Neurology Quiz | Neuroq quiz | Practice MCQ #mcq.ImBooz

• (A) C6
• (B) T2
• (C) T5
• (D) T10

Check AnswerSolution[D]:-There can be some interindividual variation; however, T10 is clearly the best choice.

• (A) Third-nerve palsy
• (B) Calf atrophy
• (C) Charcot joints
• (D) Atrophy of the intrinsic hand muscles

Check AnswerSolution[D]:-A syrinx is an abnormal fluid collection resulting in an expansion of the central canal. As the lesion in this region of the spinal cord increases in size, it may affect the lower motor neuron in the anterior horn of the spinal cord, producing weakness in the distribution of the affected motor neurons. Because it is a lower motor neuron lesion, reflexes will be lost rather than increased in the upper extremities, which may at first seem counterintuitive in a spinal cord lesion. The more laterally placed corticospinal tract may be spared, leaving leg function and reflexes relatively normal. Charcot joints are the result of cumulative damage from loss of reflexes and diminished pain awareness, classically associated with syphilis or more commonly diabetes.

• (A) C5 and C6
• (B) C6 and C7
• (C) C7 and C8
• (D) C8 and T1

Check AnswerSolution[D]:-The first dorsal interosseous muscle is innervated by the ulnar nerve. The fibers of the ulnar nerve reaching this muscle originate at the C8 and T1 roots. If the ulnar nerve itself is the neural element injured, it is usually because of damage at the elbow, where the ulnar nerve runs superficially in the groove over the ulnar condyle. All the interosseous muscles of the hand are supplied by the ulnar nerve: Complete transection of that nerve will produce interosseous wasting and impaired finger adduction and abduction. Although the lumbrical muscles are situated alongside the interosseous muscles of the hand, only two lumbricals-those on the ulnar metacarpals-are innervated by the ulnar nerve. The other two lumbricals are innervated by the median nerve. All four lumbricals insert on the extensor sheaths of the fingers and participate in extension of the digits.

• (A) Intraspinal contusion
• (B) Intraspinal transient ischemia
• (C) Intraspinal hyperthermia
• (D) Intraspinal demyelination

Check AnswerSolution[A]:-After cervical cord contusion, cyst formation may occur as damaged tissue is removed. This is especially likely if there has been extensive intraspinal hemorrhage. Ischemic damage may produce similar changes, but the ischemia must be substantial and persistent enough to produce infarction of spinal cord tissue. Demyelination does not lead to syringomyelia, even in cases with extensive intraspinal demyelination.

• (A) Initiate anticoagulation
• (B) Perform sensory-evoked potential testing
• (C) Order an MRI scan
• (D) Place a cervical collar

Check AnswerSolution[C]:-A number of spinal cord processes could have produced this evolving paraplegia. Rapid investigation is essential to maximize the likelihood that this young man will recover cord function once the lesion has been treated. Even a reversible lesion left untreated for days or weeks will lead to permanent disability. MRI scanning is the best emergent test when available, as it will show compressive lesions as well as processes, such as tumors, inflammation, or infection, that may affect the parenchyma of the spinal cord itself. Vascular lesions, such as spinal cord arteriovenous malformations, may also be seen on MRI, although spinal angiography is often required to confirm the lesion and guide therapy. Anticoagulation is ill advised, because any one of several processes, such as tumors, vascular malformations, or infections, may have already led to bleeding into the spinal cord or be susceptible to bleeding. The patient in the case history had schistosomiasis.

• (A) An intraparenchymal ependymoma
• (B) An extraparenchymal meningioma
• (C) A syringomyelia
• (D) A transverse myelitis

Check AnswerSolution[D]:-With an intraspinal hemorrhage, the CT scan would be expected to reveal the clot as a relatively dense mass within the spinal canal. Tumors, such as meningiomas and ependymomas, should have been obvious on MRI if they were producing such dramatic symptoms and signs. Similarly, a syringomyelia should be evident as a cyst that extends over several levels of the spinal cord. With a transverse myelitis, inflammation is largely limited to the substance of the cord, and there need not be an apparent mass effect. This type of reaction may occur with a variety of noninfectious processes, such as multiple sclerosis and sarcoid, or infectious processes, such as viral and parasitic infections.

• (A) Taenia solium
• (B) An extraparenchymal meningioma
• (C) Schistosoma mansoni
• (D) Entamoeba histolytica

Check AnswerSolution[C]:-T pallidum may produce a granulomatous lesion (gumma) in the spinal cord, but this young man has an ovum in the granuloma, which suggests the much more common transverse myelitis attributable to schistosomiasis. Both S mansoni and S japonicum embolize eggs to the central nervous system (CNS), but it is S mansoni that is endemic in Puerto Rico and in locations in South America and that embolizes to the lumbar spinal cord. This patient should be treated with an anti-schistosomal agent such as praziquantel. Even with treatment, the reversal of disability produced by this spinal cord injury is usually negligible.

