What Causes Abdominal Distention?

Patient Presentation
A 10-year-old male came to the emergency room with a several day history of abdominal distension and generalized abdominal pain. The patient and family could provide few details but the pain was located periumbilically, occurred only during the day and would come and go. He occasionally felt nauseous but had no emesis. He denied any fever, chills, upper respiratory illnesses or urinary symptoms. He was unsure when his last bowel movement was. He had a history of constipation where his bowel movements were large enough to block up the toilet. He said that this didn’t feel like the pain he had with his appendicitis 1 year previously. The past medical history was positive for being underimmunized and having an appendectomy 1 year previously. The social history revealed financial difficulties. The mother also had a lower intellect with some difficulties with daily activities.

The pertinent physical exam showed a well-appearing male with normal vital signs. His weight was 10% and height was 75%. His abdomen was moderately distended. He had normal bowel sounds in all quadrants. Palpation found no fluid wave or organomegaly. He had palpable loops of bowel from the left lower quadrant that followed the colon upwards and into the right abdomen. Palpation of the colonic loops reproduced the main. He denied costovertebral angle or suprapubic tenderness. There was no guarding or rebound. Genitourinary examination was normal and on the rectal examination he had a large rectal vault with stool that was guaiac negative. The diagnosis of constipation was made, but because of the recent abdominal surgery a radiograph was taken. The radiologic evaluation showed stool throughout the colon with no air fluid levels, confirming the diagnosis. The patient was given an enema in the emergency room with some production of stool. The social worker in the emergency room helped to get polyethylene glycol (MiralaxTM) from the hospital pharmacy to take home. She also helped them make an appointment in a local clinic for constipation followup and well child care. The mother refused help with transportation to the appointment, but was willing to have the social worker contact the clinic social worker who might be able to help with the family’s social needs.

Case Image

Figure 114 – Supine view of the abdomen demonstrates a moderate amount of stool throughout the colon from the cecum to the rectum.

Discussion
Constipation generally is defined as infrequent or painful defecation. It often is due to passing large hard stool infrequently which causes painful defecation and then withholding behaviors. As stool withholding continues, the rectum dilates and gradually accommodates with the normal defecation urge disappearing. Chronic rectal distension results in both loss of rectal sensitivity, and loss of urge to defecate, which can lead to encopresis. Abdominal distention because of stool retention occurs frequently. Treatment includes colonic evacuation, establishing regular bowel habits, eating a balanced diet with dietary fiber and laxatives to keep the stool soft and help promote the normal motility patterns. MiraLax is polyethylene glycol, an osmotic laxative often used to help with bowel evacuation and as a maintenance medication. The dose when used as a maintenance medication is 0.5 -1 gram/kg/day divided BID. The dose can be titrated to have one soft stool per day. The differential diagnosis of constipation can be reviewed here.

Abdominal distention is caused by some type of abdominal obstruction or space-occupying lesion that blocks or impinges on the intestinal lumen. This leads to failure of the intestinal contents to pass through the intestinal tract. Proximal to the obstruction is swallowed air and abdominal contents and secretions. The abdominal contents cannot move distal to the obstruction causing no flatus and bowel movements. If the obstruction is high in the gastrointestinal tract (generally proximal to the jejenum) then emesis is common and there will be little abdominal distention because there is no air and contents moving further into the distal tract. If the obstruction is low, then there is more of a reservoir to hold the accumulated material causing abdominal distention. Emesis is less common with distal obstructions. Fluid loss and electrolyte abnormalities secondary to emesis, dehydration, intestinal stasis, and bowel edema all can lead to bacterial invasion into the bowel wall. This accompanied with increasing intraluminal pressures can cause abnormal intestinal tract vascular flow, ischemia, necrosis and perforation of the viscous.

Abdominal pain often, but not always, accompanies abdominal distention. The causes of abdominal pain include many others that are considered medical reasons such as abdominal migraine, pelvic inflammatory disease, etc. These can be reviewed here.

