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Terms in this set (59)

Chemoprophylaxis with rifampin
At present, chemoprophylaxis is the only prophylactic measure available against N. meningitidis group B. Among the drugs listed, rifampin is the one used for the purpose. Vancomycin is not effective against most Gram-negative bacteria, including neisseria species. Oral penicillin does not eradicate N. meningitidis from the nasopharynx. The tetravalent vaccines do not contain group B polysaccharide and have no effect against group B meningococcal infection.

Close contacts of the patient with meningococcal disease are at greater risk of acquiring the infection. Prophylaxis is indicated in those individuals and in populations with increased carrier rates. Nasopharyngeal mucosa is the site of colonization of N. meningitidis. Overcrowding, as is often found dormitories, causes an increase in carrier rates. Prevalence of carriage is reported to be highest among adolescents and young adults. Transmission occurs through direct contact with large droplets of respiratory secretions from patients or asymptomatic carriers. After colonization, development of invasive disease depends on the strain, environmental, and host factors. Chemoprophylaxis eradicates the carrier state and thus prevents spread of infection. It should be administered as early as possible, ideally within 24 hours of identifying the index case, in order to be effective in preventing secondary cases. Rifampin is one of the drugs commonly used. Mass prophylaxis with rifampin during large outbreak settings is a cause for concern as it might lead to circulation of rifampin-resistant strains. However, mass chemoprophylaxis with rifampin might be considered in outbreaks involving limited populations, such as in a dormitory, single school, or college. It would be especially advisable in cases caused by serogroup B, for which an effective vaccine is not yet available. Rifampin resistance develops due to mutations in the rpoB gene. Alternative drugs that are recommended for chemoprophylaxis are ciprofloxacin and ceftriaxone. Ceftriaxone is administered intramuscularly. Ciprofloxacin is not indicated in small children.

N. meningitidis is now the leading cause of bacterial meningitis in the US, and each year 1,400-2,800 cases occur. More than 98% are sporadic infections. Localized outbreaks involving colleges, schools, and nursing homes have been reported. Groups B, C, and Y are major causes of meningococcal disease in the US, and group B is responsible for approximately 30% of cases. The disease affects mainly infants, adolescents, and young adults. No vaccine is yet available against N. meningitidis group B. Development of effective polysaccharide vaccine is hindered by the poor immunogenicity of group B polysaccharide. The lack of immunogenicity is due to immunological cross reactivity with fetal neural antigens. A vaccine containing group B polysaccharide might trigger autoimmunity because of the molecular mimicry. Vaccines using non-capsular antigens like outer membrane proteins (outer membrane vesicle vaccine) and factor H-binding protein (multi-component group B recombinant protein vaccine) are under development. These require standardization and validation.

Vancomycin is not used for chemoprophylaxis of meningococcal infection. Most of the Gram-positive normal flora is susceptible to this drug. So this antibiotic is used as a constituent of modified Thayer martin medium for selective isolation of pathogenic neisseria. The medium can be used for isolation of N. meningitidis from nasopharyngeal swabs for detection of carriers.

Immunization with tetravalent meningococcal polysaccharide vaccine (MPSV4) is not useful as a measure of prophylaxis for infection by group B meningococcus. The preparation contains only polysaccharides from groups A, C, Y, and W-135 and protects against infection by these 4 serogroups. MPSV4 is effective in older children and adults, and it is not immunogenic in children less than 2 years of age.

Oral penicillin is not used for chemoprophylaxis of meningococcal meningitis, although most strains of meningococci are sensitive to penicillin. It is not found effective in eradicating meningococci from the nasopharynx.

Tetravalent meningococcal conjugate vaccine (MCV4) is not useful against group B meningococcal infection. It contains polysaccharides from A, C, Y, and W-135 serogroups of N. meningitidis conjugated with diphtheria toxoid, and it is useful for preventing infection by these 4 serogroups. This vaccine is considered more effective than MPSV4. It stimulates both B-cell and T-cell dependent immune responses. As a result, the vaccine induces a strong booster effect that confers long-term protection, and it helps in reducing nasopharyngeal carriage. It is also reported to be safe and immunogenic in 2- to 10-year-olds.

Centers for Disease Control and Prevention recommends this vaccine for routine immunization of adolescents, college freshmen living in dormitories, military recruits, and other populations at increased risk of developing invasive meningococcal disease. MCV4 has been licensed for use in individuals 11-55 years old.
The correct response is meningococcus.

