleeding tendency, which varies according to the factor deficiency and severity. In most cases, prolonged bleeding is observed after trauma, surgery and/or invasive procedures. Haemostatic treatment is needed to prevent bleeding complications and allow a good clinical outcome. Our aim is to evaluate the management of patients with CBD in minor procedures. Method(s): Retrospective study of patients with CBD who performed minor procedures over a 7-year period, through review of clinical files. Result(s): Between January 2015 and December 2021, 249 minor procedures were performed in 113 patients with CBD: 42 had diagnosis of Haemophilia A (HA) (15 severe without inhibitors;3 severe with inhibitors;4 moderate and 20 mild);12 had Haemophilia B (HB) (7 severe without inhibitors;2 moderate and 3 mild);5 were carriers of HA and 2 of HB. 35 had von Willebrand disease (VWD);15 had rare bleeding disorders (8 FVII deficiency;6 FXI deficiency;1 FX deficiency) and 2 had diagnosis of inherited platelet glycoprotein deficiencies (1 Glanzmann thrombasthenia and 1 Bernard Soulier syndrome). Most procedures were dental treatments (189);synoviorthesis/ infiltration/mesotherapy (17);endoscopies and colonoscopies (15);skin lesions excision (8);COVID-19 vaccination (5);sebaceous cyst excision (4);cardiac catheterization (3);ureteral stent removal (3);bone marrow biopsy (2);cystoscopy (2) and breast fibroadenoma excision (1). Prophylactic treatment was performed in 237 (95%) of the procedures, respectively FVIII concentrate factor (59);FIX concentrate factor (27);DDAVP (66);von Willebrand factor/factor VIII concentrates (44);bypassing agents (24);platelet (6);inactivated human plasma (9);tranexamic acid (47) and epsilon-aminocaproic acid (161). No side effects were reported. Discussion/Conclusion: Most patients that underwent minor procedures had Haemophilia and VDW(83%). The most common procedure was dental treatment (76%). Patients with CBD require attention and special care in dental practice. The haemostatic prophylactic treatment varies according to the specific haemostatic defect, severity and type of procedure. The treatment performed has been demonstrated safe and effective, with low incidences of haemorrhagic and treatment-related complications. These patients' treatment requires multidisciplinary teams and reference centres.

Delay in desmopressin therapy: Disaster in waiting.

WHAT IS KNOWN AND OBJECTIVE: Central diabetes insipidus (DI) is a complex disease that requires firm adherence to desmopressin therapy. There is little information on the onset of hypernatremia after withdrawal of desmopressin. CASE SUMMARY: We present a case of an elderly woman with central DI whose serum sodium jumped from 141 to 171 mEq/L after 48-72 h of holding oral desmopressin. Her DI crisis resolved with intravenous desmopressin and free water administration. WHAT IS NEW AND CONCLUSION: Based on this precipitous onset of DI crisis, we recommend not withholding desmopressin for more than 24 h.

Infection with SARS-CoV-2 may alter the half-life of desmopressin (DDAVP) in patients with central diabetes insipidus.

We present a 9-year-old boy with diabetes insipidus. The boy is treated with desmopressin (DDAVP) therapy. Under this therapy, the drinking quantity and the laboratory parameters were normal. No nocturia occurred any more. In the context of a clinically mild infection with SARS-CoV-2, the duration of action of DDAVP was significantly prolonged (approximately +50%). The original dosage was then reintroduced and was still sufficient until months later. A possible connection to the infection with SARS-CoV-2 can be suspected. Our case report should make physicians who care for patients with diabetes insipidus aware of such a possible prolongation of the effect of DDAVP. More frequent monitoring may be needed in such patients to assess the risk of symptomatic dilutional hyponatremia.

Socio-economic Barriers to Care and Medical Complexity Leading to a 5-year Diagnostic Delay of Untreated Chronic Diabetes Insipidus and Rapidly Progressive Puberty in a 10-year-old Venezuelan Immigrant