• (A) Aortogram
• (B) Voiding cystometrogram
• (C) Electroencephalogram (EEG)
• (D) NONE

Check AnswerSolution[A]:-This patient has symptoms suggestive of ischemic spinal cord disease. The principal source of blood for the spinal cord is the aorta. Vessels that supply the cord are somewhat variable in their origins, but they most commonly arise as branches of the vertebral and hypogastric arteries, as well as of the aorta at the level of the upper and lower thoracic vertebrae. The artery most implicated in a patient with this constellation of symptoms is the great anterior medullary artery (of Adamkiewicz), which arises from the aorta at the level of T10 to L1 and supplies the anterior median spinal artery

• (A) At the junction of the medulla and the spinal cord
• (B) At the junction of the midbrain and the medulla
• (C) At the junction of the pons and the medulla
• (D) At the thalamus

Check AnswerSolution[A]:-The lateral corticospinal tract originates primarily in the precentral gyrus (primary motor cortex). These axons then travel in the posterior limb of the internal capsule and then the middle section of the cerebral peduncle. They enter the basal pons and continue as the pyramids in the medulla. At the decussation of the pyramids, the lateral corticospinal tract crosses and then continues down the spinal cord.

• (A) Joint proprioception
• (B) Pain
• (C) Temperature
• (D) Two-point discrimination

Check AnswerSolution[A]:-Spinal cord ischemia is usually most severe in the distribution of the anterior spinal artery. The posterior spinal artery is more a plexus of arteries with extensive anastomoses than a discrete pair of blood vessels running along the dorsal aspect of the spinal cord. With a lesion of the spinal cord from ischemia or pressure, the spinothalamic tracts, which are responsible for pain and temperature perception and for providing information for two-point discrimination and graphesthesia, are more vulnerable to injury than are the posterior columns. The posterior columns, which are primarily responsible for vibration and position sense, are supplied by the posterior spinal arteries.

• (A) Myotonia
• (B) Myokymia
• (C) Spinal claudication
• (D) Spondylolisthesis

Check AnswerSolution[C]:-With exertion, blood that would be available to the spinal cord under resting conditions might be shunted to the more patent blood vessels of the limb muscles. Unlike more typical claudication, in which leg pains develop because of poor blood flow to leg muscles, the leg pains of spinal claudication develop because of shunting of blood to the leg muscles. The pain is a reflection of ischemia to the sensory neurons in the spinal cord. Spondylolisthesis (the slippage of vertebral elements) and spondylolysis (the idiopathic dissolution of vertebral elements) may lead to pain with exertion because of the vertebral instability associated with these commonly linked conditions. However, these diagnoses should be apparent on x-ray. Myotonia and myokymia are disturbances of muscle activity that would not be expected in association with ischemic spinal cord disease.

• (A) A protein content of greater than 45 mg/dL
• (B) An increase in the CSF gamma globulin content
• (C) A depressed CSF glucose content
• (D) More than 100 red blood cells (RBCs) per ?L

Check AnswerSolution[A]:-With spinal cord infarction, as with cerebral infarction, the CSF is relatively normal. If there is an abnormality, it is most likely to be an elevated CSF protein. The gamma globulin content is not disproportionately increased, as it would be with MS. The cell count of the fluid should be normal. If the RBC content is increased, the physician must suspect hemorrhage into the CNS. An elevated WBC count suggests a wide variety of diseases, including infection, meningeal carcinomatosis, and meningeal lymphomatosis.

• (A) No flow through the artery of Adamkiewicz
• (B) Complete occlusion of the bypass graft
• (C) Complete occlusion of the hypogastric artery
• (D) Complete occlusion of the aorta below the tenth thoracic vertebra

Check AnswerSolution[A]:-Collateral flow may develop with spinal cord ischemia, but the collateral supply to the anterior cord is likely to fail if the vascular system that supplies the cord is stressed. With the aortic bypass graft, pressure is reduced in the aortic aneurysm and the risks imposed by the dissection in the aortic wall may be reduced, but the pressure forcing blood through the partially obstructed artery of Adamkiewicz is also reduced. With complete failure of flow through this spinal artery, the spinal cord infarction may extend substantially and produce irreversible deficits. Bladder and bowel control is disturbed, along with the loss of strength and sensation in the legs.

• (A) Human immunodeficiency virus (HIV)-associated neuropathy
• (B) Lyme neuropathy
• (C) Diphtheritic polyneuropathy
• (D) Tuberculous meningitis

Check AnswerSolution[B]:-The clinical scenario presented is most consistent with a neuropathy of Lyme disease, the infection caused by Borrelia burgdorferi. This spirochetal infection is tick-borne and is endemic in the area where this patient lives. The rash on his leg was most likely erythema chronicum migrans, a target-shaped lesion that enlarges as the central area returns to normal. His complaints and examination suggest a chronic meningitis preceded by an arthralgia, a common neurological scenario with Lyme disease. Facial weakness may be the only neurological sign of Lyme disease. The neurological deficits usually appear weeks after the initial rash. Untreated neurological disease may persist for months. Optic neuritis may also appear in association with the chronic meningitis of Lyme disease. A schwannoma may develop on the seventh cranial nerve, but it would produce unilateral facial weakness followed by signs of brainstem compression. The cranial nerve dysfunctions associated with the early stages of diphtheritic polyneuropathy are a consequence of a toxin released by the infectious agent. Tuberculous meningitis may produce several different cranial nerve deficits. With HIV infection, a peripheral neuropathy may develop, but it typically affects the limb nerves, not the facial nerve.

