Fulminant necrotizing enterocolitis in a multihospital healthcare system.

OBJECTIVE: A subset of necrotizing enterocolitis (NEC) cases is fulminant, characterized by rapid progression to death with massive bowel necrosis found at laparotomy or autopsy. We sought to identify and report all such cases in a multihospital healthcare system during the past 9 years and to characterize this entity using case-control methodologies. STUDY DESIGN: This was a multicentered, cross-sectional, historic cohort study conducted using Intermountain Healthcare hospital patient data. All neonates who died of NEC within 48 h of onset, during 2001 to 2009, were compared with two matched control groups: (1) demographically matched controls who developed non-fulminant NEC, (2) demographically matched controls that did not develop NEC. RESULT: During this period, 2 71 327 live births occurred in the Intermountain Healthcare hospitals. Of these, 318 had a diagnosis of NEC (Bell stage ≥II). Also during this period, 205 other neonates were transferred into an Intermountain hospital for treatment of NEC. Of these 523 NEC cases, 35 (6.7%) had a fulminant course. Compared with the non-fulminant cases, the fulminant group were born at lower weight (1088±545 vs 1652±817 g, P=0.000) and earlier gestational age (27.5±3.3 vs 31.1±4.4 weeks, P=0.000), and were more likely to have: (1) radiographic evidence of portal venous air (P=0.000), (2) hematocrit <22% (P=0.000), (3) increase in feeding volume >20 ml/kg/day (P=0.003), (4) immature to total (I/T) neutrophil ratio >0.5 (P=0.005), (5) blood lymphocyte count <4000/µl (P=0.018), (6) an increase in concentration of human milk fortifier within 48 h before developing NEC (P=0.020). CONCLUSION: Portal venous air, anemia, rapid feeding escalation, a high I/T neutrophil ratio, a low lymphocyte count and recent increases in fortifier may all be associated with fulminant NEC.

Antecedents of Bell stage III necrotizing enterocolitis.

OBJECTIVE: New biopharmaceuticals hold promise for preventing or treating necrotizing enterocolitis. However, it is unclear whether any such biopharmaceutical that requires enteral administration could be administered using an 'early-treatment' paradigm. This study was undertaken to assess this issue based on data from every case of Bell stage III NEC cared for during the past 7 years at Intermountain Healthcare. STUDY DESIGN: Patients with Bell stage III NEC were identified from electronic medical record repositories and the diagnosis was validated using operative reports. Electronic and paper records of each patient were then used to identify potential clinical and laboratory antecedents occurring within the 48 h period preceding the diagnosis of NEC. RESULT: One hundred eighteen patients had Stage III NEC. The earliest recognized antecedents were nonspecific for NEC (apnea/bradycardia, skin mottling and irritability). These were recorded at 2.8+/-2.1, 4.5+/-3.1 and 5.4+/-3.7 (mean+/-s.d.) hours, respectively, before NEC was diagnosed. The most commonly identified gastrointestinal antecedents were blood in the stools, increased abdominal girth and elevated pre-feeding gastric residuals or emesis. These were identified 2.0+/-1.9, 2.8+/-3.1 and 4.9+/-4.0 h before NEC was recognized. Thirty-eight percent had a blood transfusion (18+/-12 h) preceding the NEC. Tachycardia, tachypnea, hypotension and diarrhea were rarely identified as antecedents and no consistent laboratory antecedents were discovered. CONCLUSION: We judge that an 'early treatment of NEC' paradigm testing any pharmacological agent that must be administered enterally is not feasible. The first recognized antecedents of Bell stage III NEC are nonspecific for gastrointestinal pathology and insufficient time exists for dosing between the first gastrointestinal signs and placement of the gastric decompression tube.

Necrotizing enterocolitis in term neonates: data from a multihospital health-care system.