Meningitis is an inflammation of the membranes covering the brain and spinal cord. The most common causes of meningitis are bacterial infections that start in other parts of the body and spread to the brain or spinal cord via the bloodstream. Meningitis can be caused by bacteria, viruses, chemical irritation, or tumors. Symptoms include fever, severe headache, nausea and vomiting, stiff neck (nuchal rigidity), photophobia, and mental status changes. Complications include hearing loss, brain damage, loss of vision, and possible deafness.

Meningococcal meningitis is a life-threatening infection caused by the Neisseria meningitidis bacterium. Most cases occur in children and young adults. The onset is often abrupt, and early treatment is essential to achieving reduced morbidity and mortality. In addition to the usual symptoms, a petechial rash (non-blanching, red-brown spots on all parts of the body) is characteristic and caused by capillary leak and platelet dysfunction. Routine vaccination against meningococcus is recommended for adolescents in the United States; the first dose at age 11 or 12, and a booster dose at age 16. If this patient has had not routine medical care in many years, then he will not have been vaccinated against this disease.

Enterovirus is a term given to cases of meningitis caused by viruses. Enteroviruses, such as the Coxsackie and echovirus, account for the majority of cases of viral meningitis. Other viruses that can cause meningitis include mumps, varicella, and the human immunodeficiency virus. Viral meningitis is usually milder than that caused by bacteria; symptom onset is more gradual, and patients usually recover with conservative management.

Syphilitic meningitis is a progressive, life-threatening complication of untreated syphilis infection. In addition to the usual symptoms of meningitis, patients may present with prominent mental status changes and focal neurologic deficits. Serum VDRL or RPR along with CSF (cerebrospinal fluid) examination is diagnostic.

Pneumococcal meningitis is caused by the bacteria Streptococcus pneumoniae. Meningitis occurs as a consequence of bloodstream infection with subsequent invasion of the central nervous system. Patients often present with a history of recent pneumonia, upper respiratory infection, infective endocarditis, or ear infection.
Increased ICP
Explanation- Increased intracranial pressure (ICP) may result from cerebral edema associated with head trauma, hypoxic-ischemic events, infection, metabolic disorders, hydrocephalus, and space-occupying lesions. Besides a high-pitched cry, infants may also present with widened sutures, a bulging fontanelle, persistent downward eye deviation (sunset eye sign), and increasing head circumference. If left unrecognized and untreated, increased ICP can result in significant morbidity and mortality by causing irreversible neurologic injury.

Cri-du-chat syndrome is an autosomal deletion syndrome caused by a partial deletion of chromosome 5p. It is characterized by a distinctive mewing, catlike cry that occurs in infancy. This cry is due to structural abnormalities of the larynx and CNS dysfunction. In addition, affected individuals also display growth failure, microcephaly, facial abnormalities, and mental retardation.

Profound mental retardation is suggested by the absence of any cry.

Congenital hypothyroidism may result from absent or abnormal development, destruction, or failure of stimulation of the thyroid gland by the pituitary, and/or by defective or abnormal synthesis of thyroid hormones. Infants profoundly affected have a distinctive appearance that has been termed cretinism, which includes a puffy-appearing face, a dull look, a large protruding tongue, dry brittle hair, a low hairline, and jaundice. Feeding is poor, with possible choking; constipation is common. Cries are hoarse and infrequent, and the infants are sluggish and inactive. Muscle tone is decreased. If left untreated, it can lead to severe mental and growth retardation. If recognized and treated early, significant improvement can be seen.

Tracheomalacia is the most common cause of expiratory stridor. It is caused by a defect of the cartilage, resulting in loss of rigidity or partial collapse of the tracheal cartilage with respiration. This causes an expiratory high-pitched, crowing noise. Tracheomalacia may also be found with lesions, such as vascular rings and slings, that compress the airway Most children outgrow this condition by the time they are 3 years-old.
Bed-wetting alarm system
Bedwetting, or enuresis, is a common problem in the pediatric age group. Prevalence at the age of 5 years is 7% in males and 3% in females. At the age of 10 years the prevalence is 3% for males and 2% in females. Enuresis is divided into primary enuresis, where the child has never been dry at night, and secondary enuresis, where the child who has been continent for at least 6 months starts to wet the bed again. Primary nocturnal enuresis is associated with a smaller bladder capacity, abnormal arousal patterns during sleep, and inappropriate or inadequate toilet training. Secondary enuresis is generally precipitated by situations of psychological stress, such as a recent move, marital conflict, or a new sibling in the household. Only rarely does enuresis have an organic component and usually urological procedures are not warranted.

General treatment guidelines that patients and especially the parents should be educated on include voiding before retiring, limiting fluids prior to bedtime, and expecting older children to clean their own bedding.

