Módulo 2 Pediatría Flashcards

Question

A term neonate is small for date and has a small head. Further physical examination of the infant demonstrates small eyes with short palpebral fissures, a flattened nose, and abnormal palmar creases. With which of the following maternal conditions is this presentation most likely associated? (A) Alcohol abuse (B) Cirrhosis (C) Cocaine abuse (D) Diabetes mellitus (E) Hypothyroidism

Answer 1

Respuesta: A The correct **answer is A**. Maternal alcohol abuse is a common cause of teratogenesis. The fetal alcohol syndrome is characterized by potentially severe mental retardation secondary to impaired brain development. Other phenotypic features seen in severely affected infants include growth retardation, microcephaly, microphthalmia, short palpebral fissures, and midfacial hypoplasia. In addition, these infants may have abnormal palmar creases, cardiac defects, and joint contractures. Partial expression in mild cases is common and may make diagnosis difficult. Maternal cirrhosis (**choice B**) can decrease fertility and cause miscarriages and prematurity, but does not specifically cause fetal malformation. Maternal cocaine abuse (**choice C**) can cause spontaneous abortion, fetal death, placental abruption, low birth weight, reduced body length, and reduced head circumference. Maternal diabetes mellitus (**choice D**) can cause large-forgestational-age infants who tend to be hypoglycemic after birth. Maternal hypothyroidism (**choice E**) may worsen during pregnancy but usually does not produce prominent fetal effects.

Answer 2

Respuesta: A The correct **answer is A**. Typically, the abdominal contents herniate into the left hemithorax. This causes displacement of the heart into the right hemithorax and pulmonary hypoplasia. If gas has entered the intestinal tract during resuscitation, bowel sounds may be heard in the chest. The displacement of the abdominal contents renders the abdomen flat. In cases of severe pulmonary hypoplasia, administration of oxygen results in only a poor improvement in oxygenation. Hyaline membrane disease (**choice B**) is uncommon, if not rare, in full-term infants. Occasionally this form of respiratory distress may occur in infants of diabetic women, but this history is absent in this case. Meconium aspiration (**choice C**) should be accompanied by a history of fetal stress, meconium-stained amniotic fluid, or meconium-staining of the skin and cord. Physical findings are symmetric, there is no displacement of the heart, and breath sounds are similar bilaterally. Pneumonia (**choice D**) in the neonate is usually due to either group B beta-hemolytic streptococci or Escherichia coli, accompanied by a history of maternal fever or prolonged rupture of the amniotic membranes. Breath sounds are symmetrically diminished. Tracheoesophageal fistula (**choice E**) usually presents with a history of polyhydramnios, cyanosis with feeding, and increased oropharyngeal secretions. It is unusual for this condition to present so soon after birth with severe respiratory distress.

Answer 3

Respuesta: A The correct **answer is A**. The term kernicterus is used to denote damage to the brain by high bilirubin levels in the perinatal period. The fetal liver is less efficient at conjugating bilirubin compared with the adult liver, and neonates are consequently prone to develop hyperbilirubinemia, particularly unconjugated hyperbilirubinemia. In most cases, there are predisposing conditions, such as hemolytic anemia, polycythemia, prematurity, maternal diabetes, congenital liver or biliary tract disease, sepsis, or intrauterine infections. In contrast to what you might except, the bilirubin is not uniformly poisonous to the nervous system, but instead selectively accumulates in, damages, and stains the basal ganglia and the brain stem nuclei. Early symptoms may include lethargy, poor feeding, and vomiting. Severe kernicterus can cause opisthotonos, oculogyric crisis, seizures, and even death. The cerebellum (**choice B**), cerebral cortex (**choice C**), peripheral nerve (**choice D**), and spinal cord (**choice E**) are all much less sensitive to damage by high bilirubin levels than are the basal ganglia and brain stem nuclei.

Answer 4

Respuesta: A The correct **answer is A**. This infant already has evidence of imperforate anus and tracheoesophageal fistula with the most common configuration (blind esophageal end at the top, and fistula to the tracheobronchial tree at the bottom-that is how gas got into the gastrointestinal tract). Those two anomalies are part of the VACTERL constellation (vertebral, anal, cardiac, tracheoesophageal, renal, and limb abnormalities). The x-ray already ruled out vertebral and radial anomalies, but we still have to rule out cardiac and renal anomalies. For that reason, the infant needs the renal sonogram and the echocardiogram. No surgical repair should be planned until we know the full extent of the problem. Barium swallow (**choice B**) is not the first thing we need. If further definition of the esophageal anomaly is desired, a more gentle medium (Gastrografin) should be used to avoid aspiration of barium. Gastrostomy (**choice C**) may very well be needed if the full extent of the anomalies delays repair of the tracheoesophageal fistula. Reflux of gastric contents into the tracheobronchial tree will produce chemical damage. However, it does not take that long to do a sonogram of the kidney and an echocardiogram, and if they are negative, repair of the tracheoesophageal anomaly may be undertaken at once. Colostomy (**choice D**) is not urgent, because there is a fistula from the end of the gastrointestinal tract to the vagina. A decision as to the type of repair possible now, or to be deferred until later can be made at leisure. Surgical repair (**choice E**) has to wait until we know the full extent of the anomalies. The idea that diagnosis must precede therapy is well illustrated in this case

Answer 5

Respuesta: E The correct **answer is E**. Apparently, the girl in this clinical vignette has generalized edema (i.e., anasarca). The most common causes of swelling are nephrotic syndrome, congestive heart failure, and liver disease. Other causes include hypothyroidism, shock, mineralocorticoid excess, and malnutrition. Since there is no evidence of any abnormal cardiac or hepatic findings, urinalysisis the most appropriate initial diagnostic test to screen for proteinuria. In children with nephrotic syndrome, albumin (a serum protein) is lost in the urine and hence causes the oncotic pressure inside the vessels to decrease. Fluid there shifts from the intravascular space into the interstitial space, causing generalized edema. Liver enzymes (**choice A**), chest radiographs (**choice B**), echocardiography (**choice C**), and kidney ultrasound (**choice D**) are not indicated in this case as the initial diagnostic test.

