Hiperkalemia postoperatoria en síndrome de hueso hambriento post-paratiroidectomía por hiperparatiroidismo secundario en enfermedad renal crónica terminal / Hyperkalemia-associated hungry bone syndrome post-parathyroidectomy in end-stage denal disease

Introducción: El hiperparatiroidismo secundario (HPTS) es una complicación de la enfermedad renal crónica terminal (ERCT). A pesar de nuevas terapias médicas como calcimiméticos, en HPTS refractarios la paratiroidectomía (PTX) continúa siendo necesaria. Una complicación frecuente en estos pacientes posterior a la PTX es el síndrome de hueso hambriento (SHH), caracterizado por una profunda y prolongada hipocalcemia asociada a hipofosfatemia, secundaria a un excesivo aumento de su captación ósea. Una complicación menos descrita, pero con consecuencias graves e incluso fatales, es la hiperkalemia. El propósito de este trabajo consiste en enfatizar el riesgo de hiperkalemia por SHH a partir de un caso clínico, señalar los mecanismos fisiopatológicos, factores de riesgo y consideraciones terapéuticas. Caso clínico: Mujer de 35 años, con ERCT de causa desconocida, HPTS refractario con PTX total e implante de glándulas en antebrazo hace 9 años. Ingresa por recurrencia de HPTS. Cintigrama MIBI SPECT/CT® evidenció implante hiperfuncionante, indicándose PTX del injerto. Exámenes preoperatorios: calcemia 8.6 mg/dL, fosfatasas alcalinas 1115 UI/L (VN <100), PTH intacta (PTHi) 3509 pg/ml y kalemia 4.8 mEq/L. Biopsia: hiperplasia paratiroidea nodular. En postoperatorio inmediato presentó hiperkalemia de 7.1 mEq/L con cambios electrocardiográficos, requiriendo hemodiálisis de urgencia. Posteriormente desarrolló hipocalcemia, hipofosfatemia e hipomagnesemia, de difícil control. Discusión: El SHH post HPTS puede coexistir con hiperkalemia postoperatoria inmediata grave, incluso fatal si no se identifica y corrige a tiempo. El mecanismo fisiopatológico aún no está bien dilucidado. Varios factores pudieran intervenir, incluyendo aumento del metabolismo celular, traumatismo tisular, fármacos anestésicos, fluidos perioperatorios y flujo de iones transmembrana. El nivel de potasio previo a la cirugía, menor edad, género masculino, tiempo entre la última hemodiálisis y la cirugía, y duración de la PTX, son factores de riesgo para hiperkalemia postoperatoria. El conocimiento de esta grave complicación permitirá estar preparado para monitorizar y eventualmente tratar.

Introduction: Secondary Hyperparathyroidism (SHPT) is a complication of End-Stage Renal Disease (ESRD). Although new medical therapies (i.e.calcimimetics,) parathyroidectomy (PTX) continues to be necessary in refractory cases. A well-known complication after PTX is an entity called Hungry Bone Syndrome (HBS), characterized by deep and prolonged hypocalcemia associated with hypophosphatemia, secondary to an excessive increase in bone formation. A less reported complication, but with severe or even fatal consequences, is hyperkalemia. The purpose of this work consists of emphasizing the risk of hyperkalemia in HBS, reporting a clinical case that points out the physiopathological mechanisms, risk factors, and therapeutic considerations. Clinical case: 35-year-old woman with ESRD of unknown cause with refractory SHPT with total PTX and forearm gland grafts nine years ago. She presented SHPT recurrency. MIBI SPECT/CT® scan showed a hyperfunctioning implant, indicating graft PTX. Preoperative tests: calcemia 8.6 mg/dL, phosphatemia 7.3 mg/dL, alkaline phosphatases 1115 UI/L (VN<100), intact PTH (iPTH) 3509 pg/ml and kalemia 4.8 mEq/L. Biopsy: parathyroid nodular hyperplasia. In the immediate postoperative period, she presented hyperkalemia at 7.1 mEq/L with electrocardiographic changes, requiring emergency hemodialysis. Later she developed hypocalcemia, hypophosphatemia, and hypomagnesemia of difficult control. Discussion: HBS post PTX can coexist with severe immediate postoperative hyperkalemia, which can be even fatal if not detected and corrected. The physiopathological mechanism is still not entirely elucidated. Various factors could interfere, including an increase in cell metabolism, tissue traumatism, anesthetic drugs, intraoperative fluids, and transmembrane ion flow. Preoperative potassium levels, younger age, male gender, the time elapsed between last hemodialysis and surgery, and duration of PTX are risk factors for post-surgical hyperkalemia. Knowing this severe complication will allow the medical team to be prepared for monitoring and eventually treating it.

Hipertensión arterial en la mujer adulta / Hypertension in women

The present review examines the types of hypertension that women may suffer throughout life, their physiopathological characteristics and management. In early life, the currently used low-dose oral contraceptives seldom cause hypertension. Pregnancy provokes preeclampsia, its main medical complication, secondary to inadequate transformation of the spiral arteries and the subsequent multisystem endothelial damage caused by deportation of placental factors and microparticles. Hypertension in preeclampsia is an epiphenomenon which needs to be controlled at levels that reduce maternal risk without impairing placental perfusion. The hemodynamic changes of pregnancy may unmask a hypertensive phenotype, may exacerbate a chronic hypertension, or may complicate hypertension secondary to lupus, renovascular lesions, and pheochromocytoma. On the other hand a primary aldosteronism may benefit from the effect of progesterone and present as a postpartum hypertension. A hypertensive pregnancy, especially preeclampsia, represents a risk for cardiac, vascular and renal disease in later life. Menopause may mimic a pheochromocytoma, and is associated to endothelial dysfunction and salt-sensitivity. Among women, non-pharmacological treatment should be forcefully advocated, except for sodium restriction during pregnancy. The blockade of the renin-angiotensin system should be avoided in women at risk of pregnancy; betablockers could be used with precautions during pregnancy; diuretics, ACE inhibitors and angiotensin receptor antagonists should not be used during breast feeding. Collateral effects of antihypertensives, such as hyponatremia, cough and edema are more common in women. Thus, hypertension in women should be managed according to the different life stages.

