[Transient trochlear nerve palsy as the presenting neurological sign of panarteritis nodosa]. / Parésie trochléaire transitoire comme signe neurologique inaugural d'une panartérite noueuse.

INTRODUCTION: Panarteritis nodosa (PAN) is a systemic vasculitis affecting small and medium-sized arteries. Neuro-ophthalmological complications of PAN are rare but numerous, and may affect the eye, the visual and the oculomotor pathways. Such complications occur mainly in patients previously diagnosed with PAN. OBSERVATION: A 51-year-old woman presented with an isolated right trochlear (IV) palsy, in the setting of headaches and fluctuating fever of unknown etiology. Erythrocyte sedimentation rate was 13 mm and full blood cell count was normal. Previous chest X-ray and blood studies were negative for an infection or inflammation. Orbital and cerebral CT scan was normal. Spontaneous recovery of diplopia ensued over four days. Two days later, paresthesia and sensory paresis of the dorsal portion of the left foot were present. Lumbar puncture revealed 14 leucocytes (76 percent lymphocytes) with elevated proteins, but blood studies and serologies were negative. A diagnosis of undetermined meningo-myelo-radiculoneuritis was made. Because of a possible tick bite six weeks previously the patient was empirically treated with 2 g intravenous ceftriaxone for 3 weeks. Fever rapidly dropped. Six weeks after the onset of diplopia, acute onset of blindness in her right eye, diffuse arthralgias and fever motivated a new hospitalization. There was a central retinal artery occlusion of the right eye. Blood studies now revealed signs of systemic inflammation (ESR 30 mm, CRP 12 mg/L, ANA 1/80, pANCA 1/40, leucocytosis 12.4 G/L, Hb 111 g/L, Ht 33 percent). Biopsy of the left sural nerve revealed arterial fibrinoid necrosis. A diagnosis of PAN was made. CONCLUSIONS: Transient diplopia can be the heralding symptom of a systemic vasculitis such as PAN, giant cell arteritis and Wegener granulomatosis. In this patient the presence of accompanying systemic symptoms raised a suspicion of systemic inflammation, but the absence of serologic and imaging abnormalities precluded a specific diagnosis initially. A few weeks later, the presence of a second ischemic event (retinal) and positive blood studies led to a further diagnostic procedure. Oculomotor and abducens palsies have rarely been reported in association with PAN. We report the first case of trochlear nerve paresis as the inaugural neurological sign of PAN. This case highlights the importance of considering inflammatory systemic disorders in patients with acute diplopia particularly when they are young, lack vascular risk factors or cause, and complain of associated systemic symptoms.

[Study of panophthalmitis after cataract surgery from 1997 to 1999]. / Etude sur les panophtalmies après chirurgie de la cataracte de 1997 à 1999.

PURPOSE: To define the clinical outcome and microbiological pattern of bacterial endophthalmitis that were referred at the Jules Gonin Eye Hospital from January 1997 to September 1999. METHODS: Patients were recorded in a computerised databank and were managed according to a standard protocol. An anterior chamber tap combined with a vitreous biopsy by the pars plana was performed in all patients. The treatment included an intravitreal injection of 1 mg Vancomycin and 400 micrograms Amikacin diluted in 0.2 ml NaCl 0.9%. Postoperatively hourly therapy Cefazolin 50 mg/ml and Garamycin 9 mg/ml was applied. To determine possible risks factors a standard form was sent to all referring surgeons. The following data were analysed: delay of onset, risk factors, initial and final visual acuity. RESULTS: From January 1997 to September 1999, 31 patients were referred. 18/31 (58%) of the cases were admitted between April and June of each years. The mean age was of 75 +/- 10 years. Initial visual acuity ranged from light perception to 20/40. 17/31 of the patient's cultures were positive. The major pathogen were Staphylococcus epidermidis in 9/31 patients and Staphylococcus aureus in 4/31 patients. No correlation between the endophthalmitis and the surgical technique or perioperative management of the patient, could be determined. Visual outcome was significantly improved in 56.7% of the patients. CONCLUSIONS: The severity of outcome could be correlated to the type of bacteria isolated. The high prevalence of panophthalmitis from March to June suggests that a climatic factors may be involved in its pathogenesis.

