Hernias Flashcards
Define congenital diaphragmatic hernia (CDH).
Congenital defect in the formation of the diaphragm that leads to the protrusion of abdominal contents into the thoracic cavity.
Define inguinal hernia.
Abnormal protrusion of an intra-abdominal structure through the inguinal canal into the inguinal region or scrotum.
Explain the aetiology of congenital diaphragmatic hernia.
Diaphragmatic development is from four structures embryologically: dorsal oesophageal mesentery, pleuroperitoneal membranes, body wall and septum transversum. Defect occurs from failure of these to fuse.
What are the 4 types of congenital diaphragmatic hernias?
General: More commonly unilateral although may be bilateral. Lt > Rt. Bowel or intra-abdominal viscera may herniated. Common for liver (Rt) and also spleen (Lt) to be herniated. There may be associated abnormal hepatic vasculature. Associated with abnormalities of the pulmonary tree, vasculature and surfactant deficiency (hypoplastic lungs).
Posterolateral Bochdalek hernia: 90% of cases, commonly left-sided, posterolateral defect.
Morgagni hernia: 3% of cases, commonly right-sided (90%), anteromedial defect.
Congenital hiatus hernia: Rare, stomach herniates through the oesophageal hiatus.
What are risk factors for congenital diaphragmatic hernias?
Previous affected sibling
Cardiac anomalies (25%)
Renal anomalies
Persistent pulmonary hypertension
Malrotation of the small bowel (40%)
Explain the aetiology of inguinal hernias.
The testicle develops retroperitoneally and begins descent to the scrotum at 28/40. This is under control of both hormones and the gubernaculum. Peritoneal evagination creates the processus vaginalis and allows testicular descent thorough the ventral abdominal wall to the scrotum. This normally obliterates by term but if it remains open (patent processus vaginalis), will allow the passage of bowel (inguinal hernia) or fluid (hydrocoele) through the inguinal canal. In females, the gubernaculum becomes the ovarian ligament and round ligament; with a patent processus vaginalis, it extends into the labium majus and is known as the canal of Nuck.
What are risk factors for inguinal hernias?
Preterm infants
Low birthweight, FHx (10%)
Undescended testicles
Gastroschisis
Exomphalos
Hypospadias
Ehlers– Danlos syndrome
Cystic fibrosis
Connective tissue disorders and other conditions that “ intra-abdominal pressure.
Summarise the epidemiology of inguinal hernias.
3–5% full-term infants and 30% premature infants. M>F 5:1. Right-sided (60%), left-sided (25%), bilateral (15%). 7% develop metachronous hernia post-repair (contralateral exploration is not recommended).
What are the signs and symptoms of congenital diaphramatic hernia?
Infants may have a history of polyhydramnios. Most commonly present with a history of cyanosis and respiratory distress in the immediate neonatal period. If there is a left-sided posterolateral hernia, there may be poor air entry on the left and a shift of cardiac sounds into the right chest. Smaller defects may present later in infancy with a diagnosis of a ‘wheezy child’ or recurrent chest infection.
What are the signs and symptoms of inguinal hernias in an infant?
History of intermittent inguinal/inguinoscrotal swelling. First presentation may be with incarceration. Unable to palpate the cord superiorly (possible with hydrocoeles). Reducible unless incarcerated (tender/red/firm). Nontransluminable.
What are the signs and symptoms of an inguinal hernia in a child?
Supine and standing positions, expansile cough impulse
What are signs and symptoms of incarceration?
Unsettled, pain, tender non-reducible inguinal scrotal mass, erythema, oedema, vomiting and abdominal distension (late signs).
What are differential diagnoses for inguinal hernias?
Hydrocoeles, retractile testes, undescended testes, femoral hernias and lymphadenopathy.
What are appropriate investigations for congenital diaphragmatic hernias?
CXR, cardiac echo, renal USS and karyotyping
What are appropriate investigations for inguinal hernias?
Clinical diagnosis
