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Acute abdominal pain in children

Stuart J Fergusson and Alasdair H B Fyfe

As in adult surgery one of the most common acute presentations in paediatric surgery is abdominal pain. A thorough understanding of this topic is important not only for the paediatric surgeon but also for the general practitioner, the medical paediatrician, and the general surgeon, all of whom are often involved in these young patients’ care. This article gives a practical approach to the child with abdominal pain and some information on acute appendicitis, which is the most common surgical cause of the acute abdomen in children.

Although the broad principles of diagnosis are the same as that in adult surgery, there are important variations. Diagnosis is often difficult, even for seasoned consultants, because signs can be subtle and non-specific, and young patients do not have an adult’s ability to explain their distress. Correct diagnosis depends on good clinical judgment and experience.

History

The most important stepping stone towards a diagnosis is the history, the bulk of which is usually obtained from parents or guardians. Do not underestimate the importance of involving the patient in taking his or her history. Aside from the clinical information gained, positive interaction with the child will help you to build rapport with your patient before you start formally examining them. Talk to the children sympathetically and appropriately using words and concepts that they understand.

The details of the history follow normal conventions, with the addition of a birth history (box 1) and a history of immunisations.

Perinatal history

Knowledge of the perinatal history is important to ascertain whether the child or infant had any trauma, illnesses, or congenital abnormalities that have potential repercussions generally, or specific abdominal implications—for example, prematurity, necrotising enterocolitis, constipation from birth, or early urinary tract infection—may produce ongoing or recurrent pathology that presents with abdominal pain later in childhood. Place of birth, relating to ethnicity, is helpful to know when considering some hereditary illnesses that may present later with abdominal signs—for example, sickle cell disease or β thalassaemia.

Specific questions

After allowing the child or parent some time to present their own agenda and concerns, there are some questions which must be asked (box 2).

It is usually possible to differentiate colicky from peritonitic pain by listening carefully to the parents or child. Vomiting that is bile stained—that is, green, not merely yellow gastric juices—is often a sign that the child has substantial surgical pathology. Blood or mucus in the stool may indicate gastroenteritis, intussusception, or inflammatory bowel disease. Urinary symptoms should lead to investigation for a urinary tract infection that may be associated with a congenital urinary tract anomaly. Bladder or renal ultrasound is essential here.

Upper respiratory tract infections may be followed by abdominal pain, sometimes secondary to viral mesenteric adenitis, a common diagnosis in childhood. A lower lobe pneumonia may also result in the complaint of pain in the related upper abdominal quadrant. Another medical cause of acute abdominal pain is diabetic ketoacidosis, and this may well be the child’s first presentation with the disease.

Age of the patient

Paediatrics is a specialty governed by age, and taking a history will depend upon the patient’s stage of development. Clearly very young children cannot describe their problems, and so the parent’s perceptions will be the focus of the history. Among other important details, parents will be able to tell you how their child’s behaviour compares with normal. There is a general principle in paediatrics that you never dismiss a parent’s concern lightly, for they know their child better than anyone else. However, with experience in assessing many unwell children you will begin to place parents’ concerns in context.

In girls at or above the age of 9 years (or younger if they show signs of secondary sexual development) do not forget to take a menstrual history. In older girls it may be entirely appropriate to sensitively ask if they are sexually active. In postmenarchal girls there is always the possibility of pelvic inflammatory disease or normal or ectopic pregnancy.

Examination

Observing the patient before the formal, hands-on, part of your examination is crucial in paediatric medicine. It must be careful and discerning. Children who have peritoneal irritation, such as in appendicitis, will move reluctantly and uncomfortably and may in fact prefer to be carried by their parents. Conversely, a child who skips cheerfully towards you and interacts brightly is unlikely to have a serious acute diagnosis.

One essential step is to observe the dynamics between children and their carers. Since abdominal pain in children can be a sign of emotional or social difficulty, often within the context of a dysfunctional family unit, this sort of observation is vital and can shed light on a patient whose symptoms are difficult to interpret.

