Case Study: A 56-year-old man with Huntington’s disease presented with symptoms of Parkinson’s disease | Clinicians had to differentiate Huntington’s disease from Parkinson’s disease
A 56-year-old man with undiagnosed late-onset Huntington’s disease experienced symptoms similar to Parkinson’s disease, including bradykinesia or slowness of movement, according to a case report.
He was correctly diagnosed after clinicians learned of Huntington’s family history and ordered genetic testing.
Given the diagnosis, the researchers recommended that Huntington’s disease be considered when older patients with a family history of Huntington’s disease have Parkinson’s-like symptoms.
“Some patients may initially present with atypical movements other than the usual symptoms, such as parkinsonism, ataxia [poor muscle control]and dystonia [involuntary muscle contractions]“, wrote the team.
The case study, “Atypical parkinsonism may be a presenting feature of late-onset Huntington’s diseasewas published in the journal Clinical case reports.
Huntington’s disease vs Parkinson’s: similar symptoms
Huntington’s disease is caused by defects huntingtin (HT) embarrassed. These mutations lead to an expansion of CAG nucleotides, which are building blocks of DNA. Typically the HT The CAG gene expansion contains 10 to 35 repeats, but in people with Huntington’s disease it can be repeated from 36 to over 120 times.
These genetic defects lead to an imbalance of dopamine levels in the brain. Dopamine is a neurotransmitter, or nerve cell signaling molecule, that plays a vital role in body movement.
Abnormally high dopamine levels are thought to cause chorea – sudden, irregular and unpredictable movements. In the later stages of the disease, dopamine levels may drop, which may relieve chorea, but then show symptoms similar to Parkinson’s disease, a movement disorder characterized by abnormally low levels of dopamine. This can often lead to misdiagnosis.
Now, researchers based at Shahid Beheshti University of Medical Sciences in Iran have described the case of a man in his 50s with undiagnosed Huntington’s disease who was treated for symptoms like Parkinsons.
The man had been on treatment for depression for eight years before gradually developing other symptoms which all appeared to be signs of Parkinson’s disease. These symptoms included slurred speech, difficulty walking, an urgent need to urinate, constipation, memory problems and frequent falls.
His medical records showed no history of brain inflammation, known as encephalitis, or exposure to toxic substances. The man had also not received any drugs designed to reduce dopamine or block dopamine receptors.
Notably, her now deceased father had Huntington’s disease, as did her sister, who carried 42 CAG repeats.
On examination, the patient had an expressionless face and slow eye movements in all directions but more prominent vertically. His upper and lower limbs were rigid and he showed slowness of movement, called bradykinesia, also consistent with Parkinson’s disease.
During the examination, he exhibited repetitive hand movements and could not stand for more than three minutes to measure his blood pressure. His speech was unclear, high-pitched and whiny, and he also had significant cognitive impairment.
MRI scans demonstrated generalized atrophy or shrinkage of the brain, which was greatest in the temporal lobes and caudate nucleus. This area of the brain typically has the most nerve damage in Huntington’s disease.
Due to his family history of Huntington’s disease, he underwent genetic testing, which showed 39 CAG repeats in the HT embarrassed.
He had been treated with drugs for dementia (donepezil), to control body movement (amantadine, sold as Gocovri) and to prevent seizures (sodium valproate).
The team added the standard Parkinson’s disease therapeutic levodopa; a precursor molecule converted into dopamine in the brain. The dose was gradually increased from 25 mg three times a day to 100 mg three times a day, and the amantadine was also increased.
Treatment resulted in a slight improvement in bradykinesia, rigidity and gait.
The researchers noted that this was the fifth reported case of late-onset Huntington’s disease that had symptoms similar to Parkinson’s disease.
Huntington’s disease “should be considered as a differential diagnosis for patients with atypical parkinsonism, especially if the family history is positive,” the researchers concluded.