All of the following are true about cavernous sinus thrombosis except?
Ans. c. Loss of jaw jerk (Ref: Gray's anatomy 40/e p430; BDC 6/e Volume III/e p193, 194; Snells 9/e p544)'Any spreading infection involving the upper nasal cavities, paranasal sinuses, cheek (especially near the medial canthus), upper lip, anterior nares or even an upper incisor or canine tooth, may very rarely lead to septic thrombosis of the cavernous sinuses; infected thrombi pass from the facial vein or pterygoid venous complex into the sinus via either ophthalmic veins or emissary veins that enter the cranial cavity through the foramen ovale. This is a critical medical emergency with a high risk of disseminated cerebritis and cerebral venous thrombosis.Gray's anatomy 40/e p430Cavernous Sinus ThrombosisUsually results from infection of ethmoid and sphenoid sinusesQRoute of Spread* Ethmoid sinus (MC) via ophthalmic veinsQ* Sphenoid sinus by direct spreadQ* Frontal sinus via supraorbital and ophthalmic veinsQ* Orbit by ophthalmic veinsQ* Upper lid via angular vein and ophthalmic veinsQ* Ear by petrosal venous sinusesClinical Features:Onset is abrupt with fever, chills and rigorInvolvement of 3rd, 4th, 5th and 6th cranial nerveQChemosis of conjunctivaQProptosis of eye with limited movementsQPupils are dilated and fixedQ (due to involvement of sympathetic plexus around carotid artery )Decreased visionQ (due to optic nerve damage)Decreased sensation in distribution of 5th nerve (ophthalmic division) and engorgement of retinal vesselsQTreatment:Antibiotics in high doses for 4-6 weeks and drainage of involved sinusesQStructures Marked in the DiagramA* Oculomotor nerveB* Abducens nerveC* Ophthalmic nerveD* Maxillary nerve"The abducens nerve is the sixth cranial nerve and innervates lateral rectus exclusively. It emerges from the brain stem between the pons and the medulla oblongata and usually runs through the inferior venous compartment of the petroclival venous confluence in a bow-shaped canal, Dorello's canal. It then bends sharply across the upper border of the petrous part of the temporal bone to enter the cavernous sinus, where it lies lateral to the internal carotid artery (unlike the oculomotor, trochlear, ophthalmic and maxillary nerves, which merely in vaginale the lateral dural wall of the sinus). The abducens nerve enters the orbit through the superior orbital fissure, within the common tendinous ring, at first below, and then between, the two divisions of the oculomotor nerve and lateral to the nasociliary nerve. It passes forwards to enter the medial (ocular) surface of lateral rectus. "-- Gray's Anatomy 40/e p430 Cavernous Sinus* It is a large venous space situated In middle cranial fossa on either side of body of the sphenoid.Structures in the lateral wall of sinus from above downwardsStructures passing through centre of the sinus (content)* Oculomotor (lllrd) nerve* Trochlear nerve (IVth)* Ophthalmic (V1) nerve* Maxillary (V2) nerve* Trigeminal ganglion* Abducent (VIth) nerve Q* Internal carotid artery QContents of the Cavernous SinusTributaries of cavernous sinusFrom the orbitFrom the brainFrom the meninges* Superior Ophthalmic vein* A Branch of the inferior Ophthalmic vein* Central vein of retina* Superficial middle cerebral vein* Inferior cerebral vein* Sphenoparietal sinus* Frontal trunkof the middle meningeal vein Draining channels of cavernous sinus* Into the transverse sinus through superior petrosal sinus* Into the internal jugular vein through inferior petrosal sinus* Into the pterygoid plexus of veins through emissary veinsQ* Into the facial vein through superior ophthalmic veinQ Cranial NerveCharacteristic FeatursOlfactory (I) Nerve* Only Cranial nerve to enter cerebrum directlyQ* Only Sensory afferent pathway that reaches cerebral cortex with out synapsing in one of the thalamic nucleiQTrochlear (IV) Nerve* Smallest Cranial nerveQ* Most slender cranial nerveQ* Only nerve to emerge from dorsal (posterior) surface of brain stemQ (mid brain)* Passes anteriorly around the brain stem, running the longest intracranial (subarachnoid) courseQ* Nerve crosses the midline within the midbrain, emerges from its dorsal aspect and immediately decussates with the nerve of opposite sideQ* Sole supply is superior oblique the only extra ocular muscle that uses pulley/ trochlea to redirect its line of action Trigeminal (V) Nerve* Largest cranial nerveQ (if atypical optic nerve is excluded)* Large sensory root is composed of central processes of pseudounipolar neuronsQ, whose cell bodies make up the crescent shaped trigeminal / semilunar ganglion, which is housed with in a dural recess the trigeminal or Meckel's cave lateral to the cavernous. Abducent (VI) Nerve* Longest intradural courseQ with in the cranial cavity (from clivus to superior orbital fissure)* Involved most commonly in raised intracranial tensionQ (due to long course of the sharp bend it makes over the petrous temporal bone)* Only the cranial nerve passing through cavernous sinusQ Facial (VII) Nerve* Longest intraosseous courseQ* Most commonly paralyzed of all cranial nerves
Most commonly spreads through ethmoid sinus
Loss of sensation around orbit
Loss of jaw jerk
Infection can spread to cavernous sinus from danger area of face via inferior ophthalmic vein
Cranial Cavity