Morbidity

Despite a higher morbidity rate in recipients of living-donor grafts, patient and graft survival are similar or superior to those observed with deceased donors (Fan et al, 2002;

From: Blumgart's Surgery of the Liver, Pancreas and Biliary Tract (Fifth Edition), 2012

Chapters and Articles

Bacterial Pneumonia, Lung Abscess, and Empyema

Susan E. Crawford, Robert S. Daum, in Pediatric Respiratory Medicine (Second Edition), 2008

Prognosis

Morbidity and mortality rates from empyema remain high even in the modern era. Risk factors for bad outcome include inadequate antibiotic therapy (choice of medications, duration of therapy, or poor compliance with a prescribed un-supervised regimen), inadequate surgical management (when indicated), and probably certain underlying conditions that compromise the immune response. An important long-term consequence of untreated empyema relates to the formation of restrictive scar tissue or peel in the pleural space and includes decreased exercise tolerance, chest contour changes, and chronic restrictive pulmonary disease. Some have suggested that scoliosis can complicate empyema.638

The mortality rate among patients with empyema has been estimated at 2% to 15%.638 Risk factors for death include duration of illness, severity of infection, and young age.638

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Wilson Disease in Israel and Vicinity

Achiya Zvi Amir, ... Eyal Shteyer, in Clinical and Translational Perspectives on WILSON DISEASE, 2019

Summary

WD incidence is population-dependent, ranging for example between 1:3000 and 1:40,000 in Israel, in correlation with ethnic–social factors, notably consanguinity. The incidence in Iran and the Arab countries is largely unknown. Overall, WD presentation in the Middle East resembles global trends, perhaps with the exception of a few rare Iranian patients presenting with osseomuscular manifestation, possibly reflecting a different Asian origin. In Israel, liver disease is more common in Druze and Arabs, compared to the neuropsychiatric phenotype which is more common in Ashkenazi Jews; hematologic, renal, and endocrine manifestations were reported only in Sephardic Jews. Numerous studies describing cohorts in the Arab populations throughout the Middle East demonstrate a common finding of an early and aggressive phenotype of mainly liver disease. In the Israeli Jewish population, certain mutations are associated with specific ethnicities, with a few mutations suspected to represent founder effects. In contrast, the Arab population is characterized by a large diversity of mutations, and despite high rates of consanguinity, no clear phenotype–genotype associations or founder effects were described. Indeed, future research is necessary in order to address these unsolved questions including the effect of genetic background on expression of ATP7B.

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Pediatric Neurology Part I

A.T. Berg, ... P.M. Preux, in Handbook of Clinical Neurology, 2013

Measure of disease frequency: incidence versus prevalence

The two primary indices of disease frequency are the incidence rate and the prevalence. Incidence measures the rate at which new cases of a disease occur and is presented as the number of new cases occurring in a time period, for example, 65/100 000 per year. Prevalence reflects the current number of active cases at a given point in time (e.g. 120/100 000). Prevalence is a product of the incidence of the disease and the average duration of the disorder. High incidence diseases will, on average, have a high prevalence. Diseases of short duration (e.g., the common cold) or which are very aggressive and have a very high associated mortality (pancreatic cancer) will be less prevalent than diseases with the same incidence but a long drawn out duration (e.g., chronic epilepsy).

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Case Detection, Outbreak Detection, and Outbreak Characterization

Michael M. Wagner, ... Virginia Dato, in Handbook of Biosurveillance, 2006

4.2.3 Disease Incidence, Mortality Rates, and Attack Rates

Disease incidence is one measure of the magnitude of an outbreak (as are maps and epidemic curves). Disease incidence is the number of new cases in a population during a defined period such as a week. If disease incidence for every day or week during an outbreak is plotted, the result is an epidemic curve.

For lethal diseases, investigators gauge the severity (virulence) of the disease by the case fatality rate, which is the probability of death among diagnosed cases. Recall that investigators observed a 30% case fatality rate for the outbreak that they initially thought was Japanese encephalitis; however, the case fatality rate was highly atypical of Japanese encephalitis and led them to suspect a different disease. Investigators also compute other mortality rates. Age-specific mortality rates, for example, can help characterize an outbreak that is poorly understood by revealing that the disease affects the elderly or young with greater frequency or severity.

If investigators suspect an environmental exposure, they will calculate the attack rate, which is the fraction of people or animals exposed to a specific factor (e.g., macaroni salad or another infected individual) who subsequently contract the disease. If the attack rate in a population that is exposed to a specific factor is higher than a comparison group that is not exposed to the factor, it suggests a possible link between the factor and illness. If the analysis includes a comparison with a carefully matched control population of individuals known not to have the disease, the analysis is called a case-control study (described below). An investigator would conduct a case-control study if the less formal measurement of attack rate did not produce a definitive answer to the outbreak characteristic in question (e.g., if it did not point to macaroni salad, then the more formal case-control study likely would have).

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Diseases of the gastrointestinal system

Jenna E. Bayne, Misty A. Edmondson, in Sheep, Goat, and Cervid Medicine (Third Edition), 2021

Clinical signs.

