(4.08) "A" Vitamin to Consider: Refractory Hypercalcemia from Vitamin A Toxicity

Thursday, May 9, 2024

12:25 PM – 12:40 PM CDT

Location: ePoster Showcase, Empire Ballroom Foyer, Level 2

Submitter(s)

Wafa A. Latif, MBBS (she/her/hers)

Fellow
Atrium Health Wake Forest Baptist
High Point, North Carolina, United States

Introduction : ^{Vitamin A toxicity in humans is a rare entity, with fewer than ten cases reported annually since 1976. Its diagnosis is challenging due to nonspecific symptoms such as nausea, fatigue, dry skin, and hair loss. This diagnostic difficulty is particularly pertinent in patients with hypercalcemia, where Vitamin A toxicity is seldom considered. We present a case of refractory hypercalcemia in a nonverbal patient, where the diagnosis of Vitamin A toxicity was established through elevated vitamin A levels.}

Case(s) Description :

^{A 19-year-old male with cerebral palsy, spastic paraplegia, tracheostomy, G tube-dependent nutrition, restrictive lung disease, and epilepsy was admitted for elevated calcium levels (14 mg/dL). He experienced multiple hospital admissions over the past 18 months for lethargy and persistent hypercalcemia. This was concerning for the mother, as she states the patient has had limited mobility since birth and has had hypercalcemia in the past but not sustained as it has been recently.
Laboratory tests revealed parathyroid hormone level (PTH) at 5 pg/mL, 25-hydroxy vitamin D level at 46 ng/mL, and low 1,25-dihydroxy vitamin D levels (8.5 pg/mL). Despite extensive prior evaluations, including serum and urine protein electrophoresis and PTH-rP, no cause was identified. His diet had included a changed tube feed formula one year ago, daily vitamin D (1000 IU), and a recent probiotic addition four months ago. We reviewed the ingredients, and none had high calcium content.}

^{Vitamin A level was not checked previously and was ordered. It returned very elevated at 94.1ug/dL, with a reference range of 18.8-54.9 ug/dL. A review of the patient's formula and supplements did now show vitamin A levels above the recommended retinol activity equivalents (RAE). The patient's mother spoke to a nutritionist to recommend switching to a low vitamin A formula, and his calcium levels were lowered using intravenous fluids and one dose of IV pamidronate.}

Discussion :

^{Regarding differential diagnoses for hypercalcemia, Vitamin A toxicity remains a rare but significant cause. Despite its rarity, Vitamin A toxicity is a critical consideration, often overlooked in routine clinical evaluations. This case highlights the importance of assessing Vitamin A levels during the hypercalcemia workup, especially in patients with atypical presentations or limited communication abilities. It also aims to shed light on this often-missed diagnosis, advocating for a more inclusive diagnostic approach in hypercalcemic patients.}