Pneumonia in HIV-infected and HIV-uninfected children in developing countries: epidemiology, clinical features, and management

PURPOSE OF REVIEW: Pneumonia is a leading cause of illness and death in children younger than 5 years in developing countries, accounting for approximately 20% of childhood deaths. The HIV epidemic has sharply increased the incidence, severity, and mortality of childhood pneumonia in the developing world, particularly in sub-Saharan Africa. This article reviews recent findings on the epidemiology, clinical features, and management of HIV-infected and -uninfected children with pneumonia in developing countries. RECENT FINDINGS: Bacterial infection remains a major cause of pneumonia mortality; in HIV-infected children, a broader spectrum of pathogens including gram-negative infections and Pneumocystis jiroveci occurs. Mycobacterium tuberculosis is an important cause of acute pneumonia among children from high tuberculosis prevalence areas. Use of case management guidelines substantially reduces neonatal, infant, and under-5 mortality and pneumonia-specific mortality in developing countries. New advances in therapy include the use of short-course antibiotics and high-dose amoxicillin twice daily for ambulatory treatment of HIV-negative children with pneumonia. New preventive interventions include the development of conjugate vaccines against Streptococcus pneumoniae and Haemophilus influenzae, but these are not widely affordable nor available in developing countries. Despite a lower efficacy in HIV-infected children, these vaccines still protect against disease in a significant proportion of children. Available preventive interventions including micronutrient supplementation with zinc and vitamin A, and immunization as contained in the WHO Expanded Program of Immunization can substantially reduce the burden of childhood pneumonia. SUMMARY: Urgent measures to implement existing available, effective interventions for prevention and treatment of childhood pneumonia and achieve high coverage rates in developing countries are needed.     

Systemic complications of acromegaly: epidemiology, pathogenesis, and management

This review focuses on the systemic complications of acromegaly. Mortality in this disease is increased mostly because of cardiovascular and respiratory diseases, although currently neoplastic complications have been questioned as a relevant cause of increased risk of death. Biventricular hypertrophy, occurring independently of hypertension and metabolic complications, is the most frequent cardiac complication. Diastolic and systolic dysfunction develops along with disease duration; and other cardiac disorders, such as arrhythmias, valve disease, hypertension, atherosclerosis, and endothelial dysfunction, are also common in acromegaly. Control of acromegaly by surgery or pharmacotherapy, especially somatostatin analogs, improves cardiovascular morbidity. Respiratory disorders, sleep apnea, and ventilatory dysfunction are also important contributors in increasing mortality and are advantageously benefitted by controlling GH and IGF-I hypersecretion. An increased risk of colonic polyps, which more frequently recur in patients not controlled after treatment, has been reported by several independent investigations, although malignancies in other organs have also been described, but less convincingly than at the gastrointestinal level. Finally, the most important cause of morbidity and functional disability of the disease is arthropathy, which can be reversed at an initial stage, but not if the disease is left untreated for several years.     

Surgical wound infection: epidemiology, pathogenesis, diagnosis and management

Surgical wound infection remains a significant problem following an operation, although surveillance for such infections remains a challenge exacerbated by early discharge and outpatient surgery. The riskof such infections isdetermined by technical problems with the operation, particularly bleeding, the amount of devitalized tissue created, and the need for drains within the wound, as well as such metabolic factors as obesity and diabetes. Perioperative antibiotic prophylaxis can decrease the incidence of such infections further, but a technically perfect operation is even more important.     

Hyponatremia in cirrhosis: pathogenesis, clinical significance, and management

Hyponatremia is a frequent complication of advanced cirrhosis related to an impairment in the renal capacity to eliminate solute-free water that causes a retention of water that is disproportionate to the retention of sodium, thus causing a reduction in serum sodium concentration and hypo-osmolality. The main pathogenic factor responsible for hyponatremia is a nonosmotic hypersecretion of arginine vasopressin (or antidiuretic hormone) from the neurohypophysis related to circulatory dysfunction. Hyponatremia in cirrhosis is associated with increased morbidity and mortality. There is evidence suggesting that hyponatremia may affect brain function and predispose to hepatic encephalopathy. Hyponatremia also represents a risk factor for liver transplantation as it is associated with increased frequency of complications and impaired short-term survival after transplantation. The current standard of care based on fluid restriction is unsatisfactory. Currently, a new family of drugs, known as vaptans, which act by antagonizing specifically the effects of arginine vasopressin on the V2 receptors located in the kidney tubules, is being evaluated for their role in the management of hyponatremia. The short-term treatment with vaptans is associated with a marked increase in renal solute-free water excretion and improvement of hyponatremia. Long-term administration of vaptans seems to be effective in maintaining the improvement of serum sodium concentration, but the available information is still limited. Treatment with vaptans represents a novel approach to improving serum sodium concentration in cirrhosis.     

