Abnormal TSH regulation, pseudotumor cerebri, and empty sella after replacement therapy in juvenile hypothyroidism

Idiopathic Intracranial Hypertension following Levothyroxine Replacement Therapy: Systematic Review and a Case Report

The data on the characteristics of patients with idiopathic intracranial hypertension (IIH) following levothyroxine (LT4) replacement are limited. Here, we report a case and systematically review published cases of idiopathic intracranial hypertension (IIH) following levothyroxine (LT4) replacement. The systematic review was performed as per the PRISMA guidelines. Our patient is a 46-year-old lady with hypothyroidism (thyrotropin: 319 mIU/L, free thyroxine: 0.04 ng/dl), treated with 100 μg.d of LT4 and presented a month later with headache, visual diminution, bilateral lateral rectus palsies, and papilledema. Cerebrospinal fluid (CSF) pressure was 32 cmH2O. Drainage of CSF, oral acetazolamide, and modification of LT4 dose resulted in prompt symptomatic improvement and complete reversal of IIH. In the systematic review (n = 21), the median age of patients (7 males) was 13 (IQR: 8.8- 26.5) years. The median duration of hypothyroid symptoms was 4 (n = 10, IQR: 0.44-6.25) years whereas that from initiation of LT4 replacement to the diagnosis of IIH was 2 (n = 20, IQR: 1.17-4) months. Initial median serum thyrotropin and thyroxine were 100 (n = 14, IQR: 72.5-421.6) mIU/L, and 1.13 (n = 12, IQR: 1.0-2.45) μg/dl which changed to 2.2 (n = 7; IQR: 0.23-3.40) mIU/L and 8.90 μg/dl (n = 8, IQR: 6.43-14.85 μg/dl), respectively at diagnosis of IIH after LT4 treatment with median daily LT4 doses of 0.89 (n = 8, IQR: 0.60 - 1.17) times the maximum recommended dose for age. To conclude, we report an adult woman with IIH following LT4 replacement for primary hypothyroidism, a rare entity. Pediatric age, prolonged symptom duration, and use of higher LT4 replacement dose may be associated with IIH following LT4 replacement.

Diplopia, Convergent Strabismus, and Eye Abduction Palsy in a 12-Year-Old Boy with Autoimmune Thyroiditis

Pseudotumor cerebri (PTC) is defined by clinical criteria of increased intracranial pressure, elevated intracranial pressure with normal cerebrospinal fluid (CSF) composition, and exclusion of other causes such tumors, vascular abnormalities, or infections. The association of PTC with levothyroxine (LT4) has been reported. A 12-year-old boy has been followed up for autoimmune thyroiditis under LT4. Family history was irrelevant for endocrine or autoimmune diseases. A TSH level of 4.43 μUI/mL (0.39-3.10) motivated a LT4 adjustment from 75 to 88 μg/day. Five weeks later, he developed horizontal diplopia, convergent strabismus with left eye abduction palsy, and papilledema. Laboratorial evaluation revealed elevated free thyroxine level (1.05 ng/dL [0.65-1.01]) and low TSH, without other alterations. Lumbar puncture was performed and CSF opening pressure was 24 cm H2O with normal composition. Blood and CSF cultures were sterile. Brain MRI was normal. LT4 was temporarily discontinued and progressive improvement was observed, with a normal fundoscopy at day 10 and reversion of diplopia one month later. LT4 was restarted at lower dose and gradually titrated. The boy is currently asymptomatic. This case discloses the potential role of LT4 in inducing PTC. Despite its rarity and unclear association, PTC must be seen as a potential complication of LT4, after excluding all other intracranial hypertension causes.

Tablets or scalpel: Pituitary hyperplasia due to primary hypothyroidism

We describe a patient with pituitary hyperplasia due to primary hypothyroidism. Pituitary hyperplasia and pituitary masses cannot be reliably differentiated on imaging alone, despite significant improvement in imaging quality in recent years.

Intracranial hypertension due to levothyroxine use

We report a case of intracranial hypertension in a 13-year-old boy on levothyroxine therapy for hypothyroidism and review the literature describing this rare association. He presented with severe headaches and was found to have bilateral optic disk edema and elevated intracranial pressure shortly after an increase in his dosage of levothyroxine. The optic disk edema and headaches resolved with decreasing the levothyroxine and initiating acetazolamide.