Learning Point
The differential diagnosis of abdominal distention includes:

  • Anatomical
    • Annular pancreas
    • Antral web
    • Duplications
    • Hirschsprung disease
    • Incarcerated inguinal or umbilical hernia
    • Imperforate anus
    • Jejunal and ileal atresia
    • Meckel diverticulum
    • Persistent cloaca
  • Neonatal
    • Meconium ileus
    • Meconium plug
    • Necrotizing enterocolitis
  • Infectious/Inflammatory
    • Appendicitis
    • Ileus
    • Intussception
    • Perforated viscus
    • Organomegaly
    • Sepsis
  • Other
    • Adhesions
    • Ascites
    • Constipation
    • Colonic pseudoobstruction syndrome
    • Mass/Tumor
    • Trauma with mass, such as hematoma
    • Pregnancy

The differential diagnosis of proximal gastrointestinal obstructions includes:

  • Bezoar
  • Duodenal atresia
  • Esophageal atresia
  • Malrotation and midgut volvulus
  • Pyloric stenosis
  • Tracheoesophageal fistula

Questions for Further Discussion
1. What are the indications for a surgical consultation for abdominal distention?
2. How is intestinal obstruction evaluated?
3. How is intestinal ileus treated?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Abdominal Pain and Constipation

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Rudolph CD, et.al. Rudolph’s Pediatrics. 21st edit. McGraw-Hill, New York, NY. 2003:1376-79.

Jackson PG, Raiji MT. Evaluation and management of intestinal obstruction. Am Fam Physician. 2011 Jan 15;83(2):159-65.

ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    6. Information technology to support patient care decisions and patient education is used.
    7. All medical and invasive procedures considered essential for the area of practice are competently performed.
    8. Health care services aimed at preventing health problems or maintaining health are provided.
    9. Patient-focused care is provided by working with health care professionals, including those from other disciplines.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Systems Based Practice
    26. Partnering with health care managers and health care providers to assess, coordinate, and improve health care and how these activities can affect system performance are known.

    Author

    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital

    Date
    July 21, 2014

  • What Medications Should Be Avoided with Long QT Syndrome?

    Patient Presentation
    An 11-year-old female came to clinic with a hacking cough for the past 4 days. It was bothering her during the day and night. She had no rhinorrhea, fever, nausea, vomiting or shortness of breath. Overall she just didn’t feel well but was attending school and doing her sports activities. She had multiple family members with upper respiratory tract infection symptoms over the past 2 weeks. Her father had been diagnosed with mycoplasma pneumonia 2 days ago after he had had similar symptoms and a chest x-ray that was compatible with the diagnosis. She was fully immunized including a TdaP and influenza vaccine given 4 months previously. Pertussis was circulating in the community, but not influenza. The past and family medical history showed a history of long QT syndrome that was diagnosed after the paternal grandfather had a syncopal incident. Her father and a sibling also had long QT syndrome. She had not had any problems including when taking various antibiotics and antihistamines in the past. She had been diagnosed based on electrocardiogram and genetic testing. She had no history of asthma or other lung disease. The review of systems was otherwise normal.

    The pertinent physical exam revealed a tired appearing female with a respiratory rate of 18, normal heart rate and blood pressure. She was afebrile and had normal growth parameters. HEENT was normal. Lung examination had mild end-expiratory wheezing at the base and mid-right lung field. The rest of her examination was normal. The diagnosis of probable mycoplasma pneumonia was made but as she had not had wheezing before a chest x-ray was obtained that showed changes in the posterior basilar segment of the right lower lobe. This confirmed the diagnosis. Because of the history of long QT syndrome the patient was started on doxycycline. Medication for symptoms such as a small amount of codeine to help with sleeping was not encouraged because of the long QT syndrome. The family and patient understood this and said they had been through this before. They would use a humidifier and make sure that she was drinking well. The patient’s clinical course at one week found her to be still coughing, but not as forcefully as before and she was feeling better.

    Case Image
    Figure 113 – PA and lateral views of the chest demonstrate a faint infiltrate in the posterior basilar segment of the right lower lobe, best seen on the PA view, consistent with bacterial or mycoplasma pneumonia.

    Discussion
    Mycoplasma pneumoniae is a frequent cause of pharyngitis, pneumonia and acute bronchitis, but acute otitis media is uncommon. Symptoms are usually self-limited and variable and include cough (non-productive usually but later can be productive), fever, fatigue and occasionally headache. Coryza is rare. Cough can continue for 3 to 4 weeks and can be accompanied by wheezing. Radiographic changes include diffuse infiltrates or focal abnormalities but are variable.

