Idiopathic sclerochoroidal calcifications: Case report, metabolic causes and differential diagnosis

Calcificações esclerocoroidais idiopáticas: relato de caso, causas metabólicas e diagnóstico diferencial

Abstract

Sclerochoroidal calcifications (SC) are a rare and benign ocular condition characterized by yellow-white irregular subretinal lesions usually found in the supero-temporal arcade of the midperipheral fundus in middle-aged elderly men. We present a clinical case of a 79- year-old patient who during a fundus examination presented raised whitish nodules in the supero-temporal arcade in the right eye. After performing optical coherence tomography, ultrasound, ocular computed tomography and laboratory analysis, she was diagnosed with idiopathic sclerochoroidal calcifications The pathogenesis of sclerochoroidal calcifications remains unclear but systemic conditions should be discarded. It is important to distinguish sclerochoroidal calcifications from other conditions such as tumors.

Keywords:
Calcinosis/diagnosis; Choroid diseases/diagnosis; Scleral diseases/diagnosis; Idiopathic sclerochoroidal calcifications; Diagnosis, differential; Metabolic diseases

Resumo

Calcificações esclerocoroidais (SC) são uma condição ocular rara e benigna caracterizada por lesões sub-retinianas irregulares amarelo-brancas, geralmente encontradas na arcada superotemporal do fundo médio-periférico em homens idosos de meia-idade. Apresentamos um caso clínico de uma paciente de 79 anos que durante exame de fundo apresentou nódulos esbranquiçados elevados na arcada superotemporal do olho direito. Após realizar tomografia de coerência óptica, ultra-sonografia, tomografia computadorizada ocular e análise laboratorial, ela foi diagnosticada com calcificações esclerocoroidais idiopáticas

A patogênese das calcificações esclerocoroidais permanece incerta, mas as condições sistêmicas devem ser descartadas. É importante distinguir calcificações esclerocoroidais de outras condições, como tumores.

Descritores:
Calcinose/iagnóstico; Doenças da coróide/diagnóstico; Doenças da esclera/diagnóstico; Diagnóstico diferencial; Calcificações esclerocoroidais idiopáticas; Doenças metabólicas

Introduction

Idiopathic sclerochoroidal calcifications (SC) are commonly found in white men between 50 and 80 years of age. Described as yellowish-white plaques located in the supero-temporal arcade in the mid-peripheral retina, under retinal layers, in both eyes. Approximately 40 to 80% of cases are bilateral and asymmetric. ⁽¹⁾ with an average of two locations per eye. ⁽²⁾ They are usually a casual finding; visual disorders have rarely been described although they may be associated with choroidal neovascular membranes and neurosensory detachments. ⁽³⁾

Autofluorescence and the appearance of the lesion with ultrasound and tomography are useful for its diagnosis. ⁽⁴⁾ These plaques may simulate tumors ^(1,2) and can lead to misdiagnosis especially with choroidal osteomas. ⁽⁴⁾ Metastases, amelanotic melanomas, nevus, idiopathic choroiditis or intraocular lymphomas^(1,5) should be excluded.

This process can be associated with systemic metabolic disorders in relation to abnormal calcium-phosphorus metabolism or renal tubular syndromes with hypokalemic metabolic alkalosis. ⁽⁶⁾ It is a diagnosis of exclusion, it is important to study these electrolyte disorders. ^(1,7)

Clinical case

A 79-year-old woman who reported myodesopsias in both eyes (OU) for 1 month. Corrected visual acuity was 20/25 in BE. Biomicroscopy was normal and intraocular pressure was 18mmHg in OU. Fundoscopic examination revealed raised whitish nodules measuring 7 mm in height and 2.5 mm in width in the upper temporal arcade in the right eye. (Figure 1)

Figure 1
Retinography showing raised whitish nodules in the upper temporal arcade of the right eye

Ultrasound calcifications were found in the left eye, these were not visible in ophthalmoscopy. (Figure 2) Ultrasound B-mode examination showed an hyper-echogenic plaque at the level of the sclera and choroid with posterior acoustic shadow with a peak of high reflectivity at the site of the lesion followed by posterior low amplitude peaks (wide angle kappa) in the A- mode.