OBJECTIVE: In the past 5(1/2) years, 30 term or near-term neonates in the Intermountain Healthcare system developed necrotizing enterocolitis (NEC) Bell's stage > or =II. We sought to identify possible explanations for why these patients developed NEC, by comparing them with 5847 others that did not develop NEC, from the same hospitals and of the same gestational ages, cared for during the same 5 1/2-year period. STUDY DESIGN: Data were collected from neonates admitted to any of the Intermountain Healthcare NICUs with a birth date from 1 January 2001 to 30 June 2006, and a gestational age >36 weeks. A variety of patient features and feeding practices were compared between those that did vs did not develop NEC. RESULT: Forty-one neonates >36 weeks gestation were listed in the discharge records as having NEC of Bell's stage II or higher. However, on review of these 41 medical records, 11 were seen to have had NEC of Bell's stage I, whereas the remaining 30 had radiographs and clinical courses indicative of Bell's stage > or =II. Those 30 formed the basis of this study. Twenty-eight of the 30 developed NEC after having been admitted to an NICU for some other reason; the other two developed NEC at home, within 2 days of being discharged from an NICU. The 30 that developed NEC were more likely than the 5847 that did not develop NEC, to have congenital heart disease (P=0.000), polycythemia (P=0.002), early-onset bacterial sepsis (P=0.004) or hypotension (P=0.017). All 30 received enteral feedings before NEC developed; 29 were fed either artificial formula or a mixture of formula and breast milk. The one that was exclusively fed human milk was fed human milk with added fortifier (24 cal/oz). The 30 that developed NEC were more likely to be fed formula exclusively (P=0.000). Seven of the 30 had a laparotomy for NEC; two of the seven had total bowel necrosis and support was withdrawn. The other five had perforations and bowel resections. The mortality rate was 13% (4/30). CONCLUSION: In our series, NEC among term or near-term neonates was exclusively a complication developing among patients already admitted to a NICU for some other reason. We speculate that the combination of reduced mesenteric perfusion and feeding with artificial formula were factors predisposing them to develop NEC.

Heparin-binding EGF-like growth factor is present in human amniotic fluid and breast milk.

BACKGROUND/PURPOSE: Heparin-binding EGF-like growth factor (HB-EGF) is a member of the epidermal growth factor (EGF) family that has been implicated in the healing of various organ injuries. Endogenous HB-EGF production is upregulated in response to injury to the kidney, liver, brain, skin, and intestine. Exogenous administration of HB-EGF protects against intestinal epithelial cell apoptosis and necrosis and intestinal ischemia/reperfusion (I/R) injury. This study examines the presence of endogenous HB-EGF in human amniotic fluid and breast milk, fluids that are in intimate contact with the developing and neonatal gastrointestinal tract. METHODS: Breast milk samples were collected from lactating women and amniotic fluid was gathered from full-term uteri (cesarian sections) or preterm uteri (amniocentesis). Crude and partially purified breast milk and amniotic fluid samples were analyzed for HB-EGF levels using an HB-EGF-specific enzyme-linked immunosorbent assay (ELISA). RESULTS: Analysis results showed detectable HB-EGF levels in human amniotic fluid and breast milk, ranging from 0.2 to 230 pg/mL. Breast milk and amniotic fluid subjected to heparin affinity or HB-EGF-affinity column chromatography showed bioactivity eluting at positions consistent with those known for native HB-EGF. CONCLUSIONS: This study represents the first report of detectable HB-EGF in human amniotic fluid and breast milk. The presence of HB-EGF in these fluids may serve a role in the development of the gastrointestinal tract in utero, and in protection against gut mucosal injury after birth.

Heparin-binding EGF-like growth factor decreases apoptosis in intestinal epithelial cells in vitro.

BACKGROUND/PURPOSE: The production of heparin-binding EGF-like growth factor (HB-EGF) is upregulated during organ injury and has a cytoprotective effect during hypoxic stress in intestinal epithelial cells in vitro and intestinal ischemia-reperfusion injuries in vivo. The purpose of this study was to determine if HB-EGF-related cytoprotection is manifested through alterations in apoptosis. METHODS: Human intestinal epithelial cell monolayers (DLD-1 and Caco-2) were stimulated with interleukin (IL)-1 (20 ng/mL), tumor necrosis factor (TNF)-alpha (40 ng/mL), and interferon (IFN)-gamma (10 ng/mL) with or without HB-EGF (1, 10 or 100 ng/mL) and analyzed for rates of apoptosis utilizing a Cell Death Detection ELISA and flow cytometry. RESULTS: ELISA results showed a 3-fold increase in the level of apoptosis during stimulation with cytokines compared with nonstimulated cells (P <.05). Relative levels of cytokine induced apoptosis were reduced after 12 hours of HB-EGF exposure (P <.05) in a dose-dependent fashion. Results of flow cytometric analysis also showed a reduction in apoptosis at 6 hours when cell monolayers were stimulated with cytokines in conjunction with HB-EGF compared with cytokines alone (P <.05). CONCLUSIONS: HB-EGF downregulated apoptosis in intestinal epithelial cells exposed to proinflammatory cytokines in vitro. The results of this study suggest that alterations in apoptosis may represent a possible mechanism by which this growth factor exerts its cytoprotective effect at the mucosal level during the proinflammatory state.

