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OVERVIEW
This page is dedicated to organizing various examples of standardized exam questions whose answer is Creutzfeldt-Jakob disease (CJD). While this may seem a odd practice, it is useful to see multiple examples of how CJD 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 CJD .
Chief Complaints:
- Memory loss: of both recent and remote events. Progressive in nature
- Confusion/behavioral changes are also often observed
- Inability to walk that is a recent occurrence
- Jerking movements of any/all limbs (often stimulus induced/caused by loud noises)
Patient History:
- Rapid/progressive consent of symptoms: generally patients will deteriorate in a period of weeks to months (very quickly!)
Clinical Workup:
- Increased reflexes can be seen throughout the exam
- Myoclonic responses to stimuli (like loud noises)
- Elevated protein in CSF can be seen (generally no other abnormalities). Specifically there will be increased 14-3-3 protein that can be detected in the CSF.
- Brain atrophy on imaging (sometimes no clear findings present on imaging)
- EEG findings of generalized slowing and period sharp waves (that can be described as synchronous)
QUESTION EXAMPLES
Question # 1
A previously healthy 58 year old woman comes to the clinic with her husband because of an 7 week history of progressing confusion and memory loss. She can no longer work at her job as a bank manager because she has become so impaired. Her husband says that she always used to be outgoing and talkative, but now she hardly will say anything at all. Her speech is dysarthric. Physical exam shows diffuse hyperreflexia. The patient has a Babinksi sing bilaterally. She exhibits myoclonus in response to loud noises. Her Mini-Mental State Examination score is 8/30. Lab studies, including CSF analysis, are unremarkable. An MRI of the brain shows no abnormalities. EEG shows generalized slowing, with periodic sharp waves. What is the most likely diagnosis?
Explanation #1
Progressive confusion/memory loss + hyperreflexia + myoclonus in response to stimuli + EEG with generalized slowing/period sharp waves = CJD
Question #2
A 65 year old man is brought to the clinic by his son because he has been having difficulty remembering both recent and remote events for the past 4 months. His son also mentions that he has been making jerky movements of both his arms and legs for the past month. The patient has had recent falls where he has lost his balance when walking. A physical exam reveals the presence of frequent myoclonic jerking of all 4 limbs. There is also increased muscle tone and increased reflexes. A CT scan of the head is performed, and shows mild atrophy. A lumbar puncture is conducted and analysis of the CSF is notable only for a protein concentration of 85 mg/dL. An EEG shows a slow generalized background that his interrupted by synchronous and shape wave complexes. What is the likely diagnosis in this patient?
Explanation #2
Memory issues + myoclonic jerking of limbs + hyperreflexia + elevated protein in CSF + EEG with generalized slowing/period sharp waves = CJD
Question #3
A 70 year old male is brought to the clinic by his wife because he has been suffering from cognitive changes for the past 2 months. His wife also comments that he has been making “weird twitching movements” with all four extremities that has her quite concerned. The patient’s past medical history is unremarkable, and he does not take any chronic medications. He does not have any history of smoking, alcohol, or drug abuse. Examination reveals slight ataxic dysarthria, however muscle strength is intact throughout the upper and lower extremities. Deep tendon reflexes are increased throughout. The patient has frequent irregular jerks of the upper and lower extremities, and also has an ataxic gait. He is alert on a mental status exam, however his Mini-Mental State Exam score is 18/30. CSF analysis is conducted and shown below:
- Glucose: 75 mg/dL
- Total protein: 55 mg/dL ***
- WBC: none detected
- RBC: none detected.
An MRI of the brain is conducted that is non-contributory other then showing vague areas of abnormal T2 signal in the basal ganglia. What is the likely diagnosis in this patient?
Explanation #3
Cognitive changes + hyperreflexia + myoclonus/jerking movements + elevated protein in CSF = CJD
Question #4
A 60 year old male is brought to the clinic by his wife because he has been acting “strangely” for the past 2 months. His wife explains that she noticed something was wrong when he started having more anxiety and fatigue, that was followed by issues with his memory. About 6 weeks ago, he also began to have issues with his balance which has now progressed to the point where he can not walk without assistance. This past week he has been having “full body jerks” that occur after he hears loud noises, such as when his wife dropped and shattered a glass. An exam reveals a disoriented patient, with decreased memory, and marked ataxia that prevents him from walking. He also has stimulus induced myoclonus. An MRI reveals generalized cerebellar atrophy, but has no other findings. What is the likely diagnosis in this patient?
Explanation #4
Memory loss + full body jerking movements + stimulus induced myoclonus = CJD
COMMONLY ASKED QUESTIONS ABOUT THIS CONDITION (BEYOND ITS IDENTIFICATION)
Many questions on standardized exams go beyond simply recognizing the underlying condition. Often there are specific testable questions regarding some aspect of the diseases pathophysiology/management/clincial implications that are commonly asked. Some of these are listed below:
Cause:
- Prion protein (PrP) is the cause of CJD
- What it does: accumulates intracellularly, and causes spongiform transformation of grey matter.
Diagnosis:
- What is found in the CSF: normally only increased protein can be seen on CSF analysis (no blood or WBC) however if specifically analyzed, increased 14-3-3 protein is detected in the CSF of patients with this condition.
Page Updated: 09.17.2016