Figure 2
Ultrasound: posterior calcifications in the left eye

Visual fields were normal (Full Field 81, Humphrey), orbital tomography revealed nonspecific calcifications in the posterolateral wall of OU. (Figure 3) Angiography showed relative hypofluorescence in the arterial phase and hyperfluorescence in the venous phase that intensified in later phases (Figure 4). With indocyanine green angiography hypofluorescence was observed in vascular filling phases with posterior hyperfluorescence (Figure 5). No evidence of choroidal neovascularization was detected.

Figure 3
Orbital tomography with nonspecific calcifications in the posterolateral wall of both eyes

Figure 4
Angiography with hyperfluorescence of the lesion in the venous phase

Figure 5
Indocyanine green angiography with late hyperfluorescence of the sclerochoroidal calcification

The patient has personal history of hiatal hernia and renal cysts, long-term hypertension treated with metoprolol and lovastatin for hypertriglyceridemia. We performed haematological and hormonal studies where the first determination of PTH was 87.36 pg / ml (normal limits between), with total calcium of 9.9 mg / l (corrected with albumin of 9.6 mg / ml). dl*). Vitamin D levels of 16.41 ng /ml (lower cut-off point of 20 ng / ml) were observed. After administration of active metabolites of vitamin D PTH levels normalized.

Discussion

Sclerochoroidal calcifications have been described in the literature as a rare process found in old patients. They have been misdiagnosed and treated as tumors in the past,⁽⁴⁾ in fact the finding of idiopathic calcification was initially attributed in the literature to choroidal osteomas in older patients but were later recognized to be slcerochoroidal calcifications in 1991. ⁽⁵⁾ The ophthalmoscopic characteristics of these lesions vary from choroidal osteomas, although its colour is similar, osteomas usually affects young patients, is unifocal, large and usually locates juxtapapilar or in the papillomacular region. ⁽⁵⁾

Choroidal metastases are another entity that must be differentiated. These normally have bigger dimensions, are well defined and are often associated with serous detachments. ⁽⁵⁾ The echogenic characteristics are also different. . They may also simulate inflammations such as choroidal granulomas or choroiditis.

The deposition of calcium in ocular structures can lead to bone formation (ossification) or to calcium salts precipitation (calcification). ^{((2, 4, 5))} Choroid and scleral calcification can be classified as metastatic, dystrophic and idiopathic. There are multiple systemic causes related to abnormal calcium or phosphate metabolism disorders that can lead to sclerochoroidal calcifications, those that do not exist in these systemic associations are classified as idiopathic. ^(2,7) (Table 1)

Table 1
Causes of precipitation of calcium salts in ocular structures ^(2,6)

Metastatic: Metabolism of calcium or phosphate disorders with deposit of calcium salts in healthy tissue
Parathyroid gland disorders:	Hyperparathyroidism
	Pseudohyperparathyroidism
	Pseudo hypoparathyroidism
Diseases due to deposits of
calcium pyrophosphate (pseudogout)	Primary hypercalcemia
	Hypophosphatemia
	Disorders related to Vitamin D
	Vitamin D intoxication
	Cholecaliciferol intoxication
	Chondrocalcinosis
	Kidney disorders
	Primary tubular syndromes with hypokalemic metabolic alkalosis.
	Bartter syndrome
	Gitelman syndrome
	Chronic renal failure
	Sarcoidosis
Dystrophic: Normal metabolism of calcium or phosphate with deposit of calcium salts in abnormal tissue
Ocular trauma
Chronic intraocular inflammation
Coats disease
Degeneration senile de la sclera
Choroidal tumors:
Retinoblastoma
Choroidal hemangioma
Astrocytic hamartoma
Choroidal Nevus
Phthisis bulbi
Congenital eye deformations
Idiopathic: Normal metabolism of calcium or phosphate with deposit of calcium salts in normal tissue

The first determination of PTH in our patient was higher than normal with a total calcium determination within normal limits. This finding, together with decreased levels of Vitamin D and the subsequent normalization of PTH after administration of active metabolites of vitamin D suggests vitamin D deficiency (described in up to 25% of elderly patients in Northern countries). ⁽⁷⁾ Hyperparathyroidism and hypervitaminosis D were ruled out.

