Infectious diseases Bacterial sepsis a Meningitis a Urinary tract infection a Viral infections—enterovirus, respiratory syncytial virus, herpes simplex a Pertussis Congenital syphilis Omphalitis Cardiac disease Congenital heart disease a Supraventricular tachycardia a Myocardial infarction (most commonly aberrant left coronary artery) Pericarditis Myocarditis Kawasaki disease Endocrine disorders Congenital adrenal hyperplasia Metabolic disorders Hyponatremia, hypernatremia a Cystic fibrosis Inborn errors of metabolism, galactosemia Hypoglycemia a Drugs/toxins—aspirin, carbon monoxide Renal disorders Posterior urethral valves Hematologic disorders Severe anemia a Methemoglobinemia Kernicterus Gastrointestinal disorders Gastroenteritis with dehydration a Pyloric stenosis a Intussusception Necrotizing enterocolitis Appendicitis Volvulus Incarcerated hernia a Hirschsprung enterocolitis Neurologic disease Infant botulism Shunt obstruction, infection a Child abuse—intracranial hemorrhage a a Indicates more common causes TABLE 73.2 MOST COMMON DISORDERS THAT MIMIC SEPSIS Urinary tract infection Viremia Congestive heart failure Gastroenteritis with dehydration Pertussis causes coughing, apnea, seizures, and death during infancy Parents may report respiratory distress, cough, poor feeding, and vomiting A careful history may reveal that the vomiting is often posttussive History of exposure to pertussis may be lacking because the infant usually acquires the disease from older children or adults who have only symptoms of a common upper respiratory infection Physical examination will distinguish the infection from sepsis if the infant has a paroxysmal cough The characteristic inspiratory “whoop” after a coughing paroxysm (a hallmark in older patients) is uncommon in very young infants Auscultation of the chest is usually normal; tachypnea and cyanosis may be present The classic CBC finding of marked lymphocytosis is often absent in infants with pertussis, and a chest radiograph may not show the typical “shaggy right heart border” in this age group, though atelectasis or pneumonia may be present PCR technique can reliably identify the condition from nasopharyngeal specimens, and nasopharyngeal culture for Bordetella pertussis is confirmatory Infants with congenital syphilis may present in the first weeks of life with extreme irritability, pallor, jaundice, hepatosplenomegaly, and edema Pneumonia, painful limbs, snuffles, and skin lesions are common Consider this diagnosis if a history of maternal infection is obtained or if the child has been chronically ill prior to presentation Radiographs of the infant’s long bones may reveal diffuse periostitis of several bones, and serologic testing is needed to confirm the diagnosis Cardiac Diseases (See Chapter 86 Cardiac Emergencies ) An infant with underlying congenital heart disease (CHD), including ventriculoseptal defect, valvular insufficiency, valvular stenosis, hypoplastic left heart syndrome (HLHS), or coarctation of the aorta, may present with shock or congestive heart failure and clinical findings similar to those of an infant with sepsis Symptoms may include tachycardia, tachypnea, pallor, duskiness, or mottling of the skin Cyanosis may not be present based on the direction of shunting and the patient’s hemoglobin level, which decreases physiologically to a nadir at about weeks of age There may be sweating, decreased pulses, and hypotension caused by poor perfusion A chronic history of poor growth and poor feeding may help differentiate heart disease from sepsis The presence of a cardiac murmur, a gallop rhythm, cyanosis unresponsive to 100% oxygen administration, hepatomegaly, neck vein distention, or peripheral edema may lead one to consider primary cardiac pathology Intercostal retractions and rales, rhonchi, or wheezing are nonspecific findings and may be present on chest examination in either heart failure or pneumonia HLHS or coarctation of the aorta may present with shock toward the end of the first or second week of life as the patent ductus arteriosus (PDA) closes A difference between upper- and lower-extremity blood pressures in a young baby suggests coarctation of the aorta, though pulse differences may not be detected if cardiac output is inadequate Normal femoral pulses not exclude a coarctation because the widened PDA provides flow to the descending aorta Check the dorsalis pedis or tibialis posterior pulses; these are more sensitive for detecting coarctation or low cardiac output A chest radiograph often shows cardiac enlargement and may show pulmonary vascular engorgement or interstitial pulmonary edema rather than lobar infiltrates (as in pneumonia) The electrocardiogram (ECG) may reveal abnormalities including right-axis deviation with right atrial and ventricular enlargement in HLHS, but can be nonspecific An echocardiogram is usually required to define anatomy and confirm specific diagnoses Rarely, an infant with anomalous or obstructed coronary arteries will develop myocardial infarction and appear septic These infants may have colicky behavior, dyspnea, cyanosis, vomiting, pallor, and other signs of heart failure They usually have cardiomegaly on chest radiograph, and the ECG usually shows T-wave inversion and deep Q waves in leads I and AVL Echocardiogram or cardiac catheterization is needed to confirm the diagnosis Certain arrhythmias may cause an infant to appear ill Supraventricular tachycardia (SVT) often presents with findings similar to those of a septic infant This arrhythmia may be idiopathic (50%), associated with CHD (20%), or related to drugs, fever, or infection (20%) Young infants with SVT often go unrecognized initially as they have only poor feeding, fussiness, and some rapid breathing They eventually develop congestive heart failure as the condition goes untreated and may present with shock Fever can precipitate the arrhythmia, confusing the condition with sepsis, though the cardiac examination will reveal such extreme tachycardia in the infant that the heart rate cannot be counted, often exceeding 250 to 300 beats per minute An ECG will show regular atrial and ventricular beats with 1:1 conduction, although P waves appear different than sinus P waves and may be difficult to see as they are often buried in the T waves A chest radiograph may show cardiomegaly and pulmonary congestion Additional cardiac pathologies to consider include pericarditis and myocarditis Pericarditis may be caused by bacterial organisms such as Staphylococcus aureus; myocarditis usually results from viral infections such as coxsackievirus B These babies will appear critically ill with fever and grunting respirations, but a complete physical examination may help the physician distinguish these conditions from sepsis if signs of heart failure or unexplained tachycardia are present Pericarditis may produce neck vein distention, distant heart sounds, and a friction rub if a significant pericardial effusion exists Physical findings with myocarditis may include muffled heart sounds (due to ventricular dilatation), gallop rhythm, hepatosplenomegaly, and weak distal pulses with poor perfusion A chest radiograph in a patient with pericarditis will show cardiomegaly and a suggestion of effusion The ECG will show generalized T-wave inversion and low-voltage QRS complexes if pericardial fluid is present, and ST-T–wave abnormalities may be seen The echocardiogram will confirm the presence or absence of a pericardial effusion and poor ventricular function in the case of viral myocarditis Cardiac magnetic resonance will show inflammation, edema, and scarring Troponins can detect cardiac injury, and natriuretic peptides can help differentiate cardiac from respiratory symptoms, and though nonspecific may help in leading to a diagnosis of myocarditis Kawasaki disease with associated coronary artery aneurysms is very rare in young infants but may present with cyanosis and shock Usually, history reveals prolonged and unexplained fever, rash, and mucous membrane inflammation Neonates with Kawasaki disease often have an atypical presentation and the classic features found in older infants and children (e.g., swelling of hands and feet, cracked red lips, scleral erythema) may be absent in young babies A CBC