Table 126-8 lists common diagnoses that must be considered and their important historical features. Given the frequency of viral gastroenteritis as the etiology, it is important to be alert for unusual features that suggest another diagnosis. Viral gastroenteritis usually is not associated with severe abdominal pain or headache and does not recur at frequent intervals.
Physical examination should include assessment of the child’s hydration status, including examination of capillary refill, moistness of mucous membranes, and skin turgor (see Chapter 38). The chest should be auscultated for evidence of rales or other signs of pulmonary involvement. The abdomen must be examined carefully for distention, organomegaly, bowel sounds, tenderness, and guarding. A rectal examination and testing stool for occult blood should be considered.
Laboratory evaluation of vomiting should include serumelectrolytes, tests of renal function, complete blood count, amylase, lipase, and liver function tests. Additional testing may berequired immediately when history and examination suggest aspecific etiology. Ultrasound is useful to look for pyloric steno-sis, gallstones, renal stones, hydronephrosis, biliary obstruction,pancreatitis, malrotation, intussusception, and other anatomic
Table 126-8 Differential Diagnosis and Historical Features of Vomiting DIFFERENTIAL DIAGNOSIS HISTORICAL CLUES Viral gastroenteritis Fever, diarrhea, sudden onset, absence of pain Gastroesophageal reflux Effortless, not preceded by nausea, chronic
Hepatitis Jaundice, history of exposure
Otitis media Fever, ear pain
Urinary tract infection Dysuria, unusual urine odor, frequency, incontinence
Pneumonia Cough, fever, chest discomfort
Milk or soy protein intolerance (infants) Associated with particular formula or food, blood in stools
Peptic ulcer or gastritis Epigastric pain, blood or coffee-ground material in emesis, pain relieved by acid blockade
Appendicitis Fever, abdominal pain migrating to the right lower quadrant, tenderness
Intestinal atresia Neonate, usually bilious, polyhydramnios
Midgut malrotation Pain, bilious vomiting, GI bleeding, shock
Intussusception Colicky pain, lethargy, vomiting, currant jelly stools, mass occasionally
Duplication cysts Colic, mass
Pyloric stenosis Nonbilious vomiting, postprandial, <4 mo old, hunger, progressive weight loss
Bacterial gastroenteritis Fever, often with bloody diarrhea
Hydrocephalus Large head, altered mental status, bulging fontanelles
Meningitis Fever, stiff neck
Migraine syndrome Attacks scattered in time, relieved by sleep; headache
Cyclic vomiting syndrome Similar to migraine, usually no headache
Brain tumor Morning vomiting, accelerating over time, headache, diplopia
Motion sickness Associated with travel in vehicle
Metabolic disease Presentation early in life, worsens when catabolic or exposure to substrate
Pregnancy Morning, sexually active, cessation of menses
Drug reaction or side effect Associated with increased dose or new medication
Cancer chemotherapy Temporarily related to administration of chemotherapeutic drugs abnormalities. CT may be indicated to rule out appendicitis or to observe structures that cannot be visualized well by ultrasound. Barium studies can show obstructive or inflammatorylesions of the gut and can be therapeutic, as in the use of contrast enemas for intussusception (see Chapter 129).
Treatment needs to address the consequences and the causesof the vomiting. Dehydration must be treated with fluid resuscitation. This can be accomplished in most cases with oralfluid-electrolyte solutions, but intravenous (IV) fluids may berequired. Electrolyte imbalances should be corrected by appropriate choice of fluids. Underlying causes should be treatedwhen possible.