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1. General Principles & Basic Science MCQs

Practice Set 491 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 9801

Topic: Biology, Genetics & Bone Healing

A 12-year-old girl is diagnosed with a symptomatic, solitary eosinophilic granuloma of the proximal humerus confirmed by biopsy. Which of the following is the most appropriate minimally invasive treatment option that has demonstrated high rates of resolution?

. Intralesional injection of methylprednisolone
. Radiofrequency ablation
. Intralesional injection of denosumab
. Extracorporeal shockwave therapy
. Intravenous bisphosphonates

Correct Answer & Explanation

. Intralesional injection of methylprednisolone

Explanation

For a solitary, symptomatic eosinophilic granuloma, intralesional injection of corticosteroids (e.g., methylprednisolone) is a highly effective, minimally invasive treatment. It promotes rapid pain relief, healing, and ossification of the lesion.

Question 9802

Topic: Biomechanics & Biomaterials

A 55-year-old female with limited cutaneous systemic sclerosis (CREST syndrome) presents with hard, painful subcutaneous nodules over her extensor forearms and fingertips.

Excision is considered due to frequent skin breakdown. What is the primary composition of these deposits?

. Monosodium urate crystals
. Calcium pyrophosphate dihydrate
. Calcium hydroxyapatite
. Calcium oxalate
. Cholesterol crystals

Correct Answer & Explanation

. Calcium hydroxyapatite

Explanation

The lesions described represent calcinosis cutis, a classic feature of CREST syndrome (Calcinosis, Raynaud's, Esophageal dysmotility, Sclerodactyly, Telangiectasia). These subcutaneous deposits are primarily composed of insoluble calcium hydroxyapatite crystals.

Question 9803

Topic: Physiology & Rehabilitation

Which of the following sensory modalities is most reliably assessed by the 5.07 Semmes-Weinstein monofilament in a patient with diabetes mellitus?

. Proprioception
. Vibratory sensation
. Protective sensation
. Sharp two-point discrimination
. Hot and cold sensation

Correct Answer & Explanation

. Protective sensation

Explanation

Correct Answer: Protective sensationThe 5.07 Semmes-Weinstein monofilament is specifically used to assess protective sensation. While vibratory sensation, sharp two-point discrimination, and temperature sensation can also be affected by diabetic neuropathy, the 5.07 monofilament is the most reliable and widely accepted screening tool for protective sensation.

Question 9804

Topic: 1. General Principles & Basic Science

When performing the Semmes-Weinstein monofilament test to evaluate for loss of protective sensation, what is the correct technique for application?

. Dragging the monofilament lightly across the plantar skin
. Applying the monofilament perpendicular to the skin until it buckles
. Tapping the monofilament rapidly against the medial malleolus
. Puncturing the epidermis slightly to assess pain fibers
. Applying the monofilament parallel to the skin surface

Correct Answer & Explanation

. Applying the monofilament perpendicular to the skin until it buckles

Explanation

Correct Answer: Applying the monofilament perpendicular to the skin until it bucklesThe correct technique for using the Semmes-Weinstein monofilament involves applying it perpendicular to the skin surface and applying pressure until the filament buckles or bows. This ensures that a standardized force (10 grams for the 5.07 monofilament) is delivered to the test site.

Question 9805

Topic: 1. General Principles & Basic Science

The 5.07 Semmes-Weinstein monofilament is considered the most reliable screening tool for protective sensation in diabetic patients. The ability to perceive this monofilament primarily evaluates the integrity of which of the following nerve fiber types?

. Unmyelinated C fibers
. Small myelinated A-delta fibers
. Large myelinated A-beta fibers
. Preganglionic sympathetic fibers
. Postganglionic sympathetic fibers

Correct Answer & Explanation

. Large myelinated A-beta fibers

Explanation

Correct Answer: Large myelinated A-beta fibersThe Semmes-Weinstein monofilament tests for light touch and pressure sensation. These sensory modalities are transmitted via large, myelinated A-beta nerve fibers. In diabetic peripheral neuropathy, these fibers are often damaged, leading to a loss of protective sensation. Unmyelinated C fibers and small myelinated A-delta fibers primarily transmit pain and temperature sensation.

