Musculoskeletal and Connective Tissue Flashcards
What is the pathophysiology of this condition?
Costochondritis, inflammation of the costochondral or costosternal joints, causes localized pain and tenderness. Often, more than one of the seven costochondral joints is affected, especially between the second and fifth costosternal junctions. Repetitive minor trauma or repetitive activities are the likely causes, but bacterial and fungal infections (not likely here given the lack of swelling, erythema) and thoracic surgery may also be implicated.
What is the innervation of the intercostal space?
The intercostal nerves (thoracic spinal and ventral rami) supply general sensory innervation to the skin of the thoracic and anterior abdominal walls. The dermatomes follow a girdle-like distribution. The sensory nerves also supply the parietal pleura and parietal peritoneum. The intercostal nerves also have motor innervation through the ventral rami of T1–T12. Intercostal nerve 1 participates in the brachial plexus; nerves 2–6 innervate the thorax; and nerves 7–12 innervate the anterior abdominal wall.
What conditions, other than costochondritis, should be considered in the differential diagnosis?
Although the localized areas of tenderness suggest a musculoskeletal cause, serious conditions such as myocardial infarction and pericarditis (which has an abnormal echocardiogram, pain changes with position, and frictional rub on auscultation) need to be ruled out. Other considerations include pleuritic pain, which could be a manifestation of pneumonia, pulmonary embolism, pneumothorax, or pleuritis. Pleuritis can be seen in inflammatory conditions such as systemic lupus erythematosus (abnormal serology), fibromyalgia (tender points), and gastroesophageal reflux disorder.
What is the blood supply of the intercostal space?
At each space, there is a posterior artery and anterior set of arteries (Figure 9-1). The bottom nine posterior arteries originate from the descending thoracic aorta, whereas the anterior artery originates from the internal thoracic. The posterior intercostal vein, artery, and nerve run together as a neurovascular bundle along the lower border of each rib. Therefore, during thoracentesis the needle must be inserted just above the lower rib in the intercostal space to avoid injury to the vessels and nerve.
What is the most likely diagnosis?
The patient’s biopsy shows atypical keratinocytes that have invaded the basement membrane; therefore, malignancy is present. Although basal cell carcinoma (BCC) is the most common type of skin cancer, the description of the lesion suggests squamous cell carcinoma (SCC).
Cutaneous SCC is the second most common tumor of the skin. It arises from the malignant proliferation of epidermal keratinocytes. The condition typically presents as a firm, well-demarcated lesion that is scaling, crusting, or ulcerated. Histologic examination is necessary for a diagnosis.
What precursor lesion can lead to cutaneous squamous cell carcinoma (SCC)?
Actinic keratosis (AK), a dysplastic lesion of the epidermis, can lead to SCC. These lesions occur only on sun-exposed skin and consist of hyperkeratotic papules that have a coarse, sandpaper feel; some may present as a “cutaneous horn.”
What risk factors are associated with Cutaneous SCC?
The most important risk factor for SCC is sunlight exposure in which ultraviolet (UV) rays cause DNA damage. Other exogenous factors include ionizing radiation, immunosuppression, chronic inflammation (from burns, scars, or ulcers), and arsenic exposure.
What inherited disorders predispose patients to Cutaneous SCC?
Xeroderma pigmentosum is a rare autosomal recessive disorder that displays a defect in DNA excision repair, which impairs the ability to repair UV-induced DNA damage. Albinism is also associated with SCC because of the generalized pigment loss due to dysfunction and deficiency of melanocytes.
What is the prognosis for patients with cutaneous SCC?
Even though cutaneous SCC can be locally invasive, it rarely metastasizes (1%–5% of cases). Therefore, more than 90% of patients can be cured with local excision.
What retroperitoneal structures of the abdomen could the bullet have hit?
What layers of the lateral and anterior abdominal wall would the bullet have to penetrate to reach the peritoneum?
What is the blood supply to the kidney?
Renal artery → segmental artery → lobar artery → arcuate artery → afferent arteriole → glomerulus → efferent arteriole → vasa recta → segmental vein → renal vein
What is the blood supply to the spleen?