Introduction: Germ cell tumors, including germinomas, account for 10% of pediatric chronic Diabetes Insipidus (DI) cases. Delays in diagnosis of germinomas are generally longer than six months, however, no reported cases of suprasellar germinomas causing chronic DI and precocious puberty have been known to exceed a 5-year delay in both treatment of DI symptoms and a definitive diagnosis. Case Description: A 10-year-old Hispanic male presented with a 5-year history of polydipsia and polyuria. He underwent evaluation in Venezuela, where DI was reportedly 'ruled out';however, no head MRI was performed. After two years in the US struggling to acquire insurance, he presented to his pediatrician with worsening symptoms. A head MRI, ordered to evaluate dilute high-volume urine output, revealed a suprasellar mass. He was admitted for diagnostic evaluation and met the criteria for DI. Notably, he had an elevated Beta-Human Chorionic Gonadotropin (B-HCG) level. Biopsy confirmed the diagnosis of a Central Nervous System (CNS) germinoma. He was treated with DDAVP and proton therapy with subsequent remission of his tumor. Discussion: Throughout the patient's disease course, there were multiple delays in seeking and receiving care. These include a 5-year delay in seeking care despite worsening symptoms, a one-month delay in completing a 24-hour urine collection, a one-month delay in consulting pediatric nephrology, and another month delay before completing a retroperitoneal ultrasound. Multiple medical and socio-economic factors led to these delays. The patient did not present with symptoms more typical of CNS Germinomas like headaches, nausea, and vomiting. He had no visual disturbances despite mass effect on his optic chiasm. His increased stretched penis length and Tanner staging, which were identified later in his disease course, were contradicted by his pre-pubertal testicular volume and bone age. The patient is from a Spanishspeaking/Limited English Proficiency (SSLEP) household. While Spanish interpreters were present at each appointment, the language barrier proved to be a consistent issue. Initially, the child's mother indicated that the diagnosis of DI was 'ruled out' in Venezuela. In reality, the recommended imaging was never performed. Mychart messages left by his father further highlighted communication difficulties. Without access to an interpreter, he was forced to use broken English to relay his concerns. These frantic messages indicated misunderstandings regarding scheduling with various services and completing vital labs. Care only proceeded after significant physician intervention. Poverty in Venezuela, lack of insurance, and anxiety regarding COVID-19 also contributed to these delays. Conclusion: To our knowledge, this is the first case report of a pediatric patient presenting with a 5-year history of untreated polyuria and polydipsia due to undiagnosed DI with a B-HCG secreting CNS germinoma, without spinal metastasis. This study also illustrates the importance of supporting SSLEP families as they grapple with the complicated process of navigating our healthcare system. Sagittal T1 post gadolinium contrast image (A) and axial T2 FLAIR image (B) show an enigmatic, homogeneous, briskly enhancing mass in the suprasellar cistern (red arrow) with mass effect on the optic chiasm which is displaced upward and anteriorly (green arrow).

Central diabetes insipidus secondary to COVID-19 infection: a case report.

BACKGROUND: Novel coronavirus disease 2019 (COVID-19) mainly affects the lungs, but can involve several other organs. The diagnosis of acute and chronic sequelae is one of the challenges of COVID-19. The current literature proposes that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may involve the hypothalamic-pituitary axis. In this case report, we present a unique case of new-onset central diabetes insipidus secondary to the COVID-19 disease in a 54-year-old woman. CASE PRESENTATION: A 54-year-old woman presented with the history of excessive thirst, polyuria, and polydipsia, six weeks after being infected by COVID-19. Laboratory tests revealed low urine osmolarity and increased serum osmolarity, and the patient was diagnosed with central diabetes insipidus. After administration of nasal desmopressin, urinary osmolarity increased, and the patient's symptoms improved. However, to stabilize her condition, desmopressin treatment was required. CONCLUSIONS: We reported a unique case of diabetes insipidus in a COVID-19 patient. Central diabetes insipidus may be included in clinical manifestations of the COVID-19, in case of new-onset polyuria and polydipsia following COVID-19 disease. Nevertheless, a causal relationship has not been established between the symptoms of the patient and the SARS-CoV-2 infection.

A Fatal Case of Intraparenchymal Hemorrhage Masquerading as Central Diabetes Insipidus