Question 9806

Topic: Infection, Pharmacology & VTE

A 65-year-old male with diabetes lacks protective sensation to the 5.07 monofilament and has developed a plantar neuropathic ulcer under the first metatarsal head. The physician is considering a total contact cast (TCC) to offload the ulcer. Which of the following is an absolute contraindication to the use of a TCC in this patient?

. The presence of a superficial, uninfected Wagner Grade 1 ulcer
. A history of prior neuropathic arthropathy
. Active deep infection with palpable bone at the ulcer base
. Mild peripheral edema
. Patient age greater than 60 years

Correct Answer & Explanation

. Active deep infection with palpable bone at the ulcer base

Explanation

Correct Answer: Active deep infection with palpable bone at the ulcer baseTotal contact casting (TCC) is the gold standard for offloading plantar neuropathic ulcers. However, it has strict contraindications. Absolute contraindications include active deep infection (e.g., abscess, osteomyelitis, palpable bone), severe peripheral arterial disease (ischemia), and deep tracking sinus tracts. Applying a cast over an active deep infection can lead to rapid progression of the infection, sepsis, and limb loss. Superficial, uninfected ulcers (Wagner Grade 1) are the primary indication for TCC.

Question 9807

Topic: Infection, Pharmacology & VTE

A 54-year-old diabetic male who failed 5.07 monofilament screening presents with a foot ulcer. Examination reveals an ulceration on the plantar aspect of the foot that extends deep to the joint capsule, exposing the flexor tendon, but there is no evidence of abscess, osteomyelitis, or gangrene. According to the Wagner classification system, what grade is this ulcer?

. Grade 1
. Grade 2
. Grade 3
. Grade 4
. Grade 5

Correct Answer & Explanation

. Grade 2

Explanation

Correct Answer: Grade 2The Wagner classification is used to grade diabetic foot ulcers. Grade 0: Pre-ulcerative lesion, healed ulcer, or presence of bony deformity. Grade 1: Superficial ulcer without subcutaneous tissue involvement. Grade 2: Deep ulcer penetrating to tendon, bone, or joint capsule, but without deep infection or osteomyelitis. Grade 3: Deep ulcer with osteomyelitis, abscess, or joint sepsis. Grade 4: Localized gangrene (e.g., forefoot or heel). Grade 5: Extensive gangrene involving the entire foot.

Question 9808

Topic: 1. General Principles & Basic Science

When screening a diabetic patient for peripheral neuropathy, a 5.07 Semmes-Weinstein monofilament is utilized. The 5.07 monofilament is calibrated to buckle when a specific amount of force is applied. What is the approximate force exerted by this monofilament?

. 1 gram
. 5 grams
. 10 grams
. 50 grams
. 100 grams

Correct Answer & Explanation

. 10 grams

Explanation

Correct Answer: CThe 5.07 Semmes-Weinstein monofilament is calibrated to buckle at exactly 10 grams of linear pressure. This 10-gram threshold is the established standard for identifying the loss of protective sensation in diabetic patients.

Question 9809

Topic: Physiology & Rehabilitation

A 65-year-old male with diabetes mellitus presents for evaluation. He reports that he recently stepped on a nail but did not feel it until he saw blood on his sock. Which of the following sensory modalities is most likely deficient in this patient, and what is the most appropriate screening tool to document this deficit?

. Proprioception; tuning fork
. Protective sensation; 5.07 Semmes-Weinstein monofilament
. Two-point discrimination; calibrated caliper
. Vibratory sensation; 128-Hz tuning fork
. Thermal sensation; hot/cold test tubes

Correct Answer & Explanation

. Protective sensation; 5.07 Semmes-Weinstein monofilament

Explanation

Correct Answer: BThe patient's inability to feel a nail puncture indicates a loss of protective sensation. The most reliable and standard screening tool to document this deficit in a clinical setting is the 5.07 Semmes-Weinstein monofilament.

