Porphyria presenting as osteoporosis

Erbatur Nuriye Hale; Gonul Koc; Serife Mehlika Kuskonmaz; Cavit Culha

doi:10.1530/endoabs.90.EP198

Introduction: Secondary osteoporosis is defined as bone loss caused or exacerbated by other clinical disorders. Secondary osteoporosis can be due to a wide range of medical disorders, including endocrine disorders and genetic disorders. We are presenting a clinical case which the patient diagnosed as acute intermittent porphyria while being investigated for secondary osteoporosis.

Clinical Case: 41-year-old female patient applied with bone and back pain, itchy dark-colored lesion in the abdomen, abdominal pain during menstruation and nonspecific neurological complaints such as numbness in the arms and headache. The patient had anxiety was using sertraline for the treatment. On physical examination, brown spots were seen on the skin in the lower abdominal quadrants. In laboratory examinations, there was no hypogonadism, parathyroid and thyroid functions were normal. In 24-hour urine analysis, uroporphyrin was detected as 96.92 µg/24 h (0-33 µg/24 h). Bone mineral density (BMD) showed a Z score of −2.6 for L2 to L4, −2.7 for the femoral neck and -2.6 for total hip. Her FRAX score showed low risk of osteoporotic fracture. Genetic examination was performed for porphyria due to its clinical compatibility ant the patient was a heterozygote for an exon 9 (NM_000190) HMBS variant. The patient was evaluated as acute intermittent porphyria with clinical and genetic results. Antiresorptive treatment was not started due to the low risk of fracture. She was followed up with vitamin D and calcium.

Table 1 Laboratory findings of the patient
Laboratory test	Patient’s values	Reference range
Creatinine (mg/dl)	0.61	<1.2
ALP(U/l)	96	<98
FSH (mIU/mL)	4.7	1.5-12.4
LH (mIU/mL)	12.14	1.7-8.6
Estradiol (ng/dl)	213.3	30-400
TSH (Uu/ml)	1.26	0.27-4.2
FT4 (ng/dl)	1.3	0.89-1.76
PTH (ng/l)	27.5	15-65
25-OH-D(µg/l)	21.84	30-80
Serum calcium (mg/dl)	9.67	8.8-10.6
Serum phosphorus (mg/dl)	2.7	2.6-4.5
AFP (µg/l)	1.78	0-7
FSH: Follicle-Stimulating Hormone; LH: Luteinizing hormone; TSH: Thyroid-stimulating hormone; FT4: Free thyroxine; PTH: Parathyroid hormone; 25-OH-D: 25-hydroxy vitamin D; AFP: alpha-fetoprotein

Conclusion: In any patient evaluated for osteoporosis, secondary causes may have contributed to the condition. Various causes of osteoporosis, such as mild asymptomatic hyperparathyroidism, celiac disease, metabolic and genetic disorders, may be clinically unclear. Intensive research is particularly needed in all premenopausal women and men with atraumatic fractures or BMD below 1 SD of same-age control subjects. Porphyria should be kept in mind in patients with atypical abdominal pain or atypical neurologic findings.

Endocrine Abstracts

EP198