Case Of the Month 1: Answer

This patient has proctitis, which is inflammation of the anus or rectum.  Although other etiologies such as abscesses, diverticulitis, or other infections may be considered in this patient, he has rectal pain, blood, and discharge, so proctitis has to be the foundation of the diagnosis.  We can divide proctitis into IBD, infectious, non-infectious, and idiopathic etiologies.  It’s important to make this distinction especially between IBD and infectious as IBD treatment includes immunosuppressive therapy which could worsen a potential infectious etiology.  New cases of IBD (Crohn’s or UC) are usually diagnosed in the second or third decade of life (a smaller peak occurs around age 55-65) in what is essentially a 1:1 male:female ratio, so this patient hits the demographic target for new-onset IBD.  The most common infectious etiologies are Gonorrhea, Chlamydia, LGV, and Herpes, with syphilis also a possible organism.  This patient has a risk factor as a MSM, and this is the biggest risk factor for infectious etiologies of proctitis.  There isn’t much reason to expect non-infectious etiologies such as radiation proctitis or ischemic proctitis, however Behcet’s can present with rectal ulcers, pain, and bleeding.  Idiopathic is a last-resort diagnosis.

Dr. Birnbaum gives a great overview of the workup with Dr. Kopping’s important addition: labs with CBC, blood cultures, UA/Ux (with GC/chlamydia), RPR/treponemal antibody, VBG/shock (for lactate), anal swab for GC/Chlam (NAAT and culture) and a HIV test. Throw in a ANA if you want to r/o Behcet’s. There is concern for IBD and maybe some other insidious abdominal pathology with the lower abd tenderness so a CT scan is reasonable to look for abscesses and fistulas. You can also consult one of your fellow specialists here at Janus Medical to perform a quick bedside anoscopy which may reveal evidence of anusitis, but it is unlikely to provide diagnostic help as seeing ulcers or inflammation does not differentiate between IBD, infectious, or non-infectious etiologies.

This presentation is most consistent with LGV proctitis. This infection is most common in MSM who are having receptive anal intercourse.  LGV (which is Chlamydia serovars L1, L2, and L3) invades deeper than GC/Chlam proctitis and can cause tender LAD, abscess formation, or fistulas. Mucopurulent discharge is unlikely in IBD and almost always a sign of underlying infection.  All STI proctitis can potentially cause ulceration. This is why missing this diagnosis and referring to GI for scoping may be disasterous; they will see ulcers/fistulas, start on immunosuppressive therapy and the patient’s condition will worsen. Performing a rectal swab NAAT for GC/Chlam is crucial for treatment (see why in the Treatment discussion!); culture is also important but does not always grow the pathogens.  The anal swabs are important diagnostically because urethral swabs or urine samples for GC/Chlam may be negative if the patient only has isolated GC/Chlam proctitis.  Although standard GC or Chlamydia serovars D-K causing proctitis can present similarly, patients are frequently asymptomatic or have very mild discomfort/itching without bleeding.  Lack of skin findings puts syphilis and herpes a little less likely in this patient.

This is essentially male pelvic inflammatory disease.  LGV treatment is 3 weeks of doxycycline 100mg BID and as always, treatment for gonorrhea needs to be included in the form of a 250mg IM injection of Ceftriaxone. However, when first treating this patient for likely STI proctitis you won’t know if the Chlam serotype is D-K or L1-L3. LGV needs 3 weeks of doxy, however regular Chlamydia proctitis requires only 1 week of doxy or a single dose of 1g Azithromycin. This is why an anal swab for GC/Chlam is imperative during workup.  What I recommend is to treat all patients initially as LGV serotypes with three weeks doxy and when your anal swab tests return with the serotype, you can always call the patient to confirm whether to take the full three week treatment or just stop after one week. Make sure the patient has follow up in 3 months to have a test of cure performed to ensure eradication. Remember to tell patients to avoid sex during the treatment period and to have partners tested and treated as well.