This document provides an overview of the clinical approach and differential diagnosis of acute abdominal pain. It discusses the three types of abdominal pain and lists important factors to consider during evaluation such as associated symptoms. Common and uncommon potential causes of abdominal pain are outlined. For selected differential diagnoses, examples of relevant history, physical exam findings, working diagnoses, and recommended investigations are provided. The goal is to guide clinicians in appropriately evaluating and diagnosing the source of a patient's acute abdominal pain.

1. Clinical Approach and
Differential Diagnosis of
Acute abdominal Pain
OUSSAMA ALSAYED

2. 3 types of abdominal pain
Somatic
(parietal)
• Well
localized
• Sharp
Visceral
• Diffuse
• Dull-aching
• Autonomic
mediated
Referred
• Well
localized
• Dermatomal
mediated

3. Evaluation of abdominal pain

4. Diarrhea
Shortness
of Breath
Dysmenorr
hea
Dysuria/
hematuria
Skin
lesions
Joint
pain
Jaundice
Peritoneal
signs
Fever
Vomiting
Associated
Symptoms

5. Red flag
Is the patient septic? ► Start ABx
Is the patient dehydrated? ► Start fluid Resuscitation
Is the presentation acute abdomen? ► OR

6. Differential Diagnosis
Common
Constipation
Acute Appendicitis
Gastroenteritis
Henoch–Schönlein Purpura
Urinary tract infection
Abdominal trauma
Celiac disease
Diabetic ketoacidosis
Cholecystitis
Primary dysmenorrhea
Pneumonia
Functional abdominal pain
Uncommon
Intussception [Infants]
Meckel’s diverticulum [Infants]
Mesenteric Adenitis
Hirschsprung disease [Infants]
Inflammatory bowel disease
Malrotation [Volvulus] [Neonates]
Necrotizing enterocolitis [Neonates]
Sickle cell crisis [Infants]
Viral hepatitis
Acute pancreatitis
Hemolytic Uremic Syndrome [Infants]
Testicular torsion
Pelvic Inflammatory disease

7. Workup on
selected cases

8. Hx
P/E
Dx
Ix
Sharp or stabbing periumbilical pain
that migrates to the right lower
quadrant (RLQ) with fever, anorexia,
nausea, vomiting.
Patient avoids movement. Positive
McBurney sign (RLQ pain and
tenderness to palpation at 2/3
between umbilicus and right ASIS).
Acute appendicitis
CBC; Normal or elevated WBCs w/
neutrophilia

9. Hx
P/E
Dx
Ix
Infant aged <2 y w/ abdominal pain
and/or painless passage of blood per
rectum; often asymptomatic.
Abdominal tenderness medial to
McBurney’s point w/ guarding and
rebound (suggest diverticulitis);
palpable abdominal mass (suggest
intussception).
Meckel’s diverticulum
Abdominal U/S

10. Hx
P/E
Dx
Ix
Diffuse abdominal pain; hx of recent
URTI.
Fever, abdominal tenderness not
localized to RLQ, rhinorrhea,
pharyngitis and/or associated w/
cervical lymphadenopathy.
Mesenteric Adenitis
Abdominal U/S

11. Hx
P/E
Dx
Ix
Colicky abdominal pain with vomiting
associated w/ fever, nausea; diarrhea.
Diffuse abdominal pain not
associated w/ peritoneal signs, low-
grade fever, signs of dehydration
tachycardia, hypotension, dry MM,
poor CRT , sunken fontanelle in
infants
Acute gastroenteritis
Spot diagnosis

12. Hx
P/E
Dx
Ix
Vague abdominal pain associated w/
fever, nausea; bloody diarrhea.
Generalized edema, Severe pallor,
hypertension.
HUS
↑↑ Renal function tests

13. Hx
P/E
Dx
Ix
Colicky and poorly localized
abdominal pain, sometimes
accompanied by vomiting and bloody
diarrhoea w/ skin rash.
Erythematous, macular trunk-sparing
rash with arthritis/arthralgia
with/without Hematuria, nephrotic
syndrome. [Multiple System
Involvement].
HSP
Spot diagnosis

14. Hx
P/E
Dx
Ix
Neonates and Infants; fever, vomiting
and poor feeding. Older children;
Dysuria, polyuria, hematuria, loin pain
if progressed to PN. Hx of
constipation.
High-grade fever, supra pubic
with/without costovertebral angle
tenderness; foul-smelling urine; gross
hematuria. Not associated with skin
rash.
UTI
Urine dipsticking for nitrites,
leukocyte esterase; urine culture.