• (A) Ceftriaxone
• (B) Thiamine
• (C) Eryth0romycin
• (D) Pyridoxine

Check AnswerSolution[D]:-These antituberculous drugs should be supplemented with pyridoxine to avoid a relative pyridoxine deficiency elicited by the isoniazid. The peripheral neuropathy evoked by the antituberculous agent will appear initially as disturbed sensation in the distal limbs. Paradoxically, pyridoxine overdose may also elicit a peripheral neuropathy, but overdose sufficient to produce a peripheral neuropathy is usually only seen in persons taking many times the recommended daily allowance of pyridoxine in vitamin preparations. It does not develop from eating foods with high levels of pyridoxine. Excessive pyridoxine consumption is usually linked to hypochondriasis or compulsive behavior. Ceftriaxone and erythromycin are appropriate antibiotics in the management of Lyme disease. The cephalosporin is preferred unless the patient is intolerant of that class of antibiotics.

• (A) Borrelia radiculopathy
• (B) Diabetic mononeuritis multiplex
• (C) Isoniazid neuropathy
• (D) Rifampin toxicity

Check AnswerSolution[A]:-This patient has, in effect, developed a noncompressive sciatica, or Lyme neuropathy. Dorsiflexion of the foot is controlled primarily by the anterior tibial muscle. The deep peroneal nerve supplies this muscle and arises from the common peroneal nerve just below the knee. A sciatic nerve injury may also produce foot-drop, and irritation of spinal roots to the sciatic nerve produces the foot-drop that may occur with Lyme radiculopathy. Lyme disease causes painful radiculopathies and peripheral neuropathies. Tuberculosis may cause similar symptoms, but steroid therapy is often useful in suppressing that complaint in chronic tuberculous meningitis. Steroid-induced diabetes mellitus would be unlikely to evolve to the point that a painful neuropathy developed over so short a time

• (A) Sarcoidosis
• (B) Aberrant nerve regeneration
• (C) Recurrent meningitis
• (D) Mononeuritis multiplex

Check AnswerSolution[B]:-Aberrant regeneration of a cranial nerve is not all that uncommon, but it is more often seen after injury to the third nerve than to the seventh. For unknown reasons, the regenerating motor fibers miss their original targets and innervate new destinations. With cranial ALS, facial twitching occurs, but it is not preceded by unilateral weakness, and it is seen as the weakness evolves, not as it remits. Sarcoidosis may produce facial weakness with aberrant regeneration, but this patient’s history does not suggest this idiopathic granulomatous disease. There is nothing to suggest that his Lyme disease is recurring, although recurrent meningitis may develop with inadequate treatment.

• (A) S3 to S4
• (B) L2 to L3
• (C) L4 to L5
• (D) S1 to S2

Check AnswerSolution[B]:-Myotactic, or tendon stretch, reflexes require intact sensory supplies from the tendons and motor supplies to the muscles involved. The patellar tendon reflex entails contraction of the quadriceps femoris muscle group, a muscle group with four members: the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris. This reflex requires perception of stretch in the tendon stretch receptors innervated by L2 and L3. With tapping of the tendon that extends from the patella to the head of the tibia, spinal reflex pathways activate contraction of the quadriceps femoris group and evoke extension of the lower leg with straightening of the knee. Damage to the motor supply to the reactive muscles must be profound before the tendon reflex will be lost completely. Corticospinal tract damage will produce hyperreflexia, apparently by disinhibiting spinal cord mechanisms.

• (A) Lead
• (B) Manganese
• (C) Thallium
• (D) Cyanide

Check AnswerSolution[A]:-Lead poisoning, especially in adults, produces a painless neuropathy often targeting the radial nerve and resulting in a wristdrop. Lead poisoning in children is likely to produce increased intracranial pressure and cognitive dysfunction. Thallium poisoning may produce hair loss, stupor, gastrointestinal distress, seizures, and headaches, as well as a painful, symmetric, primarily sensory neuropathy. Manganese is also a toxin, but long-term exposure to this metal may produce parkinsonism rather than a sensory neuropathy. Cyanide was long regarded as the cause of an optic neuropathy, but this lethal toxin has probably been unjustly ascribed this capability. Mercury poisoning may produce a sensory neuropathy, but it is generally associated with paresthesias rather than dysesthesias.

• (A) Diabetes mellitus
• (B) Temporal arteritis
• (C) Sarcoidosis
• (D) Systemic lupus erythematosus

Check AnswerSolution[A]:-Diabetes mellitus is the most common cause of mononeuritis multiplex. In this disorder, individual nerves are transiently disabled. The neuropathy usually develops over the course of minutes to days, and the recovery of function may require weeks to months. Various rheumatoid diseases and sarcoidosis produce similar clinical pictures, but temporal arteritis does not typically lead to this type of neuropathy. A vascular lesion is believed to be the most common basi