More often than not the first line intervention is considered bed-wetting alarms. These have been found in multiple studies to be extremely effective in producing a long-term cure. The bed-wetting alarms are moisture-sensing devices that are placed near the child's genitals, and are activated to trigger an alarm when the child voids in bed. These alarms go off at the initial first few drops of voiding; thus awakening the child to get out of bed and finish voiding in the toilet or hold urine until later. This evokes a conditioned response of waking and inhibiting urination. They are generally recommended in children older than seven years. Therapy is recommend for at least 3 months and used every night. Parents must get up with the child to ensure the child does not just turn off the alarm and go back to sleep. If used appropriately, bed-wetting alarms are successful in 2/3 of the patients that utilize them.

Alarm therapy requires a cooperative, motivated child and family. Parental involvement plays an essential role when using alarm devices due to the consistency that is necessary. Treatment must involve education and avoidance of being judgmental and even shaming the child due to most children feeling ashamed; the goal of treatment is to help the child establish their continence and at the same time maintain or gain self-esteem.

It is recommended that children use these alarm devices until they experience three weeks of complete dryness. For complete resolution of nocturnal enuresis, the bed-wetting alarm may be needed to be used for up to 15 weeks. Relapse rates are higher when the alarm system is discontinued after shorter dry periods. Studies have shown that compared with other skill-based or pharmacologic treatments, the bed-wetting alarm has a higher success rate (75%) and a lower relapse rate.

Desmopressin and imipramine are the primary drugs used in the treatment of nocturnal enuresis but should not be considered first line interventions. Imipramine administration is only slightly less effective than the alarm systems in bringing about dryness, usually within 2 weeks. Long-term results are less promising as the enuresis tends to return while off the medication.

Desmopressin acetate typically has an excellent response over the short-term, but again, the enuresis tends to recur when the child is taken off the medication.

Fluid restriction and wearing diapers at night may resolve the consequences of the issue but will not create the behavior which will lead to the actual bedwetting from stopping; behavioral modification/training is a main key to treatment.
Kawasaki disease
Kawasaki disease is an acute arteritis involving large, medium sized, and small arteries (often the coronary arteries) and is associated with mucocutaneous lymph node syndrome. The mucocutaneous syndrome is characterized by fever, conjunctival and oral erythema, edema of the hands, feet, erythema of the palms and soles, a skin rash (often with desquamation), and enlargement of the cervical lymph nodes. It is usually self-limited. Approximately 20% develop cardiovascular sequelae with the range of severity from asymptomatic vasculitis of the coronary arteries, coronary artery ectasia, or aneurysm to giant coronary artery aneurysm (7 to 8 mm) with rupture or thrombosis, myocardial infarction, or sudden death. Acute fatalities occur in 1% of the cases due to coronary artery thrombosis or rupture of coronary artery aneurysm. Vasculitis resembles poly arteritis nodosa with necrosis and pronounced inflammation, affecting the entire thickness of the vessel wall.

Takayasu's arteritis is a granulomatous vasculitis of medium sized and larger arteries. Takayasu first described it in 1908 as a clinical syndrome characterized by ocular disturbances and marked weakening of the pulses in the upper extremities (Pulseless disease). This is related to the fibrous thickening of the aortic arch with narrowing, or virtual obliteration, of the origins or more distal portions of the great vessels arising in the arch. Microscopically, there is adventitial mononuclear infiltrate with perivascular cuffing of the vasa vasorum (initially). Later, there is intense mononuclear inflammation in the media, in some cases accompanied by granulomatous changes replete with giant cells and patchy necrosis of the media. In addition, when it heals, the inflammation is replaced by marked collagenous fibrosis involving all the layers of the vessel wall accompanied by lymphocytic infiltration.

Giant cell arteritis, or temporal arteritis, is the most common of the vasculitides. It is an acute, and chronic, granulomatous inflammation of the medium and small arteries. It affects mainly the temporal, vertebral, and ophthalmic arteries. The short segments of 1 or more arteries develop nodular thickening with the reduction of the lumen, which may become thrombosed. Histologically, there is granulomatous inflammation of the inner half of the media, centered on the internal elastic membrane. It is marked by mononuclear infiltrate, multinucleated giant cells of both foreign body and Langhans type, and fragmentation of the internal elastic lamina. Sometimes the granulomas may be absent, and there is only nonspecific polyarteritis without giant cells. The healed stage of both will reveal only collagenous thickening of the vessel wall.

