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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor=William J Gibson (Reviewed by {{YD} and {{Rim}})
|QuestionAuthor=William J Gibson (reviewed by {{Rim}})
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Genetics
|MainCategory=Genetics
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|MainCategory=Genetics
|MainCategory=Genetics
|SubCategory=Pulmonology, General Principles
|SubCategory=Pulmonology, General Principles
|MainCategory=Genetics
|MainCategory=Genetics
|MainCategory=Genetics
|MainCategory=Genetics
|MainCategory=Genetics
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|MainCategory=Genetics
|MainCategory=Genetics
|SubCategory=Pulmonology, General Principles
|SubCategory=Pulmonology, General Principles
|Prompt=A 25-year-old man, with a long history of pulmonary infections, presents to his primary care physician’s office complaining of a persistent cough and expectoration of foul-smelling greenish sputum for the past tw months. He explains that he has suffered from recurrent respiratory tract infections since birth. A few months ago, he was prescribed an antibiotic that helped him recover from a similar episode. The patient now seeks a more thorough investigation of his symptoms. On physical examination, pulmonary auscultation reveals diffuse crackles and rhonchi accompanied by a high pitched wheezing during expiration. A recent ECG and abdomninal CT scan of the patient are retrieved from the patient's medical chart and are shown below. Which of the following conditions is this patient most likely to also suffer from?
|Prompt=A 25 year old male with a long history of pulmonary infections presents to his primary care physician’s office complaining of a persistent cough. He explains that he has suffered from recurrent pulmonary infections since birth. In the past he has simply been prescribed an antibiotic and began to recover.  This time he presents with a concurrent sinus infection which has persisted for 1 month. The patient seeks a more thorough investigation of his symptoms. On physical exam, the patient is otherwise healthy appearing.  Pulmonary exam reveals diffuse crackles and rhonchi accompanied by a high pitched wheezing during expiration. Cardiovascular exam reveals distant heart sounds.  Upon more careful examination, the physician notes that heart sounds increase on the right side.  The patient denies smoking. Which of the following is this patient most likely to also suffer from?
 
|Explanation=The patient in this vignette is suffering from [[Kartagener’s syndrome]]: a rare, ciliopathic, [[autosomal recessive]] genetic disorder that causes a defect in the action of the [[cilia]] lining the respiratory tract (lower and upper, sinuses, [[eustachian tube]], [[middle ear]]) and fallopian tube, and also of the [[flagella]] of sperm in males. The main consequence of impaired ciliary function is reduced or absent mucus clearance from the lungs, and susceptibility to chronic recurrent respiratory infections, including [[sinusitis]], [[bronchitis]], [[pneumonia]], and [[otitis media]].  The distant heart sounds in the cardiac exam of this patient reveal the presence of [[situs inversus]], where the heart actually lies in the right side of the chest.
[[Image:WBR0101A.jpg|500px]]
|AnswerA=Milk allergies and diarrhea
[Image:WBR0101B.jpg|500px]]
|AnswerAExp=This finding is nonspecific but can be a feature of [[IgA deficiency]], also an immunodeficiency syndrome but not associated with [[situs inversus]].
|Explanation=Kartagener's syndrome (KS), a subtype of primary ciliary dyskinesia (PCD), is an autosomal recessive genetic disorder classically characterized by the triad of situs inversus, bronchiectasis, and chronic sinusitis. However, the clinical features of KS also include rhinitis, chronic otitis, and nasal polyposis. KS is considered a ciliopathy due to missing dynein arms. It results in impaired ciliary movement of the respiratory epithelium, leading to abnormal mucociliary transport and clearance. Similarly, KS is associated with infertility (or hypofertility) due to immobility of sperma flagella, which have core structures similar to those of cilia. Similarly in females, KS leads to hypo/infertility due to abnormal mucociliary transport within the fallopian tubes, increasing the risk of ectopic pregnancy. Finally, KS is also associated with situs inversus, defined as the position of internal organs in the opposite side. Situs inversus may be classified as situs inversus with dextrocardia or levocardia, depending on the position of the cardiac apex. The association between ciliary immobility and situs inversus is thought to be attributed to non-rotational defects of embrionary cell motility of abdominal viscera.
 
The patient in the vignette presents with recurrent respiratory tract infections with situs inversus with dextrocardia. The ECG of the patient in this vignette shows signs of dextrocardia, such as right axis deviation, tall R waves in lead V1, absent R waves in V6, negative P waves in I and aVL, and positive P waves in III and aVF. His Abdominal CT scan demonstrates situs inversus, showing the liver on the left side and the spleen on the right. 
 
