A 22-year-old woman with severe headaches, vomiting, and tonic-clonic seizures

Acute porphyrias - A neurological perspective

Acute hepatic porphyrias (AHP) can cause severe neurological symptoms involving the central, autonomic, and peripheral nervous system. Due to their relative rarity and their chameleon-like presentation, delayed diagnosis and misdiagnosis are common. AHPs are genetically inherited disorders that result from heme biosynthesis enzyme deficiencies and comprise four forms: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALA-dehydratase porphyria (ALADP). Depending on the clinical presentation, the main differential diagnoses are Guillain-Barré syndrome and autoimmune encephalitis. Red flags that could raise the suspicion of acute porphyria are neurological symptoms starting after severe (abdominal) pain, in association with reddish urine, hyponatremia or photodermatitis, and the presence of encephalopathy and/or axonal neuropathy. We highlight the diagnostic difficulties by presenting three cases from our neurological intensive care unit and give a comprehensive overview about the diagnostic findings in imaging, electrophysiology, and neuropathology.

Porphyria-induced posterior reversible encephalopathy syndrome and central nervous system dysfunction

BACKGROUND AND AIM

An association between neuropsychiatric manifestations and neuroimaging suggestive of posterior reversible encephalopathy syndrome (PRES) during porphyric attacks has been described in numerous case reports. We aimed to systematically review clinical-radiological features and likely pathogenic mechanisms of PRES in patients with acute hepatic porphyrias (AHP) and porphyric attacks.

METHODS

PubMed, Scopus, Ovid MEDLINE, and Google Scholar were searched (July 30, 2019). We included articles describing patients with convincing evidence of an AHP, confirmed porphyric attacks, and PRES in neuroimaging.

RESULTS

Forty-three out of 269 articles were included, which reported on 46 patients. Thirty-nine (84.8%) patients were women. The median age was 24 ± 13.8 years. 52.2% had unspecified AHP, 41.3% acute intermittent porphyria, 4.3% hereditary coproporphyria, and 2.2% variegate porphyria. 70.2% had systemic arterial hypertension. Seizures, mental changes, arterial hypertension, and hyponatremia occurred more frequently than expected for porphyric attacks (p < .001). Seizures and hyponatremia were also more frequent than expected for PRES. The most common distributions of brain lesions were occipital (81.4%), parietal (65.1%), frontal (60.5%), subcortical (40%), and cortical (32.5%). Cerebral vasoconstriction was demonstrated in 41.7% of the patients who underwent angiography. 19.6% of the patients had ischemic lesions, and 4.3% developed long-term sequelae (cognitive decline and focal neurological deficits).

CONCLUSIONS

Brain edema, vasoconstriction, and ischemia in the context of PRES likely account for central nervous symptoms in some porphyric attacks.

A case of hereditary coproporphyria with posterior reversible encephalopathy and novel coproporphyrinogen oxidase gene mutation c.863T>G (p.Leu288Trp)

A 21-year-old female had recurrent presentations to the emergency department with myalgia, vomiting, abdominal pain and subsequently developed generalized seizures. She was volume depleted with a plasma sodium of 125 mmol/L (reference interval: 135-145) and she had fluctuating hypertension. Acute porphyria was suspected and confirmed with raised urine porphobilinogen/creatinine ratio of 12:4 μmol/mmoL (reference interval < 1:5) and she was treated with intravenous haem arginate. Urinary porphyrin/creatinine ratio was 673 nmol/mmoL (reference interval <35) and faecal porphyrins 2430 μmol/kg dry weight (reference interval: <200) were markedly elevated, with raised faecal CIII:CI ratio, consistent with acute coproporphyria. Diagnosis was confirmed by the demonstration of a novel missense variant in the coproporphyrinogen oxidase gene c.863T > G (p.Leu288Trp) predicted to be deleterious and which segregated with three other affected family members. Although CT head was normal, magnetic resonance imaging scan revealed symmetrical signal abnormalities and swelling in the parietal and occipital lobes consistent with posterior reversible encephalopathy. Over several days, her seizures ceased and sodium and blood pressure normalized. The aetiology of the acute porphyric attack was likely multifactorial with contributions from a recent viral illness and caloric deprivation. No drug precipitant was identified. We postulate that untreated hypertension played a key role in the development of posterior reversible encephalopathy. Early clinical suspicion and urine porphobilinogen testing are the key components in preventing morbidity and mortality in acute porphyrias.

Liver failure after Hydroxycut™ use in a patient with undiagnosed hereditary coproporphyria

We report the case of a young male presenting with cholestatic liver failure. After an extensive workup, the etiology of the liver failure was determined to be due to hereditary coprophorphyria (HCP). The inciting event was the use of Hydroxycut™, an over-the-counter supplement to promote weight loss that has been reported to cause oxidative liver injury in vulnerable populations. Although HCP is a rare cause of cholestatic liver failure, it is treatable if diagnosed correctly and in a timely manner. In this clinical vignette, we discuss a case that highlights the genetic susceptibility to disease that can be unmasked by environmental exposures. We also review the relevant literature on Hydroxycut™ and how it can affect hepatic function.

Acute porphyria presenting as epilepsia partialis continua

Purpose

The porphyrias are a defect in the biosynthesis of heme which can be associated with different neurological symptoms during acute attacks such as peripheral neuropathy, mental disturbance and seizures. So far, there have only been a few case reports of status epilepticus, none of which were of epilepsia partialis continua (EPC). We present here two cases of hereditary coproporphyria (HCP) manifesting EPC as part of the clinical presentation.

Method

The patients’ medical charts, EEG and imaging studies were carefully reviewed.

Results

Case 1 is a 49-year-old male who first presented a tonic-clonic seizure. Case 2 is a 30-year-old male who came to the emergency room for a convulsive status epilepticus. Both evolved to EPC over the next days. EPC persisted despite several antiepileptic drug trials. Diagnosis of HCP was confirmed by a high level of urine, fecal and serum porphyrins in both cases and by genetic testing in one. Over the last 3 years, the first patient has continued to present non-disabling EPC and has had four tonic-clonic seizures associated with alcohol consumption. The second patient died from brain edema one month and half after admission.

Conclusion

Acute porphyrias should be included in the differential diagnosis of new onset status epilepticus, including EPC. Their recognition is important as it modifies significantly patient management, since many anticonvulsants are porphyrogenic.