Polyarteritis nodosa is systemic vasculitis characterized by necrotizing inflammation of the small or medium sized vessels, typically involving renal arteries and visceral vessels but sparing the pulmonary circulation. There is neither glomerulonephritis nor vasculitis of the arterioles, capillaries, and venules. It particularly involves the branching points, also known as the points of bifurcation. The involvement is segmental and may involve only a portion of the circumference. It causes segmental erosion with weakening of the arterial wall with aneurysmal dilatation or localized rupture. Initially, there is transmural inflammation of the vessel consisting of neutrophils, eosinophils, and mononuclear infiltrate with fibrinoid necrosis. Later, the inflammation is replaced by collagenous fibrosis. Within the same vessel, various stages of inflammation may be seen.

Microscopic polyangiitis is also called hypersensitivity, or leukocytoclastic vasculitis. It generally affects arterioles, capillaries, and venules. The lesions are thought to represent a hypersensitivity reaction that involves the skin, mucous membranes, lungs, brain, heart, gastrointestinal tract, kidneys, and muscle. Necrotizing glomerulonephritis and pulmonary capillaritis is common. The lesions are histologically similar to polyarteritis nodosa, but muscular and large arteries are spared. Histologically, segmental fibrinoid necrosis of the media may be present; however, in some, the change is limited to infiltration with neutrophils. Greater than 80% of the patients have ANCA (anti-neutrophil cytoplasmic antibodies), most often p-ANCA. In many cases, reaction to an antigen such as drugs (e.g. penicillin), microorganisms (e.g. streptococci), heterologous proteins, or tumor antigens can be traced as the precipitating cause, but there are few or no immune deposits in this type of vasculitis. Simple removal of the offending agent may help most patients with cutaneous vasculitis, but those with systemic disease may develop organ failure unless treated. Refer to the table for additional information.
Meckel's diverticulum
The Meckel diverticulum appears to be a remnant of developmental structures that were not fully reabsorbed. It is a common congenital abnormality that consists of a small pouch called a diverticulum located off the wall of the small bowel. Symptoms generally occur during the 1st few years of life. Symptoms include passing of blood either with or without stool and abdominal discomfort ranging from mild to severe. Tests should include stool smear for occult blood (stool guaiac), hematocrit, hemoglobin, and technetium scan to demonstrate diverticulum. Surgery to remove the diverticulum is recommended if bleeding develops. Iron replacement may be needed to correct anemia. If bleeding is significant, blood transfusion may be necessary.

Diverticulitis is inflammation of an abnormal pouch (diverticulum) in the intestinal wall, usually found in the large intestine (colon). Small protruding sacs of the inner lining of the intestine (diverticulosis) may occur in any part of the intestine. They occur with increasing frequency after the age of 40. Diverticulitis is an inflammatory condition where gross or microscopic perforation (hole) of the diverticula has occurred. A low-fiber diet may be a contributing factor to the development of diverticula. Symptoms include left lower abdominal pain, constipation or diarrhea, chills, fever, swallowing difficulty, stools (clay colored or bloody), nausea and vomiting, heartburn, cough, and breath odor. Tests should include colonoscopy, sigmoidoscopy, barium enema, rectal examination (showing bleeding), abdominal palpation (showing left lower quadrant mass), and stool hemoccult test (revealing blood). Treatment should include increasing the bulk in the diet with high-fiber foods and bulk additives.

Peutz-Jeghers syndrome is transmitted as an autosomal dominant trait. Pigmented spots, brownish or bluish gray, develop from infancy through childhood around the lips, gums, and mucus membranes in the mouth. Symptoms include crampy abdominal pain, vomiting, occasional gross blood in the stool, and intussusception (a telescoping of one portion of the intestine into another). Intestinal polyps also develop that can be detected with special studies. Diagnostic tests include X-ray of abdomen (shows polyposis), occult blood in stool, CBC, serum iron, serum, total iron binding capacity, and biopsy of polyps. Treatment includes surgery to remove polyps that cause chronic problems. Iron replacement therapy (iron supplements) helps counteract blood loss. Periodic studies are recommended to watch for malignant changes in polyps.

Crohn's disease (also called ileitis or enteritis) causes inflammation in the small intestine. The most common symptoms of Crohn's disease are abdominal pain (often in the lower right area) and diarrhea. Rectal bleeding, weight loss, decreased appetite, and fever may also occur. Bleeding may be serious and persistent, leading to anemia. Tests should include CBC (increased white count), upper GI, and colonoscopy. The goals of treatment are to control inflammation, relieve symptoms, and correct nutritional deficiencies. Surgery is indicated to relieve chronic symptoms that do not respond to treatment.