The main blood supply is from the splenic artery, which is a branch of the celiac trunk (the other two branches are the L gastric and common hepatic arteries). The L gastro-omental and short gastric are branches off the splenic artery.
What organs supply the splenic vein?
The splenic vein starts at the hilus of the spleen and receives blood from the stomach, pancreas, and inferior mesenteric vein. The splenic vein joins with the superior mesenteric vein to form the hepatic portal vein.
What are the histologic layers of the skin?
Listed superficially to deep: stratum corneum, lucidum (only in palms and soles), granulosum, spinosum, basale.
What is the most likely diagnosis?
What conditions should be considered in the differential diagnosis?
The young age at clinical presentation along with the tenderness, warmth, and swelling around the mass without systemic signs of infection suggests Ewing sarcoma (Figure 9-2). This diagnosis is supported by the location of the lesion and the histologic appearance (small, round, blue neuroectodermal cells), which are characteristic of this neoplasm.
Other than Ewing sarcoma, what are the other small cell tumors?
Other small cell tumors include neuroblastoma, Wilms tumor, medulloblastoma, and rhabdomyosarcoma.
What is the most likely chromosomal aberration leading to Ewing Sarcoma?
In total, 85% of Ewing sarcoma cases demonstrate a t(11;22) translocation. This translocation leads to an overexpression of the EWSR1 gene (encodes RNA binding proteins) on chromosome 22, which is translocated next to the FLI1 gene on chromosome 11 (encodes transcription factors).
What is the appropriate treatment for Ewing sarcoma?
Ewing sarcoma is known to be a systemic disease due to the high relapse rate (80%–90%) of patients who undergo only local therapy. Therefore, most patients likely have subclinical microscopic metastatic disease at the time of diagnosis, which is treated with chemotherapy.
What percentage of patients have metastatic disease at the time of diagnosis of Ewing sarcoma?
Only 25% of patients have overt metastases at the time of diagnosis.
What is the most likely diagnosis?
The most common causes of lateral hip paining elderly patients include osteoarthritis, bursitis, metastases, and femoral fracture. In this patient, the sudden onset of pain after the fall and inability to walk strongly suggest a fracture of the neck of the femur (Figure 9-3). Femoral neck fractures can be incomplete or complete with no, partial, or total displacement.
What is a potential complication of a Neck of femur fracture?
Fracture of the neck of the femur may disrupt blood supply to the head of the femur. The major arterial supply to the head of the femur is the medial and lateral circumflex femoral arteries (branches of the deep femoral artery) and the artery of the ligament of the head of the femur (branch of the obturator artery). The circumflex arteries may be disrupted by a fracture of the femoral neck, leaving only the artery of the ligament (a branch of the obturator) as a supply. Disruption of the blood supply may cause avascular necrosis of the femoral head.
What bones form the hip joint?
The hip joint consists of the head of the femur articulating with the acetabulum. The acetabulum is formed by the ilium, ischium, and pubis. The fibrocartilaginous rim, the acetabular labrum, attaches to the acetabular margin and deepens the acetabular cup.
Six weeks later, repeat x-ray shows a callus. What does the callus indicate about the patient’s stage of healing?
What is the most likely diagnosis? What would the differential diagnosis be if the patient were a child instead of a neonate?
In a newborn, a painless collection of fluid in the scrotum is almost certainly a hydrocele. It should resolve on its own by 1 year. The fact that the fluid in the scrotum is reducible indicates that the hydrocele was caused by a communication with the intraperitoneal fluid via a hernia.
What structures define the Hesselbach triangle?
The Hesselbach triangle is formed by the lateral border of the rectus abdominis muscle, the inguinal ligament, and the inferior epigastric vessels.
What distinguishes the two major types of hernia?
Direct hernias protrude through a weakness in the floor of the inguinal canal within the Hesselbach triangle (directly through the triangle) medial to the inferior epigastric vessels to enter the external ring into the scrotal sac. Indirect hernias enter the inguinal canal lateral to the Hesselbach triangle (lateral to the inferior epigastric vessels) indirectly through the internal inguinal ring (located in the fascia transversalis), then via the inguinal canal to the external inguinal ring located above and lateral to the pubic tubercle, and finally into the scrotal sac (Figure 9-4).
