Hypophosphatemia in Panic Disorder

Mr. A, a 31-year-old man with a positive family history of panic disorder and recurrent panic attacks, experienced a recurrence of panic symptoms. His symptom profile was marked by situation-independent panic attacks with concomitant somatic symptoms (continuous hiccups and paresthesia). Under a combined pharmacological treatment plan (mirtazapine and citalopram) in addition to cognitive behavior therapy, remission developed, but he experienced short relapses. A short while later, he was free of panic attacks. His clinical course was mirrored by normalization of his originally high scores on the Body Sensations Questionnaire (3) and the Agoraphobic Cognitions Questionnaire (3) as well as on the somatization, anxiety, and phobic fear dimensions of the SCL-90-R.

Upon routine laboratory testing, marked hypophosphatemia (normal range=2.5–4.5 mg/dl) was observed (1.7 mg/dl, then 1.3 mg/dl), then 1 month later, it was 1.9 mg/dl. His parathormone level was measured as normal: 31.6 pg/dl (normal range: 12–72 pg/dl). The serum phosphate level returned to normal early the next month (2.8 mg/dl), only to fall below the lower limit of normal soon thereafter (2.3 mg/dl). At the next two measurements (2.8 mg/dl) and (3.0 mg/dl), his serum phosphate level again returned to normal.