Path Labs - Brain & Behaviour Block - Movement Disorder
Department of Pathology & Laboratory Medicine
Case 1 - Answers
A1. Parkinson's disease.
Differential diagnosis:
--other neurodegenerative diseases: progressive supranuclear palsy; striatonigral degeneration
--drugs: phenothiazine; reserpins
--toxins: carbon monoxide; manganese; MPTP
--viral infections (rare): encephalitis lethargica
--trauma: dementia pugilistica
--vascular disease with lacunar infarcts in basal ganglia
A2. Loss of pigmentation of the substantia nigra.
A3. Degeneration of pigmented neurons of substantia nigra. These neurons are the major source of dopamine which is released in the striatum. The treatment is designed to replace endogenous dopamine.
A4. Lewy bodies.
A5. (i) cortical Lewy bodies.
(ii) Alzheimer pathology; senile plaques and neurofibrillary tangles.
Case 2 - Answers
A1. Atrophy of the cerebellar cortex, most severely involving the superior vermis.
A2. Loss of Purkinje cells and granular cell neurons with corresponding gliosis.
A3. Chronic alcoholism causes selective degeneration of the superior cerebellar vermis, either as a direct toxic effect or because of associated nutritional (thiamine) deficiency.
A4. The midline portion of the cerebellum (called the vermis) is functionally known as the spinocerebellum. In response to proprioceptive input from the periphery, this region influences muscle tone for posture and coordinates muscle activity for stereotyped leg movement of locomotion.
Case 3 - Answers
A1.
Figure 3-1: atrophy of the anterior roots.
Figure 3-2: loss of myelin staining of the lateral cortical spinal tracts secondary to cortical spinal tract degeneration. Note that this is not demyelination.
Figure 3-3: loss of motor neurons in the anterior horn.
Figure 3-4: atrophy of skeletal muscle. The pattern is characteristic of denervation atrophy.
A2. This patient suffered from motor neuron disease or amyotrophic lateral sclerosis (ALS).
A3. Neurologic examination had revealed signs of both upper and lower motor neuron deficits.
Case 4 - Answers
A1.
Figure 4-1: Coronal section of the brain showing severe atrophy of the caudate nuclei and lateral ventricular dilatation secondary to atrophy.
Figure 4-2: Closer view showing severe atrophy of the caudate.
Figure 4-3: Loss of neurons and gliosis of the caudate.
A2. This patient had Huntington's disease. This is an autosomal dominant disorder. Due to the late age of onset, transmission to children has often occurred before the onset of symptoms in the parent.
Genetic basis: abnormal expansion of a cytosine adenine-guanine triplet repeat sequence in a gene on chromosome 4 (the Huntington gene).
A3. The genetic basis for the reason why recent generations are affected at an earlier age, and more severely, than older generations within the same family is a progressive increase in the length in the tandem repeat sequence as the disease is passed on.