Morbidity rates are low (approximately 5%), but for every infected animal with clinical signs, several are in the subclinical state and may be a source of both horizontal and vertical transmission.4 Both sheep and goats appear to remain asymptomatic until they reach 2 to 7 years of age. The most consistent clinical sign in sheep, goats, and cervids is chronic weight loss. Chronic diarrhea occurs in approximately 20% of cases.4 Signs may appear with or be exacerbated by stress, especially after parturition.4,5 Hypoproteinemia and chronic mild anemia are the only consistent findings from clinicopathologic laboratory tests. Submandibular edema may develop as a consequence of low protein levels in infected animals, and because parasitism is ubiquitous, an accurate diagnosis may be difficult.

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Principles of Epidemiology and Public Health

Lucy A. McNamara, Stacey W. Martin, in Principles and Practice of Pediatric Infectious Diseases (Sixth Edition), 2023

Incidence and Prevalence

Characterizing disease frequency is one of the most important aspects of descriptive epidemiology. Frequency measures typically include a count of new or existing cases of disease as the numerator and a quantification of the population at risk as the denominator. Cumulative incidence is expressed as a proportion and describes the number of new cases of an illness occurring in a fixed at-risk population over a specified period of time. The incidence density or incidence rate is the rate of new cases of disease in a dynamic at-risk population; the denominator typically is expressed as the population-time at-risk (e.g., person-time).

Because the occurrence of many infections varies with season, extrapolating annual incidence from cases detected during a short observation period can be inaccurate. In describing the risk of acquiring illness during a disease outbreak, the attack rate, defined as the number of new cases of disease occurring in a specified population and time period, is a useful measure. Finally, the case-fatality rate, or proportion of cases of a disease that result in death, is used to quantify the mortality resulting from a disease in a particular population and time period.

Prevalence refers to the proportion of the population having a condition at a specific point in time. As such, it is a better measure of disease burden for chronic conditions than is incidence or attack rate, which identify only new (incident) cases. Prevalent cases of disease can be ascertained in a cross-sectional survey, whereas determining incidence requires longitudinal surveillance. When disease prevalence (P) is low and incidence (I) and duration (D) are stable, prevalence is a function of disease incidence multiplied by its average duration (P = I × D).

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INFECTION OF SPECIFIC ORGAN SYSTEMS

Sheldon L. Kaplan, Jesus G. Vallejo, in Feigin and Cherry's Textbook of Pediatric Infectious Diseases (Sixth Edition), 2009

PROGNOSIS

The morbidity and mortality rates for septic shock in children vary with age, the presence or absence of underlying diseases, and the specific microorganisms responsible for the septicemic state. Dupont and Spink64 reported a 98 percent mortality rate in their series of children with septic shock and gram-negative bacteremia. Jacobs and colleagues107 reported a 9.8 percent case-fatality rate for otherwise normal children with septic shock. In the pediatric HA-1A study, the overall mortality rate for severe sepsis or septic shock was 31 percent.188 The overall mortality rate for children with meningococcal infection was 8 percent in a 10-center surveillance study.116 For the seven-state sepsis cohort, the overall mortality rate was approximately 10 percent.234 Much progress has been made in the treatment of sepsis and septic shock since the report of Dupont and Spink was published.64 As with many infections, prevention is more desirable than is treatment. Careful attention given to sterile techniques for insertion and maintenance of intravascular or other lines and other procedures is crucial and may prevent some episodes of bacteremia and septic shock.

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Critical Care of the Patient with Acute Stroke

Dimitrios Georgiadis, ... Werner Hacke, in Stroke (Fourth Edition), 2004

Outcome

Mortality and morbidity rates after SAH have improved but remain significant in spite of the development of better management and surgical techniques. The International Cooperative Study on the Timing of Aneurysm Surgery showed that less than 60% of all patients with aneurysmal SAH were able to return to their premorbid state.264 However, case-fatality rates range from 32% to 76%, and of the patients who survive the bleed, almost one third remain dependent.263 Persistent cognitive impairment is also a common sequela of SAH. There is a significant correlation between the affected arterial distribution and the neuropsychological deficit. For instance, damage to the anterior communicating artery commonly causes amnestic deficits or personality changes. The severity of the hemorrhage correlates well with cognitive impairment. Complications of SAH such as hydrocephalus, IVH, and parenchymatous hematoma also cause cognitive deficits and exacerbate the dysfunction due to SAH alone.265

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Radiofrequency ablation for liver tumors

Anton J. Bilchik, ... David Allegra, in Blumgart's Surgery of the Liver, Pancreas and Biliary Tract (Fifth Edition), 2012

Complications of Radiofrequency Ablation

Reported morbidity and mortality rates associated with RFA (Table 85C.5) can be difficult to interpret, in part because technical approaches vary. Some investigators combine RFA with other treatments, such as liver resection, but addition of a second procedure may inflate the complication rate. Ablation of multiple tumors also increases the risk of complications such as bleeding or bile leak. Early studies often used multiple sequential RFAs for treatment of a single hepatic tumor, because the monopolar electrode gave a smaller thermal ablation field than the current cluster electrodes. The multiple ablations required to destroy larger tumors increased the potential for complications.