Ulcerative colitis is chronic, episodic, inflammatory disease of the large intestine and rectum characterized by bloody diarrhea. Ulcers form in the inner lining, or mucosa, of the colon or rectum, often resulting in diarrhea, blood, and pus. The inflammation is usually most severe in the sigmoid and rectum and usually diminishes higher in the colon. It may affect any age group, although there are peaks at ages 15 to 30 and then again at ages 50 to 70. Symptoms include diarrhea of between 10 and 25 times a day (in which blood and pus may be present), abdominal pain and cramping that usually subsides after a bowel movement, abdominal sounds (borborygmus, a gurgling or splashing sound heard over the intestine), fever, weight loss, stools (foul smelling), and tenesmus (pain while passing stool). Tests include colonoscopy with biopsy, and barium enema. The goals of treatment are to control the acute attacks and prevent recurrent attacks. Corticosteroids are prescribed to reduce inflammation. Sulfasalazine may decrease the frequency of attacks. Surgery may be indicated in refractory disease.
Radionucleotide scan
The clinical presentation of the child with intermittent painless bleeding per rectum is suggestive of Meckel diverticulum (MD), which accounts for 50% of lower GI bleeds in children below 2 years of age.

Radionuclide scan is the most sensitive study that can confirm the presence of Meckel diverticulum. It is performed after intravenous infusion of technitium-99m pertechnetate. The mucous secreting cell of the ectopic gastric mucosa in the Meckel diverticulum takes up pertechnetate so that it can be visualized on the scan. The uptake can be enhanced by ranitidine, cimetidine, or glucagon. Sensitivity of the enhanced scan is about 85%, and specificity is approximately 95%. During active GI bleeding, the radioactive red cells leak into the intestines where bleeding is occurring and will appear as 'hot areas' on the scan. 'Hot areas' are not seen on the scan in the absence of active bleeding.

Meckel divertculum is a remnant of the omphalomesenteric duct, which connects the yolk sac with the gut in the developing embryo and provides nutrition to the embryo until the placenta develops. Later this duct is obliterated and separates from the intestine. The lining of the yolk sac is similar to the lining of the stomach. Failure of involution of the omphalomesenteric duct results in various residual structures, of which Meckel diverticulum is the most common. It is a 3-6 cm long pouch of ileum, about 50-75 cm from the ileocecal valve. This distance depends on the age of the patient. Meckel divertulum is lined by the acid-secreting mucosa that can cause intermittent, painless rectal bleeding due to ulceration of the diverticular and the adjacent ileal mucosa.

Meckel divertculum can act as a lead point for intussusception or may lead to a volvulus of itself and of the small intestines, thus presenting with bowel obstruction.

Routine barium studies usually do not fill the diverticulum; hence, they are not helpful in the diagnosis. Double contrast barium enema can be performed for evaluation of unexplained lower GI bleeds. However, it should not be undertaken during acute hemorrhagic phase, as it makes subsequent diagnostic evaluation like colonoscopy very difficult. Small bowel barium examination has a low yield because the divertculum fills transiently and the surrounding loops of small bowel overlap and obscure the diverticulum.

CT scan is rarely used as a primary imaging modality where Meckel diverticulum is suspected. If Meckel diverticulum is associated with intussusception, it may be revealed as an intraluminal mass, but it cannot be differentiated from intussusception due to other causes.

Ultrasound has a limited role in evaluating GI hemorrhage. Sometimes intussusception due to Meckel diverticulum has been diagnosed by ultrasound, but the sensitivity and specificity is generally low.

Colonoscopy cannot positively diagnose bleeding from a Meckel diverticulum because the colonoscope usually cannot reach the part of small intestines where the Meckel diverticulum is located. It can be helpful in its diagnosis if blood-filled colon is seen without another source of bleeding, particularly if it is accompanied by an abnormal Meckel radionuclide scan.
Campylobacter jejuni
Post-infectious polyneuropathy, Guillain-Barré syndrome (GBS), sometimes follows a gastrointestinal infection caused by Campylobacter jejuni, which is a Gram-negative rod. About 1-12 weeks after infection, weakness frequently begins in the lower extremities and ascends to the trunk; paralysis is usually symmetric. Guillain-Barré syndrome may also be preceded by a nonspecific viral infection or a respiratory infection caused by Mycoplasma pneumoniae. Myalgia is common and children are often irritable. Cerebral spinal fluid (CSF) examination is necessary for diagnosis. Typically, CSF protein is elevated to more than twice the normal limit, while glucose is normal and pleocytosis is absent.