This is 32-year-old women presented to us on postpartum day 10 with severe covid-19 pneumonia. Hercomplaints were dyspnea and headache which she described as, frontally located, 8/10 in intensity, non-radiating and not associated with any posture. She had no prior history of migraines. She was afebrile, tachycardiac and hypoxic on exam. Physical examination was unremarkable. Patient failed trial of non-invasive ventilation following which she was intubated. CT head on admission was unremarkable.For COVID 19 ARDS, she was started on dexamethasone, tocilizumab, paralysis was achieved withcisatracurium and prone protocol was followed for refractory hypoxia. Patient was placed on DVTprophylaxis with heparin. Her pneumonia and oxygenation improved. However, on hospital day 8, herlab results were suspicious of Diabetes insipidus (DI). Her serum sodium was 152mEq/L with serumosmolarity of 360 and polyuria (more than 2L of urine in one hour). A full neurological examinationcould not be obtained as she was paralyzed, however, pupils were equal in size and reactive to light. With high clinical suspicions of diabetes insipidus she received a one-time dose of 16mcg of DDAVP andMRI of pituitary gland was ordered to delineate etiology. Subsequent improvement in polyuria wasnoted. Despite DDAVP her serum sodium continued to worsen. We continued to monitor serumsodium levels every four hours. Her serum sodium levels remained labile with a precipitous drop notedfrom 174mEq/L to 152mEq/L. Review of Pituitary MRI revealed multiple intraparenchymal hemorrhageson bilateral frontal lobes along with trans tentorial and cerebellar tonsillar herniation. Subsequently, patient underwent a brain death exam and declared brain dead. We suspect the development of intracranial hemorrhage in our patient was secondary to covid-19. Onliterature review, an incidence of 0.2% in covid-19 patients with a mortality of 48% is reported. In ourpatient, inability to perform a full neurological exam due to paralysis limited early recognition andintervention. This case highlights the need for increased awareness in patients with features of central diabetesinsipidus and the urgency to obtain CT head immediately after a diagnosis has been established. Promptconsideration of neuroimaging should be made when features of central diabetes mellitus are noted with limited neurological exam.

Better outcomes with desmopressin melt than enuretic alarm therapy in children with nocturnal enuresis during coronavirus disease 2019 (COVID-19).

Objectives: This study aimed to investigate the effect of the coronavirus disease 2019 (COVID-19) pandemic on the treatment of children with primary monosymptomatic nocturnal enuresis (MNE) with desmopressin melt versus an enuresis alarm. Materials and methods: This study included 56 children with primary MNE who were taking desmopressin melt or using an alarm. Their anxiety levels were evaluated using the Social Anxiety Scale for Children-Revised. For both treatment methods, data from a 3-month bedwetting diary between the third and sixth months of the pre-pandemic treatment were compared with those assessed during the same period during the pandemic. Results: Prior to the COVID-19 pandemic, the median 3-month mean frequency of MNE was 1 (0-7.67) in children using desmopressin melt versus 1.33 (0-6) in those using alarm treatment (p = 0.095). During the COVID-19 pandemic period, the median monthly mean frequency of MNE was 1.33 (0-7.33) in children using desmopressin melt versus 6 (1.33-13) in those using alarm treatment (p < 0.001). Conclusions: The COVID-19 pandemic and its accompanying psychological effects did not affect the treatment efficacy of desmopressin melt in children with primary MNE but did adversely affect that of enuresis alarms.

A Rare case of Pituitary Apoplexy associated with COVID infection presenting with Central Diabetes Insipidus

Introduction: Pituitary apoplexy (PA) is rare and occurs in up to 20% of patients with a non-functioning pituitary adenoma. It can occur de novo or can be precipitated by surgery, head trauma, anticoagulant therapy, and pregnancy among others. Incidence of persistent Diabetes Insipidus (DI) is only about 2% in such patients. Limited literature exists on the association of PA and COVID infection. We present a case of PA and subsequent central DI in a patient with a pituitary adenoma and severe COVID-19 pneumonia. Case Description: A 64-year-old male with a history of a non-functioning pituitary macroadenoma (2 cm) of 5 months duration, primary hypothyroidism, and acute myeloid leukemia on chemotherapy presented to the emergency department with one day of headache, fever, and cough. He was diagnosed with COVID-19 pneumonia and started on dexamethasone, broad spectrum antibiotics and supplemental oxygen. Sudden loss of peripheral vision in his left eye with a persistent headache and altered mental status led to plain computed tomography that revealed a hyperattenuating suprasellar mass compressing the optic chiasm. MRI brain showed a T2 hypointense acutely hemorrhagic suprasellar mass compressing the infundibulum and the optic chiasm indicative of PA. Labs showed thrombocytopenia with platelet count 55,000/mcL (130-400), low AM cortisol 3 mcg/dL, normal prolactin 10 ng/mL, normal thyroid function and preserved somatotrophic axis. In addition, the patient developed polyuria with a urine output of up to 8 liters in a 24-hour period, acute hypernatremia (sodium 172 mmol/L), urine specific gravity < 1.005 and serum osmolality 360 mOsm/kg (275-295 mOsm/kg). Conservative management with stress dose hydrocortisone and desmopressin was the first line of therapy. Levothyroxine was continued at home dose. After resolution of COVID-19 pneumonia and improvement in electrolyte disarray, the patient underwent pituitary decompression surgery in 3 weeks with subsequent resolution of DI post-operatively. He was discharged home on hydrocortisone (20 mg total daily dose) and levothyroxine with close endocrinology follow up. Discussion: Association of COVID infection and PA has been reported in 10 patients in the literature so far. Although the exact mechanism is unknown, SARS-CoV-2 neural invasion via cerebral ACE-2 expression can lead to oxidative stress and thrombogenesis, ultimately predisposing to neural hemorrhage. Thrombocytopenia secondary to chemotherapy can be a contributing factor in our patient. DI is rare and usually resolves after decompression surgery. Further research focusing on the association and pathophysiology of COVID-19 with PA in those without precipitating factors are needed.