[Effect of naftidrofuryl (praxilene) on optic nerve head blood flow in the patient with glaucoma]. / Effet du Naftidrofuryl (Praxilène) sur le flux sanguin de la tête du nerf optique du patient glaucomateux.

PURPOSE: To evaluate the effects of an S2 specific antiserotonine agent (Naftidrofuryl) on the optic nerve head blood flow in glaucomatous patient. PATIENTS AND METHOD: 11 glaucomatous subjects were enrolled in the study. After administration of 200 mg naftidrofuryl twice daily for 7 days: values of optic nerve head blood flow (Fonh), velocity and volume were recorded in the temporal rim and cup of the optic nerve head. Blood flow measurements were performed by laser doppler flow-metry at day 0 and day 7 before and one and two hours after drug administration. RESULTS: Our study showed a significant improvement of perfusion pressure (p = 0.02) at day 7 and an increase of mean ophthalmique artery pressure (p = 0.03). DISCUSSION: Our preliminary results on a small number of patients and a short follow-up indicate that the use of naftidrofuryl may enhance optic nerve head blood flow in glaucomatous patients. Further studies may confirm these results.

Autoregulation of human optic nerve head blood flow in response to acute changes in ocular perfusion pressure.

BACKGROUND: Studies in animals have demonstrated that optic nerve head (ONH) blood flow (F(onh)) is autoregulated, but there is a lack of evidence for such a process in humans. Therefore, we investigated the relationship between F(onh) and mean ocular perfusion pressure (PPm) in normal volunteers when PPm is decreased through elevation of the intraocular pressure (IOP). METHODS: Laser Doppler flowmetry (LDF) was used to measure relative mean velocity (Velohn), volume (Volonh) and F(onh) of blood at sites of the ONH away from visible vessels, while PPm was decreased in two ways: (1) rapidly, by IOP increments of 15 s duration, and (2) slowly, by IOP increments of 2 min duration, both by scleral suction cup in one eye of each of nine subjects. RESULTS: A rapid and large decrease of PPm of more than 100% induced a decrease of more than 80% in F(onh). With the slower decrease in PPm, F(onh) remained constant down to a PPm of approximately 22 mm Hg (IOP = 40 mm Hg) and then decreased, predominantly due to a decrease in Velohn. Immediately after removal of the suction cup, F(onh) increased transiently by 44% above baseline. CONCLUSIONS: This study demonstrates efficient blood flow autoregulation in the OHN, which is probably brought about by an increase in vascular capacitance. The magnitude of the reactive hyperaemia agrees with the compensatory decrease in ONH vascular resistance during IOP elevation. The time scale of the autoregulatory process and the dependence of the hyperaemia upon duration of IOP elevation suggest a metabolic mechanism of autoregulation.

Choroidal blood flow during isometric exercises.

PURPOSE: To investigate the response of choroidal blood flow in the foveal region of the human eye to increases in mean perfusion pressure (PPm = mean ophthalmic artery pressure - intraocular pressure; IOP) induced by isometric exercises. METHODS: Using laser-Doppler flowmetry, changes in velocity (ChBVel), number (ChBVol), and flux (ChBF) of red blood cells in the choroidal vascular system in the foveal region of the fundus were measured in both eyes of 11 normal subjects (ages 18 to 57 years) during isometric exercises. RESULTS: During 90 seconds of squatting, PPm increased by an average of 67%, from 46 to 77 mm Hg. This resulted in a significant increase of 12% in ChBFm (the mean of ChBF during the heart cycle), mainly caused by an increase in ChBVelm. A further increase in PPm to a value approximately 85% above baseline resulted in a 40% increase in ChBFm. A significant negative correlation was found between the changes in ChBVelm and ChBVolm, during squatting. CONCLUSIONS: Previous studies have demonstrated that during isometric exercise, blood pressures in the ophthalmic and brachial arteries rise in parallel. These observations and the current results indicate that an increase in PPm up to 67% induces an increase in choroidal vascular resistance that limits the increase in choroidal blood flow to approximately 12%. This regulatory process fails when PPm is further increased.