Carry out a complete physical examination. This should include examination of the external genitalia in all male patients because it is unforgivable to miss a testicular torsion. Don’t forget to examine hernial orifices in boys and girls (the presence of a hernia may be important to the diagnosis), and don’t forget to look in patient’s ears and mouths because abdominal pain may be caused by mesenteric adenitis (see above), which can follow an episode of otitis media or tonsillitis. Rectal examination is seldom indicated in children. It rarely yields unexpected or significant information and can cause considerable distress. Even if constipation is thought to be the cause of the abdominal pain, faecal masses are usually palpable in the descending colon. If a rectal examination is deemed necessary, it should ideally not be performed by anyone less experienced than a senior trainee in a paediatric discipline.

The table shows normal physiological values of heart rate, blood pressure, and respiratory rate,¹ which vary considerably between age groups. Hydration status can be assessed most accurately using these observations in combination with a consideration of urine output, but there are other “softer” signs of dehydration—dry mucous membranes, sunken eyes, decreased skin turgor, a capillary refill time of >2 seconds, decreased temperature, and (in babies) a sunken fontanelle.

Age (years)	Heart rate (beats/min)	Systolic blood pressure (mm Hg)	Respiratory rate (breaths/min)
<1	110-160	70-90	30-40
1-2	100-150	80-95	25-35
2-5	95-140	80-100	25-30
5-12	80-120	90-110	20-25
>12	60-100	100-120	15-20

Carry out abdominal examination methodically, calmly and without rushing. If necessary examine the child while on his or her parent’s lap. Do not upset your patient: this makes interpretation of your examination difficult, so be gentle and distract the child by chatting or role playing with their toys. After asking the child to show you the point of maximum tenderness with one finger, work towards this area, taking care to examine all quadrants.

Pain in children with peritoneal irritation is exacerbated by asking them to protrude and then suck in their abdomen, and it is also worsened by jumping on the spot. If a child complains of pain when the examiner pinches the skin lightly it is a sign that usually indicates a psychogenic component to the pain. This sign is not present when the pain has a surgical cause. The best way to learn good examination technique is to observe experienced practitioners at work.

Investigation

Compared with adult practice, investigations are indicated less often in children, especially if they are invasive, because it is very important to avoid causing unnecessary distress. In particular, x rays are used more discerningly because the risk of eventual harm associated with radiation is greater when exposure occurs at a young age. Box 3 shows common initial investigations and when to use them.

When there is remaining concern about a child, the most useful method of investigation is active observation in the ward, returning regularly to review his or her general condition and abdominal signs.

Acute appendicitis

The most common diagnosis of acute abdominal pain that needs surgery is appendicitis. Initial diagnosis may be difficult, particularly in the child younger than 3 years, and often a period of observation in hospital is needed to confirm clinical suspicion. It is not uncommon for the diagnosis to be delayed in this age group. Abdominal pain generally becomes more constant and more severe. The pain is heightened by movement and sometimes on micturition. Pain is initially diffuse and then usually localises in the right iliac fossa; but because the position of the appendix varies so may the location of maximum pain and tenderness. Appendicitis is often accompanied by anorexia, nausea, vomiting, or diarrhoea.

Conclusions

Get senior help without delay if you have concern about the health of the child because unwell children can deteriorate rapidly. Features of the presentation that should concern you include bile stained vomiting (think intestinal obstruction), a limp or poorly interacting child, and abnormal vital signs. Note that hypotension is a late sign of illness in children and necessitates immediate review by a senior. You should also be concerned about abdominal distension or tenderness that causes distress, particularly in the presence of guarding and always when the abdomen is rigid (peritonitic). Pyrexia should spark a search for a causative illness, but in isolation does not necessarily indicate a surgical diagnosis. A complete list of differential diagnoses can be found in a standard paediatric surgery textbook, but box 4 gives more common diagnoses according to age. There are many more causes of abdominal pain in childhood.

Competing interests: None declared.

Provenance and peer review: Not commissioned; externally peer reviewed.

For other paediatric articles visit http://student.bmj.com/topics/clinical/paediatrics.php.

Stuart J Fergusson surgical core trainee 1 Belfast City Hospital, Belfast BT9 7AB
sjfergusson@doctors.org.uk
Alasdair H B Fyfe consultant paediatric surgeon Royal Hospital for Sick Children, Glasgow G3 8SJ
Student BMJ 2008;16:410 | 10

1. Jevon P. Paediatric advanced life support: a practical guide. 2004. Butterworth Heinemann.)

       

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