Welcome to Study of the Week from Patient Worthy. In this segment, we select a study we posted about from the previous week that we think is of particular interest or importance and go more in-depth. In this story we will talk about the details of the study and explain why it’s important, who will be impacted, and more.
If you read our short form research stories and find yourself wanting to learn more, you’ve come to the right place.
This week’s study is…
Pink urine as an inkling for a diagnostic dilemma: acute hepatic porphyria
We previously published about this research in a story titled ” “Pink” Urine Helps Diagnose Acute Hepatic Porphyria” which can be found here. The study was originally published in the medical journal BMJ Case Reports. You can view the full text of the study here.
What Happened?
This research comprises a case study involving a young pregnant woman, age 23, who was reporting signs of illness. She had been pregnant for six weeks when she suddenly started experiencing pain that began to spread throughout her abdominal area. This pain was in the form of cramps that occurred at irregular intervals. The patient also reported a feeling of weakness affecting all of her limbs. Doctors noted that her eyelids were pale. However, a normal course of bloodwork and physical failed to reveal any other abnormalities.
She also underwent an ultrasound which excluded several conditions related to the pregnancy, such as early pregnancy loss, molar pregnancy (a non-viable fertilized egg or tissue mass begins to grow in the womb), or ectopic pregnancy (a fertilized egg begins growing outside the womb). Next, the doctors evaluated a sample of her urine. When the sample was put under UV light, they noticed something unusual: the sample glowed a bright, fluorescent pink.
When her symptoms receded, the next urine sample they tested did not glow pink. At this juncture, the patient was diagnosed with acute hepatic porphyria, a rare disease. The urine took on the pink color because of the oxidation of porphobilinogen into porphobilin, which is a known precursor of porphyrin. The patient expressed relief at knowing her diagnosis, and had experienced earlier, milder episodes of symptoms that she had previously tried to ignore.
About Acute Hepatic Porphyria
Porphyria is a group of diseases which are most characterized by the accumulation of porphyrins in the body, which can cause harm to the skin and nervous system. These genetic inherited diseases are either acute or chronic in form and are caused by mutations that cause a deficiency of a certain enzyme that normally processes porphyrins. Acute hepatic porphyria is a sub-group of four types in which the deficient enzyme occurs in the liver and in which symptoms appear rapidly and severely. An attack can be triggered by a variety of drugs, alcohol, smoking, stress, fasting, or hormonal changes. Symptoms include severe abdominal pain, convulsions, sensory changes, muscle weakness, hallucinations, anxiety, confusion, and irritability. An acute hepatic porphyria attack is a medical emergency and an infusion of heme arginate should be administered immediately. To learn more about acute hepatic porphyria, click here.
Why Does it Matter?
This case study highlights an approach that can help physicians easily diagnose a rare disease that otherwise can be tricky to identify, as it doesn’t present with distinct, uniform symptoms. Diagnosing porphyria can be nearly impossible for doctors that aren’t familiar with the disease, but it typically involves a combination of genetic testing and testing for porphyrin precursors or porphyrin itself in either the urine, blood, or fecal matter. Genetic tests, while accurate, are less common due to higher costs and more limited availability.
One of the most widely used tests involves searching for the precursor porphobilinogen in the urine. However, this test, despite being commonly used, is notorious for false-positive results in a certain percentage of cases. However, as this case study shows, a UV light can be a critical tool since the oxidation process of the porphyrin precursors causes a fluorescent pink coloration.
Acute AHP attacks disproportionately impact women of reproductive age but since it doesn’t always trigger skin-related symptoms (this depends on the type of AHP) like other types of porphyria, less experienced doctors can easily be led astray.
“Simple, efficient, time-effective and cost-effective methods like first-line examination of urine sample under ultraviolet light have a potential role in investigating these rare diagnostic dilemmas under appropriate clinical suspicion.”
Diagnosing acute hepatic porphyria promptly is important as a severe attack of symptoms can potentially be fatal, and treatment often needs to begin early in an episode of symptoms in order to be effective.
Doctors may also overlook other telltale signs, such as urine changing to a darker color (almost purplish) upon standing; therefore, the more widespread implementation of the diagnostic method using UV light should have a positive impact on outcomes for patients. In addition, samples need to be taken in the middle of an attack in order to be useful.