Which type of hernia is more common in infants and children?
Indirect inguinal hernias are more common in children, as they result from a congenital failure of the processus vaginalis to close.
What are the contents of the normal spermatic cord?
The spermatic cord in the inguinal canal contains the testicular artery and veins, lymphatic vessels, and the vas deferens. The sheath of the cord is formed by the internal spermatic fascia, the cremasteric muscle, and the external spermatic fascia. The ilioinguinal nerve is in the sheath and exits at the external ring; it is vulnerable to injury in surgical repairs of hernias. The genital branch of the genitofemoral nerve supplies the cremaster muscle. The processus vaginalis is an extension of peritoneum that normally obliterates spontaneously between the upper pole of the testes and the internal inguinal ring. In some cases, however, it remains patent, increasing the risk of hydrocele and indirect hernia.
What are the two main intracapsular ligaments in the knee?
The anterior cruciate ligament extends from the anterior intercondylar area of the tibial plateau and traverses superior and lateral to the medial surface of the lateral femoral condyle. The posterior cruciate ligament extends from the posterior intercondylar area of the tibial plateau and traverses superior and medial to the lateral surface of the medial condyle of the femur (Figure 9-5).
What is the blood supply to the knee?
Blood supply to the knee consists of genicular branches of the following blood vessels:
1. Anterior recurrent tibial artery.
2. Anterior tibial artery.
3. Descending branch of the lateral circumflex artery
4. Femoral artery.
5. Patellar plexus.
6. Popliteal artery.
7. Posterior tibial artery.
What is the role of the meniscus?
The half-moon-shaped meniscus is cartilage that is found between the femur and tibia. The meniscus absorbs the impact load of the joint and is involved in stability. The meniscus is mostly avascular and is divided into the anterior horn, body, and posterior horn. A medial and lateral meniscus is connected by the transverse ligament.
How do the collateral and cruciate ligaments differ in function?
The cruciate ligaments remain tight in flexion and extension and relax at 30 degrees of flexion. The collateral ligaments are tight in extension and relaxed in flexion. Also, the cruciate ligaments prevent anterior and posterior displacement of the tibia. The collateral ligaments prevent abduction/adduction of the knee.
Which ligament of the knee is most often injured?
The medial collateral ligament is weaker than the anterior or the posterior cruciate ligaments, so medial collateral ligament injuries are more common. Anterior cruciate ligaments tears are much more common than posterior cruciate ligaments tears.
What is the terrible or unhappy triad?
This is a common contact-sport injury to the knee that occurs when lateral trauma is applied to the knee joint while the foot is fixed to the ground. Subsequently, the medial collateral ligament, lateral meniscus, and anterior cruciate ligament are damaged.
What is the differential diagnosis and what is the most likely diagnosis?
Benign causes of an irregularly colored lesion include hemangioma, seborrheic keratosis, compound or junctional nevus, and pigmented dermatofibroma. But given the characteristics of this lesion, the most likely diagnosis is a malignant melanoma. The ABCD rules help distinguish melanoma from other lesions (Figure 9-6):
* Asymmetry: Malignant lesions are usually asymmetric.
* Border irregularity: Most melanomas lack smooth, round, uniform boundaries.
* Color variegation: Malignant lesions usually have variations in pigmentation and occasionally lose pigmentation.
* Diameter:A diameter >6mm greatly increases the chances of malignancy, and most lesions are >10mm.
Which cells are responsible Melanomas and what is their embryonic origin?
Melanomas originate from melanocytes, which are derived from neural crest tissue and reside in the epidermis or, less frequently, in the dermis.
What is the etiology of Malignant melanomas?
Malignant melanomas are more likely to appear on areas that receive sun exposure. Other risk factors include atypical/dysplastic nevi and family history,
What is the most important prognostic factor for malignant melanoma?