15. Hx
P/E
Dx
Ix
History of trauma and signs of
bruising and tenderness;
Skin marks reflecting mechanism of
injury;
Abdominal trauma [Blunt or Penetrating}
Abdominal U/S

16. Hx
P/E
Dx
Ix
Rapid deep breathing, abdominal
pain, vomiting, confusion; IDDM.
Hypothermia, hypotension,
tachycardia, tachypnea [Kaussmaul’s
breathing]
DKA
Urinalysis for ketones

17. Hx
P/E
Dx
Ix
Recurrent crampy abdominal pain
associated w/ menstruation.
Lower abdominal tenderness; Not
associated with fever.
Primary dysmenorrhea
Spot diagnosis

18. Hx
P/E
Dx
Ix
Infant between 3-24 m w/ colicky
abdominal pain, fever, vomiting;
episodic flexion of the legs.
Blood that is mixed w/ mucous and
have redcurrant jelly appearance,
abdominal tenderness, and sausage-
shaped abdominal mass on palpation.
Absent bowel sounds on
auscultation.
Intussception
Barium enema; filling defect

19. Hx
P/E
Dx
Ix
Male in early infancy; failure to pass
meconium in the first 36 hours of
life[Bowel Obstruction] with/without
hx of Down $
Abdominal distension in the LLQ;
palpable fecal mass; absence of
peritonitis, guarding or rebound
tenderness; dysmorphic features of
Down $
Hirschsprung disease
Abdominal X-ray

20. Hx
P/E
Dx
Ix
Early infancy age group; Hx of bilious
vomiting
Diffuse abdominal and tenderness;
absent bowel sounds [obstruction],
guarding, rebound tenderness [+ve
peritoneal signs] associated w/ low
grade fever and hematochezia.
Malrotation volvulus
Upper GI contrast study; bird beak
sign of stricture.

21. Hx
P/E
Dx
Ix
Premature neonate; feeding
intolerance, bloody stools, apnea.
Abdominal Distension, tenderness,
abdominal wall erythema,
bradycardia.
NEC
CBC; leukocytosis or leukopenia,
anemia, thrombocytopenia.

22. Hx
P/E
Dx
Ix
Malaise, fever N, V, D, headache, Dark
urine, Pale Stools.
Jaundice, tender
hepatosplenomegaly,
lymphadenopathy, generalized
wasting.
Viral hepatitis
↑↑ Liver function tests

23. Hx
P/E
Dx
Ix
Recurrent episodic RUQ colicky pain
occurs after eating fatty foods
radiating to the back; with referred
pain to the rt shoulder.
Right subcostal region tenderness;
+ve murphy’s sign during palpation.
[+ve peritoneal signs].
Acute Cholecystitis
RUQ U/S

24. Hx
P/E
Dx
Ix
N, V, epigastric colicky pain radiating
to back.
Epigastric tenderness; tachycardia
and tenderness in severe cases; +ve
Cullen sign [Discoloration around
umbilicus] or +ve Grey-Turner sign
[Discoloration around flanks]
Acute Pancreatitis
↑↑ Serum Amylase

25. Hx
P/E
Dx
Ix
Acute-onset testicular pain; N, V. Hx
of Trauma may be present.
Tender edematous testicle, affected
testes higher than non affected
associated w/ scrotal erythema and
edema; absent cremasteric reflex.
Testicular torsion
Duplex/Doppler U/S

27. Osama.Ahmed1664@alexmed.edu.eg