Effect of acute decreases of perfusion pressure on choroidal blood flow in humans.

PURPOSE: To investigate the relationship between choroidal blood velocity (ChBVel), blood volume (ChBVol) and blood flow (ChBF) in the foveal region of the human ocular fundus and ocular perfusion pressure and to determine whether the choroidal circulation has some autoregulatory capacity. METHODS: Measurements of ChBVel, ChBVol and ChBF were obtained by laser Doppler flowmetry in healthy subjects (age range, 21 to 57 years) with normal eye examination results. Measurements were performed at normal intraocular pressure (IOP) and during successive step increases in IOP induced by scleral suction. In experiment 1, in six eyes (five subjects), the IOP was increased rapidly, in steps of 50 to 100 mm Hg of suction pressure, which each lasted approximately 10 seconds to a level above diastolic ophthalmic artery blood pressure (IOP = approximately 72 mm Hg). In experiment 2, in 14 eyes (seven subjects), the IOP was increased slowly in four successive steps at 2-minute intervals to a level of approximately 42 mm Hg. We also determined the pulsatility of the flow parameters during the heart cycle, pulsatility = 1 - diast value/syst value. RESULTS: For both rates of suction cup increase, the relationship between ChBFm (mean ChBF over the heart cycle) and mean perfusion pressure was not linear. At high pressure, ChBFm was less affected by decreases in the pressure than expected from a passive vascular system. In some cases, no change in ChBFm was detectable, although significant changes in PChBF occurred. Further decreases in perfusion pressure resulted in a proportional decrease in ChBFm. On release of suction, a significant increase in ChBFm over baseline value was detectable in experiment 1. CONCLUSIONS: The relationship between ChBFm and ocular mean perfusion pressure appears to be bilinear and reveals some autoregulation for moderate step decreases in perfusion pressure. The temporal characteristics of the ChBFm-response suggest a neural or passive hemodynamical process rather than a myogenic or metabolic compensatory mechanism.

[Autoregulation in ischemia of the optic nerve in the human]. / Autoregulation du débit sanguin du nerf optique chez l'homme.

BACKGROUND: Autoregulation is defined as the maintenance of constant blood flow in a vascular system in spite of changes in perfusion pressure (PPm). MATERIALS AND METHODS: PPm was decreased by increasing the intraocular pressure (IOP) with a suction cup and optic nerve blood flow was measured with the laser Doppler flowmetry technique (LDF) in 9 normal volunteers. RESULTS: The blood flow was autoregulated down to a PPm of 13 mm Hg (IOP = 47 mm Hg). CONCLUSIONS: These results confirm previous studies in cats and monkeys. The mechanism of autoregulation is probably a decrease in resistance due to capillary recruitment.

[Effect of changes in ocular perfusion pressure on choroid ischemia in man]. / Effet des changements de la pression de perfusion oculaire sur le débit sanguin choroïdien chez l'homme.

BACKGROUND: The effect of changes in ocular perfusion pressure (PPm) on the choroidal blood flow (ChBF) in man was studied with the laser Doppler flowmetry (LDF) technique. MATERIALS AND METHODS: We changed the PPm by increasing the intraocular pressure (IOP) or by increasing the blood pressure (BP) with isometric exercises. RESULTS: We observed that a) ChBF was not significantly different from baseline up to an IOP of 27 mm Hg and b) ChBF remained constant even if PPm increased by as much as 72%. CONCLUSION: Our results suggest that ChBF is autoregulated in response to an increase in IOP up to about 27 mm Hg. ChBF remains also constant in spite of an increase in systemic BP, probably due to a vasoconstriction induced by increased sympathetic activity.