The infective agent implicated in causing GBS is Campylobacter jejuni. Clostridium botulinum, Escherichia coli, Salmonella enteritidis, and Shigella dysenteriae are not the organisms that are involved in causing GBS.

Clostridium botulinum is an anaerobic, Gram-positive rod that causes 3 main types of botulism. These include infant, food-borne and wound contamination. Botulism can be confused with GBS; however, there is descending symmetric paralysis in botulism.

Escherichia coli is a facultative, anaerobic, Gram-negative rod belonging to the family Enterobacteriaceae. It can cause urinary tract infections, neonatal meningitis, and intestinal infections (such as gastroenteritis).

Salmonella enteritidis is a Gram-negative rod that causes egg-borne salmonellosis, which is characterized by fever, abdominal cramps, and diarrhea. Symptoms occur after consuming contaminated food. In infants, the disease is very severe.

Shigella dysenteriae is a Gram-negative organism that causes dysentery. Neurological manifestations include headache, seizures, lethargy, and meningitis.
Explanation Tracheoesophageal fistula (TEF) occurs in 85% of cases of esophageal atresia, which occurs in 1 out of 3,000 to 4,500 live births. Esophageal atresia or TEF can occur separately, though this is less common. These anomalies are thought to arise from defective differentiation of the primitive foregut into the trachea and esophagus. The atresia is due to defective growth of endodermal cells and incomplete fusion of the lateral walls of the foregut during separation of trachea results in the TEF. Air will enter the abdomen when the fistula connects the distal esophagus to the trachea. The abdomen becomes distended, interferes with breathing and allows gastric acid to reflux into the lungs. Attempts to insert a nasogastric tube cause coiling of the tube in the blind pouch of the esophagus, which is diagnostic. This condition should be suspected when there is a history of maternal hydramnios, excessive secretions, choking, cyanosis and coughing with feedings, and failure to pass a nasogastric tube into the stomach. Management is surgical correction, consisting of ligating the fistula and anastomosing the two ends of the esophagus.
Gastroesophageal reflux occurs as a result of failed normal esophageal sphincter function. The lower esophageal sphincter transiently relaxes after a food bolus has entered the stomach, allowing re-entry into the esophagus. The emesis of reflux is effortless and not associated with retching or autonomic symptoms.

Esophageal atresia without TEF is less common and arises from defective growth of endodermal cells of the foregut. 30% will have associated anomalies as isolated defects or part of VATER (or VACTERL) association (vertebral, vascular defects, anal atresia, cardiac malformations, TEF, EA, radial and renal anomalies, limb defects).

Diaphragmatic hernia arising from incomplete fusion of the pleuroperitoneal membrane, usually on the left, allows passage of abdominal contents into the chest thus impeding respirations. Suggestive early findings include polyhydramnios, absent or intrathoracic stomach bubble, and mediastinal and cardiac shift away from the side of the hernia.

TEF without esophageal atresia or H-type is quite rare and will usually cause recurrent aspiration delaying diagnosis. This is also not associated with a history of hydramnios.
Meckel Diverticulum
This patient is most likely suffering from a common congenital abnormality of the development of the ileum called a Meckel's diverticulum. In the embryo, the vitelline duct is a communication between the yolk sac and the lumen of the gastrointestinal tract at the midgut. Normally, it degenerates completely, but the persistence of a portion of the vitelline duct leads to the development of a cul-de-sac on the ileum (Meckel's diverticulum). This congenital birth defect follows a rule of 2s. It occurs in 2% of the population, but only 2% show symptoms. It is usually located about 2 feet from the ileocecal valve and is about 2 inches long. It can contain 2 types of ectopic tissue: gastric or pancreatic. It usually presents by 2 years old. The presence of ectopic gastric mucosa in the diverticulum can lead to secretion of stomach acid downstream from the duodenum, which has bicarbonate-secreting submucosal Brunner glands to neutralize gastric acid. Ectopic gastric tissue in the ileal diverticulum can lead to ulceration and bleeding of the adjacent ileal mucosa.