Answer 6

Respuesta: D The correct **answer is D**. Usually, infants gain an ounce/day during the first 4 months of life. Those who gain more than this and are spitting up are probably being overfed. Adrenogenital syndrome (**choice A**), or congenital adrenal hyperplasia, presents in the first week of life with metabolic abnormalities and results in poor weight gain. Children being abused (**choice B**) would probably not be overfed. Inborn errors of metabolism (**choice C**) present in the first weeks of life and generally lead to poor weight gain. Pyloric stenosis (**choice E**) typically presents with projectile vomiting at 2 weeks of age. It is more common in boys.

Answer 7

Respuesta: A The correct **answer is A**. Aniridia describes the absence of an iris. It can be inherited as an autosomal dominant trait or it can occur sporadically. Approximately one third of sporadic cases are associated with Wilms tumor. Hemihypertrophy is also associated with Wilms tumor in some individuals. It is important to obtain an abdominal ultrasound to investigate for renal abnormalities or Wilms tumor in such cases. An echocardiogram (**choice B**) is not indicated. A neurology consult (**choice C**) is not required because aniridia and Wilms tumor are not associated with acute nervous system disease. An ophthalmology consult would be more appropriate. A rapid plasmin reagin (RPR) test (**choice D**) is not warranted because syphilis is not suggested by the clinical findings or history. Neurosyphilis is associated with the Argyll-Robertson pupil, which irregularly shaped and nonreactive to light. IV antibiotics (**choice E**) are not indicated because aniridia is not associated with in utero or perinatal infection.

Answer 8

Respuesta: B The correct **answer is B**. Anytime you see an infant with abdominal difficulties plus cystic fibrosis, think of meconium ileus. The vignette did not say that this infant had cystic fibrosis (he has not been diagnosed yet; he is only 3 days old), but the mother provides the connection. A Gastrografin enema will show the unused microcolon and the pellets of inspissated meconium higher up. As the hypertonic solution of Gastrografin draws water into the lumen, the inspissated meconium will be diluted and "unplugged.” More complete diagnostic steps and treatment for the cystic fibrosis will follow. Barium enema (**choice A**) is a tantalizing distracter because it also serves double duty as diagnosis and therapy, but not in this condition. It does so in intussusception, which we see in chubby 2- year-olds with colicky pain and the famous “currant jelly stool,” not in the newborn. Colonoscopy (**choice C**) can also do double duty, but it does so in Ogilvie syndrome, the paralytic ileus of the colon that we see in old, immobilized people. Endoscopic retrograde cholangiopancreatogram (ERCP; **choice D**) is also a diagnostic test with therapeutic value, but its role is in clearing up an obstructed biliary tract. And as for rectal biopsy (**choice E**), save it for the infant suspected of having aganglionic megacolon; it will give you the diagnosis but will not help with the therapy.

Answer 9

Respuesta: D The correct **answer is D**. Systemic lupus erythematosus (SLE) is a multisystemic rheumatologic disease. Its major clinical manifestations include fever, malaise, arthritis, arthralgia, and rash. Anorexia and weight loss are also common. The malar butterfly rash on the face that extends over the bridge of the nose, but spares the nasolabial fold, is very characteristic but is not present in all patients with SLE. Raynaud phenomenon, polyserositis, hepatosplenomegaly, lymphadenopathy, and renal disease also are frequently associated with SLE. Antinuclear antibodies are found in 97% of patients with SLE, but this finding lacks specificity. Antibodies to double-stranded DNA are more specific, and are elevated in active disease. Complement C3 and C4 levels are decreased in patients with active SLE. The American Rheumatism Association has published the criteria for the diagnosis of SLE. At least 4 of the 11 criteria must be met to diagnose SLE. These criteria can be remembered by a mnemonic SOAP BRAIN MD: Serositis, Oral ulcers, Arthritis, Photosensitivity, Blood (hemolytic anemia, leukopenia, lymphopenia, or thrombocytopenia), Renal (proteinuria or cellular cast), ANA, Immunologic (positive LE preparation, antibody to doublestranded DNA, antibody to Sm antigen), Neurologic (seizure or psychosis), Malar rash, Discoid lupus Giant cell arteritis (**choice A**), also known as Takayasu arteritis, primarily affects the aorta and other large arteries. Symptoms include fever, anorexia, weight loss, and arthritis. Laboratory findings include increased sedimentation rate, weakly positive antinuclear antibody titer, and anti-aorta antibodies. Henoch-Schönlein purpura (**choice B**) is a vasculitis of unknown etiology that occurs most commonly in boys aged between 2 and 8 years. It is characterized by nonthrombocytopenic, palpable purpuras, most commonly in shins, lower extremities, and buttocks. The syndrome also includes arthritis, abdominal pain, and nephritis. The prognosis is good in the absence of significant renal complications. Polyarteritis nodosa (**choice C**) is a vasculitis that affects small and medium-sized arteries. It can present with diverse symptoms such as fever, malaise, arthritis, abdominal pain, rash, kidney disorder, ischemic heart pain, testicular pain, peripheral nervous system disorders, lethargy, and weight loss. Antineutrophil cytoplasmic antibodies with peripheral staining (p-ANCA) are positive. Complement levels are normal. Wegener granulomatosis (choice E) is characterized by necrotizing granulomatous lesions of the entire respiratory system (airways and lungs). It is also associated with glomerulonephritis. The triad of sinusitis, pulmonary involvement, and glomerulonephritis suggests the diagnosis.