Question 9810

Topic: Physiology & Rehabilitation

A 58-year-old male with a 15-year history of type 2 diabetes mellitus presents for a routine clinic visit. The physician uses a 5.07 Semmes-Weinstein monofilament on the plantar aspect of the foot. What specific sensory modality is being evaluated?

. Proprioception
. Vibratory sense
. Protective sensation
. Two-point discrimination
. Temperature sensation

Correct Answer & Explanation

. Protective sensation

Explanation

Correct Answer: Protective sensationThe 5.07 Semmes-Weinstein monofilament is the most reliable screening tool for the presence of protective sensation. Loss of protective sensation places the patient at high risk for neuropathic ulcerations.

Question 9811

Topic: Biology, Genetics & Bone Healing

When screening a diabetic patient for loss of protective sensation using the 5.07 Semmes-Weinstein monofilament, which of the following techniques is considered the standard of care?

. Apply rapid tapping over the dorsal foot.
. Apply perpendicular to the skin until it buckles, holding for 1 to 2 seconds.
. Apply to thick calluses to test deep pressure sensation.
. Stroke the monofilament across the plantar skin.
. Apply tangentially to the skin surface without buckling.

Correct Answer & Explanation

. Apply perpendicular to the skin until it buckles, holding for 1 to 2 seconds.

Explanation

The monofilament should be applied perpendicular to the skin until it bows, held for 1-2 seconds, and then released. It should never be applied over ulcers, calluses, or necrotic tissue.

Question 9812

Topic: 1. General Principles & Basic Science

A diabetic patient presents with normal Semmes-Weinstein monofilament testing but complains of burning pain and impaired temperature differentiation in both feet. Which specific nerve fibers are most likely affected earliest in this condition?

. A-alpha fibers
. A-beta fibers
. Unmyelinated C-fibers and A-delta fibers
. Muscle spindle afferents
. Gamma motor neurons

Correct Answer & Explanation

. Unmyelinated C-fibers and A-delta fibers

Explanation

Diabetic neuropathy often begins with damage to small unmyelinated C-fibers and thinly myelinated A-delta fibers, leading to impaired pain and temperature sensation. Large fiber damage (A-beta) occurs later, affecting vibratory and monofilament pressure testing.

Question 9813

Topic: Infection, Pharmacology & VTE

A 60-year-old poorly controlled diabetic presents with a swollen, erythematous, and warm right foot with bounding pulses and no open ulceration. When the affected leg is elevated for 10 minutes, the erythema resolves completely. What is the most likely diagnosis?

. Acute cellulitis
. Deep vein thrombosis
. Acute Charcot neuroarthropathy
. Osteomyelitis
. Critical limb ischemia

Correct Answer & Explanation

. Acute Charcot neuroarthropathy

Explanation

In a neuropathic foot, a warm, red, swollen presentation can be Charcot neuroarthropathy or infection. Erythema that resolves with elevation (dependent rubor) strongly suggests acute Charcot rather than cellulitis.

Question 9814

Topic: 1. General Principles & Basic Science

Which of the following intracellular accumulations is directly implicated in the pathogenesis of diabetic peripheral neuropathy, ultimately leading to loss of protective sensation?

. Glycogen
. Sorbitol
. Fructose-1,6-bisphosphate
. Amyloid beta
. Sphingomyelin

Correct Answer & Explanation

. Sorbitol

Explanation

In hyperglycemia, the enzyme aldose reductase converts excess glucose into sorbitol. Sorbitol accumulation in Schwann cells causes osmotic stress, cellular swelling, and eventual nerve dysfunction in diabetic neuropathy.

Question 9815

Topic: Biology, Genetics & Bone Healing

During screening, a diabetic patient is found to have a localized area of thick callus with underlying ecchymosis on the plantar aspect of the first metatarsophalangeal joint. The skin is intact. How is this lesion classified under the Wagner Diabetic Foot Ulcer Classification System?

. Wagner Grade 0
. Wagner Grade 1
. Wagner Grade 2
. Wagner Grade 3
. Wagner Grade 4

Correct Answer & Explanation

. Wagner Grade 0

Explanation

Wagner Grade 0 encompasses pre-ulcerative lesions, healed ulcers, or the presence of bony deformities with intact skin. The presence of a pre-ulcerative callus with hemorrhage implies impending breakdown but remains Grade 0 if the skin is unbroken.