Vasopressin and Its Analogues: From Natural Hormones to Multitasking Peptides.

Human neurohormone vasopressin (AVP) is synthesized in overlapping regions in the hypothalamus. It is mainly known for its vasoconstricting abilities, and it is responsible for the regulation of plasma osmolality by maintaining fluid homeostasis. Over years, many attempts have been made to modify this hormone and find AVP analogues with different pharmacological profiles that could overcome its limitations. Non-peptide AVP analogues with low molecular weight presented good affinity to AVP receptors. Natural peptide counterparts, found in animals, are successfully applied as therapeutics; for instance, lypressin used in treatment of diabetes insipidus. Synthetic peptide analogues compensate for the shortcomings of AVP. Desmopressin is more resistant to proteolysis and presents mainly antidiuretic effects, while terlipressin is a long-acting AVP analogue and a drug recommended in the treatment of varicose bleeding in patients with liver cirrhosis. Recently published results on diverse applications of AVP analogues in medicinal practice, including potential lypressin, terlipressin and ornipressin in the treatment of SARS-CoV-2, are discussed.

A preterm infant with congenital disseminated herpes simplex virus following maternal COVID-19 infection

Case Report Disseminated Herpes Simplex Virus (HSV) is a feared neonatal infection typically presenting after the first week of life with sepsis-like features and encephalopathy. Congenitally acquired HSV infection represents a rare, serious variety of HSV in the neonatal period, providing a unique diagnostic challenge with significant morbidity and mortality. A female infant was delivered at 29.2 weeks gestational age via cesarean section in the setting of non-reassuring fetal heart tracings, maternal preeclampsia, gestational diabetes, and Sars- COV2 infection. Physical exam at 1 hour of life demonstrated erosive lesions of the knee, foot, and cheek. Dermatology was consulted and favored infectious source of lesions, so a sepsis evaluation including HSV, VZV, and CMV studies was performed and ampicillin, gentamicin, acyclovir, and amphotericin B were started. Given high concern for HSV vs. varicella, ophthalmology was consulted, finding bilateral, likely viral, retinitis. Laboratory evaluation revealed transaminitis, thrombocytosis, and CSF pleocytosis with elevated protein. HSV PCR was positive in blood, CSF, and cutaneous lesion, as well as HSV2 positive on surface culture, yielding the diagnosis of congenital disseminated HSV with meningoencephalitis. The remainder of infectious studies were negative. There was no known maternal HSV history, although placental pathology revealed positive immunohistochemical staining for HSV 1/2 in addition to Sars-COV2. Patient's serial CSF and blood HSV remained positive despite treatment with acyclovir. Serial HUS showed initially normal findings that progressively worsened to feature bihemispheric cystic encephalomalacia, periventricular leukomalacia with ex vacuo dilation of lateral and third ventricles. She developed central diabetes insipidus and was started on desmopressin. Ocular involvement subsequently included retinal necrosis and diffuse retinal hemorrhage. She developed severe myoclonic jerks in the absence of electrographic correlate on EEG. Levetiracetam and phenobarbital alleviated jerks, although she developed progressive hypotonia as neurologic status continued to deteriorate. Considering persistently positive HSV studies, foscarnet was added to acyclovir. However, at 3 weeks of life, she was intubated for apnea and respiratory failure, and given clinical trajectory and devastating prognosis, mother asked to compassionately withdraw support and allow natural death on day of life 25. This case of congenital, disseminated HSV is particularly unique in that it occurred in a premature infant of 29 weeks gestation and had significantly elevated copy numbers in the blood and CSF as well as skin lesions, indicating likely longstanding infection at the time of delivery. Additionally, it is unknown how concurrent placental viral infections with SARSCoV2 may have contributed to this patient's course, or if the recent maternal SARS-CoV2 infection may triggered HSV reactivation and subsequent congenital HSV.