Answer 10

Repuesta: C The correct **answer is C**. In the differential diagnosis of acute cerebral edema with convulsions in a child, ingestion of toxic substances, including lead, must be considered early. Lead toxicity is high on the differential, but a history of pica may not be elicited, and basophilic stippling and lead lines may be absent. A lead level is difficult to obtain quickly; however, a free protoporphyrin level may be obtained expediently and is an indication of lead toxicity. Biochemical evidence of lead toxicity includes elevations of blood lead and signs of interference with hemoglobin synthesis, such as an increase in free erythrocyte protoporphyrin. A positive antistreptolysin O level (**choice A**) is evidence of an infection with Streptococcus. Poststrep-tococcal glomerulonephritis is a frequent cause of the nephritic syndrome in young children, but there is no evidence of a nephritic syndrome, and antistreptolysin O titer is unlikely to be helpful. Electroencephalography (**choice B**) may be helpful to study seizure activity if the initial work-up is negative. Sharp delta waves on the EEG will be indicative of seizure activity. The patient’s white count is normal, and the Monospot test (**choice D**), is unlikely to be helpful. Heterophil antibody kits such as the Monospot test is simple and fairly sensitive. This antibody can reach high titers in patients who have infectious mononucleosis and will cause sheep erythrocytes to agglutinate. Meningitis must be considered, but the possibility of lead poisoning is more important in this case, given the history and the finding of basophilic stippling. Bacterial meningitis is always high on the differential in such situations, and, if the answer is not obtained promptly, a lumbar puncture for cell count should be done and fluid should be cultured (**choice E**) before presumptive antibiotics are started.

Answer 11

Respuesta: B The correct **answer is B**. Meconium is the fetal stool, which is mostly composed of desquamated cells from the gastrointestinal tract admixed with enough bile to give the soft stool a greenish color. A distressed fetus will pass meconium into the amniotic fluid and then may aspirate it. These infants often have placental insufficiency as a result of conditions such as maternal preeclampsia, hypertension, or postmaturity. The aspirated meconium is very irritating to the lungs and causes a chemical pneumonitis. Postmature infants are particularly likely to have severe problems, because the meconium is diluted much less in their small amniotic fluid volume. The most important initial step in therapy is prompt suction of the nasopharynx and mouth to remove the meconium before more (or even any) is aspirated. This can be performed even before the infant is fully delivered, as soon as a head coated with meconium emerges from the birth canal. Neither chest x-ray (**choice A**) nor emergency tracheostomy (**choice E**) is warranted at this point. Oxygen supplementation by face mask (**choice C**) is deferred until after the nasopharynx and mouth are cleared of meconium. Intubation with mechanical ventilation (**choice D**) may become necessary if oxygen supplementation by facemask is unsuccessful.

Answer 12

Respuesta: E The correct **answer is E**. Neonatal listeriosis presents soon after birth, usually within 5 days. The usual neonatal presentation is predominantly that of respiratory distress. Late-onset neonatal listeriosis is more likely to present with meningitis. Maternal infection is commonly acquired by contact with unpasteurized milk (mother works on a farm and drinks unprocessed milk), soft cheeses, deli meats such as hot dogs and pâté, undercooked vegetables, and undercooked poultry. Typical symptoms in adults (exhibited by the mother) include fever, diarrhea, malaise, and a flulike illness. Once maternal infection has been acquired, it can be transmitted to the fetus either vaginally or transplacentally. Amniotic fluid is often cloudy and discolored. Mothers with syphilis (**choice A**) typically have a history of chancre or rash. Discolored amniotic fluid, acute fever, and diarrheal illness are not typical. Severely affected infants may have pneumonia and hepatosplenomegaly. A symptomatic infant with congenital toxoplasmosis (**choice B**) may display such signs as hydrocephalus, microcephaly, cataracts, hepatosplenomegaly, and a petechial and/or “blueberry muffin” rash. Respiratory distress is rare. Fetal hydrops (**choice C**) is a nonspecific finding that can occur in a wide variety of conditions resulting in severe edema of the fetus. These include in utero heart failure, severe anemia, and intrauterine viral or spirochetal infection. In the present case, a typical maternal history compatible with listerial infection is obtained and no other blood or cardiac anomalies are present. Neonatal herpes (**choice D**) can present with general collapse (associated with severe respiratory distress or liver failure), or as localized disease, including meningitis, ophthalmitis, or rash. The rash in infants is vesicular in its early stages, becoming crusted as the illness progresses. Many mothers do not have symptoms during their first infection; thus, a typical history of maternal genital herpes is not obtained in 70 to 90% of cases. However, the typical prodrome of listerial infection in the mother and lack of signs of neonatal herpes in either the mother or infant make this infection less likely