Non-HFE hemochromatosis: Genetics,pathogenesis, and clinical management

Recent advances in our understanding of iron metabolism and the epidemiology of iron overload disorders have shown that hereditary forms of hemochromatosis can result from mutations in several iron metabolism genes other than HFE, including Hamp, HJV, TFR2, and SCL40A. These "non-HFE" forms of hemochromatosis are much rarer than HFE-related hemochromatosis but exhibit a similar phenotype, and with the exception of ferroportin disease, a similar pattern of inheritance and parenchymal iron accumulation. Therefore, these diseases can be thought of as variant forms of a primary hepatic iron overload syndrome; thus, a unified approach can be used for evaluation and diagnosis. Management generally consists of periodic phlebotomies until iron is depleted.     

Lyme arthritis: pathogenesis, clinical presentation, and management

Arthritis is one of the most prominent features of Lyme disease, the tick-borne illness caused by Borrelia burgdorferi. Although the pathogenesis of Lyme arthritis is complex and still under study, the clinical presentation and natural history have been established by long-term observation of untreated and treated patients. This review addresses the clinical presentation of Lyme arthritis as a mono- or oligoarticular relapsing/remitting arthritis primarily affecting the large joints and describes presentations in which arthralgias rather than arthritis are seen. Strategies for diagnosis and treatment are discussed, and methods are reviewed for addressing treatment-refractory Lyme arthritis and arthralgias that may occur after treatment of Lyme disease (sometimes as a component of what is known as the post-Lyme disease syndrome).     

Eosinophilic bronchitis: clinical features, management and pathogenesis

Eosinophilic bronchitis is a common and treatable cause of chronic cough. The major pathological feature is eosinophilic airway inflammation, similar to that seen in asthma. However, the associated airway dysfunction is quite different, with evidence of heightened cough reflex sensitivity, but no variable airflow obstruction or airway hyperresponsiveness. Recent evidence suggests that the differences in functional association are related to differences in localization of mast cells in airway wall, with airway smooth muscle infiltration occurring in asthma and epithelial infiltration in eosinophilic bronchitis. Diagnosis is usually made with induced sputum analysis after exclusion of other causes for chronic cough on clinical, radiological and lung function assessment. The cough responds well to inhaled corticosteroids but dose and duration of treatment remain unclear. Little is known about the natural history of this condition. However, some patients with COPD without a history of previous asthma have sputum eosinophilia, so one possibility is that some cases of eosinophilic bronchitis may develop fixed airflow obstruction. Further study of this interesting condition will increase our understanding of airway inflammation and airway responsiveness, leading to novel targets for therapeutics for both eosinophilic bronchitis and asthma.     

Hereditary hemochromatosis: genetics, pathogenesis, and clinical management

Recent findings have led to major advances in our understanding of genetics and pathophysiology of hereditary hemochromatosis. Many crucial genes and molecules have come to light, and the complex interrelationships between them are being studied. However, several questions still remain unanswered. Availability of genotyping has changed the approach to diagnosis, and serum markers hold promise for prognostication. However, the effectiveness of population screening continues to be an area of controversy.Finally, there is a promise of development of newer therapeutic modalities based on our understanding of the mechanism of iron absorption. In this review, we describe the current state of understanding in the clinical features, pathophysiology and treatment of hereditary hemochromatosis.     

Osteonecrosis in HIV disease: epidemiology,etiologies, and clinical management

Osteonecrosis has been increasingly associated with HIV disease throughout the 1990s, and the incidence appears to be rising. The hip is most commonly involved and often bilaterally. Although anecodotal reports suggest an association between osteonecrosis and highly active antiretroviral therapy, controlled epidemiologic studies do not support a direct link. Many patients with osteonecrosis have established risk factors, some of which may be related to HIV disease or its therapy, including corticosteroid use and hyperlipidemia. Alcoholism, hypercoagulability, megesterol acetate use, immune reconstitution, and other factors may also contribute. Plain radiographs and magnetic resonance imaging are the cornerstones of diagnosis. Management is dependent on the stage of bone disease and ranges from observation to total joint arthroplasty. Clinicians may help to prevent HIV-associated osteonecrosis by encouraging patients to limit their exposure to the established risk factors for the disease.     

Congenital dyserythropoietic anemias: epidemiology,clinical significance,and progress in understanding their pathogenesis

The congenital dyserythropoietic anemias (CDAs) comprise a group of rare hereditary disorders of erythropoiesis, characterized by ineffective erythropoiesis as the predominant mechanism of anemia and by distinct morphological abnormalities of the majority of erythroblasts in the bone marrow. The classification in three types as proposed in 1968 is still valid, but there is genetic heterogeneity within each type, and there are additional variants of unknown genetic basis. CDA II is the most frequent, and the nonfamilial type of CDA III the rarest group. The genes of CDA II and CDA III were mapped to chromosome 20 and 15, respectively, and the gene of CDA I on 15q was recently cloned. Therapeutic decision making requires definition of the type, an estimate of individual severity, and presence of or risk for complications. Therapeutic measures include interferon-alpha for CDA I, splenectomy for CDA II, and iron depletion for all individuals at risk for secondary hemochromatosis.     

