The surgical management of renal hyperparathyroidism.

Secondary and tertiary hyperparathyroidism (HPT) develop in patients with renal failure due to a variety of mechanisms including increased phosphorus and fibroblast growth factor 23 (FGF23), and decreased calcium and 1,25-dihydroxy vitamin D levels. Patients present with various bone disorders, cardiovascular disease, and typical laboratory abnormalities. Medical treatment consists of controlling hyperphosphatemia, vitamin D/analog and calcium administration, and calcimimetic agents. Improved medical therapies have led to a decrease in the use of parathyroidectomy (PTX). The surgical indications include parathyroid hormone (PTH) levels >800 pg/ml associated with hypercalcemia and/or hyperphosphatemia despite medical therapy. Other indications include calciphylaxis, fractures, bone pain or pruritis. Transplant recipients often show decreased PTH, calcium and phosphorus levels, but some will have persistent HPT. Evidence suggests that PTX may cause deterioration in renal graft function in the short-term calling into the question the indications for PTX in these patients. Pre-operative imaging is only occasionally helpful except in re-operative PTX. Operative approaches include subtotal PTX, total PTX with or without autotransplantation, and possible thymectomy. Each approach has its proponents, advantages and disadvantages which are discussed. Intraoperative PTH monitoring has a high positive predictive value of cure but a poor negative predictive value and therefore is of limited utility. Hypocalcemia is the most common complication requiring aggressive calcium administration. Benefits of surgery may include improved survival, bone mineral density and alleviation of symptoms.

Ductus venosus closure results in transient portal hypertension--is this the silent trigger for necrotizing enterocolitis?

INTRODUCTION: The etiology of necrotizing enterocolitis (NEC) remains elusive and no definite trigger has been identified. There are no studies to date examining the potential role of closure of the ductus venosus (DV), its effect on increasing portal venous pressure (PVP) and its association to mesenteric venous ischemia in the development of NEC. Our aim was to develop an animal model to examine this physiology. METHODS: Fifteen near-term lambs were used. The DV was occluded in experimental animals by a balloon tip catheter, while the sham controls underwent catheterization without DV occlusion. Vital signs and PVP were monitored for 4h, followed by intestinal biopsy. RESULTS: The experimental group (n=5) demonstrated a significant increase in PVP following DV occlusion (11.87 mm Hg [95% CI: 11.40-12.34]), compared to controls (8.95 mm Hg [95% CI: 8.34-9.56]) (F=12.16, p=0.001). Histology of the terminal ileum showed vacuolar degeneration, indicative of reversible cellular damage in the experimental group. CONCLUSIONS: We demonstrate that DV closure in the neonatal lamb leads to transient portal hypertension which is associated with cellular damage and inflammatory changes of the intestinal mucosa. Additional studies will be necessary to determine if the transient portal hypertension following DV closure leads to clinically apparent intestinal ischemia and NEC.

Fulminant hepatic failure attributed to ackee fruit ingestion in a patient with sickle cell trait.

We report a case of fulminant liver failure resulting in emergent liver transplantation following 3 weeks of nausea, vomiting, and malaise from Jamaican Vomiting Sickness. Jamaican Vomiting Sickness is caused by ingestion of the unripe arils of the Ackee fruit, its seeds and husks. It is characterized by acute gastrointestinal illness and hypoglycemia. In severe cases, central nervous system depression can occur. In previous studies, histologic sections taken from patients with Jamaican Vomiting Sickness have shown hepatotoxicity similar to that seen in Reye syndrome and/or acetaminophen toxicity. We highlight macroscopic and microscopic changes in the liver secondary to hepatoxicity of Ackee fruit versus those caused by a previously unknown sickle cell trait. We discuss the clinical variables and the synergistic hepatotoxic effect of Ackee fruit and ischemic injury from sickled red blood cells, causing massive hepatic necrosis in this patient.

A murine model of graft-vs-host disease after in utero hematopoietic cell transplantation.

