Approach Considerations
Laboratory studies are not specific for hernia but may be useful for general medical evaluation. Imaging studies are not required in the normal workup of a hernia [7, 8] ; however, radiography, computed tomography (CT), or ultrasonography (US) may be considered in certain circumstances. Sigmoidoscopy is no longer recommended as a screening test.
Evaluation for potential reversal of provocative factors (eg, prostatism, chronic cough, severe constipation, rectal cancer, and ascites) is important.
Laboratory Studies
Laboratory studies that may be helpful include the following:
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Stain or culture of nodal tissue - This can help diagnose atypical tuberculous adenitis
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Complete blood count (CBC) - Results are nonspecific, but leukocytosis with left shift may occur with strangulation
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Electrolyte, blood urea nitrogen (BUN), and creatinine levels - It is advisable to assess the hydration status of the patient with nausea and vomiting; these tests are rarely needed for patients with hernia except as part of a preoperative workup
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Urinalysis - This can help narrow the differential diagnosis of genitourinary causes of groin pain in the setting of associated hernias
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Lactate levels - Elevation may reflect hypoperfusion; a normal level does not necessarily rule out strangulation
Radiography
Plain radiographs taken tangentially may show air in the intestine outside the abdomen, as may contrast studies of the bowel. Unfortunately, visualization of the perineum and pelvis is poor with these studies. Higher yields can be obtained with dynamic changes in position, intra-abdominal pressure, or both during the imaging studies. Better assessments of the perineum and pelvis are possible via external views of the intestine and their domain with herniography.
Careful instillation of water-soluble nonionic contrast through the abdominal wall helps to define most hidden hernias, such as interparietal, pelvic, obturator, sciatic, and other poorly palpable hernias (eg, small recurrent hernias). [28] However, unintentional luminal contrast injection may lead to infection.
If an incarcerated or strangulated hernia is suspected, the following imaging studies may be helpful:
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Upright chest radiograph to exclude free air (extremely rare)
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Flat and upright abdominal films to diagnose a small bowel obstruction (neither sensitive or specific) or to identify areas of bowel outside the abdominal cavity
Computed Tomography
CT of the abdomen and pelvis with oral and intravenous (IV) contrast can help detect many elusive hernias by demonstrating extracoelomic location of the bowel, bladder, or female internal reproductive organs. [29] CT may be indicated in the diagnosis of a spigelian or obturator hernia and in cases where the patient’s body habitus makes it difficult for the physician to perform a good physical examination.
Ultrasonography
US is helpful in narrowing the differential on both scrotal masses and masses below the inguinal ligament. It can also aid in the decision to drain or aspirate a nodal abscess. Like CT, US may be indicated when a spigelian or obturator hernia is suspected or when the patient’s body habitus hinders physical examination.
Infants with omphaloceles require prompt, thorough evaluations to detect associated anomalies. Initial studies should include bilateral renal US and echocardiography, as well as karyotyping and plain radiography of the sacrum.
Histologic Findings
Pathologic evaluation of pediatric hernia sacs offers little relevant clinical information. Tubular structures found during pathologic examination may indicate aberrant ductuli of Haller or duplications instead of segments of the vas deferens. Ductuli are 50-100 µm in size, much smaller than even the infant vas deferens; duplications can be proved only through reexploration.
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Large right inguinal hernia in 3-month-old girl.
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In this baby with gastroschisis, bowel is uncovered and presents to right inferior aspect of cord.
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Hernia of umbilical cord.
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Note translucent sac in baby with large omphalocele. Umbilical vessels attach to sac.
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Hernia content balloons over external ring when reduction is attempted.
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Hernia can be reduced by medial pressure applied first.
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Infant with Silon chimney placed in treatment of gastroschisis.
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Atrophy of right testis after hernia repair. Note adult-type incision.
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Iatrogenic cryptorchid testis in child. Taking care to position testis in scrotum is integral part of completion of hernia repair in boys.
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Erythematous edematous left scrotum in 2-month-old boy with history of irritability and vomiting for 36 hours. Local signs of this magnitude preclude reduction attempts.
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Testis at operation in 2-month-old boy with history of irritability and vomiting for 36 hours. Capsulotomy was performed, but atrophy occurred. Patient also required bowel resection.
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Ventriculoperitoneal shunt, decreased activity, and acute scrotal swelling in 6-month-old boy.
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Ventriculoperitoneal shunt, decreased activity, and acute scrotal swelling in 6-month-old boy. Abdominal radiograph shows incarcerated shunt within communicating hydrocele. Repair of hydrocele relieved increased intracranial pressure.
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Bassini-type repair approximating transversus abdominis aponeurosis and transversalis fascia to iliopubic tract and inguinal ligament.
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Anatomic locations for various hernias.
