Integumentary system US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Integumentary system. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Integumentary system US Medical PG Question 1: A 41-year-old male who takes NSAIDs regularly for his chronic back pain develops severe abdominal pain worse with eating. Upper endoscopy is performed and the medical student asks the supervising physician how the histological differentiation between a gastric ulcer and erosion is made. Which of the following layers of the gastric mucosa MUST be breached for a lesion to be considered an ulcer?
- A. Epithelium, lamina propria
- B. Epithelium
- C. Epithelium, lamina propria, muscularis mucosa (Correct Answer)
- D. Epithelium, lamina propria, muscularis mucosa, submucosa, and adventitia
- E. Epithelium, lamina propria, muscularis mucosa, and submucosa
Integumentary system Explanation: ***Epithelium, lamina propria, muscularis mucosa***
- A **gastric ulcer** by definition involves a breach of the **entire mucosal thickness**, meaning the lesion extends through the muscularis mucosa.
- This deep penetration distinguishes an ulcer from an erosion, which is a more superficial lesion confined to the epithelium and lamina propria.
*Epithelium, lamina propria*
- This describes an **erosion**, a superficial lesion of the gastric mucosa that does not penetrate the **muscularis mucosa**.
- While erosions can cause symptoms, they are generally less severe and have a lower risk of complications like perforation compared to ulcers.
*Epithelium*
- A lesion confined solely to the **epithelium** would be considered a very superficial mucosal injury, often referred to as an **erosion** or sometimes a **superficial abrasion**.
- This degree of injury does not meet the criteria for either an erosion or an ulcer in a histological context.
*Epithelium, lamina propria, muscularis mucosa, submucosa, and adventitia*
- Penetration through the **submucosa** means the ulcer has become a **deep ulcer** or potentially a **perforating ulcer**, if it breaches the entire wall to the adventitia (serosa in the GI tract).
- While an ulcer *can* extend to these layers, only reaching the muscularis mucosa is the *minimum* requirement to be classified as an ulcer.
*Epithelium, lamina propria, muscularis mucosa, and submucosa*
- An ulcer that extends into the **submucosa** is indeed a true ulcer and a more severe one, but the defining histological feature separating an erosion from an ulcer is the breach of the **muscularis mucosa**.
- Therefore, reaching the submucosa is beyond the *minimum* requirement for an ulcer classification.
Integumentary system US Medical PG Question 2: A 15-year-old boy comes to the physician because of skin changes on his face, chest, and back over the past year. Treatment with over-the-counter benzoyl peroxide has been ineffective. Physical examination shows numerous open comedones, inflammatory papules, and pustules on his face, chest, and back. Which of the following is the most likely underlying mechanism of this patient’s skin condition?
- A. Hyperkeratinization of hair follicles (Correct Answer)
- B. Type IV hypersensitivity reaction
- C. Formation of superficial epidermal inclusion cyst
- D. Excess androgen production
- E. Hyperplasia of pilosebaceous glands
Integumentary system Explanation: **Hyperkeratinization of hair follicles**
- The primary event in the pathogenesis of **acne vulgaris** is the **shedding of hyperkeratinized corneocytes** into the lumen of the hair follicle, which then combines with sebum to form a microcomedone.
- This process leads to the **obstruction of the pilosebaceous unit**, creating an anaerobic environment conducive to the proliferation of *Cutibacterium acnes* and the development of inflammatory lesions like papules and pustules.
*Type IV hypersensitivity reaction*
- This mechanism involves **T-cell mediated delayed hypersensitivity**, leading to conditions like **allergic contact dermatitis** or **tuberculosis**.
- Acne vulgaris is not primarily an allergic reaction mediated by T cells; its pathogenesis involves follicular obstruction, sebum production, bacterial colonization, and inflammation.
*Formation of superficial epidermal inclusion cyst*
- Epidermal inclusion cysts (also known as epidermoid cysts) are typically solitary, slow-growing cysts that result from the **implantation of epidermal cells into the dermis**, often due to trauma or blocked hair follicles, but they are not the underlying mechanism for widespread acne.