Answer 13

Respuesta: A The correct **answer is A**. After a first seizure, there is a high likelihood (approximately 60 to 70%) that a child will not experience another seizure episode again. Extensive laboratory examination and hospital admission (**choice B**) are not necessary, unless physical examination reveals some organic disease that may be related to the onset of the seizure. However, the majority of seizures of new onset are idiopathic, i.e., no cause can be identified with the commonly available diagnostic tools. Children developing a first-time seizure do not need antiepileptic drugs. Furthermore, approximately two thirds of children who develop a second episode will not have additional seizures. Medication may reduce the risk of having a second or third episode but does not affect the long-term outcome, i.e., the probability that a patient will be seizure-free 2-3 years after the first seizure. Thus, the only measure to take in this situation is to provide reassurance to both patient and family by explaining that the child probably will not have any other seizures and that isolated seizures do not cause any damage to the brain. Electroencephalographic (EEG) studies (**choice C**) would most likely yield no information. In fact, there is not a single test that can diagnose or rule out epilepsy. In addition, continuous EEG monitoring with or without video-monitoring is very expensive. It is indicated only when seizures are frequent during the day and it is necessary to establish a relationship between neurologic manifestations and abnormal electrical activity. CT/MRI studies of the brain (**choice D**) are rarely necessary after a single episode, unless there is some clinical evidence suggesting a focal intracranial lesion. Starting antiepileptic medication (**choice E**) would be unnecessary following a first episode. In fact, there is still controversy whether it should be started even after a second episode (that is, once a diagnosis of epilepsy is made).

Answer 14

Respuesta: A The correct **answer is A**. The thalassemias are due to inadequate production of alpha or beta hemoglobin chains. The genes coding for the alpha chain have been duplicated, producing a total of four copies. If all four alpha genes are normal, or if three are normal and one is thalassemic, the person is clinically normal. If two are abnormal, the person has alpha-thalassemia trait with mild hypochromic anemia. If three are abnormal, the patient has HbH disease with hemolytic disease. If all four are abnormal, hydrops fetalis, clinically similar to that produced by Rh disease, is produced. Newborns with alphathalassemia trait, HbH disease, or hydrops fetalis produce HbBarts, which corresponds to a tetramer of four gamma chains. Adults with HbH disease, and sometimes those with alpha-thalassemia trait, produce HbH, a tetramer of four beta chains. HbC (**choice B**) is an abnormal hemoglobin that, like HbS, can be associated with variable degrees of anemia. HbGlower 2 (**choice C**) is a hemoglobin present in first trimester embryos. HbH (**choice D**) is seen in adults with alpha-thalassemia (three abnormal genes), but is made in infants. HbS (**choice E**) is associated with sickle cell anemia and trait.

Answer 15

Respuesta: D The correct **answer is D**. Neuroblastoma arises from neural crest tissue and occurs in infancy. It is the most common solid tumor in children other than brain tumors. Eighty-five percent of neuroblastoma cases are diagnosed in children younger than 2 years. The clinical presentation varies with the tumor’s location. Common signs and symptoms include asymptomatic abdominal mass, Horner syndrome, persistent cough, superior vena cava syndrome, bone pain, cord compression, subcutaneous nodules (“blueberry muffin” lesions), hypertension, opsoclonus (“dancing eyes”), and myoclonus (“dancing feet”). Astrocytoma (**choice A**) and glioblastoma multiforme (**choice B**) are intracranial tumors and are therefore incorrect. The typical presentation of a brain tumor is early morning headache and vomiting, ataxia, cranial nerve palsies, nystagmus, and papilledema. Hyperthyroidism (**choice C**) does not cause opsoclonus or myoclonus, although it can cause tremor. Other typical features in children are irritability, excessive appetite, weight loss, increased perspiration, tachycardia, and goiter. Of note, hyperthyroidism occurs most frequently in children aged 12-14 years; only 2% of patients present before 10 years of age. Wilms tumor (**choice E**) occurs in the metanephric cells in the kidney. It is not associated with nervous system involvement.

Answer 16

Respuesta: A The correct **answer is A**. Nasal congestion, rhinorrhea, sneezing, and itchy nose and eyes are the most characteristic manifestations of allergic rhinitis, whether due to seasonal or perennial triggers. Nasal congestion can be particularly bothersome to patients with this condition. It is due to edema of the nasal mucosa, with resultant narrowing of the nasal passages. Patients are forced to breathe through their mouth, causing nasal speech and snoring. Over time, children will acquire what is known as “adenoidal facies,” with flat malar eminences, narrow maxillae, and an arched palate. Pharmacotherapy becomes necessary if avoidance of allergens is not feasible or sufficient to provide satisfactory relief. Alpha-adrenergic drugs, such as phenylephrine and pseudoephedrine, are most effective in relieving nasal congestion because of their vasoconstricting action. Two important side effects are rebound congestion and rhinitis medicamentosa. Antihistamines such as chlorpheniramine (**choice B**), i.e., firstgeneration antihistamines, are useful in treating symptoms of rhinitis, especially sneezing, rhinorrhea, and itching, but are less effective in preventing congestion. These drugs cause sedation and anticholinergic side effects. Antihistamines such as loratadine (**choice C**), i.e., second-generation antihistamines, do not cause sedation and have therapeutic effects similar to first-generation antihistamines. Cromoglycate, or similar mast cell stabilizers (**choice D**), have therapeutic effects comparable to antihistamines but are not useful in relieving nasal congestion. These drugs are most effective when administered prior to allergen exposure. Ipratropium bromide (**choice E**) is an anticholinergic agent that blocks cholinergic-mediated mucus secretion and vasodilatation. It can prevent rhinorrhea but is less effective for congestion.