    Long QT syndrome (LQTS) is a group of disorders that have a prolonged QT interval and a polymorphic ventricular tachycardia. Torsade de pointes (“twisting of the points”) is a particular type of polymorphic ventricular tachycardia that can be associated with LQTS. LQTS can be congenital or acquired. It is increasingly being recognized and may be as common as 1:2500.

    Congenital LQTS has many different types. It is associated with chromosomal changes which cause myocardial ion channel problems which interferes with normal cardiac polarization-repolarization leading to arrhythmias. LQT1 accounts for 30-35% of LQTS. LQT2 accounts for 25-40%. LQT3 accounts for 5-10% of patients, and the others account for the remaining percentages. Phenotypically there are two main clinical phenotypes. Romano-Ward syndrome is an autosomal dominant trait that has LQTS without sensorineural deafness. Jervell and Land-Nielsen syndrome is an autosomal recessive trait that has LQTS with bilateral sensorineural deafness. Interestingly, some studies have reported up to 4% of patients who have sensorineural hearing loss to have Jervell and Lange-Nielsen syndrome, but a 2013 study of patients with sensorineural hearing problems identified in statewide newborn hearing screening program found no cases of Jervell and Lange-Nielsen syndrome.

    Acquired LQTS usually occurs because of medications but also through various metabolic disorders (particularly hypokalemia or hypomagnesemia), bradyarrhythmias, and other miscellaneous causes.

    LQTS manifestations include syncope, ventricular tachyarrhythmias, torsade de pointes and also cardiac arrest or unexplained sudden death. Patients may also be identified through family history or incidental ECG findings. LTQTS subtypes influence the arrhythmia risk and also the choice of treatment including no specific treatment for some patients. Maintenance of normal electrolytes, avoidance of extreme exertion and many different medications are necessary for many patients. The mainstay of treatment for many patients is beta-blockers. Additionally implantable cardiac defibrillators or permanent pacemakers are also used. Surgical denervation of the heart through ligation of the stellate ganglion is also sometimes used.

    Episodes can be precipitated by emotion, stress, sleep, sudden noises, and exertion.

    Learning Point
    Medication choice always requires careful consideration. Patients with LQTS need particular attention as many medications can interfere with cardiac polarization/repolarization.

    There are several categories of common medications that should be avoided in patients with LQTS including:

    • Antibiotics – macrolides, fluoroquinolones, trimethoprim-sulfa
    • Antifungals – some azole antifungals
    • Antihistamines – terfenadine and astemizole have been withdrawn from the market because of this risk
    • Antiemetics and promotility agents – ondansteron, phenergen, cisapride
    • Cough/cold medications – pseudoephedrine
    • Stimulant medications – methylphenidate
    • Pain and sedatives – chloral hydrate, oxycodone, methadone
    • Anti-depressants – including tricyclic antidepressants and some selective serotonin reuptake inhibitors including citalopram, fluoxetine.
    • Other groups include antiarrhythmic drugs, antineoplastic drugs, diuretics (because of electrolyte abnormalities), other psychotropic medications and even some herbs.

    The list of medications to avoid changes with new medication availability, and new knowledge about the medications and LQTS itself. CredibleMeds® sponsored by the non-profit organization Azcert.org provides one list of medications that should be avoided with LQTS. It is available here. Consultation with the patient’s cardiologist and pharmacist should also be considered when treating patients. Real-life conundrums occur when patients with LQTS have competing problems and risks that also must be addressed such as the need for sedation or patients with asthma who need beta-agonists. Team management with appropriate personnel in concert with cardiologists and prior planning for such problems can assist other care providers when these situations arise.

    Questions for Further Discussion
    1. What tests are available for mycoplasma?
    2. What is the difference between an implantable pacemaker and an implantable defibrillator?

    Related Cases

      Symptom/Presentation: Cough

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

    Information prescriptions for patients can be found at MedlinePlus for these topics: Arrhythmia and Pneumonia.

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Mikesell CE, Atkinson DE, Rachman BR. Prolonged QT syndrome and sedation: a case report and a review of the literature. Pediatr Emerg Care. 2011 Feb;27(2):129-31.

    Collins S, Widger J, Davis A, Massie J. Management of asthma in children with long QT syndrome. Paediatr Respir Rev. 2012 Jun;13(2):100-5.

