A couple of Jewish descent comes to the hospital for evaluation. They have had four children and two of them (a boy and a girl) have died of a disease. Neither parent has the disease.
What is the most likely mode of inheritance of the disease?
Correct Answer B:
Both children who died were most likely affected by a genetic disease. We are also given information about the health status of the parents, therefore this makes our ability to deduce the mode of inheritance much easier. Since none of the parents has the disease, it is clear that the disease is of an autosomal recessive inheritance pattern and the parents are simply carriers (choice B).
→ Autosomal dominant (choice A) is incorrect. At least one of the parents would have to be affected for this to be an autosomal dominant inheritance. It is transmitted by both sexes, all generations are affected, and there's no carrier state. Examples include polycystic kidney disease, Marfan syndrome,neurofibromatosis, and osteogenesis imperfecta.
→ X-linked dominant (choice C) is associated with manifested disease in females but is usually lethal in males. Examples include hypophosphatemic rickets and the majority of Alport syndrome cases. In this question X-linked dominant inheritance is incorrect because the mother is not affected by the disease.
→ X-linked recessive (choice D) is incorrect as only males would be affected.
→ Mitochondrial inheritance (choice E) is incorrect as the mother is not affected. Mitochondria are inherited only in the maternal ova and not in sperm.
Key point:
If 2 children of opposite sex have been affected by a genetic disease in a family, the mode of inheritance could be autosomal recessive, autosomal dominant, or X-linked dominant. If parents are free of the disease, it is most likely to be a case of autosomal recessive inheritance pattern with parents being carriers of the gene.
A 12-year-old boy presents to the emergency room complaining of pain and swelling at the left mid-femur area for approximately two weeks. On review of systems, he has had on/off low-grade fever for the last month, and the mother says it looks like he has lost some weight, but she had attributed this to a recent growth spurt. You perform an X-ray and notice a bizarre periosteal reaction, which the radiologist describes as "onion skinning." The following day, a biopsy is performed and shows small, round blue cells.
Given this history and these findings, what is the most likely diagnosis?
Correct Answer C:
Ewing sarcoma is the correct answer in this case. It is a malignant, small round blue cell tumor. It is the second most common malignant bone tumor (after osteosarcoma). It tends to peak between 10-20 years of age. Symptoms typically include pain and swelling, usually involving the midshaft of long bones, flat bones of the ribs and pelvis. Constitutional symptoms or signs, such as fever, fatigue, weight loss, or anemia, are present in about 10 to 20 percent of patients at presentation. Radiograph studies have typical features of multiple layers of periosteum around the tumor site described as "onion-skinning" pattern.
→ Osteosarcoma (choice A), while it is the most common malignant bone tumor, it typically does not present with systemic symptoms and radiographs typically show a "sunburst" pattern (soft tissue mass with radial calcifications).
→ Osteoid osteoma (choice B) is a benign bone-forming tumor, which produces high levels of prostaglandins (pain typically responds to NSAIDs). The lower extremity is most frequently affected; the proximal femur is the most common site. Boys are affected two to three times as often as girls. On plain radiographs, osteoid osteoma appears as a small, round lucency (nidus) with a sclerotic margin.
→ Chondroblastoma (choice D) is a benign cartilage-forming tumor that usually arises in the epiphyses of long bones and typically presents during the teenage years. On plain radiographs, chondroblastomas appear as small, well-defined lesions with a sclerotic border that may cross the physis (growth plate).
→ Nonossifying fibroma (choice E) is a benign fibrous lesion that is also known as metaphyseal cortical defect. It is a developmental defect in which areas that normally ossify are filled with fibrous connective tissue. On plain radiographs, nonossifying fibromas appear as small, well-defined, eccentric, expansile, lytic lesions located in the metaphysis with scalloped sclerotic borders.
When benign bone tumors are symptomatic, they may present with localized pain, swelling, deformity, or pathologic fracture. Malignant bone tumors include the same symptoms, but also usually accompanied by systemic symptoms (fever, weight loss, night sweats).
