Acute intermittent porphyria presenting as acute muscle pain, fever, and weakness

Acute Hepatic Porphyrias: "Purple Flags"-Clinical Features That Should Prompt Specific Diagnostic Testing

BACKGROUND

Porphyrias are a group of rare diseases leading to dysregulation in heme biosynthesis and the accumulation of heme precursors, including porphyrinogens, which in their oxidized states [porphyrins] are reddish or purple. Acute hepatic porphyrias (AHP) comprise four diseases that cause acute debilitating neurovisceral attacks. Despite diagnostic advances, AHP is often undiagnosed or misdiagnosed due to a lack of disease awareness, low clinical suspicion, variable presentation, and nonspecific symptoms that mimic more common diseases. Delays in diagnosis and treatment increase the risk of serious acute and chronic complications.

METHODS

In order to assess whether symptoms alone or in combination might be utilized as important indicators or "purple flags" that, when present, should alert clinicians to suspect AHP and pursue specific diagnostic testing, we conducted a comprehensive review of the literature on AHP, including cohort studies and case reports over two epochs, from 1980 to 2006 and from 2012 to 2018.

RESULTS

We found that severe abdominal pain, with or without acute central nervous system manifestations and peripheral neuropathy, continues to be the most frequent symptom. Hyponatremia, change in urine color, and certain chronic symptoms were also identified as features that should raise suspicion of AHP. To improve diagnosis of AHP, clinicians need to take a broad perspective, including demographic data and medical history, into consideration.

CONCLUSIONS

The clinical features of AHP continue to be severe pain, especially pain in the abdomen. Other features that should raise suspicion are autonomic, peripheral, or central neuropathies, hyponatremia, and red-purple urine color.

Secondary myopathy due to systemic diseases

Background

Some systemic diseases also affect the skeletal muscle to various degrees and with different manifestations. This review aimed at summarizing and discussing recent advances concerning the management of muscle disease in systemic diseases.

Method

Literature review by search of MEDLINE, and Current Contents with appropriate search terms.

Results

Secondary muscle disease occurs in infectious disease, endocrine disorders, metabolic disorders, immunological disease, vascular diseases, hematological disorders, and malignancies. Muscle manifestations in these categories include pathogen‐caused myositis, muscle infarction, rhabdomyolysis, myasthenia, immune‐mediated myositis, necrotising myopathy, or vasculitis‐associated myopathy. Muscle affection may concern only a single muscle, a group of muscles, or the entire musculature. Severity of muscle affection may be transient or permanent, may be a minor part of or may dominate the clinical picture, or may be mild or severe, requiring invasive measures including artificial ventilation if the respiratory muscles are additionally involved. Diagnostic work‐up is similar to that of primary myopathies by application of non‐invasive and invasive techniques. Treatment of muscle involvement in systemic diseases is based on elimination of the underlying cause and supportive measures. The prognosis is usually fair if the causative disorder is effectively treatable but can be fatal in single cases if the entire musculature including the respiratory muscles is involved, in case of infection, or in case of severe rhabdomyolysis.

Conclusion

Secondary muscle manifestations of systemic diseases must be addressed and appropriately managed. Prognosis of secondary muscle disease in systemic diseases is usually fair if the underlying condition is accessible to treatment.

Is screening for urinary porphobilinogen useful among patients with acute polyneuropathy or encephalopathy?

Acute porphyrias are a group of inherited metabolic disorders representing overproduction syndromes with the formation of neurotoxic haem precursors. Clinical manifestations consist of acute attacks, which include abdominal pain, dysautonomia, mental symptoms, polyneuropathy and seizures mimicking many other acute neurological disorders.Porphyrin metabolites were screened in 108 patients with acute polyneuropathy or encephalopathy associated with pain and/or dysautonomia, who attended neurological wards, in order to evaluate the number of patients with acute porphyria.Urinary porphyrins and their precursors were increased in 21% of the cases. Surprisingly many patients (11%) had previously undiagnosed acute porphyria. Half of these patients had had mild to moderate symptoms of acute porphyria previously. Secondary porphyrinuria, which was mainly transient coproporphyrinuria because of hepatopathy, was also common (10%). Of the 108 patients studied, the levels of urinary porphyrins or their precursors were normal in the majority (79%) of the cases, who commonly had Guillain-Barré syndrome (40%). Epileptic seizures were also frequent (18%), but none of the patients with acute porphyria had solely epileptic seizures without prolonged confusion (>or= 1 day).Based on our findings, acute inherited porphyria is not infrequent among the selected group of neurological patients and screening of urinary PBG is cost-beneficial. Since the correct diagnosis of a hereditary disease is essential, genetic screening should be performed whenever possible for patients with clinically and biochemically confirmed acute porphyria.