Post-immunization multisystemic inflammatory response in non-COVID patient

Case Report Moderna vaccine postvaccination symptoms include local and systemic reactions. Local side effects include pain after injection, erythema, induration, tenderness, and lymphadenopathy. Systemic reactions include fever, headache, fatigue, myalgia, arthralgia, nausea/vomiting, or chills. We describe a case of severe postvaccination symptoms that occurred after administration of Moderna vaccine in an individual with no prior history of COVID infection. Case 73-year-old male with a past medical history of diabetes, atrial fibrillation, hypertension, and hyperlipidemia presented to the Emergency Department secondary to an elevated white blood cell count (WBC). Patient started with weakness, low appetite, fever, chills, and headaches 2 days after receiving the Moderna vaccine. COVID-19 antigen and PCR test were negative. He was hemodynamically stable and afebrile. Laboratories showed WBC of 35.16 K/μL, sodium of 120 mmol/L, alanine transaminase of 84 IU/L, and aspartate transaminase of 116 IU/L. The patient denied having unintentional weight loss, fever, adenopathy, rash, pruritus, new medications, or recent infection. Chest x-ray did not show pleural effusion, consolidation or pneumothorax. Patient was started on broad spectrum antibiotics, and on hypertonic saline, fluid restriction and desmopressin for severe hyponatremia. Liver ultrasound ruled out cirrhosis;his hepatitis panel was negative. Peripheral blood smear showed normocytic anemia, neutrophilia, monocytosis, lymphopenia, and thrombocytosis. Workup for myeloproliferative process including Jak2, CALR, MPL, BCR -ABL, was negative. No bone marrow biopsy was performed as the smear results were considered a reactive process. Blood and urine cultures were negative. The patient was briefly transferred to ICU secondary to worsening hyponatremia, decreased mental status, and acute kidney injury (AKI). He developed erythematous non-pruritic rash on his arms and upper chest on day 13 which resolved after oral antihistamines. Transaminitis, hyponatremia, and AKI resolved, and patient was discharged 18 days later with WBC of 14.42 K/μL. Discussion Post-immunization side effects have been widely described after COVID vaccination. A new entity called adult multisystem inflammatory syndrome (MIS-A) which includes some of those symptoms has been described. Diagnostic criteria include severe illness requiring hospitalization in a person ≥ 21 years, positive COVID test during admission or in the previous 12 weeks, extrapulmonary organ system dysfunction, severe inflammation on laboratory test, and absence of severe respiratory illness. Our patient had characteristics consistent with MIS-A, except for negative COVID test. To our knowledge, there is only one reported case of multisystemic inflammatory syndrome associated with vaccine. Although MIS-A criteria establish that a patient must have a positive COVID test, it is worthwhile examining if there is any role of the vaccination per se on its presentation.

