Absence of septum pellucidum

Overview

Absence of septum pellucidum (medical condition) is the absence of the thin membrane that separates the two halves of the brain. The defect itself is not a disorder but is usually observed as a characteristic of a condition called septo-optic dysplasia which also involves optic nerve and pituitary abnormalities.

Symptoms

  • Blindness
  • Reduced vision
  • Nystagmus
  • Dilated pupils in light
  • Inward deviation of eyes
  • Outward deviation of eyes
  • Hormonal problems
  • Low muscle tone
  • Seizures
  • Jaundice
  • Impaired intelligence
  • Mental retardation
  • Learning disabilities
  • Neurological problems
  • Developmental delay

Causes

  • Transient vision loss (24 hours: Sudden, painless Retinal artery or vein occlusion
  • Ischemic optic neuropathy (must rule out giant cell/temporal arteritis to prevent permanent bilateral vision loss)
  • Vitreous or aqueous hemorrhage (hyphema)
  • Retinal detachment
  • Other retinal or CNS disease (e.g., cortical blindness due to occipital lobe CVA)
  • Exposure (“Welder's flash”) or prolonged exposure to intense sunlight # Vision loss >24 hours: Gradual, painless Cataract # Refractive error # Open angle glaucoma # Chronic retinopathy (e.g., age-related macular degeneration, diabetic retinopathy) # Chronic corneal disease (e.g., corneal dystrophy) # Optic neuropathy/atrophy (e.g., compressive lesion, toxic-metabolic cause, dominant optic neuropathy, radiation) # Retinitis pigmentosa # Pseudotumor cerebri # Vision loss >24 hours: Painful Acute angle closure glaucoma # Optic neuritis (pain with extraocular motion) # Orbital apex/superior orbital fissure/ cavernous sinus syndrome # Uveitis # Corneal hydrops (keratoconus)
  • Ocular onchocerciasis (“river blindness”) –Common cause of blindness in developing nations due to Onchocerca volvulus worm
  • Corneal abrasion or ulcer
  • Herpes simplex or zoster infection

Prognosis

The absence of the septum pellucidum alone is not a disorder. However, when it is part of septo-optic dysplasia the prognosis varies according to the presence and severity of associated symptoms.

Treatment

Absence of the septum pellucidum alone is not a disorder but is instead a characteristic noted in children with septo-optic dysplasia.

  • Treat underlying causes (e.g., brain tumor, carotid stenosis, cardiac valvular vegetations, hypotension)
  •  Temporal arteritis: Systemic steroids
  • Nonarteritic ischemic optic neuropathy: Aspirin
  • Optic neuritis: Systemic steroids
  • Glaucoma: Topical antiglaucoma medications; peripheral iridotomy for angle closure
  • Retinal detachment: Surgical repair
  • Cataracts: Surgical removal
  • AV fistula: Embolize
  • Cavernous sinus thrombosis: Antibiotics, anticoagulation
  • Mucormycosis: Amphotericin B, debridement
  • Pituitary apoplexy: Systemic steroids, neurosurgical intervention
  • Herpes zoster: Systemic acyclovir
  • Tolosa-Hunt: Systemic steroid
  • Keratoconus/corneal hydrops: Cycloplegic, hypertonic (5%) NaCl ointment, corneal transplant