Answer 17

Respuesta: C The correct **answer is C.** Typical findings of congenital hypothyroidism include constipation (35%), prolonged jaundice (75%), failure to thrive (35%), an enlarged fontanel (33%), and an umbilical hernia (50%). This constellation of findings is typical of the month-old hypothyroid patient. Alpha- 1-antitrypsin deficiency (**choice A**) is an uncommon cause of prolonged jaundice in the neonate. About 10% of infants with this condition present with prolonged neonatal jaundice. It is usually associated with increased conjugated bilirubin. Constipation is not a common feature of this illness in the infant. Biliary atresia (**choice B**) presents with prolonged jaundice, but is accompanied by pale (acholic) stools. Hepatomegaly and increased venous patterning over the abdomen will appear later. Congenital myasthenia gravis (**choice D**) is a disorder of the neuromuscular junction with heterogenous causes and which presents with hypotonia at or close to birth. Fatigable muscle weakness is seen most often in the ocular, bulbar, respiratory, and limbs. Deep tendon reflexes are reduced. A decremental repetitive stimulation response is found. Acetylcholine-receptor antibody tests are negative. Although infants with pyloric stenosis (**choice E**) are often jaundiced, the classic intestinal symptom is projectile vomiting after feedings without any of the other physical signs mentioned. Stool color and consistency are generally unremarkable. Syphilis (**choice F**) is accompanied by hepato-splenomegaly, a rash, and an elevated direct bilirubin. Infants may also develop “snuffles,” a persistent watery to mucoid nasal discharge. Werdnig-Hoffmann disease (**choice G**) is a form of spinal muscular atrophy. The earliest feature may be decreased fetal movements during late pregnancy. Despite being alert, the infant is floppy and weak at birth. The weakness is maximal in the shoulder and hip girdle muscles. Muscle fasciculation, especially of the tongue, may be seen. Other features of the disease include deformed chest with seesaw respiration, frog-leg position of the limbs, and absent reflexes.

Answer 18

Respuesta: D The correct **answer is D**. Measurements of T4 and TSH levels are the most appropriate tests to confirm congenital hypothyroidism. Alpha-1-antitrypsin genotyping (**choice A**) is used to confirm alpha1-antitrypsin deficiency. Barium swallow (**choice B**) will indicate the presence of pyloric stenosis (“string” sign = narrowing of barium stream passing through the duodenum; “umbrella” sign = the holdup of barium in the stomach). A liver and spleen scan (**choice C**) is useful to indicate the absence of the biliary tree or blockage of the extrahepatic bile ducts and is therefore most useful to confirm biliary atresia. Muscle biopsy (**choice E**) is used to diagnose myopathic conditions, including Werdnig-Hoffmann disease, muscular dystrophy, and metabolic inclusion diseases. The RPR and FTA (**choice F**) are serologic tests for syphilis.

Answer 19

Respuesta: G The correct **answer is G**. The search for a cause of anemia is important in children because it can result in diminished bone growth and learning. Nutritional anemia is the most common anemia in infants of this age. Infants consuming cow milk have a greater incidence of iron deficiency because bovine milk has a higher concentration of calcium, which competes for iron absorption. The major physical finding is pallor. Infants may also be lethargic, irritable, and tired easily. Classic peripheral blood smear findings are described here, and a cell blood count (CBC) characteristically shows decreased mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC). Diagnosis can be further confirmed with iron studies, TIBC, and serum ferritin. Acute myelogenous leukemia (**choice A**) results in pancytopenia due to bone marrow failure. Neoplastic proliferation of blast cells occurs in the bone marrow and presents clinically with anemia, bleeding, fatigue, nonspecific body aches, and vulnerability to infection. Pancytopenia with circulating blasts is characteristically found on peripheral blood smear. Anemia of chronic disease (**choice B**) can impair erythropoietin production, resulting in decreased red cell production. A normocytic, normochromic pattern is seen on peripheral blood smear and CBC. Red cell destruction, as seen in glucose 6-phosphate (G6PD) deficiency (**choice C**), can be the cause of anemia. G6PD is a red cell enzyme abnormality that causes intrinsic hemolysis of red blood cells. Bite cells are usually seen on peripheral blood smear. Anemia due to blood loss can be seen in hookworm infections (**choice D**). Although the anemia found in hookworm infection is due to the loss of bleeding and ultimately iron deficiency, there is nothing in the history to suggest a hookworm infection in this child. The most likely cause of the anemia is the ingestion of whole cow milk that results in the inadequate absorption of nutritional iron. Hypothyroidism (**choice E**) can cause normochromic, normocytic anemia. Infants with hypothyroidism present with cretinism, whereas children may show lethargy, constipation, dry skin, and mental retardation. Folic acid deficiency (**choice F**) is a cause of megaloblastic anemia when there is insufficient leafy vegetables in the diet. However, the peripheral blood smear and CBC findings in this case reveal a microcytic anemia.

Answer 20

Respuesta: C The correct **answer is C**. Because the most likely clinical diagnosis at this time is iron deficiency anemia, it would be appropriate to offer dietary advice (iron-fortified cereal, meat, green vegetables, egg yolk) and provide supplemental iron in the form of drops. A reticulocytosis typically occurs with a peak response in 5 to 7 days, followed by an increase in hemoglobin over the next 1 to 4 weeks. This treatment is both diagnostic and therapeutic. Antibiotic therapy (**choice A**) may also be used in hookworm infections to prevent further loss of blood and may be useful in the treatment of other concurrent infections, but it will have no effect in this child’s nutritional iron deficiency anemia due to cow milk ingestion. Bone marrow biopsy (**choice B**) is helpful in evaluating the presence of malignant cells and bone marrow failure, in the case of leukemia. Red cell enzyme studies (**choice D**) are used to diagnose glucose 6- phosphate (G6PD) deficiency and pyruvate kinase as the cause of intrinsic hemolysis and subsequent anemia. Thyroid studies (**choice E**) can diagnose hypothyroidism as a cause of anemia. However, clinical and laboratory features of this child’s anemia suggest nutritional iron deficiency.