A rare case of reactive arthritis secondary to COVID-19

Case report-IntroductionIn December 2019, the first cluster of Coronavirus disease 2019 (COVID-19) cases caused by the novel coronavirus SARS-CoV-2 was identified in Wuhan, China. The disease was declared a global pandemic on 11th March 2020. COVID-19 was initially thought to cause respiratory complications only, however several extra pulmonary manifestations of the infection have since emerged.We report a rare case of reactive arthritis (ReA), urticarial rash and angioedema in a young female secondary to COVID-19 infection. Rashes were recently added to the World Health Organisation (WHO) criteria for diagnosis of COVID-19 demonstrating their significance.Case report-Case descriptionA 31-year-old female doctor was admitted with acute swelling of her lips, dysphagia, and a widespread urticarial rash. Preceding this she had a one-week history of fever, cough, and constitutional symptoms of malaise and weight loss. Her symptoms had started at the end of April 2020 during the peak of the COVID-19 pandemic in the United Kingdom. Three days later she developed painful swelling of her wrists, elbows, knees, and hands. She reported no back or sacroiliac joint pain, enthesitis or any previous history of inflammatory joint pains. She had a history of platelet dysfunction and was treated with Desmopressin.Clinical examination revealed a widespread urticarial rash over her face, limbs, and trunk, with no nail abnormalities. She had active synovitis in her right wrist, elbow, and mild bilateral knee effusions. All other joints including spine and sacroiliac joints were normal. She had no dactylitis or enthesitis. Systemic examination was normal. Investigations revealed Hb 113 g/L, MCV 88.2 fL, Platelets 282 x 109/L, WCC 6.6 x 109/L and Lymphocytes of 0.63 x 109/L with normal neutrophil and eosinophil count. CRP was raised at 107mg/L. She had a negative autoimmune screen including ANA, ANCA, IgM-RF, anti-CCP antibodies and HLA B27. Plain radiographs of knees were normal. SARS CoV-2 PCR was positive following a nasal swab. Urine and blood cultures were negative. Treatment was commenced with intravenous hydrocortisone and antihistamines with resolution of her angioedema symptoms;however, her rash and arthritis persisted.The patient was diagnosed with Reactive Arthritis (ReA), urticarial rash and angioedema secondary to COVID-19 infection. Prednisolone 30mg daily was started, and within a week her arthritis and rash markedly improved. Prednisolone was tapered over six weeks. By her two-month clinic follow up, she reported no further joint swelling and was functioning normally.Case report-DiscussionThe most common complication of COVID-19 is Acute Respiratory Distress Syndrome (ARDS) however several other serious complications have been identified including cardiac injury, thromboembolic events, neurological abnormalities, and an aggravated inflammatory response causing a cytokine storm.ReA is a post infectious arthritis commonly seen following gastrointestinal or genitourinary infections and is yet to be recognised as a complication of this disease. ReA most commonly presents as an asymmetrical peripheral or axial spondyloarthropathy. The affected joints do not contain pathogen. More than half of ReA cases resolve spontaneously within six months without requiring long-term treatments.Up to 20% of patients with COVID-19 infection have been shown to develop cutaneous manifestations including erythematous rash, vesicular rash, acral ischaemia, rash with petechiae, and widespread urticaria. This has led to the recent addition of rashes to the World Health Organisation (WHO) Criteria for diagnosis of COVID-19 infection. Additionally, as COVID-19 has an incubation period of 14 days where patients can be asymptomatic, cutaneous manifestations may serve as an early indicator of infection, aiding in a more rapid diagnosis.Case report-Key learning pointsWe present a rare case of ReA secondary to COVID-19 infection, with complete resolution of symptoms following administration of oral glucocorticoids. A detailed history and examination of t e musculoskeletal system should be undertaken in all patients presenting with COVID-19. Urticarial rashes should be considered as an early symptom of COVID-19 infection as per the WHO criteria for diagnosis. Glucocorticoids can be considered in treating patients with this presentation, where traditional anti-inflammatory agents have been refractory or contraindicated.

Hyponatremia in Children and Adults with Prader-Willi Syndrome: A Survey Involving Seven Countries.

In Prader-Willi syndrome (PWS), conditions that are associated with hyponatremia are common, such as excessive fluid intake (EFI), desmopressin use and syndrome of inappropriate antidiuretic hormone (SIADH) caused by psychotropic medication. However, the prevalence of hyponatremia in PWS has rarely been reported. Our aim was to describe the prevalence and severity of hyponatremia in PWS. In October 2020, we performed a retrospective study based on the medical records of a large cohort of children and adults with PWS from seven countries. Among 1326 patients (68% adults), 34 (2.6%) had at least one episode of mild or moderate hyponatremia (125 ≤ Na < 135 mmol/L). The causes of non-severe hyponatremia were often multi-factorial, including psychotropic medication in 32%, EFI in 24% and hyperglycemia in 12%. No obvious cause was found in 29%. Seven (0.5%) adults experienced severe hyponatremia (Na < 125 mmol/L). Among these, five recovered completely, but two died. The causes of severe hyponatremia were desmopressin treatment for nocturnal enuresis (n = 2), EFI (n = 2), adrenal insufficiency (n = 1), diuretic treatment (n = 1) and unknown (n = 1). In conclusion, severe hyponatremia was very rare but potentially fatal in PWS. Desmopressin treatment for nocturnal enuresis should be avoided. Enquiring about EFI and monitoring serum sodium should be included in the routine follow-ups of patients with PWS.