Differential Diagnosis
This booklet is intended as a practical guide to patient care for registrars, medical officers, interns and medical students attached to the gynaecology units at the University of the Witwatersrand Academic Hospitals. Anyone can use it.
Lower abdominal pain (LAP) is a frequent presenting symptom in gynaecology. A full history & full examination are essential. Consider the differential diagnosis. Many patients end up being branded as ‘PID’ or ‘chronic PID’ – doxycycline & metronidazole must be amongst the most abused drugs in medicine.
DIFFERENTIAL DIAGNOSIS
Each condition will be covered in detail in this or other chapters.
Pelvic inflammatory disease (PID) – Overdiagnosed & underdiagnosed; from mild to severe. A vaginal discharge is not essential for the diagnosis. Cervical excitation/motion tenderness must be present.
Irritable bowel syndrome (IBS) – 50% of all LAP in women is caused by IBS. The pain is chronic, severe, & intermittent. Bowel habit disorders may be mild. Dyspareunia is usually absent. Tenderness is usually felt in the iliac fossae & suprapubically, i.e. higher in the abdomen than in mild PID. Bimanual examination is normal.
Primary and secondary dysmenorrhea – pain associated with menstruation. Take a good menstrual history. In secondary consider fibroids, endometriosis, adenomyosis, & chronic PID as causes.
Endometriosis/adenomyosis – A cause of secondary dysmenorrhea. Pain is chronic & must worsen with menstruation. There may be associated deep dyspareunia, sometimes infertility. Clear physical signs may be present.
Ovarian cyst accidents – Ovarian cysts twist (torsion), rupture, bleed, or expand. Cysts may produce little pain, then present with a sudden onset of severe pain. Feel for a mass. Ultrasound will show the cyst (remember a normal ovarian follicle, mid-cycle, may be up to 2.5cm)
Urinary tract infection – May be overdiagnosed (like PID), but can be easily missed. Take a proper urinary history & test the urine with reagent strips.
Pregnancy complication – Ectopic pregnancy. Always consider. Check the last menstrual period. Do a urine pregnancy test if ectopic pregnancy is even a slight possibility. Remember that an ongoing pregnancy & PID do not coexist in the first trimester unless there has been interference.
Lumbosacral root pain – This is referred to the lower abdomen; associated with back pain; worse on movement or lifting, or getting up in the morning. There is back tenderness & an absence of abdominal signs.
Acute appendicitis – Surgeons & gynaecologists frequently disagree and debate PID or appendicitis. Misdiagnosis is easy. Look for abdominal signs that exceed pelvic findings to suggest appendicitis.
Renal colic – This is not seen often, especially not in black South African women. Look for the restless patient with severe pain of sudden onset, sometimes radiating to the renal angle. Microscopic haematuria should be present.