Vascular malformations, intussusception, and coagulation disorders are more likely to manifest themselves in the first year of life. Cow's milk colitis is a problem of the first year of life and spontaneously resolves by the end of that year for most children. NEC is a problem of the stressed, usually premature, newborn. Rectal polyps are likely to present in older children, as is HSP. Babies and older children can have gastric bleeding from gastritis or gastric ulcers. Duodenal ulcers are much more common in older children.
Awareness of self and the surrounding environment or consciousness may be altered into different abnormal states of consciousness. Consciousness can shift from loss of clear thinking or confusion, usually accompanied by disorientation, to delirium, a succession of confused and unconnected ideas manifested in children as extreme mental and motor excitement, to lethargy, a profound type of slumber where movement or speech is limited, to stupor or deep sleep where arousal is achieved only by repeated vigorous stimuli, finally to coma, unresponsiveness to even painful stimuli. Non-traumatic coma is most common in infants and toddlers with another smaller peak of occurrence in adolescence. The most common cause of non-traumatic altered level of consciousness in children is infection of either the brain (encephalitis), meninges (meningitis), or both; infections account for more than 1/3 of cases.

Prolonged seizures, anticonvulsive therapy, and postictal states can also lead to altered levels of consciousness.

The most common metabolic cause of alteration of consciousness is diabetic ketoacidosis, which can occur at any age, but is most common in adolescence. Caused by severe insulin deficiency, hyperglycemia and ketogenesis lead initially to polyuria, polydipsia, hyperpnea, vomiting, and abdominal pain. As the process progresses, hyperosmolar dehydration and acid/base and electrolyte disturbances occur. Advanced stages alter level of consciousness and can lead to coma.

Alterations of consciousness due to inborn errors of metabolism that present with electrolyte and glucose abnormalities typically present in infancy. The availability of gluconeogenic precursors or the functions of the enzymes required for production of hepatic glucose are affected. Metabolic defects causing hypoglycemia include glycogen storage disease, galactosemia, fatty acid oxidation defects, carnitine deficiency, several of the amino acidemias, hereditary fructose intolerance, and defects of other gluconeogenic enzymes.

Toxic ingestion and exposure are very common in toddlers and adolescents, with a toddler's ability to explore his environment filled with often brightly colored medications and intentional ingestion by adolescents typically involving over-the-counter medications or psychotropic drugs such as antidepressants.
Barium Enema
Intussusception, in which a part of the bowel telescopes into an adjacent part of the bowel, is the most common cause of bowel obstruction in children between ages 6 months and 3 years of age. Typical presenting signs include intermittent colicky, abdominal pain, vomiting, and bloody, mucousy stools sometimes described as "currant-jelly" in appearance. Some children may present with only irritability and progressive or alternating lethargy. On abdominal examination, a slightly tender, sausage-shaped palpable mass is characteristic.

Most cases are idiopathic; however, it is felt that hypertrophied Peyer's patches in the ileum stimulate peristalsis and cause the intussusception. Other causes, usually found in older children, include polyp, lymphoma, intestinal parasites, Meckel diverticulum, intramural hematoma, and hemangioma. Ileocolic intussusceptions are by far the most common, but cecocolic and ileoileal presentations may occur.

The telescoping of the bowel causes diminished venous blood flow resulting in edema and hemorrhage, leading to decreased arterial blood flow, ischemia, and infarction. Left untreated, death occurs in most cases. The diagnostic test of choice is to perform a barium enema; it helps in confirming the diagnosis because the enema shows a typical "cervix-like mass" or a "coiled spring" appearance on the evacuation film. Treatment by hydrostatic reduction with the same barium enema is successful in 50 - 90% of cases. Air contrast enemas are being used widely now, but barium enemas are still standard as well. If the intussusception is not reducible by the enema, then surgical treatment is indicated.

Imaging with CT scan is usually not indicated for establishing the diagnosis of intussusception, unless a lead point is suspected. A lead point is found in only 10% of children less than 2 years old.

Plain radiographs may be normal or show a pattern of small bowel obstruction with no gas in the right colon, indicating intussusception; however, it needs to be followed up with barium enema for confirmation.

An upper GI endoscopy would be unlikely to demonstrate any pathology at the ileocolic level, and a colonoscopy would not be as helpful in either identifying the intussusception or providing therapeutic relief.
A 12-year-old girl presents with a 3-day history of progressive dysarthria, dysphagia, and weakness. The patient was well until 3 days prior to admission to the hospital; at that time, she developed the onset and subsequent gradual worsening of dysarthria. She attributed the dysarthria to a sore throat that she had had about 2 weeks earlier. 3 days prior to admission, she also had the onset of mild dysphagia; it mostly occurred with liquids. 24 hours prior to admission, she developed weakness in both upper extremities, which increased and began to involve the lower extremities. This limb weakness was neither worsened by activity nor improved by rest. She also developed tingling in her toes 24 hours prior to presentation. When she became unable to walk without assistance on the day of admission, she decided to seek medical attention and was admitted to the hospital.