- While some severe acne lesions can rarely lead to cyst formation, the presence of numerous **comedones, papules, and pustules** indicates typical acne vulgaris, not primarily cyst formation.
*Excess androgen production*
- While **androgens stimulate sebum production**, which is a contributing factor to acne, they are not the initiating mechanism for the follicular obstruction itself.
- Most adolescents with acne have **normal androgen levels**; the skin's sebaceous glands are simply more sensitive to circulating androgens, leading to increased sebum.
*Hyperplasia of pilosebaceous glands*
- **Sebaceous gland hyperplasia** refers to an increase in the number and size of sebaceous glands, leading to an overproduction of sebum, which contributes to acne.
- However, the fundamental initiating event for comedone formation in acne is the **follicular hyperkeratinization and obstruction**, rather than simply the glands being hyperplastic.
Integumentary system US Medical PG Question 3: A 52-year-old Caucasian man presents to the clinic for evaluation of a mole on his back that he finds concerning. He states that his wife noticed the lesion and believes that it has been getting larger. On inspection, the lesion is 10 mm in diameter with irregular borders. A biopsy is performed. Pathology reveals abnormal melanocytes forming nests at the dermo-epidermal junction and discohesive cell growth into the epidermis. What is the most likely diagnosis?
- A. Desmoplastic melanoma
- B. Lentigo maligna melanoma
- C. Superficial spreading melanoma (Correct Answer)
- D. Nodular melanoma
- E. Acral lentiginous melanoma
Integumentary system Explanation: ***Superficial spreading melanoma***
- This is the **most common type of melanoma**, accounting for 70% of cases, and typically presents with a **radial growth phase** showing irregular borders and enlarging size.
- Histopathology revealing **nests of abnormal melanocytes at the dermo-epidermal junction** and **discohesive cell growth into the epidermis** (pagetoid spread) is characteristic of superficial spreading melanoma.
*Desmoplastic melanoma*
- Characterized by **fibrous stroma** and often **neural invasion**, with a less pigmented appearance, which is not described.
- Typically presents as a firm, often amelanotic nodule, and can be more aggressive.
*Lentigo maligna melanoma*
- Primarily found in **chronically sun-damaged areas** of the elderly, often on the face, and begins as a flat, tan-brown macule that slowly enlarges.
- Histologically, it shows **atypical melanocytes along the basal layer** of a thinned epidermis, not necessarily forming nests or extensive discohesive growth into the epidermis early on.
*Nodular melanoma*
- This type of melanoma has a **vertical growth phase from the outset**, appearing as a rapidly growing, dark, elevated lesion without a significant preceding radial growth phase.
- Histologically, it involves a substantial dermal component with **minimal or absent intraepidermal radial growth**.
*Acral lentiginous melanoma*
- Occurs on the **palms, soles, or under the nails (subungual)**, and is less associated with sun exposure, often presenting as a dark, spreading lesion.
- Its histological features involve **lentiginous proliferation of atypical melanocytes** along the dermo-epidermal junction with spread into the rete ridges in an acral distribution.
Integumentary system US Medical PG Question 4: A 35-year-old man is brought to the emergency department from a kitchen fire. The patient was cooking when boiling oil splashed on his exposed skin. His temperature is 99.7°F (37.6°C), blood pressure is 127/82 mmHg, pulse is 120/min, respirations are 12/min, and oxygen saturation is 98% on room air. He has dry, nontender, and circumferential burns over his arms bilaterally, burns over the anterior portion of his chest and abdomen, and tender spot burns with blisters on his shins. A 1L bolus of normal saline is administered and the patient is given morphine and his pulse is subsequently 80/min. A Foley catheter is placed which drains 10 mL of urine. What is the best next step in management?
- A. Additional fluids and escharotomy (Correct Answer)
- B. Escharotomy
- C. Continuous observation
- D. Moist dressings and discharge
- E. Additional fluids and admission to the ICU
Integumentary system Explanation: ***Additional fluids and escharotomy***
- The patient has **circumferential full-thickness burns** on both arms (dry, nontender), which require **escharotomy** to prevent compartment syndrome and vascular compromise to the limbs.