The most concerning factor is vertical invasion, as deeper lesions have a worse prognosis. Detection of melanoma at early stages is crucial and prognosis is excellent if treated early. However, after the tumor has penetrated the basement membrane and entered the subcutaneous fat, 5-year survival is only 49%. The S-100 protein can help determine prognosis; elevated S-100 serum levels correlate with a worse prognosis.
How and where does melanoma tend to spread?
Initial lesions usually spread superficially and horizontally across the skin and then enter a vertical growth phase into the deeper layers of the skin. Melanomas may then spread either lymphatically or hematogenously; earliest detectable metastases occur in regional lymph nodes. Classic sites of hematogenous spread include brain, lung, liver, and bone; however, melanomas are notorious for metastasizing to odd locations.
What is the appropriate treatment for melanoma?
Surgical excision with optional regional node dissection for more advanced disease remains the first-line treatment.
What is the likely diagnosis and what is the pathogenesis of the disorder?
Duchenne muscular dystrophy (DMD) is an X-linked recessive (Xp21) disorder marked by a deficiency of functional dystrophin, a 23,000-kB protein that helps stabilize muscle fibers. Approximately one-third of cases are sporadic and due to spontaneous mutations (noninherited) that arise from a misalignment of chromosomes during a recombination event.
What is the prognosis for patients with Duchenne muscular dystrophy (DMD)?
Patients with DMD are usually unable to walk by the end of the first decade and are confined to a wheelchair by 12 years of age. Most patients die by the end of the second decade; respiratory failure is the leading cause of death. Dilated cardiomyopathy and/or conduction abnormalities are common and can be fatal.
What tests are used to diagnose Duchenne muscular dystrophy (DMD)?
If DMD is clinically suspected, serum creatine kinase levels are markedly elevated, and electromyography shows myopathic changes, genetic testing or a muscle biopsy can confirm the diagnosis. Muscle biopsy shows atrophic muscle fibers of various sizes in disarray, degeneration, and necrosis of individual muscle fibers with fibrous replacement.
What is the likely diagnosis?
What conditions should be considered in the differential?
The asymmetric, gradually progressive joint pain and stiffness in this case point to osteoarthritis (x-ray findings confirm). Physical examination findings in osteoarthritis include tenderness to palpation without signs of inflammation, joint effusions, crepitus, and bony enlargement of affected joints.
What genetic syndromes do this man and woman have?
The woman has neurofibromatosis type 1 (NF1, or von Recklinghausen neurofibromatosis), and the man has neurofibromatosis type 2 (NF2). NF1 is characterized by café-au-lait spots, meningiomas, neurofibromas (subcutaneous nodules), and axillary freckling. NF2 presents with bilateral acoustic neuromas (vestibular schwannomas).
What is the probability that the couple will have an asymptomatic child?
NF1 and NF2 are both autosomal dominant genes. On the basis of their family histories, the man and woman must be heterozygous for NF2 and NF1, respectively. Thus, each mutant gene has a 50% chance of being inherited by the child. NF1 is on chromosome 17, and NF2 is on chromosome 22; therefore, the inheritance of each mutant gene occurs independently of the other. The probability of two independent events occurring at once is the product of the probability of each event: 50% × 50% = 25%.
What is the differential diagnosis for recurrent fractures in children?
- Accidental injury.
- Birth trauma.
- Bone fragility (including osteogenesis imperfecta and rickets).
- Child abuse (which accounts for the vast majority of cases).
What is the most likely diagnosis?
The most likely diagnosis is osteogenesis imperfecta (OI), which is an inherited disorder involving defects in type I collagen, usually due to mutations in the COL1A1 or COL1A2 gene. It is also known as brittle bone disease, and its most common form has autosomal dominant inheritance.
What is the most likely diagnosis?
Rheumatoid arthritis (RA)
Clinical features of RA include the followiing:
1. Morning stiffness for more than 1 hour that is present for more than 6 weeks.
2. Arthritis in three joints or more for more than 6 weeks.
3. Arthritis of hand joints for more than 6 weeks.
4. Symmetric joint swelling and involvement.
5. Rheumatoid subcutaneous nodules.
6. Positive serum rheumatoid factor and/or anti-cyclic citrullinated protein antibodies (anti-CCP).
7. Abnormal C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR).
8. Typical radiographic changes (shown in Figure 9-9).
What underlying condition contributed to these fractures?
