Pathology Lab-Demyelinating CNS Flashcards
A 32-year-old woman presented with a 3-month history of waxing and waning unilateral visual impairment and facial numbness. MRI of the brain revealed several sharply circumscribed demyelinating white matter lesions adjacent to the lateral ventricles and involving the visual pathways. CSF protein electrophoresis revealed “oligoclonal bands.” What is causing her condition?
Multiple sclerosis. This is a Th1 autoimmune response against myelin that leads to destruction of oligodendrocytes.
A 50-year-old male presented with hand weakness that made handwriting and shirt buttoning difficult. Progressive upper and lower extremity weakness, with both lower motor neuron (muscle atrophy and fasciculations) and upper motor neuron (hyperreflexia and Babinski sign) signs. This was followed by brainstem manifestations consisting of tongue weakness, atrophy and fasciculations, facial musculature weakness, dysarthria and impairment of chewing and swallowing. Ocular motor function, bodily sensation, intelligence and awareness were unaffected. The patient died from progressive respiratory weakness and aspiration pneumonia, 4 years after onset of symptoms. What is causing his condition?
25% of the hereditary (10% of all cases) cases have a mutation in SOD1. Misfolding of superoxide dismutase initiates apoptosis of alpha-motor neurons that causes some forms of ALS.
A 62-year-old woman with a 6-year history of progressive severe memory loss and dementia, was admitted to a psychiatric hospital where she was diagnosed with Alzheimer Disease (AD) and died subsequently of sepsis. Labs: Low amyloid B 42 protein identified in CSF. Review of prior MRI study disclosed bilateral medial temporal lobe atrophy. What would you expect to see on histology of this patient’s brain?
Neurofibrillary tangles in neuron cytoplasms (tau and ubiquitin). Neuritic plaques (beta-amyloid)
8-year-old male child admitted with fever and neck rigidity. Shortly thereafter, he developed cramping muscle pain, spasms, coarse twitching and weakness in upper and lower extremities, progressing to quadriplegia and paralysis of the respiratory musculature. Died of pneumonia despite antibiotics and supportive therapy. Why should this kid have entered the lottery?
1% of people who develop gastroenteritis from poliovirus have CNS infection. 1% of people who have CNS involvement will develop permanent paralysis.
A 34-year-old female diplomat was in good health until January 1999, when she was diagnosed with a tapeworm infection while in Brazil. In July 2001 she experienced sudden onset of seizures manifested initially as difficulty with speech and secondary generalization, and later with left-side headache, flashing lights in the right peripheral field, and right visual field haziness. She continued to have periodic episodes of symptoms including grand mal seizures despite Dilantin treatment. At presentation and in August 2001 and October 2001, CT scans, EEGs, cerebral arteriograms, and lumbar punctures failed to detect abnormalities. In January 2002 she again experienced headache, flashing lights, and grand mal seizures. Brain CT revealed multiple round, noncystic enhancing lesions in the left frontal, parietal, and occipital regions. Stool examinations were negative for ova and parasites. A “Swiss cheese” homonymous partial field defect in the right upper quadrant was documented. Patient has nodules on her right thigh. Serum enzyme-linked immunoelectrotransfer blot (IETB) detects anticysticercal antibodies. CSF ELISA were negative for anticysticercal antibodies and for cysticercal antigens. Plain X-ray films of thigh reveal “cigar-shaped” calcifications in thigh and calf muscles. How did she get this condition?
Eggs from the parasite taenia solium land in the skeletal muscle, skin, brain and heart, where they form cysts in pork. When you eat pork meat, which contains muscle, you swallow the cyst which turns into a tapeworm. The tapeworm then makes eggs and causes you to form cysts in your own muscle, skin, brain and heart.
A 25-year-old U.S. Marine corporal was bitten by a raccoon while hiking at Great Falls Park. Two months later he was admitted to Walter Reed National Military Medical Center with evidence of encephalitis, including agitation, confusion, seizures, fever, cranial nerve palsies, difficulty swallowing with excessive salivation resulting in “foaming at the mouth,” and finally coma. He died 4 days after the onset of symptoms. What would you expect to see on histology of this patient’s hippocampus or cerebellum?
He was infected by the rabies RNA virus. Negri bodies.
Why do patients with multiple sclerosis present with oligoclonal bands?
Oligoclonal bands are a limited number of antibodies produced by B cells in response to specific antigens in autoimmune disease.
What would you likely see on histology of the different marked areas in the image below?
Note the grayish plaques adjacent to the lateral ventricles indicating multiple sclerosis. MS plaques show perivascular lymphocyte and monocyte inflammation.
Virchow-Robin space
Perivascular lympho-monocytic inflammation in MS.
What condition is indicated in the myelin stain shown below?
MS, note decreased myelin. Note that the demyelinated neuron is still there, where it wouldn’t be in ALS.
What are fasciculations in the tongue pathognomonic for?
ALS
What condition is this?
ALS. Note degeneration of the primary motor cortex which houses the alpha motor neurons.
What is your diagnosis?
Note areas of pallor in the lateral cortical spinal tract and anterior horn, indicating ALS. Remember that it is loss of neurons, not only loss of myelin.
A patient presents with loss of bladder control, widened gait and dementia. What is the condition?
Normal pressure hydrocephalus. Expanding ventricles from decreased CSF reabsorption impinges the surrounding brain and causes these symptoms.
Why are Alzheimer’s patients at increased risk for brain hemorrhage?
Amyloid angiopathy weakens the blood vessels. Atrophy of the brain increases tension on bridging veins.
What is the pathophysiology of the paralysis that you sometimes see with poliovirus infection?
Inflammation and hemorrhage of alpha motor neurons.
What are the different ways you can acquire these in your bladder?
Eggs lead to cysts. Cysts lead to tapeworm. Tapeworm leads to eggs. Ingestion of anyone of these.
