Martin, Pierre-Yves

Pennisi, Pietra

Rizzoli, René

Robert, John

Stoermann, Catherine

Trombetti, Andrea

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Nephrol Dial Transplant (2005) 20: 217–219doi:10.1093/ndt/gfh567Case ReportTransient diplopia after parathyroidectomy for hyperparathyroidismin chronic haemodialysed patientsAndrea Trombetti1, Catherine Stoermann2, Pierre-Yves Martin2, Pietra Pennisi1, John Robert3and Rene´ Rizzoli11Service of Bone Diseases (WHO Collaborating Center for Osteoporosis Prevention),Department of Rehabilitation and Geriatrics, 2Service of Nephrology, Department of Internal Medicine and3Thoracic Surgery Unit, Department of Surgery, University Hospital of Geneva, SwitzerlandKeywords: chronic renal failure; extraocular muscles;parathyroid surgery; tetanyIntroductionAn increase in serum levels of the parathyroid hor-mone (PTH) and hyperplasia of the parathyroid glandshave been observed to occur in the early stages ofchronic kidney disease with decreased renal function,in an attempt to maintain serum calcium within thenormal range [1]. However, this secondary hyperpara-thyroidism becomes maladaptive when chronic renalfailure progresses to end-stage renal failure, leadingto severe hyperparathyroidism, which is refractory tomedical therapy. When severe hyperparathyroidismis associated with hypercalcaemia and/or hyperphos-phataemia, parathyroidectomy (PTX) should be con-sidered. However, PTX in such cases can often resultin an acute decrease of serum calcium and is one ofthe leading causes of acute hypocalcaemia. Hypocal-caemia is associated with a wide spectrum of symp-toms and signs, mostly related to acute changes inserum calcium, rather than constantly low levels [2].Among them, neuromuscular dysfunction, includingtetany and seizure, is the hallmark of the clinicalmanifestations of acute hypocalcaemia. On the otherhand, transient diplopia has been reported only rarely.To illustrate this association, we report on threepatients who, following PTX for severe hyperparathy-roidism, experienced acute hypocalcaemia and there-after transient diplopia, a rare complication ofhypocalcaemia.CasesCase 1The ﬁrst patient was a 39-year-old man on maintenancehaemodialysis (HD) since November 1990, with end-stage renal failure secondary to chronic glomerulone-phritis. In 1992 and 1996, he underwent cadaverickidney transplantation with an unsuccessful outcome.Due to severe hyperparathyroidism, a total PTX withautotransplant of parathyroid tissue in the right armwas performed in August 1993. From 1999 onwards,secondary hyperparathyroidism progressively recurred,with a serum PTH level of 173 pmol/l (normal range:1.1–6.9 pmol/l). Serum calcium was normal at2.39mmol/l (normal range: 2.2–2.6mmol/l). Thepre-operative serum alkaline phosphatase level wasalso normal at 82U/l (normal range: 30–125U/l).Recurrence was attributed to hyperplasia of the rightarm’s parathyroid tissue. The patient was receiving1600mg elemental calcium a day, but no vitamin Dderivatives. Excision of the remaining parathyroidtissue of the patient’s right arm was carried out inFebruary 2003. Three days after surgery, he experi-enced general numbness due to severe hypocal-caemia. Since his albumin-adjusted calcium was only1.5mmol/l, he was prescribed a calcium supplement(1000mg daily), calcitriol and the dose of active vitaminD was progressively increased. The dialysate calciumlevel was also increased from 1.5 to 1.75mmol/l. Theserum calcium level (and associated symptoms) thenbegan to ﬂuctuate, being normal immediately after hisdialysis session and low in-between. One week later, hecomplained of transient diplopia along with generalizeddysesthesia (pins and needles) associated with musclecramps. Horizontal binocular diplopia was noticedwhile looking on the right side, with weakness of the leftmedial rectus. No other speciﬁc neurological abnorm-alities were