Osteoporosis. This disease is characterized by reduced bone mass with microarchitectural disruption, porosity, and skeletal fragility. Osteoporosis is difficult to diagnose, as a fracture is often the first clinical manifestation.
What conditions should be considered in a patient with trauma to the chest?
Direct injury can cause pulmonary or myocardial contusion, rib or sternal fractures, diaphragmatic injury, vessel laceration, and aortic damage, which is often fatal. Conditions associated with chest trauma include pneumothorax, flail chest, hemothorax, and cardiac tamponade.
What are the major arteries and veins of the thorax?
Among the conditions that can cause shoulder pain in elderly patients, what is the most likely diagnosis in this case?
What events commonly precipitate Rotator cuff tears?
What tendons are likely involved in rotator cuff tear injuries and what is their distal attachment?
The rotator cuff is made up of the tendons of the “SITS” muscles: Supraspinatus (the most commonly affected tendon with rotator cuff tears), Infraspinatus, and Teres minor insert on the greater tuberosity, and the Subscapularis inserts on the lesser tuberosity (Figure 9-10).
What are the innervations and actions of the rotator cuff muscles?
What is the most likely diagnosis? What explains the friction rub on auscultation?
Systemic lupus erythematosus (SLE). SLE is a multisystem autoimmune connective tissue disease with a variable clinical presentation that most commonly affects young women in their 20s and 30s. Most manifestations of SLE are secondary to immune complex deposition.
SLE patients can develop pericarditis leading to friction rub.
What is the most likely diagnosis and what are the two forms of this condition?
Systemic sclerosis (scleroderma), an autoimmune connective tissue disorder (Figure 9-11). Scleroderma exists in two forms, limited and diffuse, both of which occur in the setting of Raynaud phenomenon (exaggerated vasoconstriction in response to cold or stress leading to sharply demarcated color changes of the fingertips). This patient displays the limited form in which the skin of the fingers, forearms, and face are often affected with distinctive thickening.
Diffuse systemic sclerosis eventually involves visceral organs as well as the gastrointestinal tract (particularly the esophagus), heart (myocardial fibrosis), muscles, lungs (interstitial lung disease is seen in the majority of patients, causing dyspnea on exertion and cough), and kidneys. This results in dysphagia, respiratory difficulty, arrhythmias, and mild proteinuria. The most concerning manifestation of this disease is malignant hypertension leading to renal failure.
What is the most likely diagnosis and what are the two forms of this condition?
Systemic sclerosis (scleroderma), an autoimmune connective tissue disorder (Figure 9-11). Scleroderma exists in two forms, limited and diffuse, both of which occur in the setting of Raynaud phenomenon (exaggerated vasoconstriction in response to cold or stress leading to sharply demarcated color changes of the fingertips). This patient displays the limited form in which the skin of the fingers, forearms, and face are often affected with distinctive thickening.
Diffuse systemic sclerosis eventually involves visceral organs as well as the gastrointestinal tract (particularly the esophagus), heart (myocardial fibrosis), muscles, lungs (interstitial lung disease is seen in the majority of patients, causing dyspnea on exertion and cough), and kidneys. This results in dysphagia, respiratory difficulty, arrhythmias, and mild proteinuria. The most concerning manifestation of this disease is malignant hypertension leading to renal failure.
What is the most likely diagnosis?
Klumpke palsy results from birth injury to the lower trunk of the brachial plexus (C8 and T1 nerve roots). It is a proximal brachial plexus neuropathy.
What are 3 other injuries that can cause Klumpke palsy?
What is the differential diagnosis for acute joint pain? 4 categories?
What is the most likely diagnosis?
Gout, secondary to hyperuricemia. Gout characteristically causes monoarticular arthritis, often of the first metatarsophalangeal joint (podagra).
What are common causes of gout?
What are the appropriate treatments for gout?
- Acute attacks?
- Prevention?