Site-directed mutagenesis of heparin-binding EGF-like growth factor (HB-EGF): analysis of O-glycosylation sites and properties.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a 22 kDa, O-glycosylated protein. HeLa cells infected with a recombinant vaccinia virus expressing human HB-EGF produced a secreted, bioactive protein, with Mr 22,000 that was decreased to 14,000 by treatment with O-glycanase. Site-directed mutagenesis of HB-EGF cDNA using oligonucleotide- and PCR-directed techniques was performed to change the potential glycosylation sites, Thr75 and Thr85, to alanine residues to prevent O-glycosylation. Purification and characterization of the mutant proteins demonstrated that: (i) both O-glycosylation sites of HB-EGF are utilized, (ii) HB-EGF secretion does not require O-glycosylation, (iii) removal of O-glycans does not affect proteolytic cleavage of the HB-EGF precursor, nor does it influence HB-EGF intracellular trafficking or subcellular localization, and (iv) HB-EGF produced by HeLa cells is heavily sialylated. Comparisons between glycosylation mutants and wild-type HB-EGF revealed no significant apparent differences in receptor binding activity.

Heparin-binding EGF-like growth factor decreases inducible nitric oxide synthase and nitric oxide production after intestinal ischemia/reperfusion injury.

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) has been shown to protect intestine from ischemia/reperfusion (I/R) injury in vivo and to down-regulate inducible nitric oxide synthase (iNOS) and nitric oxide (NO) production in intestinal epithelial cells in vitro. The present study was undertaken to investigate whether HB-EGF could modulate the iNOS/NO axis after total midgut I/R injury in rats. I/R injury induced a significant increase in iNOS gene expression (quantified by real-time RT-PCR) and protein production (detected by western blots), as well as elevation of serum NO levels (measured by chemiluminescence assay). Nitrotyrosine (NT) and iNOS production colocalized immunohistochemically, with positive staining found mainly in villous and crypt epithelial cells, as well as ganglion cells. Intraluminal administration of HB-EGF 45 min after the start of a 90-min ischemic interval significantly decreased I/R-induced iNOS gene expression and protein production, as well as serum NO levels. Immunohistochemically, HB-EGF administration led to elimination of iNOS and NT staining in crypt epithelial cells and ganglion cells, with only weak staining that remained in villous epithelial cells. Thus, HB-EGF protects the intestine from I/R injury, at least partially, through down-regulation of the iNOS/NO/NT pathway, a mechanism that is central to I/R injury in multiple organ systems.

Collision tumors in children: a review of the literature and presentation of a rare case of mesoblastic nephroma and neuroblastoma in an infant.

A mass made up of 2 distinct synchronous primary malignant tumors is a rare event in adults, and exceedingly so in children. Such lesions have been called collision tumors. Reported here is an infant who was found to have a collision tumor comprised of a neuroblastoma and a congenital mesoblastic nephroma, in contiguity, in the right kidney. This is the first report of a collision tumor in an infant. This also is the first report of a synchronous occurrence of a neuroblastoma and a congenital mesoblastic nephroma. The authors present this case and discuss the available literature.

Fall injuries in the pediatric population: safer and most cost-effective management.

BACKGROUND: At our children's hospital, 30% of all trauma admissions are from falls. The aim of this study was to outline inefficiencies and unnecessary costs incurred in the care of these patients. METHODS: The charts of 127 children admitted for falls (height > or = 9 feet) from 1993 to 1996 were reviewed. Patient demographics, injuries, and treatment costs were recorded and analyzed. RESULTS: Fifty-seven children (45%) were evaluated at an outside facility before transfer. Of these, 73% had injuries requiring treatment at the pediatric center. Local hospital work-up resulted in an average treatment delay of 4.5 hours. Additionally, significant cost was incurred by duplication of radiographic studies, the majority of which were normal. CONCLUSION: Improved and more cost-effective care in pediatric falls can be ensured by immediate transfer of patients with significant injuries, omission of radiographs before transfer, and avoidance of multiple routine x-ray films, the majority of which are normal.

