This page is dedicated to organizing various examples of standardized exam questions whose answer is acute intermittent porphyria. While this may seem a odd practice, it is useful to see multiple examples of how acute intermittent porphyria will be characterized on standardized exams (namely the boards and the shelf exams). This page is not meant to be used as a tradition question bank (as all of the answers will be the same), however seeing the classic “test” characterization for a disease is quite valuable.
KEY CHARACTERISTICS OF THIS CONDITION (ON EXAMS)
When it comes to standardized exams, each condition has its own “code” marked by key buzzwords, lab findings, clues, etc. If you are well versed in this code you will be able to more quickly identify the condition that is being discussed, and get the right answer on the exam you are taking. Below is the “code” for acute intermittent porphyria.
- Abdominal pain is a common complaint
- Peripheral neuropathy: can be patchy numbness and paresthesias
- Psychological disturbances: can include anxiety, confusion, psychosis, dementia
- History of calorie restriction: patients who are dieting may cause ALA synthase induction, causing this condition
- Symptoms precipitated by drugs: drugs that enhance P-450 activity, sulfa drugs, barbiturates, some antipsychotics, alcohol
- Family history of similar symptoms: this is an autosomal dominant condition. Patients can have a family history of it.
- Colored urine: “port-wine” is the buzzword. Happens after exposed to the light (can comes out colorless)
- Increased porphobilinogen/ALA in samples: can be detected on urine studies or serum studies.
- Symptoms resolved by giving glucose or heme: giving dextrose/glucose or a heme solution to the patient will resolve their symptoms.
Question # 1
A 45 year old woman comes to the clinic because she is having suicidal thoughts, depression, and difficulty concentrating. She is not able to remember when exactly all of this began. She notes that both her father and mother have a history of similar symptoms. She notes that she also has intermittent abdominal pain. She does not drink alcohol, or take any medications because they worsen her gastrointestinal symptoms. He abdominal exam does not show any abnormalities. Neurological exam reveals decreased joint poison sense and Romberg sign is present. Her mental status exam is notable for a depressed mood and she does have evidence of suicidal ideation. What is this patient’s most likely diagnosis?
Psychological disturbances + abdominal pain + pain made worse with medication/alcohol + neuropathy (and associated Romberg sign) = acute intermittent porphyria
Question # 2
A 24 year old woman comes to the hospital complying of a 5-day history of constipation, nausea, and severe generalized abdominal pain. She also explains that she has been feeling very anxious lately, has trouble sleeping, can not concentrate on her graduate school work, and feels tingling in her limbs. She has had several episodes of these same symptoms in the past. She denies taking any medications or any drugs. She admits to restricting her diet recently in order to shed some weight for “beach season”. A exam reveals a soft, contender, and non-distedned abdomen. The patient is given an IV infusion of a heme preparation that quickly resolves her symptoms. What might this patient be suffering from?
Psychological disturbances + abdominal pain + neuropathy + restricted diet + symptoms resolved by IV heme = acute intermittent porphyria
Question # 3
A 30 year old woman comes to the emergency room with acute abdominal pain, nausea, and altered mental status. She has no notable past medical history and does not use any alcohol as it makes her feel sick. Her serum lipase and LFTs are all within normal limits. A CT scan of the abdomen is performed and does not explain the patient’s abdominal pain. A same of the patient’s urine is collected and is reddish in color, and darkens after standing for the day. IV dextrose is given to the patient and improves her symptoms. What might this patient be suffering from?
Abdominal pain + psychological disturbances (altered mental status) + alcohol makes symptoms worse + urine darkens after standing around + IV dextrose improves symptoms = acute intermittent porphyria
Question # 4
A 33 year old female comes to the emergency department after the onset of acute severe abdominal pain. She also is suffering from confusion. It is discovered that her sister, mother, and maternal grandmother all have a history of similar symptoms. She explains that a few weeks ago she began a new low calorie diet. Her vitals are: a heart rate of 115 bpm, blood pressure of 155/110 mm Hg. A physical exam shows a restless, diaphoretic, and tremulous patient. The abdominal exam is unremarkable. Urine studies show an increased concentration of porhobilinogen present. What is the likely condition this patient is suffering from?
Abdominal pain + psychological disturbances (confusion) + family history of same symptoms + low calorie diet + increased porhobilinogen in urine = acute intermittent porphyria
Question # 5
A 29 year old male is brought to the clinic by his husband because he has been acting irrationally for the past day, and also complains of severe abdominal pain. He was treated with antibiotics for a UTI about 3 days ago. His father and paternal grandfather also have similar symptoms. His urine was collected and turned a light burgundy color after sitting in the toilet about a year ago. Currently he is anxious and restless. His vitals are within normal limits. Serum studies show increased concentrations of ALA and porphobilinogen. What is this patient suffering from?
Abdominal pain + psychological disturbances (altered mental status) + family history of same symptoms + made worse with medications (UTI abx) + port-wine urine + increased ALA and porphobilinogen in serum = acute intermittent porphyria
TESTABLE FACTS ABOUT THIS CONDITION (BEYOND ITS IDENTIFICATION)
Many questions on standardized exams go beyond simply recognizing the underlying condition. Often there are specific testable facts regarding some aspect of the disease’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:
- Genetic cause: porphobilinogen deaminase deficiency
- Inheritance pattern: autosomal dominant mutation
- Accumulated substance: Porphobilinogen, ALA
- Other causes: dietary/calorie restriction (induces ALA synthase)
- Glucose and heme (inhibit ALA synthase)
Page Updated: 09.17.2016