- The **oliguria** (10 mL urine output) despite a 1L fluid bolus indicates **inadequate fluid resuscitation** from burn shock. With approximately 40% TBSA burns, the patient requires aggressive fluid resuscitation per the Parkland formula (4 mL/kg/% TBSA), which would be approximately 11 liters in the first 24 hours. Adequate resuscitation targets urine output of 0.5-1 mL/kg/hr (35-70 mL/hr for this patient).
- Both interventions are immediately necessary: fluids for burn shock and escharotomy for circumferential burns.
*Escharotomy*
- While **escharotomy** is essential for the circumferential full-thickness burns to prevent compartment syndrome, it alone will not address the **severe fluid deficit** causing oliguria and hypoperfusion.
- The low urine output reflects systemic hypovolemia from burn shock, not just local compartment issues, requiring aggressive fluid resuscitation.
*Continuous observation*
- **Continuous observation** is inappropriate given the patient's critical findings: circumferential full-thickness burns requiring urgent escharotomy and oliguria indicating inadequate resuscitation.
- Delaying escharotomy can lead to irreversible ischemic damage to the limbs, and inadequate fluid resuscitation can progress to multiorgan failure.
*Moist dressings and discharge*
- This option is completely inappropriate for a patient with **extensive deep burns** (approximately 40% TBSA) including full-thickness injuries requiring hospitalization and specialized burn care.
- Discharge would lead to severe complications including infection, inadequate fluid resuscitation, compartment syndrome, and potential limb loss.
*Additional fluids and admission to the ICU*
- While ICU admission and additional fluids are necessary components of care, this option is **incomplete** because it omits **escharotomy**, which is urgently needed for the circumferential full-thickness burns.
- Escharotomy is a time-sensitive procedure that must be performed promptly to prevent ischemic injury to the limbs from vascular compromise.
Integumentary system US Medical PG Question 5: A 52-year-old woman sees you in your office with a complaint of new-onset headaches over the past few weeks. On exam, you find a 2 x 2 cm dark, irregularly shaped, pigmented lesion on her back. She is concerned because her father recently passed away from skin cancer. What tissue type most directly gives rise to the lesion this patient is experiencing?
- A. Neural crest cells (Correct Answer)
- B. Endoderm
- C. Mesoderm
- D. Ectoderm
- E. Neuroectoderm
Integumentary system Explanation: ***Neural crest cells***
- The suspected lesion, given its description and the patient's family history of skin cancer, is likely a **melanoma**.
- Melanoma originates from **melanocytes**, which are derived from **neural crest cells** during embryonic development.
*Endoderm*
- The endoderm gives rise to the **lining of the gastrointestinal and respiratory tracts**, as well as organs such as the liver and pancreas.
- It is not involved in the formation of melanocytes or skin lesions like melanoma.
*Mesoderm*
- The mesoderm forms tissues such as **muscle, bone, cartilage, connective tissue**, and the circulatory system.
- It does not directly give rise to melanocytes, which are the cells of origin for melanoma.
*Ectoderm*
- The ectoderm gives rise to the **epidermis, nervous system**, and sensory organs.
- While melanocytes are found in the epidermis, they are specifically derived from the **neural crest (a sub-population of ectoderm)**, not the general ectoderm.
*Neuroectoderm*
- Neuroectoderm specifically refers to the ectoderm that develops into the **nervous system**.
- While neural crest cells originate from the neuroectoderm, "neural crest cells" is a more precise answer for the origin of melanocytes.
Integumentary system US Medical PG Question 6: A 65-year-old male is evaluated in clinic approximately six months after resolution of a herpes zoster outbreak on his left flank. He states that despite the lesions having resolved, he is still experiencing constant burning and hypersensitivity to touch in the distribution of the old rash. You explain to him that this complication can occur in 20-30% of patients after having herpes zoster. You also explain that vaccination with the shingles vaccine in individuals 60-70 years of age can reduce the incidence of this complication. What is the complication?
