**4. Investigations**

*Sino-Nasal and Olfactory System Disorders*

risk of meningitis with conservative treatment [2].

lesions carry a reported 0.5–15% incidence of CSF leak [3].

conjunction with spontaneous CSF leaks.

**2.2 Encephalocele**

**3. Clinical presentation**

tion and straining.

spontaneously with observation and conservative management which may include bed rest, head of bed elevation, and lumbar drainage. Overall, there is a 30–40%

Surgical causes (planned and unplanned) make up a large portion of leaks requiring intervention. Functional endoscopic sinus surgery (FESS) carries <1% incidence of CSF leak. The most common site of skull base injury is the lateral lamella of the cribriform plate. The posterior ethmoid skull base is at greater risk when the maxillary sinus is highly pneumatized in the superior–inferior dimension, which creates a relatively decreased posterior ethmoid height. Neurologic Surgery caries an increased risk albeit typically include planned CSF leak with expected violation of the meninges. Transsphenoidal approach for sellar and suprasellar

Neoplasms can result in CSF leak via direct tumor invasion and/or mass effect

Encephaloceles can occur in both the skull and spinal column. Twenty percent occur within the cranium and 15% of these are associated with the nasal cavity. Nasal encephaloceles are divided into two types: sincipital and basal. Sincipital (anterior and superior) encephaloceles make up approximately 60% of nasal encephaloceles and typically present as a soft compressible mass over the glabella. Basal encephaloceles occur through the skull base more posteriorly and make up approximately 40% of nasal encephaloceles. They may remain hidden for many

Clear rhinorrhea that is unilateral, watery, and salty to taste is the most common complaint in CSF leaks. It may run out of the nose in more anterior leaks, or down the back of the throat in more posterior leaks. The drainage can be exacerbated by the Dandy maneuver, which entails tilting the head forward into a chin-tuck posi-

Patients with an encephalocele will often present with rhinorrhea or recurrent meningitis and may have a broad nasal dorsum or hypertelorism. Encephaloceles may

years because they are located more posteriorly than the sincipital type.

leading to intracranial hypertension. Congenital causes result from failure of closure of developmental spaces with resultant herniation of intracranial contents. Foramen cecum is the most common location. Spontaneous leaks are often the result of idiopathic intracranial hypertension (IIH) resulting from decreased CSF reabsorption. Patient characteristics and symptoms often include middle-age, obesity, female, pressure-type headaches, pulsatile tinnitus, and balance dysfunction. Empty sella syndrome is a radiographic appearance of CSF-filled sella due to flattening of the pituitary gland which is an endocrine gland that resides in the sella turcica and functions to control other endocrine glands by secretion of controlling hormones. Empty sella syndrome can be seen in IIH, which typically affects obese women. Patients typically will present with headaches, pulsatile tinnitus, and diplopia. A hallmark physical exam finding is bilateral optic disc edema secondary to increased intracranial pressure (ICP). Treatment is focused on decreasing ICP with pharmacologic therapy consisting of acetazolamide and furosemide to lower ICP, and headache management, which may include amitriptyline and propranolol. In severe cases with vision problems, surgical intervention may be required, including optic nerve decompression or CSF shunting. Empty sella syndrome can be seen in

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The most sensitive and specific test is qualitative β2-transferrin evaluation of the nasal drainage. β2-transferrin is detected in few fluids in the body including CSF, perilymph, and aqueous humor. Only 0.2 mL is needed for an adequate specimen. β2-transferrin has a sensitivity of 97% and specificity of 93%. False positive results can occur with abnormal transferrin metabolism from chronic liver disease, glycogen metabolic disease, and carcinomas; therefore, results should be verified with a negative serum β2-transferrin. β-trace protein is a newer laboratory test with higher sensitivity and specificity which offers faster results than β2-transferrin.

The radiologic evaluation of a CSF leak can be extensive and often begins with a fine cut maxillofacial CT scan to demonstrate bony abnormalities such as defects and fractures. CT is the mainstay for radiologic workup of CSF rhinorrhea with a sensitivity of 92% and a specificity of 92–96%. If the initial imaging does not show an obvious abnormality but suspicion is still high, a CT cisternogram may be useful. This study entails injection of radiopaque material through a lumbar drain into the intrathecal space to help delineate the CSF leak. Presence of contrast within the nasal space or paranasal sinuses indicates a CSF leak. CT cisternography has a sensitivity of 92% with an active leak to 40% with an intermittent leak. MRI cisternography (T2 weighted fast-spin protocol) can be helpful in cases of neoplasm, meningoencephalocele, encephalocele, and in patients with an iodine allergy.
