Neurovisceral syndromes are characterized by the simultaneous involvement of the nervous system and visceral organs, often presenting with abdominal pain, seizures, autonomic instability, and electrolyte disturbances. These conditions are particularly challenging in adolescents due to their nonspecific and fluctuating presentation. Acute intermittent porphyria (AIP), a disorder of heme biosynthesis, is an important but often overlooked cause of such presentations. It commonly manifests with abdominal pain, neuropsychiatric symptoms, and autonomic dysfunction without cutaneous features. Due to its rarity and varied presentation, AIP is frequently misdiagnosed as epilepsy or psychiatric illness. This case is important because it highlights a classical yet easily missed presentation of AIP, presenting as a hypertensive crisis with seizures and hyponatremia, emphasizing the need for early suspicion and appropriate evaluation. CASE PRESENTATION A 14-year-old female presented with recurrent generalized seizure-like episodes for three days. The episodes involved tonic posturing of the upper limbs with up-rolling of the eyes, lasted for less than five minutes, and were aborted with intravenous midazolam. Post-ictal confusion was noted during the earlier episodes, while the later episodes were associated with transient altered sensorium and slurred speech. She also complained of severe epigastric and hypogastric abdominal pain for three days, along with one episode of non-bilious, non-projectile vomiting. On examination, the patient had persistent severe hypertension, with a blood pressure of up to 160/120 mmHg, requiring multiple antihypertensive agents. Neurological examination between the episodes was unremarkable. A menstrual trigger for the acute episode was ruled out. INVESTIGATIONS Table 1. Investigations Investigation Result Hemoglobin 8.2 g/dL Serum Sodium (Na⁺) 122 mEq/L Liver Function Tests Mild transaminitis Cardiac Markers Elevated Troponin I and CK-MB Renal Function Tests Within normal limits Thyroid Profile Within normal limits Serum Ammonia Within normal limits Pancreatic Enzymes Within normal limits CT Aortogram Mild narrowing of the right renal artery Secondary Hypertension Workup ANA, VMA, C-ANCA, and P-ANCA negative Upper GI Endoscopy Positive for H. pylori Urinary δ-ALA Elevated Urinary Porphobilinogen Positive MRI Brain Hyperintensities observed DIFFERENTIAL DIAGNOSIS The patient presented with recurrent seizure-like episodes, severe abdominal pain, persistent hypertension, and hyponatremia, prompting consideration of several differential diagnoses. Structural intracranial pathology, including intracranial hemorrhage, ischemic stroke, and space-occupying lesions, was considered but excluded based on neuroimaging findings. Infectious causes such as meningoencephalitis were considered; however, the absence of clinical and laboratory evidence made these unlikely. Autoimmune disorders associated with seizures and hypertension, including systemic vasculitis, were ruled out as antinuclear antibody (ANA), C-ANCA, and P-ANCA were negative. Endocrine and metabolic causes, including thyroid dysfunction and hyperammonemia, were excluded by normal thyroid profile and serum ammonia levels. Secondary causes of hypertension, including pheochromocytoma and renovascular hypertension, were also investigated. Although CT aortography showed mild narrowing of the right renal artery, the overall workup, including urinary vanillylmandelic acid (VMA), was not suggestive of a secondary endocrine cause. The presence of recurrent neurovisceral symptoms associated with persistent hypertension, hyponatremia, elevated urinary δ-aminolevulinic acid, and positive urinary porphobilinogen established the diagnosis of acute intermittent porphyria. TREATMENT • Benzodiazepines for seizure control • Antihypertensives for blood pressure management • Correction of hyponatremia • Supportive care (hydration, pain management) • High carbohydrate therapy (10% dextrose infusion) • Avoidance of porphyrinogenic drugs. OUTCOME AND FOLLOW-UP The patient showed gradual clinical improvement following initiation of appropriate treatment. Her blood pressure stabilized with antihypertensive therapy, neurological symptoms resolved, and the electrolyte imbalance was corrected. She was discharged in a stable condition with advice for regular follow-up, avoidance of porphyrinogenic drugs, and adherence to dietary recommendations, including a high-carbohydrate diet.

Acute intermittent porphyria (AIP) is an autosomal dominant metabolic disorder caused by a deficiency of the enzyme porphobilinogen deaminase in the heme biosynthesis pathway. This enzymatic defect leads to the accumulation of neurotoxic intermediates such as delta-aminolevulinic acid (ALA) and porphobilinogen (PBG), which are responsible for the neurovisceral manifestations. AIP typically presents after puberty and is more common in females. Precipitating factors include infections, fasting, hormonal changes, and certain drugs, particularly enzyme-inducing antiepileptic medications. The clinical presentation is often nonspecific and includes abdominal pain, which is the most common symptom, followed by neurological manifestations such as seizures, peripheral neuropathy, and altered sensorium. Autonomic dysfunction may manifest as hypertension, tachycardia, and gastrointestinal dysmotility. Hyponatremia is a frequent finding and is usually attributed to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). In this case, the combination of recurrent seizures, abdominal pain, persistent hypertension, and hyponatremia formed a classical but often overlooked presentation of AIP. MRI of the brain demonstrated hyperintensities suggestive of posterior reversible encephalopathy syndrome (PRES), supporting the association between severe hypertension and neurological manifestations. One of the major challenges in AIP is misdiagnosis. Patients are often treated as primary epilepsy cases, and the administration of porphyrinogenic antiepileptic drugs can exacerbate the condition by inducing hepatic heme synthesis, thereby increasing the accumulation of toxic intermediates. Hypertension in AIP is due to autonomic overactivity and may lead to complications such as posterior reversible encephalopathy syndrome (PRES). The MRI findings of hyperintensities were consistent with PRES, a recognized complication of autonomic dysregulation and severe hypertension in AIP. Diagnosis is confirmed by demonstrating elevated urinary ALA and PBG levels. In acute settings, spot urine testing is often sufficient for diagnosis. Management of AIP involves both supportive and specific therapy. Removal of precipitating factors is essential. A high-carbohydrate intake suppresses hepatic ALA synthase activity, thereby reducing the production of toxic metabolites. Intravenous hemin is the definitive treatment in severe cases, although it may not always be available. Symptomatic management includes control of seizures with safe medications, management of hypertension, and correction of electrolyte imbalances. Care must be taken to avoid drugs known to precipitate porphyria. This case highlights the importance of maintaining a high index of suspicion for AIP in adolescents presenting with unexplained neurovisceral symptoms. Early recognition not only prevents complications but also avoids inappropriate treatments that may worsen the condition. LEARNING POINTS/TAKE HOME MESSAGES • Acute intermittent porphyria should be suspected in patients presenting with seizures, abdominal pain, hypertension, and hyponatremia. • Early recognition and avoidance of porphyrinogenic medications are essential to prevent potentially life-threatening neurological complications. • Urinary ALA and porphobilinogen are important tests for confirming acute intermittent porphyria. • Porphyrinogenic drugs should be avoided as they can worsen acute attacks. • Timely treatment can lead to good clinical recovery and improved patient outcomes.

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