Pseudohypoparathyroidism is characterized by the lack of response of the kidney to PTH stimulation and normally affects children. ⁽⁷⁾ Hypocalcemia, hyperphosphatemia, together with decreased urinary phosphate excretion is characteristic of the genetic subtypes of this condition. In our patient, calcium and phosphorus determinations were normal (inorganic phosphorus: 4.6mg/dl), as well as urinary phosphate excretion (627mg / l of phosphorus in 24h urine).

Another entity associated with sclerochoroidal calcifications is the pseudogout. Deposition of calcium pyrophosphate crystals in tendons, synovium, cartilage and ligaments are found. The patient had history of hip osteoarthritis but this is an infrequent manifestation of pseudogout. ⁽⁸⁾

Bartter's syndrome and Gitelman's syndrome are two rare conditions that can associate sclerochoroidal calcifications. Both are autonomic recessive ion transport disorders¡ of the nephron. Hypokalemic metabolic alkalosis with normal blood pressure is characteristic. ⁽⁸⁾ The first occurs in childhood along with growth retardation and the second in adolescence (associated with severe hypomagnesemia). The patient did not present any of these characteristics (advanced age, normal potassium, magnesium and chlorine levels, together with essential arterial hypertension).

Those associated with senile changes are considered idiopathic. It has been speculated that the chronic traction of the oblique muscles causes calcium to deposit near its insertions. ⁽⁹⁾ Once the electrolyte disorders presented were discarded, we classified the findings as idiopathic.

It is important early diagnose of sclerochoroidal calcifications to avoid misdiagnosis and non-useful treatments.

References

• ¹
  Shields JA, Shields CL. CME review: sclerochoroidal calcification: the 2001 Harold Gifford Lecture. Retina. 2002;22(3):251-61.
• ²
  Kim M, Pian D, Ferrucci S. Idiopathic sclerochoroidal calcification. Optometry. 2004;75(8):487-95.
• ³
  Leys A, Stalmans P, Blanckaert J. Sclerochoroidal calcification with choroidal neovascularization. Arch Ophthalmol. 2000;118(6):854-7.
• ⁴
  Cooke CA, McAvoy C, Best R. Idiopathic sclerochoroidal calcification. Br J Ophthalmol. 2003;87(2):245-6.
• ⁵
  Sivalingam A, Shields CL, Shields JA, McNamara JA, Jampol LM, Wood WJ, et al. Idiopathic sclerochoroidal calcification. Ophthalmology. 1991;98(5):720-4.
• ⁶
  Shields CL, Hasanreisoglu M, Saktanasate J, Shields PW, Seibel I, Shields JA. Sclerochoroidal calcification: clinical features, outcomes, and relationship with hypercalcemia and parathyroid adenoma in 179 eyes. Retina. 2015;35(3):547-54.
• ⁷
  Honavar SG, Shields CL, Demirci H, Shields JA. Sclerochoroidal calcification: clinical manifestations and systemic associations. Arch Ophthalmol. 2001;119(6):833-40.
• ⁸
  Pott's JT Jr. Diseases of the parathyroid gland and other hyper- and hypocalcemic disorders. In: Harrison's principles of internal medicine. 17th ed. New York: Mcgraw-Hill ; 2008. p .2377-416.
• ⁹
  Cogan DG, Kuwabara T. Focal senile translucency of the sclera. Arch Ophthalmol. 1959;62(4):604-10.

Publication Dates

• Publication in this collection
  20 Nov 2020
• Date of issue
  Sep-Oct 2020

History

• Received
  24 Mar 2020
• Accepted
  06 July 2020