Unfortunately, the reporting of morbidities is not standardized. Some authors regard low-grade fevers, transient liver function test elevations, small pleural effusions, and right upper quadrant pain as minor complications, whereas others believe these are expected events that should not be reported. As expected, studies undertaken at institutions with skilled interventionalists or surgeons report fewer complications. Variations in patient selection and disease type also confound interpretation of results: for example, patients with HCC have different comorbid factors than those with colorectal metastases, and a patient's preprocedural state may influence the outcome of RFA.

Direct complications of RFA include biloma, biliary fistula, ascites, hepatic insufficiency, arteriovenous fistula, symptomatic pleural effusion, abscess, pain, hemorrhage, hydropneumothorax, pneumothorax, and thermal injury to surrounding structures. Burns related to grounding pads have also been reported, but these can be avoided by proper positioning of the pads, by using more pads for longer ablations, and by carefully following the manufacturer's directions. Other potential complications are those related to an operative procedure, such as myocardial infarction, cardiac arrhythmias, and pneumonia.

As illustrated by the following two cases, RFA should be undertaken only by skilled physicians able to identify and manage its complications and only at centers equipped with appropriate staff and equipment for acute care. Figure 85C.9 shows a bile duct injury caused by RFA of a colorectal cancer metastasis near the porta hepatis. The injury was treated with endoscopic retrograde cholangiopancreatography (ERCP) and biliary stenting. Figure 85C.10 shows a hepatic artery pseudoaneurysm attributed to RFA of liver metastases. This was successfully treated with embolization by a skilled interventionalist.

The best way to avoid potential complications of percutaneous RFA is to understand its technical limitations. A large multicenter study reported morbidity and mortality rates of 0.3% and 2.2%, respectively (Livraghi, 2003b). In this study, about 33% of all deaths and 10% of morbidities were associated with gastrointestinal thermal injury and perforation. Patients with prior abdominal surgeries resulting in adhesions and those with peripheral liver tumors had an increased risk for gastrointestinal injury during percutaneous ablation. The authors recommended consideration of open or laparoscopic RFA, instead of percutaneous RFA, for tumors within 1 cm of the liver edge adjacent to bowel.

Injury to the diaphragm is also a potential complication during percutaneous RFA, especially when tumors at the dome of the liver are treated. In an animal model, carbon monoxide was introduced into the peritoneal cavity to separate the diaphragm and the liver; although this reduced severe diaphragmatic injury during superficial hepatic RFA (Raman et al, 2004), the technique needs further clinical testing.

Abscess, one of the most frequent complications of RFA, typically occurs 1 week after ablation and requires percutaneous or surgical drainage (de Baere et al, 2003; Wood et al, 2000). Patients with bilioenteric anastomosis or biliary stenting appear to have a higher rate of abscess formation. All patients undergoing RFA should receive periprocedural antibiotics that cover coliforms as well as skin flora, and temperature and leukocyte counts should be followed after the procedure. Normally, low-grade fever and fatigue may occur immediately after RFA for up to 7 to 10 days, a so-called postablation syndrome; however, any persistent significant fever or elevation of white blood cell count should prompt CT imaging for possible hepatic abscess.

Reports of tumor seeding vary from 0.5% to 12% (de Baere et al, 2003; de Sio et al, 2001; Llovet et al, 2001), possibly reflecting differences in follow-up. Llovet and colleagues (2001) found that tumor seeding during RFA was related to subcapsular tumor location and poor tumor differentiation. Recent tumor biopsy, multiple needle insertions, and tumor hemorrhage during treatment may also increase the risk of needle-tract seeding. This complication can be avoided by limiting the number of needle insertions, angling the needle to traverse normal hepatic parenchyma prior to entering the tumor, and cauterizing the tract upon withdrawal of the needle. Nicoli and colleagues (2004) reported rapid diffusion of neoplastic cells after the creation of an arteriovenous fistula following RFA. The authors attributed seeding of tumor cells to the pressure gradient between the high-pressure tumor arteries and the low-pressure portal system; however, this is the only report of this complication in several thousand RFAs to date.

Injury to bile ducts during RFA can result in stenosis and proximal biliary dilation (see Chapter 42Chapter 42AChapter 42B). Most physicians agree that tumors within 15 to 20 mm of a major bile duct should not be treated by RFA (Mulier et al, 2002); however, Elias and colleagues (2001) introduced intraductal cooling to prevent RFA-associated biliary stenosis. They infused cooled (4° C) Ringer's lactate through a catheter after choledochotomy. Intraductal cooling was undertaken in 13 patients undergoing RFA of tumors within 6 mm of a central bile duct; one patient had a local recurrence, and one developed biliary stenosis (Elias et al, 2004). Biliary stenting also can prevent biliary injury during ablation of tumors near the bile ducts (Wood et al, 2000).

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