A 16-month-old male is brought to the emergency department by his mother because of coughing and severe shortness of breath. The cough is described as nonproductive. He was born at 40 weeks gestation with 3.4 kg and he has been meeting all developmental milestones. The mother denies any recent family travel or exposure to any toxic gases. She reports that the child’s 3-year-old sister had flu, conjunctivitis, and hemorrhagic cystitis 3 weeks ago. Around the same time the boy had what seemed to be common cold for 2 days but it had resolved spontaneously. On physical examination the child has intercostal retractions, wheezes, and fine crackles. Chest X-ray reveals peribronchial thickening, lowered diaphragm, increased air contrast of the lungs, and right lower lobe atelectasis.
Which of the following is most likely to occur as a result of this condition?
Correct Answer A:
The child’s clinical picture is suggestive of bronchiolitis obliterans secondary to adenovirus respiratory infection. Adenovirus infections commonly affect children between 1 and 3 years of age and besides respiratory infection it may cause follicular conjunctivitis, gastroenteritis, intussusception, hemorrhagic cystitis, and myocarditis. Adenovirus pneumonitis is associated with the development of bronchiolitis obliterans.
The diagnosis of bronchiolitis obliterans can be made based on history, physical examination, imaging and ventilation/perfusion scan. Initial symptoms may be cough, chest pain, or hemoptysis. After the initial episode a clinical plateau ensues that may last several days to one month during which symptoms appear to abate. However, following this period dyspnea worsens and cough becomes more frequent. Chest X-ray findings are non-specific and include peri-bronchial thickening and hyperinflation. The latter is characterized by lowered diaphragm, increased air contrast of the lungs, and increased retro-sternal space in the lateral view. Atelectasis is also a common finding. Ventilation/Perfusion scans show the distinctive pattern of a matched ventilation-perfusion defects and the segmental or lobar distribution of post-infectious bronchiolitis obliterans. This provides an assessment of the distribution pattern of the compromised areas of the lung. On histo-pathology, early lesions of bronchiolitis obliterans demonstrate submucosal lymphocytic inflammation and disruption of the epithelium of small airways, followed by an ingrowth of fibromyxoid granulation tissue (polyploid plug of fibrotic tissue) into the airway lumen, resulting in partial or complete obstruction (choice A).
→ Progressively worsening emphysema and development of liver cirrhosis (choice B) would occur in a patient with anti-trypsin deficiency.
→ Bronchieactasis and pancreatic enzyme insufficiency with fat malabsorption (choice C) would be seen in a patient with cystic fibrosis.
→ Bronchogenic adenocarcinoma at the periphery of the lungs (choice D) is incorrect as there’s no association between adenovirus pneumonitis and lung cancer.
→ Systemic dissemination with nodules consisting of central caseating necrosis (choice E) would be seen in miliary tuberculosis. This child’s clinical picture is more consistent with adenovirus infection.
In pediatric patients bronchiolitis obliterans is often a complication of adenovirus infection of lower respiratory tract. In later stages, its histopathology is characterized by fibromyxoid granulation tissue in the airway lumen, resulting in partial or complete obstruction.
A 6-week-old infant is brought to your department because of yellow skin. He also has dark urine and light stools. Physical examination reveals icteric sclera and hepatosplenomegaly. Laboratory studies are significant for conjugated bilirubin. Ultrasonography reveals shrunken gallbladder and liver biopsy reveals portal fibrosis and bile duct proliferation.
What is the most appropriate next step in management?
This child has elevated direct bilirubin, ultrasonography shows a shrunken gall bladder, and biopsy reveals portal fibrosis and bile duct proliferation, which all point to a diagnosis of biliary atresia. It is characterized by obliteration or discontinuity of the extrahepatic biliary system. Once the diagnosis is confirmed with biopsy, the most appropriate initial treatment is a Kasai procedure, the most successful version being a Roux-en-Y hepato-porto-jejunostomy (choice A). It has been observed that prognosis is significantly improved if surgery is done before 8 weeks of age.
→ Pancreaticoduodenectomy (choice B) also known as Whipple’s procedure is the treatment of choice for pancreatic cancer. It is not appropriate for biliary atresia.
