# A presentation of systemic lupus erythematosus manifesting as abdominal pain: a case report

## TL;DR

A teenage girl with lupus first showed stomach pain linked to her menstrual cycle, making diagnosis difficult due to atypical symptoms and fluctuating test results.

## Contribution

This case highlights a rare initial presentation of lupus with gastrointestinal symptoms and fluctuating lab findings tied to the menstrual cycle.

## Key findings

- The patient's lupus symptoms and lab results fluctuated with her menstrual cycle, complicating diagnosis.
- Kidney biopsy confirmed lupus nephritis after initial symptoms and lab findings resolved post-menstruation.
- The case demonstrates the diagnostic challenge of lupus without consistent clinical or serologic criteria.

## Abstract

Systemic lupus erythematosus is a multisystem inflammatory disease with a broad range of clinical and serologic presentations. The heterogeneity of presentation poses diagnostic challenges for the clinician, and a high index of suspicion is required. Classification systems exist for both clinical and immunologic criteria; however, they may lack sensitivity in assisting with diagnosis of atypical presentations. We present a case of an initial presentation of systemic lupus erythematosus consisting of nonspecific gastrointestinal symptoms with clinical and immunologic findings that fluctuated with menstrual cycles.

A 15-year-old Hispanic female initially presented with 2 days of epigastric abdominal pain, non-bloody and non-bilious emesis, and diarrhea. There was no fever, rash, weight loss, arthralgias, or dysuria. Menses started 1 day prior to presentation. She was persistently hypertensive throughout her admission. She developed respiratory distress with supplemental oxygen requirement due to pleural effusions identified on chest x-ray. Computed tomography of the abdomen showed large-volume ascites. Extensive evaluation was negative for malignancy and cardiac, gastrointestinal, or infectious etiologies. She demonstrated hypocomplementemia, which self-resolved without intervention. She initially had proteinuria, which resolved after menstruation. She was discharged without a specific diagnosis as her clinical status improved. She presented 2 weeks later for recurrent symptoms at the start of her next menstrual cycle with hypocomplementemia and proteinuria that persisted after menses. Elevated 24-hour urine protein led to a kidney biopsy, which showed mesangial proliferative lupus nephritis class II. The patient was formally diagnosed with systemic lupus erythematosus.

We present a case of new onset systemic lupus erythematosus with initial gastrointestinal symptoms occurring and receding concomitantly with the patient’s menstrual cycle. Interpretation of the urinalysis was complicated by active menses, and both hematuria and proteinuria initially resolved at the completion of her menstrual cycle. In addition, her symptoms and hypocomplementemia resolved without intervention, making the diagnosis more challenging with insufficient clinical criteria for systemic lupus erythematosus. Clinicians should maintain a high index of suspicion for autoimmune disorders, as symptoms may unfold over time. Although rare, systemic lupus erythematosus may initially present with gastrointestinal symptoms without other classic clinical findings. Absence of serologic criteria and spontaneous resolution of hypocomplementemia also add to the novelty of this case.