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Neurology India, Vol. 55, No. 4, October-December, 2007, pp. 413-415 Case Report Acute intermittent porphyria presenting with neurological emergency: Review of six cases Dhanpat K. Kochar, Mahender Pal, Sanjay Kumar Kochar, Arvind Vyas*, Abhishek Kochar, Dinesh Bindal, Rajender Prasad Agrawal Department of Neurosurgery and University of Missouri-Columbia Division of Neurosurgery Date of Acceptance: 18-Jan-2007 Code Number: ni07122 Abstract Acute intermittent porphyria presenting with short duration of gastrointestinal symptoms followed by rapidly progressive fulminant neurological syndrome during first attack is relatively uncommon. It is a neurological emergency and mimics many other psychiatric and medical disorders and can be fatal if it remains undiagnosed and untreated. Further, specific treatment in the form of Heme arginate is not universally available and very costly, so high clinical suspicion and early diagnosis and management of acute attack and prevention of further attacks are very important. We report a series of six cases who presented with convulsion and/or polyneuropathy early in the course of disease to highlight this fact.Keywords: Acute intermittent porphyria, convulsion, neurological emergency Acute intermittent porphyria (AIP) is an autosomal dominant disorder, resulting from partial deficiency of porphobilinogen deaminase (PBGD) enzyme in the haem biosynthetic pathway. [1] The presentation of AIP as an acute abdomen is well known, but a short duration of gastrointestinal symptoms followed by a rapidly progressive course of neuropsychiatric manifestations including peripheral neuropathy, respiratory paralysis, seizures and loss of consciousness during the first attack may also occur. The relationship of seizures with porphyria is complex and the most common description is the presence of acute symptomatic generalized seizure occurring in the context of AIP in relapse. [2] Convulsive seizure may be the presenting symptom of an acute relapse. [3] The knowledge of convulsion in AIP is very essential because the use of enzyme-inducing antiepileptic drugs can cause worsening of the convulsion leading to death. Thus, a strong clinical suspicion, early diagnosis and adequate management of convulsion and prevention of further attacks are of paramount importance in reducing the morbidity and mortality. We present a report of six cases who had convulsion and/or other severe neurological dysfunction along with fulminant course of illness. Case Report We present a report of six cases of AIP who had convulsions and/or other neurological manifestation along with fulminant course of illness [Table 1]. Soon after suspicion of AIP, urine and blood samples were collected for Watson-Swartz test, urine PBG level, routine cytology, blood biochemistry and electrolyte estimation and patients were put on high carbohydrate diet by oral root or Ryle′s tube along with intravenous glucose so as to provide at least 400g of glucose to the patient each day. All the patients were kept under close observation so that they can be put on ventilatory support if required. One patient needed ventilatory support for five days. Apart from the observations as written in [Table 1], one pregnant woman had rapid deterioration in her condition and therefore was advised to go for MTP (Medical Termination of the Pregnancy) after which she improved. Those patients who developed convulsion were treated by gabapentin and IV lorazepam. All the patients recovered fully in the course of one week to four months.Discussion Early in the last century, Waldenstrom [4] called AIP as the little imitator distinct from the more common manifestation of neurosyphilis. The severe constipation and episode of abdominal pain, hypertension and tachycardia seen during an acute attack of porphyria may be because of an autonomic neuropathy. A predominantly axonal neuropathy, which can be acute and involve the bulbar cranial nerves and respiratory muscle is well described. [5] Involvement of the central nervous system is comparatively less common. Several mechanisms have been proposed to explain the neurological symptoms of AIP, which includes overproduction of ALA and PBG and their accumulation in nervous tissue exhibiting neurotoxic properties. [6],[7] Convulsion can occur at any time during acute illness but acute symptomatic seizures are a well recognized feature of porphyria in relapse [8],[9] and subsequent use of enzyme-inducing antiepileptic drugs can cause a worsening of condition and new symptoms, such as acute neuropathy and respiratory paralysis. Further, it is less well documented that these manifestations can occur as a rapid progressive course during the first attack of AIP. All the cases presented in this series attended the emergency room with almost similar attacks of AIP with short duration of gastrointestinal symptoms followed by very rapidly progressive course of neuropsychiatric manifestations in the form of peripheral neuropathy, respiratory paralysis and seizures with loss of consciousness. In four patients there was no past history of similar episodes and they were not known cases of AIP. Family history of AIP was present in four cases. Four of our cases (no. 1-4) presented with gastrointestinal symptoms and seizure, case no. 5 with pain abdomen and polyneuropathy and case no. 6 presented with pain abdomen and altered sensorium. No definitive cause was revealed for CNS dysfunction except in case no. 5 in which hyponatremia was documented. Diagnosis of all cases was done by past history of similar episode, family history of AIP, clinical feature and Watson-Swartz test and further confirmed by quantitative PBG / ALA estimation, but further evaluation by PBG deaminase enzyme assay or mutation analysis was not done because these tests are not available. Heme arginate (IV) is the treatment of choice and very effective if given early in the course (within one-two days) of illness and leads to biochemical reemission followed by clinical improvement in one to two weeks but it is less effective if treatment is delayed. [10],[11] Limitations for using heme arginate are that it is not universally available, very costly (four-day course costs approximately $8000) and can cause severe coagulopathy and anaphylactic reactions sometimes. Since definite diagnostic facilities are not available widely, high clinical suspicion and early diagnosis by Watson-Swartz test and effective management of acute attacks is very important in reducing mortality and morbidity. [11] Acute intermittent porphyria should always be considered as differential diagnosis in case of abdominal pain with neuropsychiatric manifestation, whether family history of AIP is present or not. Finally, once the diagnosis has been confirmed, the family members must be screened for the PBGD enzyme level and/or mutation analysis to diagnose asymptomatic carriers. References
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