Nonconvulsive status epilepticus secondary to acute porphyria crisis

Porphyria: a case report

BACKGROUND

Prompt diagnosis of metabolic disorders in a resource-limited country like Nepal is daunting. Acute intermittent porphyria is a rare but common hepatic porphyria mostly seen in females of the reproductive age group. As its incidence is quite uncommon, conjectures about porphyria diagnosis are often duped into a diagnostic conundrum.

CASE PRESENTATION

Here we unravel a case of a 15-year-old Hindu Nepalese girl distraught by the myriad of symptoms in the setting of severe abdominal pain accompanied by constipation and limb pain as the chief complaints. She presented with acute severe hypertension with marked persistent hyponatremia (up to 109 mEq/L). Despite conservative management of hypertension and electrolytes, unresolved electrolyte imbalance led us to the speculation of disturbance in the renin-angiotensin-aldosterone system. Due to her exacerbating neurovisceral status, she also required intensive care during the disease course. After thorough investigations and exemption of presumed provisional diagnoses, based on sustained symptomatic presentation, the clinical suspicion was driven towards a diagnosis of porphyria-related disorders. Positive Watson-Schwartz test substantiated the diagnosis of acute intermittent porphyria. Her symptoms gradually abated after the consumption of high carbohydrate diets.

CONCLUSION

This case highlights the baffling amalgamation of symptoms that simulate common diseases of concern yet are buried in the realm of porphyric disorders. Porphyria can be diagnosed using simple screening tools and timely treatment can diminish serious consequences.

Neurological Manifestations of Acute Porphyrias

PURPOSE OF REVIEW

Porphyrias constitute a group of rare metabolic disorders that result in a deficiency of the heme biosynthetic pathway and lead to the accumulation of metabolic intermediaries. Patients with porphyria can experience recurrent neurovisceral attacks which are characterized by neuropathic abdominal pain and acute gastrointestinal symptoms, including nausea, vomiting, and constipation. Depending on the type of porphyria, patients can present with cutaneous manifestations, such as severe skin photosensitivity, chronic hemolysis, or evidence of neurologic dysfunction, including alterations in consciousness, neurovascular involvement, seizures, transient sensor-motor symptoms, polyneuropathy, and behavioral abnormalities.

RECENT FINDINGS

More recently, cases of posterior reversible encephalopathy syndrome, cerebral vasoconstriction, and acute flaccid paralysis have also been described. While the exact pathogenic mechanisms linking the accumulation of abnormal heme biosynthetic intermediaries to neurologic manifestations have not been completely elucidated, it has been proposed that these manifestations are more common than previously thought and can result in permanent neurologic injury. This article reviews the basic principles of heme synthesis as well as the pathogenic mechanism of disease, presentation, and treatment of acute hepatic porphyrias with emphasis on those with neurologic manifestations.

Clinical features of catatonic non-convulsive status epilepticus: A systematic review of cases

OBJECTIVE

Non-convulsive status epilepticus (NCSE) can manifest as catatonia, although it is unclear how frequently such cases have been reported. The common clinical features of these two conditions are also unclear.

METHODS

Using the MEDLINE and Embase databases, we performed a systematic literature search to identify cases diagnosed with both catatonia, according to the Bush-Francis Catatonia Rating Scale, and NCSE, according to the Salzburg Consensus Criteria (last search: March 29, 2021). We extracted data on demographics, clinical features of catatonia, EEG findings, and treatments.

RESULTS

A total of 66 patients with catatonic NSCE (men, 49%; mean age, 42.0 years) were identified from our search. Of the 66 cases described: 30 (46%) showed motor symptoms; 35 (38%) occurred in patients with preceding episodes of epileptic seizures; 19 (29%) showed subtle ictal clinical phenomena, such as minor twitching of the mouth, periorbital region, and extremities; 22 (33%) presented with psychiatric symptoms prior to the onset of catatonia; 17 (26%) had a history of psychiatric diseases; and in 10 cases (15%), NSCE was confirmed by intentional or non-intentional long-term EEG monitoring. Benzodiazepines were used as the initial treatment for NCSE in 30 cases (49%), of which 20 cases (73%) improved with monotherapy.

DISCUSSION

A substantial number of cases included in the present review involved catatonia without any symptoms indicative of epilepsy, suggesting that NCSE may be misdiagnosed as a psychiatric disease, and highlighting the importance of the accurate diagnosis and treatment of NCSE in patients presenting with catatonia.

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.

Neurology of the acute hepatic porphyrias

Porphyrias are a set of rare inherited metabolic disorders, each of them representing a defect in one of the eight enzymes in the haem biosynthetic pathway resulting in the accumulation of organic compounds called porphyrins. Acute hepatic porphyrias (AHP) are those in which the enzyme deficiency occurs in the liver, of which acute intermittent porphyria is by far the most common subtype. Neurology of the AHP is still challenging in practice, and patients rarely receive the correct diagnosis early in the disease course. For AHP, which primarily affects the central and peripheral nervous system, the cause of symptoms seems to be the increased production of neurotoxic precursors, in particular delta-aminolaevulinic acid and porphobilinogen. Neurological complications usually result from severe episodes of acute attacks. The neurologic hallmark of porphyrias is an acute predominantly motor axonal neuropathy resembling a Guillain-Barré syndrome that generally occurs after the onset of other clinical features such as abdominal pain and central nervous system manifestations. Neuropsychiatric syndromes, seizures, encephalopathy, and cerebrovascular disorders are among the possible central nervous system presentations. Therapeutic approach to AHP is divided into management and prophylaxis of an acute attack, including long standing options such as intravenous hematin and new therapeutic agents such as givosiran.