Hyponatremia is a commonly encountered electrolyte imbalance with varied etiology. Hyponatremia can be broadly classified as hypotonic, isotonic, and hypertonic hyponatremia based on the tonicity of plasma. Hypotonic hypovolemia is further classified as hypovolemic, euvolemic, and hypervolemic hyponatremia based on the volume status. Gastrointestinal fluid and electrolyte losses, secondary to vomiting and diarrhea, is an important predisposition to hypotonic hypovolemic hyponatremia. The renin-angiotensin-aldosterone system (RAAS) and antidiuretic hormone (ADH) play a pivotal role in maintaining intravascular volume and serum sodium concentration. Dexamethasone is a potent glucocorticoid with minimal mineralocorticoid activity. It negatively affects the hypothalamic-pituitary-adrenal axis and the renin-angiotensin-aldosterone system, particularly with prolonged administration. In the index case, acute severe hypovolemic hyponatremia ensued on the third post-procedure (endovascular embolization of traumatic carotico-cavernous fistula (CCF)) day while the patient was on intravenous dexamethasone. This case underscores that even small fluid and electrolyte imbalance in the setting of dexamethasone therapy may lead to severe hypovolemic hyponatremia, which requires specific therapy.

Fungal infections of the orbit are infrequent. They typically affect immunocompromised individuals but, in some instances, can also affect an immunocompetent person. They mimic much orbital pathology clinically. Ours is a series of three patients eventually diagnosed with orbital aspergillosis but who, initially, were thought to have some other pathology.

BACKGROUND: Injuries to the internal carotid artery close to the cavernous sinus may result in a fistulous connection between the artery and the venous sinus. Symptoms include pulsatile tinnitus, intracranial bruit, ophthalmological symptoms, and risk of intracerebral hematoma in cases of cortical venous reflux. Previous treatment strategies have included detachable latex balloons, coils, covered stents, or combinations thereof. Today, detachable latex balloons are phased out or withdrawn from several markets. Acrylic glue is a proven stable material used for embolization of arteriovenous shunts. It is a precise, fast, and cost-effective method of endovascular embolization, and it does not cause artifacts on MRI or MRA.
METHODS: We treated nine patients suffering from direct fistulas with acrylic glue without any permanent neurological adverse events.
RESULTS: Four patients were treated with glue embolization of the fistula without occlusion of the parent artery. Five patients with long-lasting symptomatology, large tears in the ICA, and with full collateral cerebral circulation were treated with glue embolization of the fistula and sacrifice of the ICA antero- and retrograde via the ICA and the posterior communicating artery.
CONCLUSIONS: We suggest acrylic glue to be added to the panel of embolic materials used to treat CCFs.

This study determined the utility and accuracy of susceptibility-weighted MRI (SWI) for the detection of carotid cavernous fistulas. We retrospectively compared SWI images in nine patients (Group 1, case group) of DSA-proved carotid cavernous fistula (CCF) and 19 DSA negative cases for CCF as a control group (Group 2). Group 1 was again sub-grouped into direct and indirect types. Using uniform region-of-interest measurements, signal intensity within the superior ophthalmic vein (SOV) and the superior sagittal sinus (SSS) were measured on magnitude images of SWI. The SOV/SSS signal intensity ratio was calculated in each case and the mean values of the two groups were compared. Eleven SOV/SSS signal intensity ratios in Group 1 (7 unilateral and two bilateral CCF), 38 in Group 2 (both sides in 19 control subjects) were included. Median ± interquartile range of SOV/SSS ratios for Group 1, Group 2, indirect and direct type CCFs were 1.07 ± 0.43, 0.39 ± 0.23, 0.83 ±0.29, 1.4 ±0.38 respectively. Mann-Whitney test between Groups 1 and 2 was statistically significant with P<0.0001. All cases and controls were reliably distinguished with SOV/SSS signal intensity ratio of 0.64 as cut-off. Direct CCF cases had consistently higher ratios than indirect CCF. SWI was highly sensitive for detection and differentiation of both direct and indirect CCF. Only one case of corticovenous reflux was missed by SWI. SWI is useful for detection of CCF and to differentiate between direct and indirect CCF.

BACKGROUND: We present a case of direct carotico-cavernous fistula (CCF) and its successful treatment.
METHODS: A 55-year-old male presented with left eye discomfort, diplopia and pulsatile tinnitus. He had a recent history of head injury. Examination showed proptosis, chemosis, orbital bruit, and abducens nerve palsy. Digital subtraction angiography confirmed CCF, which was managed endovascularly. The patient recovered fully after treatment.
CONCLUSIONS: CCF has a variety of presenting clinical signs, imaging manifestations, and treatment options available.
CONCLUSIONS: CCF is a rare and dangerous neurological disorder that should be promptly diagnosed and treated.