MRI-demonstrable regression of a pituitary mass in a case of primary hypothyroidism after a week of acute thyroid hormone therapy

Although magnetic resonance imaging (MRI) characteristics of pituitary gland hyperplasia in primary hypothyroidism have been previously described, the time span necessary for the regression of the hyperplasia in response to acute thyroid hormone (TH) therapy has not been defined. A 26-yr-old woman underwent 131I ablation 11 yr before admission. Intermittent poor compliance to levothyroxine (LT4) therapy led to inappropriately high serum thyroid-stimulating hormone (TSH) for her triiodothyronine (T3) and thyroxine (T4) levels. The patient was investigated to rule out TSH-secreting pituitary adenoma or resistance to TH. On admission, the patient's clinical features and thyroid function tests, as well as thyrotropin-releasing hormone (TRH) and acute T3 suppression tests, were in favor of profound primary hypothyroidism. MRI revealed symmetrical enlargement of the pituitary gland with distinct morphological characteristics of a macroadenoma. The patient began high-dose TH therapy and was rescanned six days later. The follow-up scan revealed a dramatic shrinkage of the pituitary gland. Four weeks later, serum T4 and TSH were within the normal range, and repeat MRI scan of the pituitary at that time showed a normal gland. This case is the first to document dramatic shrinkage of pituitary hyperplasia in long-standing primary hypothyroidism within one week of acute TH therapy. MRI alone is unable to reliably differentiate between a TSH-secreting pituitary adenoma and hypothyroidism-induced pituitary hyperplasia. Dynamic endocrine testing as well as repeat pituitary MRI after a brief TH trial may provide a firm diagnosis in similar cases.

Idiopathic intracranial hypertension in children: the Iowa experience

Idiopathic intracranial hypertension is an uncommon condition in children and is seen only about once a year in a large referral hospital. Sex incidence is equal, and obesity is a feature in about one third of patients. This article reviews the 30-year experience in an institution where idiopathic intracranial hypertension in adults has been extensively studied. Symptomatic causes of intracranial hypertension and both medical and surgical therapeutic options are reviewed.

Primary hypothyroidism with intracranial hypertension and pituitary hyperplasia

A 12-year-old girl presented with primary hypothyroidism, secondary pituitary hyperplasia, and intracranial hypertension. Cranial computed tomography revealed a sellar mass with suprasellar extension. She responded to medical treatment. Intracranial hypertension may be associated with primary hypothyroidism prior to thyroxine treatment. Because significant pituitary hyperplasia can be associated with primary hypothyroidism, it is vital to have endocrine investigation prior to consideration of surgical removal of an apparent pituitary tumor.

Psychologic and psychoeducational consequences of thyroxine therapy for juvenile acquired hypothyroidism

The observation of severe behavioral reactions or learning problems in three teenagers treated with L-thyroxine for juvenile acquired hypothyroidism prompted us to conduct a prospective study of achievement and behavioral characteristics of patients with newly diagnosed juvenile acquired hypothyroidism. On diagnosis of juvenile acquired hypothyroidism and before treatment with L-thyroxine, 23 children and adolescents underwent a comprehensive battery of psychoeducational tests, which was repeated after 3, 12, and 24 months of replacement therapy. Results revealed that adverse behavioral reactions and learning problems were relatively rare in these children, although symptoms of juvenile acquired hypothyroidism were associated with increased distractibility, hyperactivity, and poorer achievement. The least gain in achievement was made by children with more severe hypothyroidism at diagnosis; children with the best psychologic outcome were those who achieved euthyroidism more slowly. We conclude that severe behavioral manifestations of L-thyroxine therapy for juvenile acquired hypothyroidism are uncommon, but mild behavioral symptoms and poorer school achievement may occur in about 25% of patients, who represent the most severe cases at diagnosis.

Primary empty sella syndrome in childhood: association with precocious puberty

Primary empty sella syndrome has been considered an infrequent finding in childhood. One hundred and twelve cases have been reported in children ages 0.7 to 18 years. The frequency of primary empty sella ranged from 1% to 58%. Endocrine abnormalities were described in nearly all children while visual abnormalities were noted in only 6%. Growth hormone deficiency was the single most common hormonal dysfunction noted in children with primary empty sella. Precocious puberty has been rarely reported in association with primary empty sella. We report the case of a 7-1/2 year old girl with gonadotropin dependent central precocious puberty and a partially empty sella who had no other hypothalamic-pituitary dysfunction. We suggest that pubertal abnormalities be included among the endocrine disorders potentially associated with the primary empty sella syndrome.

Empty sella syndrome in childhood

The empty sella syndrome is common in middle-aged women, usually presenting with headache, and only occasionally associated with endocrine or visual abnormalities. It is rare in childhood. Childhood cases tend to present either with endocrine disturbances, visual symptoms, or with craniofacial syndromes. We present three cases of complete empty sella with childhood onset, each discovered unexpectedly during evaluation of endocrine or visual dysfunction.