Nokea
What is the biological vector for African sleeping sickness?
- A. mosquito
- B. tsetse fly
- C. deer tick
- D. sand fly
Correct Answer: B
Rationale: The correct answer is B: tsetse fly. Tsetse flies are the biological vectors for African sleeping sickness, caused by the parasite Trypanosoma brucei. Tsetse flies transmit the parasite through their bite, leading to the infection in humans. Mosquitoes (choice A), deer ticks (choice C), and sand flies (choice D) are vectors for other diseases such as malaria, Lyme disease, and leishmaniasis, respectively. Therefore, they are not associated with the transmission of African sleeping sickness.
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A previously healthy 68-year-old male presents with progressive muscle weakness in his right hand, swallowing difficulty and difficulty with walking. He believes these symptoms occurred "out of the blue" and have worsened over the last 2-3 months. His temperature is 98.6 deg F (37 deg C), blood pressure 145/86 mmHg, pulse is 80/min, and respirations are 17/min. Neurologic examination is significant for mild dysarthria. He has atrophy of the thenar muscles of the right hand and forearm, and 2/5 strength on wrist extension and flexion, as well as 3/5 power in intrinsic hand muscles on right. He has some fasciculations in his right thigh, and mild (4+/5) weakness of hip flexors bilaterally. Tone is increased in both legs. Sensory examination is intact. 3+ patellar reflexes are noted on the left lower extremity. On gait testing, the patient has poor balance, and spastic gait. Which of the following is the most likely diagnosis?
- A. Guillain-Barre syndrome
- B. Amyotrophic lateral sclerosis
- C. Myasthenia gravis
- D. Multiple sclerosis
Correct Answer: B
Rationale: The patient's presentation of progressive muscle weakness, atrophy, fasciculations, and spasticity with hyperreflexia is classic for amyotrophic lateral sclerosis (ALS). ALS involves both upper and lower motor neuron degeneration, leading to a combination of weakness, atrophy, and spasticity. The absence of sensory deficits and the presence of bulbar symptoms (dysarthria, swallowing difficulty) further support this diagnosis. Guillain-Barre syndrome typically presents with ascending paralysis and areflexia, while myasthenia gravis is characterized by fatigable weakness without atrophy or fasciculations. Multiple sclerosis and dermatomyositis do not fit the clinical picture.
Where would you see the nodes of Ranvier?
- A. on an axon
- B. in the cell body
- C. on a dendrite
- D. a and c
Correct Answer: A
Rationale: Nodes of Ranvier are small gaps in the myelin sheath along the axon of a neuron. They play a critical role in the rapid conduction of electrical signals, as the action potential 'jumps' from one node to the next in a process called saltatory conduction. This increases the speed and efficiency of neural communication. Nodes of Ranvier are essential for proper nerve function and are found exclusively on axons.
An elderly patient is brought to the clinic for confusion, horizontal eye movement bilaterally, and intermittent disorientation to time and place over the past 3 months. The patient has a history of alcoholism for 30 years. Which dementia type is the patient most likely experiencing?
- A. Wernicke’s encephalopathy
- B. Pick’s disease
- C. Lewy bodies
- D. Parkinson’s disease
Correct Answer: A
Rationale: The correct answer is A: Wernicke's encephalopathy. This patient's history of chronic alcoholism puts them at risk for thiamine deficiency, leading to Wernicke's encephalopathy. Symptoms such as confusion, horizontal eye movement abnormalities (nystagmus), and disorientation are classic features. Pick's disease (B) is a rare form of frontotemporal dementia with distinct pathological features. Lewy bodies (C) are associated with dementia with Lewy bodies, characterized by visual hallucinations and parkinsonism. Parkinson's disease (D) primarily presents with motor symptoms like tremors and rigidity, not cognitive deficits like this patient.
The 4th cranial nerve supplies
- A. Lateral rectus
- B. Inferior oblique
- C. Orbicularis oris
- D. Superior oblique
Correct Answer: D
Rationale: The trochlear nerve (IV) innervates the superior oblique muscle, which depresses and abducts the eye. It is the only cranial nerve that exits dorsally from the brainstem.
In performing range of motion (ROM) with a patient, the nurse puts each joint through its full movement. Which joints are capable of abduction and adduction (select all that apply)?
- A. Hip
- B. Knee
- C. Wrist
- D. Elbow
Correct Answer: A
Rationale: Hips, thumbs, and shoulders allow abduction/adduction.