detected. Chvostek’s and Trousseau’ssigns were absent. Laboratory investigations revealedCorrespondence and offprint requests to: Rene´ Rizzoli, MD, Serviceof Bone Diseases, Department of Rehabilitation and Geriatrics,University Hospital of Geneva, CH-1211 Geneva 14, Switzerland.Email: Rene.Rizzoli@medecine.unige.chNephrol Dial Transplant Vol. 20 No. 1  ERA–EDTA 2005; all rights reservedhypocalcaemia (1.79mmol/l) and hyperphosphataemia(1.92mmol/l; normal range: 0.80–1.40mmol/l). Serumpotassium and magnesium were within the normalrange. The intact PTH level (12.4 pmol/l) had decreasedmarkedly as compared with its pre-operative leveland the acid–base balance was unremarkable. Within24 h of transient normalization of the serum calciumwith a dialysis session, diplopia did not recur.Case 2This patient was a 26-year-old woman with end-stagerenal failure secondary to reﬂux nephropathy, on main-tenance HD since 1995. A subtotal PTX was performedin June 2003 for secondary hyperparathyroidism witha very high serum PTH (453 pmol/l) and serum alkalinephosphatase levels (632U/l; normal range: 32–104U/l),although the protein-corrected serum calcium levelwas normal (2.28mmol/l). At the time of surgery, shewas receiving 1200mg elemental calcium and 0.25 mgcalcitriol a day. The day after surgery, she experiencedvery transient diplopia with dysesthesia and musclecramps. At that time, ophthalmological and neuro-logical evaluations were normal, but Chvostek’s andTrousseau’s signs were present. A marked decrease inserum calcium to 1.74mmol/l, with a possible hungrybone syndrome (the intact PTH level was 32 pmol/l),developed the day after surgery. Laboratory investiga-tion also revealed hyperphosphataemia (2.02mmol/l)and hyperkalaemia (7.2mmol/l; normal range: 3.6–4.6mmol/l), although magnesium concentration wasnormal (0.79mmol/l; normal range: 0.65–1.05mmol/l),as was the bicarbonate level. After intravenousadministration of large amounts of calcium gluconate(10%) and oral calcium over the next 24 h, the levelof serum calcium became normal and the symptomsdisappeared.Case 3The third patient was a 42-year-old man with pre-dialysis renal failure secondary to obstructive nephro-pathy. In January 2000, he underwent a total PTXwith autotransplantation for severe hyperparathyroid-ism [intact PTH: 132 pmol/l; protein-corrected serumcalcium: 2.20mmol/l; high levels of alkaline phos-phatase: 403U/l (normal range: 98–279U/l)]. At thattime, he was receiving 1.5 mg calcitriol once a day.Hypocalcaemia developed 24 h after surgery. Despitethe introduction of a large dose of calcium (12 g perday) and increasing the dose of calcitriol to 2 mg perday, 10 days after surgery he complained of paresthe-siae of the distal extremities and circum-oral area,Chvostek’s and Trousseau’s signs and muscle cramps.He also complained of transient diplopia, but clinicalexamination revealed no abnormalities. Laboratoryinvestigations on readmission after surgery showedmarked hypocalcaemia (1.32mmol/l), hyperphos-phataemia (2.17mmol/l) and hypomagnesaemia(0.57mmol/l). Hypoparathyroidism was diagnosed onthe basis of low levels of PTH in the serum (1.1 pmol/l).With calcium supplements and active vitamin D deriva-tives, the serum calcium increased slowly and becamenormal within 1 week.DiscussionWe have described three patients with ESRD whopresented with transient diplopia, in the absence ofother causes of neurological disorder, and acute hypo-calcaemia following a PTX for renal hyperparathy-roidism. The common characteristic of these patientswas rapidly developing hypocalcaemia as well asmanifestations of neuromuscular irritability. In allthree cases, the duration of double vision was briefand binocular and on clinical examination no speciﬁcophthalmological or neurological abnormalities weredetected.Diplopia in these cases was most probably a mani-festation of tetany of the extraocular muscles inducedby