PURPOSE: Graft-vs-host disease (GvHD) is a known complication of in utero bone marrow transplantation. However, GvHD has been difficult to study owing to frequent fetal demise. We describe the first consistent murine model of GvHD with postnatal survival after in utero hematopoietic cell transplantation. METHODS: A 50/50 mixture of bone marrow and splenocytes (10(6)) from 6-week-old C57/BL6 (H2-b) mice was injected intraperitoneally into Balb/c (H2-d) fetuses at e14 to 16. Live born pups were followed for clinical GvHD. Peripheral blood and hematopoietic organ chimerism was confirmed by flow cytometry and polymerase chain reaction. Organ samples were isolated for histology. RESULTS: Twenty-seven (75%) of 36 surviving pups displayed clinical GvHD by 2 weeks compared with 9 developmentally normal pups. Mean difference in weight between the 2 groups was 2.9 g at 7 days and 5.2 g at 14 days of life (P < .0001). All 27 pups with clinical GvHD and 1 normal-appearing pup had blood chimerism ranging from 1.5% to 65%. Eight of the 9 normal-appearing pups had 0% chimerism. Histologic analysis revealed findings of GvHD in liver, spleen, small intestine, and skin specimens of only chimeric pups. CONCLUSIONS: A consistent murine model of GvHD can be achieved after in utero transplantation of major histocompatibility complex-mismatched bone marrow and splenocytes. Future studies will use this model to examine approaches to prevent GvHD after in utero stem cell transplantation.

Safety of minimal immunosuppression in liver transplantation for hepatoblastoma.

BACKGROUND: Despite aggressive chemotherapy, recurrence of disease remains the leading cause of death after liver transplantation (LTx) for hepatoblastoma (HB). Unfortunately, little is known about the effects of immunosuppression on recurrence and posttransplant outcomes. We hypothesized that minimal immunosuppression can be safely used in these recipients. METHODS: In 2004, we adopted a minimal immunosuppression regimen using daclizumab induction and tacrolimus monotherapy. Kaplan-Meier survival curves were generated. RESULTS: From 2004 to 2006, 6 children underwent primary LTx for HB with neoadjuvant and adjuvant chemotherapy. Patient survival was 100% at 12 months and at 24 months, without graft loss. One patient died 28 months after transplantation. Recurrence-free survival was 83% at 12 months and at 24 months. Despite minimal immunosuppression (IS), 4 of 6 HB recipients remained rejection-free. When compared to other LTx recipients receiving minimal IS, HB recipients trended to have better rejection-free survival (HB, 83% at 12 months and 62.5% at 24 months vs all others, 36% and 36%, respectively; P = .19). CONCLUSION: Our short-term patient and graft survival rates are comparable to those reported for all HB recipients in the United Network for Organ Sharing database. Although not statistically significant, our rejection-free survival data suggest that HB recipients may be less likely to reject than other recipients.

Ileal exclusion for refractory symptomatic cholestasis in Alagille syndrome.

BACKGROUND: Alagille syndrome (AGS) can result in pruritic self-mutilation and disabling or disfiguring xanthomas. Though external biliary diversion and transplantation have been described for AGS, few data exist for the use of ileal exclusion (IE) in this setting. METHODS: Three patients with AGS with symptomatic cholestasis despite maximal medical management underwent IE. In each case, small bowel length was measured and the terminal 15% of ileum was excluded using stapled division and ileocecal anastomosis. Symptom scores were collected after institutional review board approval and are presented here as mean (range). Pruritus and xanthomas were graded as follows: 0 = none, 1 = mild scratching/minimal, 2 = active scratching/moderate, 3 = abrasions/disfiguring, 4 = mutilation/disabling. RESULTS: Mean follow-up was 30 months (4-45 months). Pruritus score decreased from 3.33 (3-4) to 0.33 (0-1). Xanthoma score decreased from 3.67 (3-4) to 1.67 (1-2). All patients were maintained on nutritional supplements pre- and postoperatively without a change in management. No patients experienced diarrhea or dehydration postoperatively. There were no complications. CONCLUSIONS: Ileal exclusion effectively decreases refractory pruritus and xanthoma burden in AGS. This procedure offers the advantages of reversibility, avoidance of a stoma, and technical ease. Ileal exclusion should be considered for symptomatic AGS refractory to medical management as an alternative to external biliary diversion or liver transplantation.