Terapia antihipertensiva en enfermedad renal crónica / Treatment of hypertension in chronic kidney disease

La enfermedad renal crónica (ERC) constituye una de las causas más frecuentes de hipertensión arterial (HTA) secundaria. Existe una nueva clasificación de la ERC basada en la presencia de un daño estructural con o sin un deterioro de la velocidad de filtración glomerular (VFG). La prevalencia de la HTA varía principalmente según la magnitud de la VFG y la etiología de la enfermedad del parénquima renal. Los mecanismos hipertensógenos primordiales son: la retención de sodio e hipervolemia, y la activación del eje renina angiotensina aldosterona. La HTA es también un factor de progresión de la ERC. La terapia se basa en la restricción de sodio, diuréticos y bloqueadores del eje renina angiotensina. Consideraciones farmacológicas y clínicas son fundamentales para un efectivo uso de esta terapia. Los objetivos son la prevención cardiovascular y renal, a través de la obtención de determinados niveles de presión arterial (PA).

Chronic kidney disease (CKD) is one of the most common causes of secondary hypertension (HTN). Currently, there is a new classification of CKD based on the presence of structural damage with or without glomerular filtration rate(GFR) deterioration. The prevalence of HTN in CKD varies mainly depending on the magnitude of the GFR and the etiology of renal parenchymal disease. Main hipertensive mechanisms are: salt retention with fluid overload, and reninangiotensin aldosterona axis activation. HTN is also a factor for CKD progression. The current therapy is based on sodium restriction, diuretics and renin angiotensin system blockers. Pharmacological and clinical precautions are essential foran effective use of this therapy. Objectives are to prevent cardiovascular and renal events, through obtaining certain blood pressure (BP) levels.

Síndrome de lisis de glóbulos blancos después de un trasplante autólogo de células troncales hematopoyéticas en el tratamiento de la amiloidosis AL renal: Caso clínico / White blood cell lysis syndrome after autologous peripheral blood stem cell transplantation in the treatment of renal AL amyloidosis: Case report

The treatment of AL amyloidosis was not successful until the advent of myeloablative chemotherapy consisting of high-dose intravenous melphalan followed by autologous peripheral blood stem cell transplantation. This new treatment has achieved better survival rates and, remarkably, it has obtained complete remission. Among patients with renal involvement, achievement of a complete hematological response was associated with a 50% reduction in proteinuria and stable creatinine clearance in more than 2/3 of patients. Despite of these excellent results, this new therapy is associated with significant toxicity, including the development of acute renal failure due to white blood cell lysis syndrome. We report a 59 year-old female with a nephrotic syndrome due to primary amyloidosis successfully treated autologous stem cell transplantation who developed acute renal failure caused by white blood cell lysis syndrome. The patient required treatment with granulocytic colony stimulating factor and intermittent hemofiltration and was discharged 23 days after melphalan administration with a satisfactory renal function and white blood cell count. After one year of follow up, she maintains a good glomerular filtration rate, a proteinuria of less than, 1 g/day and normal hematological values.

Hipotensión ortostática: una manifestación sugerente de feocromocitoma / Orthostatic hypotension: as an unusual manifestation of pheochromocytoma

Pheochromocytoma, though an uncommon cause of hipertension, can be a lethal condition. Because of this it is mandatory to diagnose it or rule it out in presence of suggestive symptoms. Typical symptoms are palpitations, sweating, severe headaches and hypertension. However, there are other suggestive symptoms of this dangerous endocrine entity, one of which is the orthostatic hypotension. We report the case of a 65 years old female patient with long standing hypertension in whom the pheochromocytoma was suspected after episodes of orthostatic hypotension. Although this manifestation was described almost fifty years ago, its frequency and pathophysiology has not yet been well established and fully elucidated. Moreover, it has meaningful implications in relation to preoperatory management and the timing of surgery (Rev Méd Chile 2003; 131: 1429-33).

Insuficiencia renal y respiratoria en una embarazada con esclerosis sistémica progresiva: caso anatomo-clínico / Renal and respiratory failure in a pregnant woman with progressive systemic sclerosis: anatomical clinical case

Pregnancy in patients with systemic sclerosis may predispose to a fast progression of the disease. We report a woman with systemic sclerosis and a multiple visceral involvement that during the third trimester of pregnancy developed a respiratory failure caused by interstitial fibrosis complicated with alveolar hemorrhage, bronchopneumonia and respiratory distress syndrome and a renal failure. On admission, she was subjected to a cesarean section, delivering a 1205 g newborn. In spite of intensive care support, the multisystemic failure became unmanageable and the patient died 15 days after admission. Literature review, although sometimes controversial, indicates that pregnancy is a situation with definitive death risk for patients with systemic sclerosis, that requires a close follow up