Answer 21

Respuesta: G The correct **answer is G**. Approximately 50% of children with Down syndrome are born with endocardial cushion defects, such as ventricular septal defect, atrial septal defect, or complete atrioventricular canal defect. Aortic insufficiency (**choice A**) is associated with Marfan syndrome. Aortic dissections are also seen in this condition and can be lethal. Coarctation of the aorta (**choice B**) is seen in 35% of patients with Turner syndrome. Complex congenital heart defects (**choice C**) is too broad an answer choice and cannot be correlated with one congenital syndrome in particular. Congenital heart block (**choice D**) can occur in infants born to mothers with systemic lupus erythematosus. Dextrocardia (**choice F**) is a common finding in patients with Kartagener syndrome. Patent ductus arteriosus (**choice H**) can be seen in infants with congenital rubella infection. However, it is usually the result of prematurity, sepsis, metabolic acidosis, or pulmonary defects not associated with congenital syndromes.

Answer 22

Respuesta: I The correct **answer is I**. Williams syndrome is a deletion of the 7q chromosome, causing short stature, hypercalcemia, or hypercalciuria in infancy; developmental delay; dysmorphic features; overly friendly personality; and supravalvular aortic stenosis. Without surgical correction, the cardiac disease will progress and can cause sudden death. Aortic insufficiency (**choice A**) is associated with Marfan syndrome. Aortic dissections are also seen in this condition and can be lethal. Coarctation of the aorta (**choice B**) is seen in 35% of patients with Turner syndrome. Complex congenital heart defects (**choice C**) is too broad an answer choice and cannot be correlated with one congenital syndrome in particular. Congenital heart block (**choice D**) can occur in infants born to mothers with systemic lupus erythematosus. Dextrocardia (**choice F**) is a common finding in patients with Kartagener syndrome. Patent ductus arteriosus (**choice H**) can be seen in infants with congenital rubella infection. However, it is usually the result of prematurity, sepsis, metabolic acidosis, or pulmonary defects not associated with congenital syndromes.

Answer 23

Respuesta: E The correct **answer is E**. DiGeorge syndrome is caused by microdeletions in the 22q11 chromosome region. Features include facial dysmorphisms, thymic hypoplasia with resultant hypocalcemia, and conotruncal abnormalities, such as truncus arteriosus or total anomalous pulmonary venous return. The child in this vignette had a hypocalcemic seizure and cyanosis caused by truncus arteriosus. Therapy includes surgical correction of the heart defect and dietary supplementation with calcium and vitamin D. Aortic insufficiency (**choice A**) is associated with Marfan syndrome. Aortic dissections are also seen in this condition and can be lethal. Coarctation of the aorta (**choice B**) is seen in 35% of patients with Turner syndrome. Complex congenital heart defects (**choice C**) is too broad an answer choice and cannot be correlated with one congenital syndrome in particular. Congenital heart block (**choice D**) can occur in infants born to mothers with systemic lupus erythematosus. Dextrocardia (**choice F**) is a common finding in patients with Kartagener syndrome. Patent ductus arteriosus (**choice H**) can be seen in infants with congenital rubella infection. However, it is usually the result of prematurity, sepsis, metabolic acidosis, or pulmonary defects not associated with congenital syndromes.