- A. Ramsay-Hunt syndrome
- B. Post-herpetic neuralgia (Correct Answer)
- C. Recurrent zoster
- D. Secondary bacterial infection
- E. Acute herpetic neuralgia
Integumentary system Explanation: ***Post-herpetic neuralgia***
- This condition is characterized by **persistent pain** (burning, throbbing, or shooting) and **allodynia** (hypersensitivity to light touch) in the dermatomal distribution of a resolved herpes zoster rash.
- It occurs due to **nerve damage** caused by the varicella-zoster virus and is more common in older adults, with symptoms persisting for months to years, consistent with the patient's presentation and the statistic of 20-30% incidence.
*Ramsay-Hunt syndrome*
- This syndrome is a complication of **herpes zoster oticus**, affecting the facial nerve (cranial nerve VII).
- It presents with **facial paralysis**, rash in the ear or mouth, and sometimes hearing loss or vertigo, which is not described in this patient's symptoms.
*Recurrent zoster*
- While possible, **recurrent zoster** would involve the reappearance of the vesicular rash and associated acute pain, not persistent burning and hypersensitivity after the original rash has resolved.
- The patient describes a "resolved" outbreak, indicating the skin lesions are gone, and only the nerve pain remains.
*Secondary bacterial infection*
- A **secondary bacterial infection** would manifest as redness, warmth, swelling, pus, and increased acute pain at the site of the skin lesions.
- The patient's symptoms of chronic burning and hypersensitivity in the absence of active lesions are not consistent with a bacterial infection.
*Acute herpetic neuralgia*
- **Acute herpetic neuralgia** refers to the pain experienced *during* the active herpes zoster outbreak and up to 30 days after the rash onset.
- In this case, the pain persists six months *after resolution* of the rash, indicating a chronic condition rather than acute pain.
Integumentary system US Medical PG Question 7: Linear growth of bone is disturbed when a fracture occurs in which part?
- A. Epiphysis
- B. Diaphysis
- C. Metaphysis
- D. Epiphyseal plate (Correct Answer)
- E. Periosteum
Integumentary system Explanation: ***Epiphyseal plate***
- The **epiphyseal plate**, also known as the **growth plate**, is a cartilaginous disc responsible for the **longitudinal growth** of long bones.
- A fracture in this region can damage the **chondrocytes** and disrupt the normal process of endochondral ossification, leading to **growth arrest** or limb length discrepancy.
*Epiphysis*
- The **epiphysis** is the end part of a long bone, often covered by **articular cartilage**, forming a joint.
- While an epiphyseal fracture can affect joint function, it typically does not directly disturb the **linear growth** of the bone unless it extends into the growth plate.
*Diaphysis*
- The **diaphysis** is the main or midsection of a long bone, composed primarily of **compact bone**.
- Fractures in the diaphysis generally heal through **callus formation** and remodeling, usually without significantly impacting the overall **linear growth** of the bone.
*Metaphysis*
- The **metaphysis** is the wider portion of a long bone, adjacent to the growth plate and diaphysis.
- Though highly vascular, fractures to the metaphysis usually heal well and do not directly control **linear bone growth** like the epiphyseal plate.
*Periosteum*
- The **periosteum** is the fibrous membrane covering the outer surface of bones, important for **appositional growth** (bone widening) and fracture healing.
- While it contains osteogenic cells that contribute to bone repair and thickness, it does not control **longitudinal bone growth**, which is the function of the epiphyseal plate.
Integumentary system US Medical PG Question 8: A 14-year-old boy is brought to the physician for the evaluation of back pain for the past six months. The pain is worse with exercise and when reclining. He attends high school and is on the swim team. He also states that he lifts weights on a regular basis. He has not had any trauma to the back or any previous problems with his joints. He has no history of serious illness. His father has a disc herniation. Palpation of the spinous processes at the lumbosacral area shows that two adjacent vertebrae are displaced and are at different levels. Muscle strength is normal. Sensation to pinprick and light touch is intact throughout. When the patient is asked to walk, a waddling gait is noted. Passive raising of either the right or left leg causes pain radiating down the ipsilateral leg. Which of the following is the most likely diagnosis?