hypocalcaemia. Acute hypocalcaemia directlyincreases peripheral neuromuscular irritability [3]. Theprimary determinants of symptoms and signs inpatients with hypocalcaemia are related to the kineticsand relative change of serum calcium. PTX performedon these patients led to a marked decrease in serumcalcium within a few days of the operation.Other factors could contribute to this clinicalpresentation, including the acid–base status (althoughno such modiﬁcations were observed), magnesiumdepletion, a potassium imbalance and emotionalstress after surgery, all of which could affect epinephr-ine concentrations and elicit tetany in patients withhypocalcaemia [4].Classically, tetany can affect all muscles exceptthe extraocular ones [5]. Nevertheless, diplopia hasbeen observed in patients with hypocalcaemia. Forexample, a report described a 15-year-old boy com-plaining of attacks of a thick tongue, double visionand heart failure. He was diagnosed as havingidiopathic hypoparathyroidism with marked hypo-calcaemia (1.09mmol/l) [6]. Another report describeda 74-year-old male with idiopathic hypoparathy-roidism revealed by a non-insulin-dependent dia-betes mellitus and severe hypocalcaemia (1.6mmol/l)[7]. However, to our knowledge, diplopia was notobserved after PTX. An article published in 1960stated that patients with severe hypocalcaemia aftera subtotal PTX for renal hyperparathyroidism couldexperience blurring of vision and difﬁculty in accom-modation [8].These case reports raise the question of preventionof post-PTX hypocalcaemia. Given the frequency ofthis complication, a daily follow-up of serum calciumis mandatory. Pre-operative administration of calcitriolto all such patients if they are not already being treatedwith a vitamin D metabolite should be recommendedas well as early administration of high doses of oralcalcium. Accordingly, a clinical algorithm has beenproposed recently [9].218 A. Trombetti et al.In conclusion, diplopia is a rare manifestation ofacute hypocalcaemia and should be noted as a potentialcomplication of PTX in dialysis patients. Althoughrare, if this complication were made known tonephrologists it could avoid unnecessary neurologicalinvestigations.Acknowledgements. We acknowledge the editorial assistance ofDr Anne Appleton, Me´decin-Chef, Unite´ de Se´nologie (BreastUnit), Clinique de Genolier, CH-1272 Switzerland, Mrs MariannePerez and Mrs Bhalla Praveen.Conﬂict of interest statement. None declared.References1. Slatopolsky E, Gonzalez E, Martin K. Pathogenesis and treat-ment of renal osteodystrophy. Blood Purif 2003; 21: 318–3262. Fonseca VA, Bloom RD, Dick R, Dandona P. Tetany despitenormocalcemia and normomagnesemia following parathyroi-dectomy. Postgrad Med J 1987; 63: 885–8863. Maceﬁeld G, Burke D. Parasthesiae and tetany induced byvoluntary hyperventilation: increased excitability of humancutaneous and motor axons. Brain 1991; 114: 5274. Harvey AM, Lilenthal JL, Jr. Observations of the nature of tetany.The effect of adrenaline. Johns Hopkins Med J 1942; 71: 1635. AdamsRD.Principles of Neurology. McGrawhill, NewYork, 19936. Karsten J, Szijjarto L, Lebbink J. A boy with heart failure,a thick tongue, and double vision. Lancet 1997; 349: 15167. Itoh H, Matsuda Y, Nishiyama M et al. Non-insulin-dependentdiabetes mellitus complicated with idiopathic hypoparathyroid-ism. Intern Med 1995; 34: 904–9078. Stanbury SW, Lumb GA, Nicholson WF. Elective subtotalparathyroidectomy for renal hyperparathyroidism. Lancet 1960;1: 793–7999. Cozzolino M, Gallieni M, Corsi C, Bastagli A, Brancaccio D.Management of calcium reﬁlling post-parathyroidectomy in end-stage renal disease. J Nephrol 2004; 17: 3–8Received for publication: 8.7.04Accepted in revised form: 5.10.04Diplopia and hypocalcaemia 219

Transient diplopia after parathyroidectomy for hyperparathyroidism in chronic haemodialysed patients

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