The only effective therapy in the fulminant variety, associated with thrombosis of the anterior portion of the sinus, is the administration of high doses of antibiotics aimed at coagulase-positive staphylococci, and probably gram-negative pathogens and at anaerobes if there has been sinusitis. As with septic lateral sinus phlebitis, anticoagulants have been used, but their value has not been proved. In cases under our observation, the cranial-nerve palsies have resolved to a large extent, but visual loss, if it occurs, has tended to remain, with findings suggestive of infarction of the retroorbital part of the optic nerve. Cavernous sinus thrombosis must be differentiated from mucormycosis infection of the sinuses and from orbital cellulitis, which usually occur in patients with uncontrolled diabetes, and from other fungus infections (notably Aspergillus), Tolosa-Hunt syndrome (see Chap. 44), cavernous-carotid fistula, Wegener granulomatosis, and sphenoid wing meningioma.
Septic Thrombosis of the Superior Sagittal Sinus
This entity is now less common than at a time when septic transverse sinus thrombosis from uncontrolled ear and sinus infections were frequent. The disorder manifests as fever, headache, unilateral convulsions (most frequent or prominent in the leg), and weakness, first on one side of the body, then on the other, as a result of extension of the thrombophlebitis into the cortical veins that drain into the sinus. Papilledema and increased intracranial pressure often accompany these signs. Severe generalized and vertex headache is a typical but not invariable complaint. Because of the localization of function in the cortex that is drained by the sinus, the weakness may take the form of a crural (lower limb) monoplegia or, less often, of paraplegia. Sensory loss may occur in the same distribution. Homonymous hemianopia or quadrantanopia, aphasia, paralysis of conjugate gaze, and urinary incontinence (in bilateral cases) have also been observed.
As in the case of aseptic thrombosis, loss of the flow void in the superior sagittal sinus in the MRI demonstrates the clot. A similar change can be seen on axial images of the contrast-enhanced CT scan by altering the viewing windows so as to show the clot within the posterior portion of the sagittal sinus. The CT scan performed early in the illness without contrast infusion usually shows the high-density clot within cortical veins as well, but only if carefully studied by altering the viewing window.
Treatment consists of high doses of antibiotics and temporization until the thrombus recanalizes. Although not of proven benefit (as it is in bland cerebral vein thrombosis), we have used heparin in these circumstances unless there are very large biparietal hemorrhagic infarctions. Because of the highly epileptogenic nature of the attendant venous infarction, we have also administered antiepileptic drugs prophylactically, but there is no clinical study to guide the clinician in this regard. Recovery from paralysis may be complete, or the patient may be left with seizures and varying degrees of spasticity in the lower limbs.
All types of thrombophlebitis, especially those related to infections of the ear and paranasal sinuses, may be simultaneously associated with other forms of intracranial purulent infection, namely bacterial meningitis, subdural empyema, or brain abscess. Therapy in these complicated forms of infection must be individualized. As a rule, the best plan is to institute antibiotic treatment of the intracranial disease and to decide, after it has been brought under control, whether surgery on the offending ear or sinus is necessary. To operate on the primary focus before medical treatment has been discouraged. In cases complicated by bacterial meningitis, treatment of the latter usually takes precedence over the surgical treatment of complications, such as brain abscess and subdural empyema.