Key Takeaways
A 35-year-old man presented to the emergency room with persistent watery diarrhoea with mucus for 11 days. Initially diagnosed with gonorrhoea, further tests revealed a coinfection with Shigella.
The Patient and His History
The patient was admitted to the emergency department in Toronto, Ontario, Canada, with diarrhoea, abdominal pain, and pain during defecation, along with fever since the onset of symptoms. His medical history included HIV, which was being treated with medication.
The patient reported that his symptoms began on the fifth day of a trip through Portugal and Spain, during which he had consumed raw seafood, unprocessed dairy products, and tap water. Despite these exposures, his fellow travellers remained healthy. His sexual history revealed unprotected intercourse with multiple partners, and he had previously used doxycycline for preexposure prophylaxis.
Findings and Diagnosis
On physical examination, the patient had a temperature of 39.7 °C and tachycardia of 106 beats/min.
Blood tests showed a normal white blood cell count of 5.4 × 10⁹/L (normal range: 4.0-11.0 × 10⁹/L) and neutrophil count of 2.7 × 10⁹/L (normal range: 2.0-7.5 × 10⁹/L). A contrast CT scan of the pelvis and abdomen revealed acute proctocolitis. Blood and stool cultures were collected, along with a rectal swab to assess for gonorrhoea, chlamydia, and herpes simplex.
The patient received 1 g of intramuscular ceftriaxone and was prescribed doxycycline 100 mg for 7 days to treat gonorrhoea and chlamydia. Due to persistent fever, he was referred to a Tropical Disease Unit for further evaluation.
Diarrhoea and abdominal pain persisted, although fever and mucus in the stool had resolved. Examination revealed a blood pressure level of 102/66 mm Hg, a heart rate of 77 beats/min, and a body temperature of 37.6 °C.
Notable findings included pain in the left lower quadrant of the abdomen and palpable inguinal lymphadenopathy. Stool samples were evaluated for Clostridium difficileinfection, chronic or helminthic infections such as strongyloidiasis and schistosomiasis, and dengue virus infection.
Stool cultures confirmed positive results for Neisseria gonorrhoeae and Shigella flexneri. Shigella infection explained the persistence of symptoms despite treatment for gonorrhoea. The patient was treated with ciprofloxacin (500 mg twice daily). Symptoms resolved within 48 hours.
Discussion
Shigellosis is an acute diarrhoeal disease transmitted via the faecal-oral route or sexual contact. Indirect transmission, such as through used condoms, is also possible during sexual contact.
Risk groups include travellers to endemic areas, homeless individuals, and children in resource-limited settings, such as daycare. Men who have sex with men are at a higher risk due to reduced immune function.
The disease is caused by four species of Shigellabacteria: Shigella sonnei, S flexneri, Shigella dysenteriae, and Shigella boydii. The incubation period is 1-4 days, and it typically self-resolves within 5-7 days. However, resistance is increasing.
Shigella isolates collected from men who have sex with men in the UK have been reported to have high rates of azithromycin resistance and outbreaks of S flexneri 3a, S flexneri 2a, and S sonnei. Outbreaks of multidrug-resistant S sonnei have been documented in Montreal, Quebec, Canada, and S flexneri serotype 1 in Vancouver, British Columbia, Canada.
Gonorrhoea is caused by gram-negative diplococcus N gonorrhoeae, which has seen a 182% increase in cases between 2010 and 2019. Men who have sex with men are at a higher risk for resistance due to factors such as multiple sexual partners and drug misuse.
Acute travel-related diarrhoea and sexually transmitted infections (STIs) are common causes of fever in returned travellers. Male travellers are twice as likely to be diagnosed with an STI.
Coinfection should be considered in men who have sex with men who have sex-related gastrointestinal infections. Up to 40% of individual men with shigellosis who have sex also have an STI, such as gonorrhoea.
To summarise, this case report describes a returned traveller who had both shigellosis and gonorrhoea. The authors emphasise that shigellosis should be considered in cases of acute gastroenteritis or proctocolitis, given the range of potential transmission pathways.
This case highlighted the importance of maintaining a broad differential diagnosis for proctocolitis.
A thorough sexual history, overlapping symptoms, and screening for parasitic, enteric, and STI infections are important to identify possible polymicrobial infections in this population.
This article was translated from Univadis Germany, using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