Focused abdominal sonography for trauma (FAST) in children with blunt abdominal trauma.

BACKGROUND: Focused abdominal sonography for trauma (FAST) has been well reported in adults, but its applicability in children is less well established. We decided to test the hypothesis that FAST and computed tomography (CT) are equivalent imaging studies in the setting of pediatric blunt abdominal trauma. METHODS: One hundred seven hemodynamically stable children undergoing CT for blunt abdominal trauma were prospectively investigated using FAST. The ability of FAST to predict injury by detecting free intraperitoneal fluid was compared with CT as the imaging standard. RESULTS: Thirty-two patients had CT documented injuries. There were no late injuries missed by CT. FAST detected free fluid in 12 patients. Ten patients had solid organ injury but no free fluid and, thus, were not detected by FAST. The sensitivity of FAST relative to CT was only 0.55 and the negative predictive value was only 0.50. CONCLUSION: FAST has insufficient sensitivity and negative predictive value to be used as a screening imaging test in hemodynamically stable children with blunt abdominal trauma.

Heparin-binding epidermal growth factor-like growth factor protects rat intestine from ischemia/reperfusion injury.

BACKGROUND: We have shown previously that heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) is cytoprotective for intestinal epithelial cells exposed to hypoxia in vitro. We now examine the effects of HB-EGF on the recovery of small intestine from ischemic injury in vivo. METHODS: Segmental intestinal ischemia of 60-min duration was produced in adult rats by occlusion of a first-order branch of the superior mesenteric artery. Recombinant HB-EGF (100 microg) was injected intraluminally into the proximal small bowel after 45 min of ischemia in experimental animals, and buffered saline was injected in control animals. Animals were sacrificed after 48 h, and the affected bowel was resected, processed, and examined microscopically, with histologic grading of the ischemic injury. Additional animals were allowed to recover for up to 1 month to evaluate mortality differences. RESULTS: Intraluminal administration of HB-EGF resulted in significantly decreased extent and severity of ischemia/reperfusion injury, with significantly decreased grade of injury in the HB-EGF-treated compared with nontreated animals (average injury grade 0.66 compared with 2.44, respectively). Moreover, the mortality rate was significantly lower in the HB-EGF-treated animals compared with nontreated animals (0% vs 25%, respectively). HB-EGF-treated animals had increased weight gain in the postischemia recovery period. CONCLUSIONS: We conclude that HB-EGF, given intraluminally, reduces both the amount and the severity of ischemia/reperfusion injury in the small bowel, reduces the mortality associated with intestinal ischemia, and may enhance intestinal recovery. The in vitro and in vivo cytoprotective effects of this growth factor suggest that it may, in the future, be clinically useful in treating patients with intestinal ischemia.

Induction of anchorage independent growth by heparin-binding EGF-like growth factor (HB-EGF).

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) is initially synthesized as a membrane bound protein that is subsequently processed to yield an approximately 74 amino acid secreted product. To investigate the biological activities of HB-EGF and its role(s) in tumor formation, the full-length HB-EGF cDNA was cloned under the regulation of the mouse metallothionein promoter and stably expressed in HB-EGF deficient mouse L cells. HB-EGF immunoreactive proteins of 21 and 24 kDa were observed from transfected MLC lysates, and these lysates exhibited the ability to bind to the EGF receptor, stimulate 3H-thymidine uptake in BALB/c-3T3 cells, and induce anchorage independent growth (AIG) of normal rat kidney (NRK) cells. Furthermore, NRK cells treated with either E. coli-derived or vaccinia virus-derived HB-EGF, as well as NRK cells directly transfected with the HB-EGF construct, demonstrated AIG. We conclude that HB-EGF is a potent growth factor capable of stimulating altered cell growth and anchorage independence.

Herpetic tracheitis and brachial plexus neuropathy in a child with burns.