→ Liver transplantation (choice C) is successful as the definitive treatment of biliary atresia in one third of biliary atresia patients. But the Kasai procedure is usually done as the initial treatment to allow biliary drainage.
→ Ursodeoxycholic acid (choice D) has been shown to promote bile flow in cholestatic conditions associated with a patent extrahepatic biliary system. It is used to enhance biliary drainage after a Kasai procedure has been performed, but it would not be helpful before the procedure.
→ Observation until 1 year (choice E) is incorrect. Studies have shown that children who have the Kasai procedure before 60 days of age have a better prognosis, while those who are operated later than 90 days of age are at disadvantage.
Conjugated bilirubinemia, shrunken gall bladder on ultrasonography, and a biopsy that reveals portal fibrosis and bile duct proliferation are suggestive of biliary atresia. Kasai procedure is the best initial treatment in children with biliary atresia and is most beneficial when performed before 60 days of age.
An 8-year-old girl presents to the emergency department with a poorly healing wound on the lateral side of her right leg 5 cm below the knee. She was injured when she fell down while playing with her friends. Her mother cleaned the area and it has been conservatively managed at home for the last 4 days. Her mother noted that the site has become very warm to touch, the child is becoming anxious and it has affected the way she walks so she decided to bring her for evaluation. Past medical history is not remarkable. Her immunizations are upto-date.
On physical examination, her temperature 38.8°C, Pulse is 105 bpm, respirations 23/min, BP is 110/65 mmHg. A poorly healing excoriation of the skin that contains some pus is noted. The area is tender to touch, hot, and swollen. While limited range of motion is noted because of pain, joints are not involved. 1 cm lymphadenopathy is palpable in the right popliteal area. Incision and drainage are done at the office and bacterial culture is performed. Based on the most common infections and antibiotic sensitivities, which of the following medications are most appropriate to prescribe?
This child has cellulitis of her lower extremity. Risk factors include cracks or peeling of skin, peripheral vascular disease, injury or trauma, insect bites and stings, diabetes associated ulcers, immunosuppressive drugs use, and recent surgery. The most common causative organisms are Streptococcus pyogenes and Staphylococcus aureus, but other organisms may be involved if cellulitis originates from animal or human bites, is hospital acquired, or occurs in an immunocompromised host. Tests are ordered depending on the severity of the infection. Most cases of early or mild cellulitis, especially those without fever, do not require laboratory testing. If there is an abscess or pustule, incision and drainage with a wound culture of the purulent discharge can be helpful for focused and appropriate antibiotic therapy.
While group A Streptococcus is sensitive to penicillin and cephalosporins, community acquired methicillin resistant Staphylococcus aureus is quite common, therefore, the selected antibiotics should take into account this reality. There’s less community acquired Staphylococcus aureus resistance to clindamycin and trimethroprim-sulfamethoxazole. Topical mupirocin is effective in managing Streptococcus pyogenes associated cellulitis. Therefore, the best choice in this scenario is clindamycin and topical mupirocin (choice B).
→ IV vancomycin (choice A) is indicated for severely ill patients with MRSA infections, those who are unable to tolerate oral medications, or those whose conditions worsen despite empirical antibiotic therapy.
→ Doxycycline and topical nystatin (choice C) is used in aquatic in lacerations and puncture wounds sustained in an aquatic environment; nystatin is an anti-fungal and this child’s wound infection is most likely bacterial.
→ Erythromycin and topical neomycin (choice D) both are known to have high resistance.
→ Amoxicillin-clavulanate (choice E) is indicated in cellulitis caused by Pasteurela multocida after a dog bite. For topical medications, mupirocin is the most effective with efficacy considered equivalent to oral systemic antibiotics. There’s much resistance against topical neomycin.
Cellulitis is a nonnecrotizing inflammation of the skin and subcutaneous tissues, usually from acute infection. There's little resistance against clindamycin and TMP-SMX, and they are effective in treating this condition. Topical mupirocin is more effective than neomycin and bacitracin.
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