Anti-retroviral treatment interruptions in HIV-infected adults: causes,clinical, immunological and virological consequences

INTRODUCTION: This retrospective study analyses causes as well as clinical, immunological and virological consequences of antiretroviral treatment interruptions (Ti) of more than 30 days in HIV-1 infected adults. METHODS: This causes were classified as related to drug toxicity, therapeutic or adherence failure. We studied therapeutic regimens before Ti and after treatment reinitiation (TR), clinical events related to Ti, CD4 cells and viral loads before Ti and at months 3, 6, 9, and 12 after TR. RESULTS: Out of 188 Ti analysed, 42.6% were related to therapeutic failure, 33.5% to drug toxicity, and 23.9% to adherence failure. Eight Aids defining clinical events were reported during Ti, in patients with low CD4 cells and high viral load (P < 0.05). Viral loads evolution after TR was better if Ti was related to treatment failure (P < 0.05), was prolonged (P < 0.05), and if CD4 cells were high before Ti and at TR (P < 0.05). Median CD4 cells was of 296/mm(3) at month 12 after TR vs 382 before Ti. CONCLUSIONS: Ti consequences are strongly related to CD4 cells, which decrease sharply during Ti, increasing Aids defining events probability. Prospective randomised clinical studies are needed to define usefulness of Ti.     

Pulmonary arterial hypertension in collagenoses: clinical features, epidemiology, pathogenesis, diagnosis and treatment

Pulmonary arterial hypertension (PAH) is a severe vasculopathy, which is characterised by progressive narrowing and obliteration of the pulmonary arterioles and increased endothelin-1 levels. The increase of vascular resistance in the lung vessels leads to chronic pressure overload and to right heart failure, if untreated. PAH often occurs in association with rheumatic-inflammatory diseases (e.g., in 15% of patients with systemic sclerosis (SSc), especially in the limited form or in CREST patients) and determines their prognosis: in advanced stages, untreated patients die within a short period. Therefore all SSc patients, particularly the newly diagnosed ones, should be screened for PAH with echocardiography. If PAH is suspected, a right heart catheter should be performed, and if PAH is confirmed, adequate treatment should be initiated. While few years ago lung transplantation was the only option for patients with severe PAH, in recent years enormous progress was seen in drug treatment. Today prostanoids (Ventavis) and the endothelin receptor antagonist bosentan (Tracleer) are available for patients with PAH in WHO/NYHA stage III: they have substantially improved the prognosis of PAH in the last years. Since few months, also the phosphodiesterase inhibitor sildenafil (Revatio) is available. The combination of drugs with different mode of action will likely further improve the prognosis of PAH patients.     

Advances in the epidemiology, pathogenesis, and management of Cushing's syndrome complications

Cushing's syndrome (CS) is a clinical condition resulting from chronic exposure to glucocorticoid excess. As a consequence, hypercortisolism contributes significantly to the early development of systemic disorders by direct and/or indirect effects. Complications such as obesity, hypertension, diabetes, dyslipidemia, and hypercoagulability cause premature atherosclerosis and increase cardiovascular mortality. Impairment of the skeletal system is a relevant cause of morbidity and disability in these patients especially due to the high prevalence of vertebral fractures. In addition, muscle weakness, emotional lability, depression, and impairment of quality of life are very common. Clinical management of these patients is complex and should be particularly careful in identifying global cardiovascular risks and aim at controlling all complications. Although the primary goal in the prevention and treatment of complications is the correction of hypercortisolism, treatment does not completely eliminate these comorbidities. Given that cardiovascular risk and fracture risk can persist after cure, early detection of each morbidity could prevent the development of irreversible damage. In this review we present the various complications of CS and their pathogenetic mechanisms. We also suggest the clinical management of these patients based on our extensive clinical experience and on the available literature.     

Advances in the epidemiology, pathogenesis and management of diabetic peripheral neuropathy

Diabetic peripheral neuropathy (DPN) affects up to 50% of patients with diabetes and is a major cause of morbidity and increased mortality. Its clinical manifestations include painful neuropathic symptoms and insensitivity, which increases the risk for burns, injuries and foot ulceration. Several recent studies have implicated poor glycaemic control, duration of diabetes, hyperlipidaemia (particularly hypertryglyceridaemia), elevated albumin excretion rates and obesity as risk factors for the development of DPN. Although there is now strong evidence for the importance of nerve microvascular disease in the pathogenesis of DPN, the risk factors for painful DPN are not known. However, emerging evidence regarding the central correlates of painful DPN is now afforded by brain imaging. The diagnosis of DPN begins with a careful history of sensory and motor symptoms. The quality and severity of neuropathic pain if present should be assessed using a suitable scale. Clinical examination should include inspection of the feet and evaluation of reflexes and sensory responses to vibration, light touch, pinprick and the 10-g monofilament. Glycaemic control and addressing cardiovascular risk is now considered important in the overall management of the neuropathic patient. Pharmacological treatment of painful DPN includes tricyclic compounds, serotonin-norepinephrine reuptake inhibitors (e.g. duloxetine), anticonvulsants (e.g. pregabalin), opiates, membrane stabilizers, the antioxidant alpha lipoic acid and others. Over the past 7 years, new agents with perhaps less side effect profiles have immerged. Management of patients with painful neuropathy must be tailored to individual requirements and will depend on the presence of other co-morbidities. There is limited literature with regard to combination treatment.