- A. Spondylolisthesis (Correct Answer)
- B. Overuse injury
- C. Ankylosing spondylitis
- D. Disc herniation
- E. Facet joint syndrome
Integumentary system Explanation: ***Spondylolisthesis***
- The patient presents with **back pain worse with exercise and reclining**, along with **palpable displacement of adjacent vertebrae** at different levels, which are classic signs of spondylolisthesis. The **waddling gait** and pain radiating down the leg upon passive leg raising (suggesting nerve root irritation) further support this diagnosis.
- Spondylolisthesis, particularly **isthmic type**, is common in adolescent athletes involved in sports like swimming and weightlifting due to repetitive hyperextension leading to stress fractures in the pars interarticularis.
*Overuse injury*
- While overuse injuries are common in athletes, they typically present with generalized pain or tenderness in the affected area without distinct **vertebral displacement** or neurological signs like radiating pain and a waddling gait.
- The specific signs of palpable vertebral displacement and nerve root irritation point to a more severe structural issue than a simple overuse soft tissue injury.
*Ankylosing spondylitis*
- **Ankylosing spondylitis** usually presents with **inflammatory back pain** that improves with exercise, not worsens, and often affects young adults, not typically a 14-year-old with these specific physical findings.
- It would not explain the **palpable vertebral displacement** or the sudden onset of neurological symptoms like radiating leg pain and waddling gait.
*Disc herniation*
- While disc herniation can cause **radiating leg pain** and back pain, it typically doesn't present with **palpable vertebral displacement** or a waddling gait in an adolescent without a history of significant trauma.
- The physical exam finding of displaced vertebrae is more indicative of a structural instability like spondylolisthesis rather than an isolated disc problem, even though a father has a history.
*Facet joint syndrome*
- Facet joint syndrome usually results in localized back pain that **worsens with extension and rotation** but typically does not cause **palpable vertebral displacement** or neurological deficits like radiating pain and a waddling gait.
- It is also more common in older adults due to degenerative changes, rather than a 14-year-old athlete.
Integumentary system US Medical PG Question 9: A 53-year-old man with a history of alcoholic liver cirrhosis was admitted to the hospital with ascites and general wasting. He has a history of 3-5 ounces of alcohol consumption per day for 20 years and 20-pack-year smoking history. Past medical history is significant for alcoholic cirrhosis of the liver, diagnosed 5 years ago. On physical examination, the abdomen is firm and distended. There is mild tenderness to palpation in the right upper quadrant with no rebound or guarding. Shifting dullness and a positive fluid wave is present. Prominent radiating umbilical varices are noted. Laboratory values are significant for the following:
Total bilirubin 4.0 mg/dL
Aspartate aminotransferase (AST) 40 U/L
Alanine aminotransferase (ALT) 18 U/L
Gamma-glutamyltransferase 735 U/L
Platelet count 11,000/mm3
WBC 4,300/mm3
Serology for viral hepatitis B and C are negative. A Doppler ultrasound of the abdomen shows significant enlargement of the epigastric superficial veins and hepatofugal flow within the portal vein. There is a large volume of ascites present. Paracentesis is performed in which 10 liters of straw-colored fluid is removed. Which of the following sites of the portocaval anastomosis is most likely to rupture and bleed first in this patient?
- A. Superior and middle rectal vein – inferior rectal veins
- B. Umbilical vein – superficial epigastric veins
- C. Esophageal branch of left gastric vein – esophageal branches of azygos vein (Correct Answer)
- D. Paraumbilical veins – inferior epigastric veins
- E. Short gastric veins – intercostal veins
Integumentary system Explanation: ***Esophageal branch of left gastric vein – esophageal branches of azygos vein***
- The gastroesophageal junction is the most frequent site of **life-threatening variceal bleeding** in patients with portal hypertension due to liver cirrhosis. The elevated portal pressure forces blood from the **left gastric (coronary) vein** into the thinner-walled esophageal veins which drain into the azygos system.