Past medical history is significant for measles and mumps. Because of family religious beliefs, she has not had any immunizations. She is very athletic, and frequently plays soccer with friends and siblings in the fields on her grandfather's horse farm. Physical examination reveals a well-developed, well-nourished girl. She is awake, alert, cooperative, and in no acute distress. Temperature is 98.7 F by mouth, blood pressure of 140/80 mm Hg, heart rate is 84/min and regular, and respirations are 22/min and unlabored. There are multiple scratches and abrasions in varying stages of healing over most of her extremities. Her speech is moderately dysarthric. She experiences some mild choking when she tries to drink a glass of water. She can smile weakly, but she cannot raise her eyebrows against resistance. She shows mild bilateral weakness of eye adduction. Pupillary responses are normal. There is mild to moderate upper extremity and mild lower extremity weakness, greater distally than proximally. Her motor strength is sustained over at least 30 seconds without fatigue. Her gait is ataxic, and she cannot walk without assistance. Reflexes are hypoactive to absent, and the response to plantar stimulation is downgoing bilaterally. Sensation is intact, except for mildly impaired position and vibratory sensation in both feet. A complete blood count, chemistry profile, chest X-ray, and EKG are all normal. Computed tomography of the brain, with and without contrast, is negative. A nerve conduction study reveals a moderate degree of mostly motor demyelinating peripheral neuropathy, highly suggestive of Guillain-Barre.

What statement best describes the patient's prognosis?

Answer Choices
1 With a predominantly demyelinating rather than axonal neuropathy, her prognosis is especially bad
2 Mortality is 25-30%
3 Full functional recovery is expected in 45% in several months to a year
4 Whether recovery is full or partial, relapses do not occur during the recovery phase
5 Her rapidly evolving clinical course indicates a poor prognosis
IV empirical antibiotics
The infant in the vignette appears to have bacterial meningitis. The initial approach to the patient should be the "ABCs." After assessing and stabilizing the patient's airway and obtaining IV access, intravenous antibiotics should be given immediately. As bacterial meningitis is associated with high morbidity and mortality, prompt initiation of empirical antibiotics is crucial for better prognosis. The choice of antibiotics is dependent on the patient's age and specific predisposing conditions. Use of broad-spectrum cephalosporins, such as ceftriaxone or cefotaxime with vancomycin, may be used in infants more than 1 month old. Ideally, serum glucose, blood culture, complete blood count, and serum chemistries should be drawn when IV access is obtained; however, drawing labs should not delay beginning antibiotics.

Intravenous glucose is necessary if the patient is found to be hypoglycemic; bedside serum glucose is mandatory in any patient that presents with a seizure. Intravenous phenytoin and an MRI of the head might also be necessary for a patient such as the one in the vignette, but would not emergently precede antibiotics.

The diagnosis of bacterial meningitis rests on CSF examination performed after lumbar puncture. However, LP is deferred in patients with evidence of increased intracranial pressure, new onset seizure, cardiorespiratory compromise, or focal neurological deficits. Antibiotics should be given, and CT scan of the head should be performed. If CT scan is negative, LP can be performed.
GH deficiency
A Growth hormone (GH) deficiency is defined as a decreased growth velocity, delay in skeletal maturation, absence of other explanations for poor growth (lack of intake), and laboratory tests demonstrating decreased GH secretion. Etiology of GH deficiency can be congenital, genetic, acquired, or idiopathic, which is the most common. Infants usually have a normal birth weight and may have a slightly decreased length. In addition, most infants present with other endocrine deficiencies like hypoglycemia, hypothyroidism, and/or adrenal insufficiency. Children may present with truncal adiposity because growth hormone promotes lipolysis. Serum GH or intrinsic growth factor levels may or may not be decreased. In patients who do not have a demonstrated decrease in these hormones, a trial period with GH is indicated. These patients and positive GH-deficient patients receive a once-daily subcutaneous injection of recombinant human GH. Congenital hypothyroidism typically presents with short stature (typically noted after the 4-month newborn visit), delayed epiphyseal development, delayed closure of fontanelles, and retarded dental eruption in addition to other signs of hypothyroidism. Cushing disease typically presents with truncal adiposity with thin extremities, muscle wasting, decreased growth rate, and moon facies. Laboratory results show elevated adrenocorticosteroids both in urine and serum, hypokalemia, eosinopenia, and lymphocytopenia. Typically, in patients younger than the age of 12, Cushing disease is secondary to administration of ACTH or glucocorticoids. Congenital adrenal hyperplasia typically presents with pseudohermaphroditism in females or salt-losing crisis in males with or without isosexual precocity. There is an increased linear growth and advanced skeletal maturation.