Answer 24

Respuesta: J The correct **answer is J**. Mesenteric adenitis is an important cause of right iliac fossa pain in children. It is due to a nonspecific inflammation of mesenteric lymph glands that, in turn, is due to viral and bacterial infections. The most common causes are Yersinia species, Streptococcus viridans, and Campylobacter jejuni. The clinical picture includes abdominal pain, which may be generalized or localized and is usually in the right iliac fossa. There is moderate tenderness but little guarding or rebound. The patient may have mild pyrexia, and there may be diarrhea (with or without vomiting) or there may have been a recent upper respiratory tract infection. Mesenteric adenitis is, at times, difficult to differentiate from acute appendicitis, but in this case, it is differentiated by the lack of abdominal rebound and guarding and by a normal appetite. Ultrasonography of the right lower quadrant with graded compression has been the mainstay of diagnosis in children. The abdominal pain of appendicitis (**choice A**) classically begins as a crampy epigastric or periumbilical pain and progresses to a constant pain in the right lower quadrant. It is associated with vomiting and anorexia. On clinical examination, there are signs of peritoneal inflammation in the right iliac fossa, fever, and tachycardia, and there may be a positive Rovsing, obturator, or psoas sign. Constipation (**choice B**) may occur at any age and is usually the cause of recurrent, crampy abdominal pain, especially after meals. Constipation may occur if there is inadequate food or fluid intake. Children who drink a lot of milk may have hard stools that are difficult to pass. Feces is often palpable on examination, and there is no associated fever. The abdominal pain associated with gastroenteritis (**choice C**) is diffuse in nature, with no localized physical signs and with associated diarrhea, nausea, or vomiting and fever. The etiology is usually viral, most often due to rotavirus. The presentation of blood, mucus, and frequent small motions is suggestive of a bacterial cause. With progression, the child may become lethargic and dehydrated, with accompanying acidosis. Inflammatory bowel disease (**choice E**) is suggested in children with chronic abdominal pain, episodes of diarrhea that may be bloody, fever, and weight loss. One of the most important clues is growth failure, especially in adolescents. Crohn disease is a transmural process that may affect any part of the gastrointestinal tract, whereas in uncomplicated ulcerative colitis, inflammation is confined to the muscosa of the colon. Inguinal hernia (**choice F**) in infants and early childhood results from a patent processus vaginalis. The defect can be large enough to allow abdominal or pelvic organs to descend. The parents may report that the swelling appears with straining or crying, only to disappear at rest. Lactose intolerance (**choice H**), in its congenital form, is characterized by severe diarrhea, abdominal pain, and distension that appear soon after birth due to marked lactase deficiency in the small intestine. Lactase normally catalyzes the cleavage of lactose into glucose and galactose. Symptoms disappear with milk withdrawal (the source of lactose). Stool pH is acidic because of the presence of lactic acid resulting from the bacterial fermentation of the ingested lactose. Colicky abdominal pain and vomiting may be the presenting symptoms of acute lead poisoning (**choice I**) in children. Poisoning due to absorption or ingestion of lead affects the brain, nervous and digestive systems, and blood. Clinical features following ingestion of lead also include encephalopathy (ataxia, drowsiness, convulsions), pica, and papilledema. Pneumonia (**choice K**) can cause referred abdominal pain, especially when the infection is located in the lower lobes. Look for other symptoms that will suggest pneumonia as the cause of the abdominal pain, including fever, tachycardia, tachypnea, nasal flaring, cough, and crackles on auscultation. A chest x-ray will help with diagnosis. Nonorganic causes of abdominal pain, the most common of which is psychosomatic (**choice L**), are common causes of recurrent abdominal pain in childhood. Features that suggest nonorganic pain include pain occurring only on school days or certain social circumstances, nonorganic abdominal pain that is usually umbilical, a family history of recurrent abdominal pain of unknown etiology, and distractibility and variability of pain on examination. Torsion of the testis (**choice M**) is a surgical emergency that typically presents with a tender, swollen scrotum and lower abdominal pain. Although it occurs in all age groups, torsion is most common in adolescents, who have the highest incidence of undescended testes. There may be a history of mild trauma to the testis or a history of episodes of testicular pain due to torsion and untwisting. A urinary tract infection (**choice N**) is an important cause of lower abdominal pain in children because missing its diagnosis may damage the developing kidney. Presenting features include fever, loin pain and tenderness, dysuria, and urinary frequency. Diagnosis is made on urinalysis with culture and microscopy.

Answer 25

Respuesta: G The correct **answer is G**. Intussuscepton causes paroxysms of severe, crampy abdominal pain and early-onset vomiting in children under 5 years old, with peak presentation at 6 months of age. It is caused by the invagination of one portion of the bowel into the lumen of the immediately adjoining bowel. The most common form is ileocolic intussusception. Classic findings on physical examination are a walnut-sized mass palpated abdominally, a highpitched peristalsis on auscultation, and “currant-jelly” stools on rectal examination. In the absence of treatment, this condition is usually fatal. Barium enema is both diagnostic (“stack of coins” sign) and therapeutic in reducing the invaginated segment. Surgical reduction is performed in some cases. The abdominal pain of appendicitis (**choice A**) classically begins as a crampy epigastric or periumbilical pain and progresses to a constant pain in the right lower quadrant. It is associated with vomiting and anorexia. On clinical examination, there are signs of peritoneal inflammation in the right iliac fossa, fever, and tachycardia, and there may be a positive Rovsing, obturator, or psoas sign. Constipation (**choice B**) may occur at any age and is usually the cause of recurrent, crampy abdominal pain, especially after meals. Constipation may occur if there is inadequate food or fluid intake. Children who drink a lot of milk may have hard stools that are difficult to pass. Feces is often palpable on examination, and there is no associated fever. The abdominal pain associated with gastroenteritis (**choice C**) is diffuse in nature, with no localized physical signs and with associated diarrhea, nausea, or vomiting and fever. The etiology is usually viral, most often due to rotavirus. The presentation of blood, mucus, and frequent small motions is suggestive of a bacterial cause. With progression, the child may become lethargic and dehydrated, with accompanying acidosis. Inflammatory bowel disease (**choice E**) is suggested in children with chronic abdominal pain, episodes of diarrhea that may be bloody, fever, and weight loss. One of the most important clues is growth failure, especially in adolescents. Crohn disease is a transmural process that may affect any part of the gastrointestinal tract, whereas in uncomplicated ulcerative colitis, inflammation is confined to the muscosa of the colon. Inguinal hernia (**choice F**) in infants and early childhood results from a patent processus vaginalis. The defect can be large enough to allow abdominal or pelvic organs to descend. The parents may report that the swelling appears with straining or crying, only to disappear at rest. Lactose intolerance (**choice H**), in its congenital form, is characterized by severe diarrhea, abdominal pain, and distension that appear soon after birth due to marked lactase deficiency in the small intestine. Lactase normally catalyzes the cleavage of lactose into glucose and galactose. Symptoms disappear with milk withdrawal (the source of lactose). Stool pH is acidic because of the presence of lactic acid resulting from the bacterial fermentation of the ingested lactose. Colicky abdominal pain and vomiting may be the presenting symptoms of acute lead poisoning (**choice I**) in children. Poisoning due to absorption or ingestion of lead affects the brain, nervous and digestive systems, and blood. Clinical features following ingestion of lead also include encephalopathy (ataxia, drowsiness, convulsions), pica, and papilledema. Pneumonia (**choice K**) can cause referred abdominal pain, especially when the infection is located in the lower lobes. Look for other symptoms that will suggest pneumonia as the cause of the abdominal pain, including fever, tachycardia, tachypnea, nasal flaring, cough, and crackles on auscultation. A chest x-ray will help with diagnosis. Nonorganic causes of abdominal pain, the most common of which is psychosomatic (**choice L**), are common causes of recurrent abdominal pain in childhood. Features that suggest nonorganic pain include pain occurring only on school days or certain social circumstances, nonorganic abdominal pain that is usually umbilical, a family history of recurrent abdominal pain of unknown etiology, and distractibility and variability of pain on examination. Torsion of the testis (**choice M**) is a surgical emergency that typically presents with a tender, swollen scrotum and lower abdominal pain. Although it occurs in all age groups, torsion is most common in adolescents, who have the highest incidence of undescended testes. There may be a history of mild trauma to the testis or a history of episodes of testicular pain due to torsion and untwisting. A urinary tract infection (**choice N**) is an important cause of lower abdominal pain in children because missing its diagnosis may damage the developing kidney. Presenting features include fever, loin pain and tenderness, dysuria, and urinary frequency. Diagnosis is made on urinalysis with culture and microscopy.