Diagnosis of KS is generally made based on clinical features and radiological imaging. However, the ciliary defect among patients with KS may be visually observed using electron microscopy, and use of ciliary beat frequencies can also be helpful in establishing the diagnosis. Management is similar to other cases of bronchiectasis. It is mainly preventative and symptomatic, with goals aimed at providing appropriate prophylactic measures, such as influenza and pneumococcal vaccine, and reducing the disease progression. Rarely do patients require segmental lung resection or lobectomy (eg. to treat recurrent pneumonias or hemoptysis associated with the disease). The prognosis of KS is generally good, with many patients surviving until late adulthood.
|AnswerA=Milk allergy and diarrhea
|AnswerAExp=This finding is nonspecific; it can be a feature of [[IgA deficiency]], also an immunodeficiency syndrome but not associated with [[situs inversus]].
|AnswerB=Ataxia
|AnswerB=Ataxia
|AnswerBExp=Ataxia is a feature of [[ataxia telangiectasia]], also an immunodeficiency syndrome but not associated with [[situs inversus]].
|AnswerBExp=Ataxia is a feature of [[ataxia telangiectasia]], also an immunodeficiency syndrome but not associated with [[situs inversus]].
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|AnswerCExp=[[Spider angiomas]] are a feature of [[ataxia telangiectasia]], also an [[immunodeficiency syndrome]] but not associated with [[situs inversus]].
|AnswerCExp=[[Spider angiomas]] are a feature of [[ataxia telangiectasia]], also an [[immunodeficiency syndrome]] but not associated with [[situs inversus]].
|AnswerD=Eczema
|AnswerD=Eczema
|AnswerDExp=[[Eczema]] is a feature of [[Wischott-Aldrich syndrome]] and [[IgA deficieny]], both of which can cause recurrent pulmonary infections but are not associated with [[situs inversus]].
|AnswerDExp=[[Eczema]] is a feature of [[Wischott-Aldrich syndrome]] and [[IgA deficieny]] both of which can cause recurrent pulmonary infections but would not cause [[situs inversus]].
|AnswerE=Infertility
|AnswerE=Infertility
|AnswerEExp=[[Kartagener’s syndrome]] is caused by ciliary dynein arm defects. It is classically described as a triad of situs inversus, bronchiectasis, and chronic sinusitis. It is associated with infertility.
|AnswerEExp=[[Kartagener’s syndrome]] is caused by defects in ciliary proteins. Functional [[cilia]] are required for [[sperm]] motility, see explanation.
|EducationalObjectives=[[Kartagener’s syndrome]] is characterized by recurrent and chronic sinopulmonary infections, bronchiectasis, and [[situs inversus]]. It is associated with infertility in both males and females.
|EducationalObjectives=[[Kartagener’s syndrome]] is associated with recurrent sinus and pulmonary infections, [[situs inversus]], and [[infertility]] in males.
|References=Casanova MS, Tuji FM, Yoo HJ, et al. Kartagener syndrome. Dentomaxillofac Radiol. 2006;35(5):386-9<br>
|References=First Aid 2014 page 78
First Aid 2014 page 78
|RightAnswer=E
|RightAnswer=E
|WBRKeyword=Genetics, Kartagener's, Cilia, Pulmonary, Infection, Pulmonary infection, Immunodeficiency
|WBRKeyword=Genetics, Kartagener's, Cilia, Pulmonary, Infection, Pulmonary infection, Immunodeficiency
|Approved=Yes
|Approved=Yes
}}
}}

Revision as of 19:45, 3 September 2014
Author [[PageAuthor::William J Gibson (reviewed by Rim Halaby, M.D. [1])]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Genetics
Sub Category SubCategory::Pulmonology, SubCategory::General Principles
Prompt [[Prompt::A 25 year old male with a long history of pulmonary infections presents to his primary care physician’s office complaining of a persistent cough. He explains that he has suffered from recurrent pulmonary infections since birth. In the past he has simply been prescribed an antibiotic and began to recover. This time he presents with a concurrent sinus infection which has persisted for 1 month. The patient seeks a more thorough investigation of his symptoms. On physical exam, the patient is otherwise healthy appearing. Pulmonary exam reveals diffuse crackles and rhonchi accompanied by a high pitched wheezing during expiration. Cardiovascular exam reveals distant heart sounds. Upon more careful examination, the physician notes that heart sounds increase on the right side. The patient denies smoking. Which of the following is this patient most likely to also suffer from?]]
Answer A AnswerA::Milk allergies and diarrhea
Answer A Explanation [[AnswerAExp::This finding is nonspecific but can be a feature of IgA deficiency, also an immunodeficiency syndrome but not associated with situs inversus.]]
Answer B AnswerB::Ataxia
Answer B Explanation [[AnswerBExp::Ataxia is a feature of ataxia telangiectasia, also an immunodeficiency syndrome but not associated with situs inversus.]]
Answer C AnswerC::Spider angiomas
Answer C Explanation [[AnswerCExp::Spider angiomas are a feature of ataxia telangiectasia, also an immunodeficiency syndrome but not associated with situs inversus.]]
Answer D AnswerD::Eczema
Answer D Explanation [[AnswerDExp::Eczema is a feature of Wischott-Aldrich syndrome and IgA deficieny both of which can cause recurrent pulmonary infections but would not cause situs inversus.]]
Answer E AnswerE::Infertility
Answer E Explanation [[AnswerEExp::Kartagener’s syndrome is caused by defects in ciliary proteins. Functional cilia are required for sperm motility, see explanation.]]
Right Answer RightAnswer::E
Explanation [[Explanation::The patient in this vignette is suffering from Kartagener’s syndrome: a rare, ciliopathic, autosomal recessive genetic disorder that causes a defect in the action of the cilia lining the respiratory tract (lower and upper, sinuses, eustachian tube, middle ear) and fallopian tube, and also of the flagella of sperm in males. The main consequence of impaired ciliary function is reduced or absent mucus clearance from the lungs, and susceptibility to chronic recurrent respiratory infections, including sinusitis, bronchitis, pneumonia, and otitis media. The distant heart sounds in the cardiac exam of this patient reveal the presence of situs inversus, where the heart actually lies in the right side of the chest.

Educational Objective: Kartagener’s syndrome is associated with recurrent sinus and pulmonary infections, situs inversus, and infertility in males.
References: First Aid 2014 page 78]]

Approved Approved::Yes
Keyword WBRKeyword::Genetics, WBRKeyword::Kartagener's, WBRKeyword::Cilia, WBRKeyword::Pulmonary, WBRKeyword::Infection, WBRKeyword::Pulmonary infection, WBRKeyword::Immunodeficiency
Linked Question Linked::
Order in Linked Questions LinkedOrder::
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