    Mycoplasma pneumoniae and Other Mycoplasma Species Infections. Report of the Committee on Infectious Diseases. Pickering LK, ed., 29th ed. American Academy of Pediatrics, Elk Grove Village, IL, 2012.

    Chang RK, Lan YT, Silka MJ, Morrow H, Kwong A, Smith-Lang J, Wallerstein R, Lin HJ. Genetic variants for long QT syndrome among infants and children from a statewide newborn hearing screening program cohort. J Pediatr. 2014 Mar;164(3):590-5.

    ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    7. All medical and invasive procedures considered essential for the area of practice are competently performed.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

  • Interpersonal and Communication Skills
    17. A therapeutic and ethically sound relationship with patients is created and sustained.

    Author

    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital

  • How Much Cetirizine Can Be Used?

    Patient Presentation
    A 6-year-old male came to clinic with a history of seasonal allergic rhinitis. Loratadine usually controlled his symptoms well, but this spring seemed to be worse than usual. His mother was giving him the medicine in the morning but by the evening he was having increased sneezing, watery eyes and his mouth was itching. He was having problems sleeping also because of the increased rhinorrhea and was more tired during the day. “I started giving him some Benadryl® at night to try to help him sleep,” she said. “The medicine is just not working.” The past medical history revealed some mild atopic eczema, two episodes of bronchospasm that responded to albuterol, and seasonal allergic rhinitis that was worse in the spring and fall. The family history was positive for exercise-induced asthma and seasonal allergies on both sides of the family. The review of systems was negative.

    The pertinent physical exam showed a healthy boy with normal growth parameters. His eyes had allergic shiners and cobblestoning of the palpebral conjunctiva. There was mild redness of the bulbar conjunctiva bilaterally. His nose showed copious clear rhinorrhea with boggy turbinates without polyps. His lungs were clear. His skin had some mild keratosis pilaris on the upper arms. The rest of his examination was negative.

    The diagnosis of seasonal allergic rhinitis and conjunctivitis not responding to his regular antihistamine treatment was made. The physician recommended changing to cetirizine and to use more medicine than what was on the label. He said, “The allergists like this medicine because it seems to work without many side effects, and you can use alot of this medicine. We can increase it to help his symptoms.” He went on, “For your son, I would start with 20 mg or two tablets in the morning, but after a few days if he is still having problems, add another tablet at night. If that isn’t working then you can add another tablet. That would be 40 mg a day. If you look at the label it will tell you only 10 mg a day. It’s a very safe medicine, but let’s start low and see how much he needs to help his symptoms. As things improve with the summer then you can decrease the amount of the medicine too.” The physician also prescribed antihistamine eye drops to help control the eye symptoms, but his mother did not want to use nasal steroids at that time. “Call me in about 5 days or so and let me know how things are going, and we can decide if he needs more of the medicine and also about continuing the eye drops,” he instructed. The patient’s clinical course over the next two weeks showed him needing 20 mg BID to control his symptoms but he was now not using his eye drops. He was not having any medicine side effects and was able to sleep and play. Over the next few months, the boy was able to decrease the cetirizine to 10 mg a day in the summer, but needed 20 mg BID of cetirizine again in the fall.

    Discussion
    Antihistamine medications have been available for over 70 years. The original H1-antihistamines, while effective in treated allergic rhinitis, urticaria and other allergic problems, easily penetrated the blood-brain barrier and caused somnolence. The newer, second generation H1-antihistamines have much less somnolent side effects because of poor penetrance.

    Fexofenadine (Allegra®), desloratadine (Claritin®) and levocetirizine (Zyrtec®) are commonly used H1-antihistamines in the US today. Previously Astemazole (Hismanal®) and Terfanadine (Seldane®) were used but were withdrawn because of problems with cardiac arrhythmias with a propensity to prolong the QT interval. Fexofenadine in studies has the same somnolence producing effect as placebo. Desloratadine and cetirizine both can have some sedative effects.