Herpetic tracheobronchitis is a well-recognized clinical entity that most commonly occurs in immunocompromised patients, including patients with burns. Although the diagnosis of herpetic tracheobronchitis is usually not made until postmortem examination, the presence of the condition can be established when histologic specimens of a patient with upper airway obstruction are studied. In this article, a case is described in which a child developed herpetic tracheitis after undergoing elective intubation after the grafting of burns of the face, neck, and upper extremity. The tracheitis resulted in severe upper airway obstruction that required tracheal dilatation and sequential bronchoscopic excisions of granulation tissue. The patient also developed a brachial plexus neuropathy that was most likely related to herpetic infection.

Bronchopexy for congenital bronchomalacia in the newborn.

Congenital bronchomalacia is a very unusual cause of respiratory distress in the newborn. The surgical management of this anomaly is challenging. The authors report on a newborn with congenital bronchomalacia successfully treated with bronchopexy.

Preliminary experience with focused abdominal sonography for trauma (FAST) in children: is it useful?

BACKGROUND/PURPOSE: Most pediatric surgeons and pediatric radiologists consider computed tomography (CT) the best radiological test for the evaluation of children with suspected intraabdominal injury. The majority of injured children evaluated with CT will be found to have a normal scan. Focused abdominal sonography for trauma (FAST) has been shown to be a useful screening test in the evaluation of adult patients with suspected intraabdominal injury. Limited data exist regarding the use of FAST in children. Our aim was to evaluate the usefulness of FAST as a screening test in the evaluation of children with suspected intraabdominal injury in an attempt to minimize the number of normal CT scans performed. METHODS: Hemodynamically stable children evaluated for suspected intraabdominal injury were prospectively screened with FAST. FAST, real-time sonography at four sites, was performed by staff pediatric radiologists. The average duration of the examination was 2 minutes. Positive and negative FAST scan findings were defined prospectively. The result of each FAST was recorded (positive or negative) and then all patients underwent CT as a control. All management decisions were based on CT results. RESULTS: Forty-six patients were included in the study. FAST identified four children with positive findings (free intraperitoneal fluid), whereas CT showed 13 children with injuries (nine with associated free intraperitoneal fluid and four with only solid organ injury and no associated intraperitoneal fluid). There were nine false-negative and no false-positive FAST scans. The sensitivity of FAST was 0.3 and the specificity was 1.0. Injuries missed by FAST included liver laceration, adrenal hematoma, renal laceration, small bowel injury and splenic laceration. CONCLUSION: Preliminary results suggest that FAST alone is not a useful screening test in the evaluation of children with suspected intraabdominal injury.

A standardized model of partial thickness scald burns in mice.

BACKGROUND: Large mammal partial thickness wound models were developed primarily for their anatomical similarity to human wounds, yet lack the economy, ease of handling, and statistical power afforded with rodent models. Previous small mammal models of partial thickness burn injury have failed to demonstrate complete reepithelialization in less than 3 weeks. We present a murine partial thickness scald model with a reepithelialization rate comparable to that of porcine wound models. METHODS: Thirty-eight adult male mice were secured in a burn template allowing exposure of a 2 x 3-cm area of the shaved dorsum to 60 degreesC water for 45 s, followed by 4 degreesC water for 45 s. Four wounds were harvested daily on Postburn Days 1-7, 10, and 14 for histologic evaluation. RESULTS: Histologic evidence of partial thickness dermal injury with sparing of dermal appendage epithelial cells was seen in all wounds. Of 134 wound sections evaluated 26 contained some areas of full thickness dermal injury, with only 8 of these 26 sections showing full thickness injury in 50% or more of the cross-sectional area of the wounds. Complete wound reepithelialization was seen between Postburn Days 10 and 14. The viable dermal thickness in all burn cross sections was at least 40-80 micrometers, and up to 1400 micrometers in reepithelialized wounds. CONCLUSIONS: This murine model of partial thickness scald injury provides a standardized thermal wound with consistent depth of injury, low mortality, and a reepithelialization rate between 10 and 14 days. A simple protocol allows easy production of 30-50 wounds daily with one technician.

Pediatric testicular problems.

Testicular problems in children may be both congenital and acquired. These problems are often difficult to diagnose and carry significant sequelae if untreated. Early surgical consultation is often needed for correction of the problem. This article reviews the pathophysiology of the most common pediatric testicular abnormalities with emphasis on the diagnostic modalities employed and current treatment alternatives.