Answer 26

Respuesta: D The correct **answer is D**. The cardinal features of HenochSchönlein purpura (HSP) are gastrointestinal, joint, and renal manifestations due to widespread vasculitis of the arterioles and small capillaries. The dominant clinical features are shown in this case: cutaneous purpura, arthritis, abdominal pain (gastrointestinal bleeding may also occur), orchitis, and nephritis (hematuria and proteinuria). In up to two thirds of patients, clinical onset is preceded by an upper respiratory tract infection. In general, HSP is an acute, self-limited illness, but one third of patients has one or more recurrences. The most feared complication is progressive renal disease. Scrotal involvement is common and may mimic testicular torsion The abdominal pain of appendicitis (**choice A**) classically begins as a crampy epigastric or periumbilical pain and progresses to a constant pain in the right lower quadrant. It is associated with vomiting and anorexia. On clinical examination, there are signs of peritoneal inflammation in the right iliac fossa, fever, and tachycardia, and there may be a positive Rovsing, obturator, or psoas sign. Constipation (**choice B**) may occur at any age and is usually the cause of recurrent, crampy abdominal pain, especially after meals. Constipation may occur if there is inadequate food or fluid intake. Children who drink a lot of milk may have hard stools that are difficult to pass. Feces is often palpable on examination, and there is no associated fever. The abdominal pain associated with gastroenteritis (**choice C**) is diffuse in nature, with no localized physical signs and with associated diarrhea, nausea, or vomiting and fever. The etiology is usually viral, most often due to rotavirus. The presentation of blood, mucus, and frequent small motions is suggestive of a bacterial cause. With progression, the child may become lethargic and dehydrated, with accompanying acidosis. Inflammatory bowel disease (**choice E**) is suggested in children with chronic abdominal pain, episodes of diarrhea that may be bloody, fever, and weight loss. One of the most important clues is growth failure, especially in adolescents. Crohn disease is a transmural process that may affect any part of the gastrointestinal tract, whereas in uncomplicated ulcerative colitis, inflammation is confined to the muscosa of the colon. Inguinal hernia (**choice F**) in infants and early childhood results from a patent processus vaginalis. The defect can be large enough to allow abdominal or pelvic organs to descend. The parents may report that the swelling appears with straining or crying, only to disappear at rest. Lactose intolerance (**choice H**), in its congenital form, is characterized by severe diarrhea, abdominal pain, and distension that appear soon after birth due to marked lactase deficiency in the small intestine. Lactase normally catalyzes the cleavage of lactose into glucose and galactose. Symptoms disappear with milk withdrawal (the source of lactose). Stool pH is acidic because of the presence of lactic acid resulting from the bacterial fermentation of the ingested lactose. Colicky abdominal pain and vomiting may be the presenting symptoms of acute lead poisoning (**choice I**) in children. Poisoning due to absorption or ingestion of lead affects the brain, nervous and digestive systems, and blood. Clinical features following ingestion of lead also include encephalopathy (ataxia, drowsiness, convulsions), pica, and papilledema. Pneumonia (**choice K**) can cause referred abdominal pain, especially when the infection is located in the lower lobes. Look for other symptoms that will suggest pneumonia as the cause of the abdominal pain, including fever, tachycardia, tachypnea, nasal flaring, cough, and crackles on auscultation. A chest x-ray will help with diagnosis. Nonorganic causes of abdominal pain, the most common of which is psychosomatic (**choice L**), are common causes of recurrent abdominal pain in childhood. Features that suggest nonorganic pain include pain occurring only on school days or certain social circumstances, nonorganic abdominal pain that is usually umbilical, a family history of recurrent abdominal pain of unknown etiology, and distractibility and variability of pain on examination. Torsion of the testis (**choice M**) is a surgical emergency that typically presents with a tender, swollen scrotum and lower abdominal pain. Although it occurs in all age groups, torsion is most common in adolescents, who have the highest incidence of undescended testes. There may be a history of mild trauma to the testis or a history of episodes of testicular pain due to torsion and untwisting. A urinary tract infection (**choice N**) is an important cause of lower abdominal pain in children because missing its diagnosis may damage the developing kidney. Presenting features include fever, loin pain and tenderness, dysuria, and urinary frequency. Diagnosis is made on urinalysis with culture and microscopy.