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OVERVIEW
This page is dedicated to organizing various examples of standardized exam questions whose answer is Friedreich ataxia. While this may seem a odd practice, it is useful to see multiple examples of how Friedreich ataxia 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 topic 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 Friedreich ataxia.
Chief Complaints:
- Unstable gait that is progressive. Might be described as general “movement issues”
- Difficulty speaking that is progressive
Patient History:
- Hypertrophic cardiomyopathy/congestive heart failure: are caused by this condition (and may be presented in the patient history/family history)
- Sibling who died form vague neurological condition: this may be present in the family history (hinting at a sibling that has suffered from the same condition).
Clinical Workup:
- Gait ataxia
- Dysarthria
- Dysmetria
- Scoliosis/kyphoscoliosis
- Foot abnormalities: such as hammer toes, high plantar arches
- Loss of position/vibration sensation
QUESTION EXAMPLES
Question # 1
A 16 year old boy is brought to the clinic for the evaluation of an unstable gait and speech difficulty that is getting worse over time. His past medical history is unremarkable, he si not taking any medications, he has no allergies, and he denies smoking/alcohol usage. His blood pressure is 120/80 mm Hg, pulse is 75/min, and temperature is 98.7°F. A musculoskeletal exam reveals the presence of scoliosis and hammer toes. His neurological exam is notable for dysarthria, dysmetria, nystagmus, and the absence of plantar reflexes bilaterally on his lower extremities. What is the likely diagnosis in this patient?
Explanation # 1
Unstable gait + speech difficulty/dysarthria + scoliosis + foot abnormalities (hammer toes) = Friedreich ataxia
Question # 2
A 14 year old is brought to the clinic because he has been having “issues with movement” and difficulty with walking. The patient has been very active with soccer, however recently has had to quit because his symptoms have been progressively worsening. A physical exam reveals kyphoscoliosis and his feet have high plantar arches. His family history is notable for an older brother who was diagnosed with a neurological disorder and died from heart failure before the age of 30. What is the likely diagnosis in this patient?
Explanation # 2
Movement issues + kyphoscoliosis + foot abnormalities (high plantar arches) + family history of heart failure + neurological disorder = Friedreich ataxia
Question # 3
A 15 year old female has a past history of gait instability, dysarthria, and dysmetria that has been worked up for the past few years. Her symptoms initially began as weakness and clumsiness, that have progressed to the point that she needs to brace herself on the walls to avoid falling when walking down the hallway in her house. A physical exam reveals the presence of kyphoscoliosis and pes cavus. A neurological exam reveals that joint position and vibration sensation is impaired. What is the likely diagnosis in this patient?
Explanation # 3
Gait instability + dysarthria + dysmetria + kyphoscoliosis + foot abnormalities (pes cavus) = Friedreich ataxia
TESTABLE FACTS ABOUT THIS TOPIC (BEYOND ITS IDENTIFICATION)
Many questions on standardized exams go beyond simply recognizing the underlying topic. Often there are specific testable facts regarding some aspect of the topic’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:
Cause:
- Mutation in the frataxin (FXN) gene. This gene codes for an essential mitochondrial protein that is involved in the assembly of iron-sulfur enzymes.
- Type of mutation: increased number of trinucleotide repeats (GAA) which causes decreased gene expression.
- Consequence of mutation: Decreased mitochondrial energy production, increased oxidative stress, degeneration of neural tracts and peripheral nerves.
- Inheritance pattern: autosomal recessive
Neurological implications:
- Degeneration of spinocerebellar tracts: causes the ataxia
- Degeneration of dorsal columns: results in the loss of position and vibratory sense.
- Degeneration of perisperhal nerves: loss of deep tendon reflexes.
Complications:
- Cardiomyopathy will occur in many patients. Carries greatest risk of death (congestive heart failure)
- Diabetes mellitus occurs in a sizable fraction of patients
Page Updated: 11.25.2016