    Cetirizine is extensively and rapidly absorbed by the gut allowing a rapid onset of action. It interacts with target receptors at effective concentrations, and organs where it would not be effective or toxic are avoided. There is no hepatic metabolism (thus avoiding many potential drug-drug interactions) and the drug is excreted unchanged by the kidney. The half-life is about 10.5 hours in adults. Cetirizine has higher binding affinity for receptors than other similar drugs thus it has “…a more potent, faster onset and longer duration of action…” when used for seasonal allergic rhinitis. “…[T]here is evidence that continuous treatment with cetirizine is more effective than on-demand treatment in achieving significantly greater inflammatory and clinical control in [allergic rhinitis] patients.” Cetirizine does not have cardiotoxic side effects, and is a pregnancy category B medicine ( = without harm to animal fetus and no human studies available). It is excreted in breast milk therefore is not recommended during lacatation. Cetirizine is contraindicated for people with known hypersensitivity to its components or hydroxyzine.

    Learning Point
    Cetirizine is a safe and effective medication, and because of this some allergists will use it off label in higher doses. As with any time a medicine is used off-label, it is important to monitor the patient closely for efficacy and especially for potential side effects. It is the human metabolite of hydroxyzine (Atarax®) that is used for severe urticaria/pruritis and seasonal allergic rhinitis.
    Normal dosing for cetirizine is:
    6 months-2 years, 2.5 mg daily to BID
    2-5 years, 2.5 mg daily to BID
    6-11 years, 5-10 mg daily to BID
    > 12 years, 5-10 mg daily to BID

    Hydroxyzine is often used at doses of 2 mg/kg/day up to 75 mg BID. Hydroxyine to cetirizine as an equivalent is 25 mg of hydroxyzine to 10-20 mg cetirizine equivalent (personal communication with pediatric allergist).

    Thus for a hydroxyzine dose of 75 mg/dose, the cetirizine dose would be 30-60 mg/dose. Using an average of 20 kg weight for the 6 year old above, the dose would be 16-30 mg/dose. Thus the physician above starting at 20 mg once a day was within this range and the amount the child needed to control his symptoms (40 mg/day) was also within this range.

    A reported overdose in an adult of 150 mg caused somnolence but no other problems. An overdose in an 18 month old patient of ~180 mg caused restlessness, irritability and then drowsiness. There were no other problems.

    Questions for Further Discussion
    1. What are indications for use of intranasal steroids for seasonal allergic rhintis?
    2. What are indications for use of antihistamine eye drops for allergic conjunctivitis?

    Related Cases

    To Learn More
    To view pediatric review articles on this topic from the past year check PubMed.

    Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

    Information prescriptions for patients can be found at MedlinePlus for these topics: Allergies and Cough and Cold Medicines.

    To view current news articles on this topic check Google News.

    To view images related to this topic check Google Images.

    To view videos related to this topic check YouTube Videos.

    Cetirizine. RxList. Available from the Internet at http://www.rxlist.com/zyrtec-drug.htm (rev. 5/16/2007, cited 5/26/2014).

    Zhang L, Cheng L, Hong J. The clinical use of cetirizine in the treatment of allergic rhinitis. Pharmacology. 2013;92(1-2):14-25.

    Church MK, Church DS. Pharmacology of antihistamines. Indian J Dermatol. 2013 May;58(3):219-24.

    ACGME Competencies Highlighted by Case

  • Patient Care
    1. When interacting with patients and their families, the health care professional communicates effectively and demonstrates caring and respectful behaviors.
    2. Essential and accurate information about the patients’ is gathered.
    3. Informed decisions about diagnostic and therapeutic interventions based on patient information and preferences, up-to-date scientific evidence, and clinical judgment is made.
    4. Patient management plans are developed and carried out.
    5. Patients and their families are counseled and educated.
    8. Health care services aimed at preventing health problems or maintaining health are provided.

  • Medical Knowledge
    10. An investigatory and analytic thinking approach to the clinical situation is demonstrated.
    11. Basic and clinically supportive sciences appropriate to their discipline are known and applied.

  • Practice Based Learning and Improvement
    12. Evidence from scientific studies related to the patients’ health problems is located, appraised and assimilated.
    13. Information about other populations of patients, especially the larger population from which this patient is drawn, is obtained and used.

  • Interpersonal and Communication Skills
    17. A therapeutic and ethically sound relationship with patients is created and sustained.

  • Systems Based Practice
    23. Differing types of medical practice and delivery systems including methods of controlling health care costs and allocating resources are known.

    Author

    Donna M. D’Alessandro, MD
    Professor of Pediatrics, University of Iowa Children’s Hospital