Question 9816

Topic: Biology, Genetics & Bone Healing

During a diabetic foot screening, the examiner uses a 10g Semmes-Weinstein monofilament. What is the proper technique for applying this device to ensure an accurate assessment of Loss of Protective Sensation (LOPS)?

. Swiftly brush the monofilament parallel to the skin surface
. Apply perpendicular to the skin until it buckles and hold for 1-2 seconds
. Apply directly over plantar calluses until buckling occurs
. Press firmly without allowing the monofilament to buckle
. Tap the skin repeatedly to assess vibratory threshold

Correct Answer & Explanation

. Apply perpendicular to the skin until it buckles and hold for 1-2 seconds

Explanation

The monofilament should be applied perpendicular to the skin until it buckles and held for 1-2 seconds. It should never be applied directly over calluses or active ulcers to ensure accurate assessment of Loss of Protective Sensation.

Question 9817

Topic: 1. General Principles & Basic Science

A patient with long-standing diabetes presents with dry, fissured skin on the plantar aspect of the feet and bounding pedal pulses. These findings are most characteristic of which underlying pathophysiology?

. Somatic motor neuropathy
. Autonomic neuropathy
. Peripheral arterial disease
. Small fiber sensory neuropathy
. Venous stasis dermatitis

Correct Answer & Explanation

. Autonomic neuropathy

Explanation

Autonomic neuropathy results in sudomotor dysfunction and sympathetic denervation. This leads to anhidrosis, dry, and fissured skin, as well as arteriovenous shunting which produces bounding pedal pulses.

Question 9818

Topic: 1. General Principles & Basic Science

In clinical settings where a 10g monofilament is unavailable, the Ipswich Touch Test is a validated alternative for screening LOPS. What is the correct technique for this test?

. Using a 256 Hz tuning fork on the medial malleolus
. Lightly resting the index finger on the tips of the 1st, 3rd, and 5th toes for 1-2 seconds
. Dragging a sterile safety pin across the plantar arch
. Applying warm and cold test tubes to the heel
. Measuring two-point discrimination on the hallux

Correct Answer & Explanation

. Lightly resting the index finger on the tips of the 1st, 3rd, and 5th toes for 1-2 seconds

Explanation

The Ipswich Touch Test is a validated, simple screening tool for Loss of Protective Sensation. The examiner lightly rests their index finger on the tips of the 1st, 3rd, and 5th toes of both feet to assess tactile perception.

Question 9819

Topic: Infection, Pharmacology & VTE

During the physical examination of a chronic diabetic foot ulcer, a sterile blunt probe is introduced into the wound. The examiner feels a hard, gritty surface. This 'probe-to-bone' test has the highest positive predictive value for which condition?

. Malignant transformation (Marjolin's ulcer)
. Underlying osteomyelitis
. Acute Charcot neuroarthropathy
. Deep vein thrombosis
. Necrotizing fasciitis

Correct Answer & Explanation

. Underlying osteomyelitis

Explanation

A positive probe-to-bone test, where a sterile blunt probe touches a hard, gritty surface, is highly specific and has a high positive predictive value for underlying osteomyelitis in the setting of a diabetic foot ulcer.

Question 9820

Topic: 1. General Principles & Basic Science

What is the primary pathophysiologic mechanism leading to neuropathic ulceration in a diabetic patient with confirmed Loss of Protective Sensation?

. Acute macrovascular occlusion causing focal gangrene
. Direct bacterial invasion through intact epidermal layers
. Unperceived repetitive biomechanical microtrauma
. Spontaneous auto-amputation of the digits
. Venous valvular incompetence

Correct Answer & Explanation

. Unperceived repetitive biomechanical microtrauma

Explanation

Due to the loss of protective sensation, patients cannot perceive normally painful stimuli. Consequently, they sustain unperceived, repetitive biomechanical microtrauma during ambulation, leading to progressive tissue breakdown and ulceration.

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