Nonteratomatous germ cell tumors in children.

BACKGROUND/PURPOSE: Totipotential germ cells may give rise to a broad range of tumors. The teratomatous variety of germ cell tumors has been the subject of several large studies. The goal of the current study was to describe the clinical features of nonteratomatous germ cell tumors (NTGCT) by reviewing a large series of patients. METHODS: Between 1945 and 1997, there were 78 cases of nonteratomatous germ cell tumors (NTGCT's) in children at The Children's Hospital, Columbus. Their records were reviewed retrospectively. There were 35 boys and 43 girls (M:F ratio 0.8). Mean follow-up was 87 months. RESULTS: Histological subtypes included germinoma (33 cases, 42%), endodermal sinus tumor (24 cases, 31%), embryonal carcinoma (12 cases, 15%), gonadoblastoma (4 cases, 5%), mixed histology (4 cases, 5%), and choriocarcinoma (1 case, 2%). Forty-two tumors were in gonadal sites, but a significant percentage were extragonadal (36 cases, 46%). Forty-six patients (59%) had localized disease, 18 (23%) had regional disease, and 14 (18%) had metastases. Treatment consisted of surgery and selective chemotherapy and radiation. Complete tumor resection was more likely for gonadal (29 of 42, 69%) than extragonadal primaries (15 of 36, 41%; P < or = .05). Forty-nine (63%) of all patients survived, whereas 29 (37%) died of their disease. Survival in patients with gonadal primaries (32 of 42, 76%) exceeded that in patients with extragonadal primaries (17 of 36, 47%; P < or = .01). Survival in patients with localized disease (34 of 46, 74%) exceeded that in patients with regional extension or metastases (15 of 32, 47%; P < .05). CONCLUSIONS: This study highlights the fact that tumor location, gonadal versus extragonadal, was important in determining prognosis, whereas tumor histology was not. This may be the result of a higher rate of complete tumor resection for gonadal primaries and underscores the important role of surgery in the optimal treatment of these unusual tumors.

Segmental intestinal ischemia: an improved method of producing small bowel injury.

Previous animal models of intestinal ischemia-reperfusion have been successful in causing considerable mucosal damage, cellular destruction and sepsis. However, this often results in the death of the animal, making it impossible to examine the effects of modulators of the ischemic event. The sequence of morphologic and physiologic changes in the bowel from such injuries continues to be an area of intense examination. We have studied these changes by producing segmental intestinal ischemia in vivo in a rat model. By occluding a first-order branch of the superior mesenteric artery (SMA) and by selectively ligating terminal collateral branches, reproducible segmental intestinal ischemia was achieved. Bowel damage ranged from alterations in the villus structure to frank hemorrhagic necrosis of the intestinal wall. This model allows the study of hypoperfusion injury to the small intestine without total SMA occlusion, thus reducing the overall mortality.

Integra Artificial Skin as a useful adjunct in the treatment of purpura fulminans.

Purpura fulminans is a devastating disorder characterized by rapidly progressing hemorrhagic necrosis of the skin, vascular collapse, and disseminated intravascular coagulation. It is most often seen in children, and it is usually preceded by meningococcemia or another infection. Most often, the disorder results in severe skin loss, but it can also result in the need for extremity amputations. In extreme cases, wound coverage after excision may be problematic because of the limited existence of donor sites and the need for amputation revisions. The case of a 21/2-year-old male requiring amputations of all four extremities due to severe purpura fulminans is presented to illustrate the use of Integra Artificial Skin (Integra Lifesciences Corp., Plainsboro, NJ) to obtain immediate wound closure. Integra Artificial Skin is a bilayered skin substitute that engrafts to a viable wound bed. In the case presented here, where the viability of the underlying tissue of the amputated stumps was questionable, the artificial skin acted as an indicator of that viability. It engrafted well onto the upper extremity stumps, which were of excellent viability, but it needed to be replaced on the lower extremity stumps, which required further debridement and amputation revisions. The use of artificial skin spared the patient the immediate use of his limited and valuable autograft sites. In conclusion, Integra Artificial Skin can be a useful adjunct in the treatment of severe purpura fulminans that includes skin and extremity necrosis.