- The patient's history of **alcoholic liver cirrhosis** makes portal hypertension and subsequent esophageal varices highly likely. While other portocaval anastomoses exist, esophageal varices are clinically the most significant due to their propensity for rupture and severe hemorrhage.
*Superior and middle rectal vein – inferior rectal veins*
- This anastomosis concerns the rectums, involving the **superior rectal vein (portal system)** and the **middle/inferior rectal veins (systemic system)**.
- While portal hypertension can lead to **anorectal varices**, also known as hemorrhoids, these are less prone to life-threatening hemorrhage compared to esophageal varices and typically present with bleeding on defecation or discomfort.
*Umbilical vein – superficial epigastric veins*
- This anastomosis is responsible for the formation of a **caput medusae**, which is a sign of portal hypertension where prominent periumbilical veins radiate from the navel. The patient presents with prominent "radiating umbilical varices," which is consistent with this finding.
- While visually striking and indicative of portal hypertension, these superficial varices are generally **not associated with significant or life-threatening hemorrhage** compared to esophageal varices.
*Paraumbilical veins – inferior epigastric veins*
- The paraumbilical veins run within the falciform ligament and connect the portal system to the systemic circulation via the **epigastric veins**.
- This anastomosis contributes to the formation of caput medusae but is **not a common site for clinically significant bleeding** requiring intervention compared to esophageal varices.
*Short gastric veins – intercostal veins*
- The short gastric veins drain into the splenic vein (part of the portal system) and connect to systemic veins such as the intercostal veins via retroperitoneal anastomoses.
- While this is a potential site of portosystemic shunting, the short gastric veins are more commonly implicated in **gastric varices**, particularly in the fundus. However, gastric varices are less frequent and **rupture less commonly than esophageal varices**, although hemorrhage from them can be more severe when it does occur.
Integumentary system US Medical PG Question 10: A 72-year-old male presents to a cardiac surgeon for evaluation of severe aortic stenosis. He has experienced worsening dyspnea with exertion over the past year. The patient also has a history of poorly controlled hypertension, diabetes mellitus, and hyperlipidemia. An echocardiogram revealed a thickened calcified aortic valve. The surgeon is worried that the patient will be a poor candidate for open heart surgery and decides to perform a less invasive transcatheter aortic valve replacement. In order to perform this procedure, the surgeon must first identify the femoral pulse just inferior to the inguinal ligament and insert a catheter into the vessel in order to gain access to the arterial system. Which of the following structures is immediately lateral to this structure?
- A. Lymphatic vessels
- B. Femoral vein
- C. Sartorius muscle
- D. Pectineus muscle
- E. Femoral nerve (Correct Answer)
Integumentary system Explanation: ***Femoral nerve***
- The **femoral nerve** lies lateral to the **femoral artery** within the **femoral triangle**.
- The order of structures from **lateral to medial** under the inguinal ligament is remembered by the mnemonic **NAVEL**: **N**erve, **A**rtery, **V**ein, **E**mpty space, **L**ymphatics.
*Lymphatic vessels*
- **Lymphatic vessels** and nodes are located most medially within the femoral triangle, medial to the femoral vein.
- This position is not immediately lateral to the femoral artery.
*Femoral vein*
- The **femoral vein** is located immediately medial to the **femoral artery**.
- It would not be found immediately lateral to the femoral artery.
*Sartorius muscle*
- The **sartorius muscle** forms the lateral boundary of the **femoral triangle** but is not immediately adjacent and lateral to the femoral artery within the triangle itself.
- The femoral nerve is enclosed within the iliopsoas fascial compartment, which runs deep to the sartorius.
*Pectineus muscle*
- The **pectineus muscle** forms part of the floor of the **femoral triangle**, but it is deep to the neurovascular structures.
- It is not immediately lateral to the femoral artery.
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