Hypotony

Anterior uveitis and neutropenia are fairly common side effects of cidofovir therapy. Ocular hypotony and metabolic acidosis are rare. Exposure to therapeutic levels of cidofovir causes cancer in rats therefore, this drug should be considered a potential human carcinogen. Animal studies have also shown cidofovir to produce embryotoxic and teratogenic effects and to impair fertility. 

Serious adverse reactions may include proteinuria (80%), nephrotoxicity (53%), neutropenia (31%), elevated serum creatinine levels (29%), infection (24%), anemia (20%), ocular hypotony (a decrease in intraocular pressure 12%), and pneumonia... 

The measurement of intraocular pressure (lOP) is essential in the initial assessment and ongoing management of uveitis. In the early stages of uveitis the lOP is typically low, due to secretory hypotony within the ciliary body. Over time, however, the lOP may normalize or rise to abnormal levels due to numerous mechanisms, including trabecular blockage by inflammatory debris and synechia formation. Elevated lOP usually indicates a more chronic condition. 

In the case of ocular hypotony and a positive Seidel s sign with a formed anterior chamber in the early postoperative period, the treatment of choice is to discontinue the steroid to encourage wound closure and avoid secondary infection. The patient should be placed on a third- or fourth-generation topical fluoroquinolone. A topical aqueous suppressant may also be used to ensure secure wound closure.The patient is asked to limit activities and is given an eye shield to wear at night. An alternative treatment may include the use of a topical antibiotic and a 24-hour pressure patch with an eye shield while sleeping. If the wound feils to seal after several days to 1 to 2 weeks, surgical repair should be considered. 

Serious Side Effects. Corneal decompensation in patients with preexisting endothelial compromise (e.g., Fuchs endothelial dystrophy) and hypotony have been reported with topical CAIs. Common adverse reactions to oral CAIs are summarized in Box 34-6. 

Highly probable uveitis (related to immune-recovery uveitis, or IRU), hypotony, macular edema, preretinal macular gliosis. Uveitis seen especially if i.v. cidofovir has been administered previously. Recurrences are common and VL is more significant than that due to CMV retinitis alone. 

During long-term follow-up of patients with AIDS treated with parenteral cidofovir for CMV retinitis, the median time to discontinuation for intolerance was 6.6 months (11). Cidofovir-associated uveitis occurred in 10 of 58 patients and ocular hypotony (a 50% fall in intraocular pressure from baseline to below 5 mmHg) occurred at a rate of 0.16 per person-year. There were 51 episodes of proteinuria in 30 of the 58 patients and 82% of these episodes resolved on withdrawal (median time to resolution 20 days). No nephrotoxic events required dialysis. 

Akler ME, Johnson DW, Burman WJ, Johnson SC. Anterior uveitis and hypotony after intravenous cidofovir for the treatment of cytomegalovirus retinitis. Ophthalmology 1998 105(4) 651-7. 

A heavier-than-water fluorinated silicone oil was used in the treatment of 30 selected cases of complicated retinal detachment due to proliferative vitreoretinopathy (n = 19), proliferative diabetic retinopathy with traction detachment (n = 2), giant retinal tears (n = 5), ruptured globe with retinal detachment (n = 2), massive choroidal effusion with retinal detachment (n = 1), and acute retinal necrosis with retinal detachment (n = 1) (13). Initial retinal reattachment was achieved in all cases. Complications included redetachment (n = l), cataract (n = 6), raised intraocular pressure (n = 4), hypotony (n = 4), keratopathy (n = 3), uveitis sjme-chia formation (n = 3), phthisis (n = 2), choroidal hemorrhage (n — 1), and vitreous hemorrhage n = 1). 

NepAirotaciotx. teratogeTnC, CMd rogerrlr With intraocular admmi tation hypotony, kitisr utritis. 

Antigen-rechallenged eyes treated with sustained-release dexamethasone also had less inflammation than control eyes and late complications including corneal neovascularization, cataract, and hypotony were less prevalent in treated eyes. A separate toxicity study also demonstrated that sustained-release dexamethasone was safe using clinical, electrophysiological, and histological parameters (12). 

Some other uncommon complications include macular edema, vitreous hemorrhage, hypotony, cataract (Fig. 6), temporary reduced vision secondary to astigmatism, implant malposition, and retinal detachment, which is more likely if the CMV infection involves over 25% of the retina (100). Lim and colleagues evaluated a series of 110 ganciclovir implant procedures and noted posterior segment complications in 12% (111). Some of these eyes had undergone multiple prior implant procedures and... 

Davis JL, Taskintuna I, Freeman WR, et al. Iritis and hypotony after treatment with intravenous cidofovir for cytomegalovirus retinitis. Arch Ophthalmol 1997 115 733-740. 

GABA a receptor agonists dizziness sleepiness ataxia, tremor, coma, psychomotonc excitation hypotony depressed respiration head ache gastrointestinal disorder nausea, nystagmus... 

Nephrotoxicity is the principal dose-limiting side effect of intravenous cidofovir. Proximal tubular dysfunction includes proteinuria, azotemia, glycosuria, and metabolic acidosis. Concomitant oral probenecid and saline prehydration reduce the risk of renal toxicity. On maintenance doses of 5 mg/kg every 2 weeks, up to 5Wo of patients develop proteinuria, 10-15% show an elevated serum creatinine, and 15-20% develop neutropenia. Anterior uveitis that is responsive to topical glucocorticoids and cycloplegia occur commonly and ocular hypotony occurs infrequently with intravenous cidofovir. Administration with food and pretreatment with antiemetics, antihistamines, and/or acetaminophen may improve tolerance. 

Patients experience less discomfort associated with ocular hypotony and the collapse of the anterior chamber together with quickly improved vision. 

Sodium hyaluronate is applied in the treatment of postoperative ocular hypo-tony in glaucoma surgery. Ocular hypotony caused by overfiltration (Fig. 104) is not only relevant in the development of visual acuity (Schwenn et al., 1996) but also subject to numerous complications. Sodium hyaluronate is particularly well suited for treatment of shallowed anterior chambers (Fig. 105) with threatening lentocorneal contact. 

Yet the authors feel the use of high viscous cohesive viscoelastics to be appropriate in inhibiting the threat of corneal injury. Prevention of hypotony and recognition of potential causes (e.g., outward fistula-formation) are of superior significance. 

Cadera W, Harding PW, Gonder JR, Hooper PL. Management of severe hypotony with intravitreal injection of Healon. Can J Ophthalmol 1993 28 236-237 Cairns JE. Trabeculectomy. Am J Ophthalmol 1968 66 673-679... 

Fisher YL, Turtz AI, Gold M. Use of sodium hyaluronate in reformation and reconstruction of the persistent flat anterior chamber in the presence of severe hypotony. Ophthalmic Surg 1982 13 819-821... 

Doherty MD, Wride NK, Birch MK, Figueiredo FC. Choroidal detachment in association with topical dorzolamide is hypotony always the cause Clin Experiment Ophthalmol 2009 37(7) 750-2. 

Fineman MS, Katz LJ, Wilson RP. Topical dorzolamide-induced hypotony and ciliochoroidal detachment in patients with previous filtration surgery. Arch Ophthalmol 1996 114(8) 1031. 

X-ray examination of the gastrointestinal tract shows distention of the small bowel similar to that found in celiac disease. Segmental puddling of the small intestine and hypotony of the colon were described (Friedman et al. 1960). A marked exaggeration of the mucosal folds may exist in the upper jejunum (Mier et al. 1960). 

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