What does atretic mean in a medical context?

Definition of Atresia in Medical Context

Atresia refers to the congenital absence or abnormal closure of a body passage, tube, or natural opening that is normally present. This condition can affect various parts of the body and represents a significant structural abnormality that often requires medical or surgical intervention 1.

Types and Anatomical Locations of Atresia

Atresia can occur in multiple body systems:

1. Choanal Atresia

   • Congenital blockage of the nasal passage between the nose and pharynx
   • Incidence: 1 in 7000-8000 live births
   • Types: Purely bony (30%) or mixed bony/membranous (70%)
   • Female predominance (2:1 ratio)
   • Can be unilateral (60%) or bilateral (40%) 1

2. Intestinal Atresia

   • Complete obstruction of the intestinal lumen
   • Caused by vascular issues or failure of recanalization during fetal development
   • Can affect any part of the intestinal tract 2

3. Cardiac Atresia

   • Absence of normal openings between heart chambers
   • Examples include:
     • Right atrioventricular orifice atresia (formerly called "tricuspid atresia")
     • Pulmonary atresia 1, 3

4. Atretic Cephaloceles

   • Herniation of intracranial contents through a skull defect
   • Most commonly located in parietal (55%) or occipital (37%) regions
   • Often associated with other CNS anomalies 4, 5

5. Atretic Meningocele

   • Appears as a small, flat area of dysplastic skin
   • Often described as "scarified," "cigarette paper," or "cigarette burn" in appearance
   • Usually has an underlying fibrous tissue tract 1

Clinical Significance and Presentation

The clinical presentation varies by location:

• Bilateral choanal atresia: Presents as a neonatal emergency with respiratory distress, cyanosis, and feeding problems as newborns are obligate nasal breathers 1

• Unilateral choanal atresia: May present later in life with unilateral nasal obstruction

• Intestinal atresia: Presents with vomiting, abdominal distension, and failure to pass meconium 2

• Cardiac atresia: Presents with cyanosis, heart failure, or both depending on associated defects 1, 3

• Atretic cephaloceles: Often present as nodular extrusions on the scalp; clinical outcomes are worse when associated with other CNS anomalies 4, 5

Diagnostic Approaches

Diagnosis depends on the type of atresia but generally includes:

• Physical examination
• Imaging studies (CT, MRI)
• Endoscopic evaluation
• Contrast studies (for GI atresia)
• Echocardiography (for cardiac atresia)

For choanal atresia specifically, diagnosis includes:

• Inability to pass a catheter through the nostril into the pharynx
• Nasal endoscopy
• CT scan to determine the nature and extent of the atretic plate 1

Management Considerations

Treatment is typically surgical and varies by location:

• Choanal atresia: Micro-endoscopic endonasal approach is preferred, with postoperative dilations for up to one year. Stenting should be avoided as it stimulates granulation formation and restenosis 1

• Intestinal atresia: Surgical excision and anastomosis of the remaining normal canalized intestine 2

• Cardiac atresia: Complex surgical palliation, often requiring multiple staged procedures 1

• Atretic cephaloceles: Observation is sufficient for asymptomatic cases, but surgical intervention may be needed for symptomatic ones 4

Associated Conditions

Atresia is frequently associated with other congenital anomalies:

• Choanal atresia is associated with CHARGE syndrome in about 20% of cases 1
• Cardiac atresia may be associated with other cardiac defects 1, 3
• Atretic cephaloceles are associated with CNS anomalies in 73.3% of parietal cases and 32.4% of occipital cases 4

Prognosis

Prognosis depends on:

• Location and extent of atresia
• Associated anomalies
• Timing of diagnosis and intervention
• Surgical outcomes and complications

For choanal atresia, surgical success rates are high when using modern techniques, though revision surgery is sometimes needed 1.