Case Presentation: A 21-year-old African American, primigravid presented at eight weeks gestation with a two-week history of progressively worsening lower abdominal and back pain, as well as intractable nausea and vomiting. Her symptoms were accompanied by tachycardia, hypertension, constipation, dark urine and blistering lesions on her lips. On exam, she was tender across her abdomen and lower back. Laboratory findings revealed electrolyte disturbances (Serum Na 123 mmol/L; Urine Na 132 mml/d; Urine Osm 446 mOsm/kg; Serum Osm 255 mOsm/kg; Serum Mg 1.1 mmol/L), elevated enzymes (Lipase 1508 U/L; Amylase 361 U/L; AST 48 U/L), and an acute kidney injury (Serum Creatinine 2.41 mg/dL). Her urinalysis was nitrite and leukocyte esterase positive, with few bacteria, and orange in color. Her bHCG was appropriate for 6-8 weeks gestation. Several panels were ordered, including lupus, HIV, hepatitis, RSV, and HSV I/II, cortisol, which were all negative. Abdominal, renal, and transvaginal ultrasounds were unremarkable, except for a single, viable pregnancy; MRI abdomen was negative for pathologic processes. We did not perform a CT scan due to the potential risk to the fetus. In addition to a negative work-up, there was no improvement in the patient’s clinical status despite supportive care and empiric antibiotics for a urinary tract infection. Labs were sent out for porphyria and there was modest clinical improvement after the patient was empirically started on intravenous infusion of D5W and a high carbohydrate diet. Upon the resulting labs, acute porphyria was determined to be the underlying pathologic process [Urine Porphobilinogen 358 µmol/L (≤ 8.8 µmol/L); Total Porphyrin 63 nmol/L (≤ 15 nmol/L); Aminolevulinic acid urine per volume/24 hours 196 µmol/d (≤ 60 µmol/d); Fecal Coproporphyrin 165 nmol/g (≤ 45 nmol/g); Fecal Protoporphyrin 8 nmol/g (≤ 100 nmol/g)]. Subsequently, we began the administration of intravenous hemin 3 mg/kg every 24 hours for four days. The patient’s hyponatremia and acute kidney injury resolved during the course of her hemin treatment, with marked improvement in her pain.
Discussion: Acute attacks in genetically predisposed individuals are triggered by progesterone surges, oral contraceptives, insufficient calorie intake, alcohol, and smoking 1,3. Our patient’s disease was unmasked early in her pregnancy, likely due to the physiologic increase in progesterone during the first trimester.Acute episodes typically present with abdominal pain, electrolyte abnormalities and CNS disturbances 2. Additionally, the excess porphyrin levels in the body can cause photosensitivity, leading to blistering lesions of the skin; heme pathway intermediates can also change urine color to shades of red and brown when excreted 1. Additionally, the characteristic abdominal pain has a poor response to opioid medication. Patients that require escalating doses of opioid analgesia in the context of episodic negative work-ups are frequently labeled with “drug-seeking behavior” 1, which can further contribute to a delay in appropriate management.
Conclusions: Our patient demonstrates the challenges of diagnosing porphyria. The isolated exam and lab findings fit the picture for acute porphyria, but require a high level of clinical suspicion. We suggest that clinicians consider porphyria in clinically unexplained abdominal pain, especially in the setting of autonomic, electrolyte, or neurologic abnormalities.