Gonococcal Arthritis

Gonococcal arthritis is a manifestation of disseminated gonococcal infection (DGI), occurring when Neisseria gonorrhoeae spreads hematogenously from a mucosal site (genital, rectal, or pharyngeal) to distant sites, most commonly joints and skin.

It remains the most common cause of septic arthritis in sexually active young adults in many settings, and disproportionately affects women, in whom the primary mucosal infection is more often asymptomatic and therefore untreated before dissemination occurs.

DGI classically presents in one of two overlapping patterns. The arthritis-dermatitis syndrome (more common) features fever, migratory polyarthralgia, tenosynovitis (particularly of the wrists, fingers, ankles, and toes, a relatively distinctive feature), and a sparse pustular or vesiculopustular rash on an erythematous base, typically on the distal extremities and trunk. The purulent arthritis syndrome features a true septic monoarthritis or oligoarthritis, most commonly affecting the knee, wrist, or ankle, without the preceding migratory or dermatologic features, and mimics other causes of septic arthritis clinically.

Blood cultures are positive in a minority of cases (particularly the arthritis-dermatitis pattern), but should always be sent
Synovial fluid analysis and culture (from the purulent arthritis pattern) has low culture sensitivity for gonococcus specifically, given its fastidious growth requirements; NAAT of synovial fluid, where available, offers substantially higher sensitivity
NAAT testing of all mucosal sites (urethral/vaginal, rectal, pharyngeal) regardless of symptoms is essential, since this is often where the organism is most reliably detected, even when disseminated cultures and joint fluid are negative
Skin lesion Gram stain and culture, if pustules are present
Synovial fluid should still be sent for standard cell count, Gram stain, and culture as for any suspected septic arthritis (see that entry), given the differential includes other bacterial causes

Ceftriaxone 1 g IV/IM once daily, continued for 24 to 48 hours after clinical improvement begins, then stepped down to an oral agent (guided by susceptibility if available, otherwise cefixime 400 mg PO bd, or per local resistance patterns) to complete a total treatment course of 7 days
Given the frequency of chlamydial coinfection, add doxycycline 100 mg PO bd for 7 days empirically unless chlamydia has been specifically excluded
Purulent arthritis with a significant joint effusion may require joint aspiration or surgical drainage in addition to antibiotics, following the same principles as any septic arthritis (see that entry)
Sexual partners in the preceding 60 days should be tested and treated
Follow local antimicrobial resistance guidance closely given rising, regionally variable gonococcal resistance

Referral: rheumatology or orthopedics for joint aspiration/drainage where indicated; sexual health services for partner notification and full STI screening.

Schistosomiasis

Also known as: Bilharzia, Snail fever

Schistosomiasis is a chronic parasitic infection caused by trematode flukes of the genus Schistosoma, acquired through skin contact with fresh water containing infective cercariae released by an intermediate snail host.

It remains a major cause of chronic morbidity in many parts of sub-Saharan Africa, the Middle East, South America, and parts of Asia.

The three species of greatest clinical significance differ in their primary organ tropism: Schistosoma haematobium predominantly affects the urinary and genital tract, while Schistosoma mansoni and Schistosoma japonicum predominantly affect the intestinal tract and, via portal venous migration, the liver, causing periportal fibrosis and portal hypertension over time.

Cercarial dermatitis ("swimmer's itch") may occur at the point of skin penetration, typically within hours to days of exposure, causing a transient, itchy papular rash.
Acute schistosomiasis (Katayama fever) occurs weeks after heavy primary exposure, particularly in previously unexposed travelers to endemic areas, and presents with fever, urticaria, myalgia, cough, hepatosplenomegaly, and eosinophilia, reflecting an acute immune response to migrating and newly egg laying worms.
Chronic urinary schistosomiasis (S. haematobium) presents with terminal hematuria (blood at the end of micturition, a relatively distinctive feature), dysuria, and, over years, progressive bladder wall fibrosis and calcification, hydronephrosis, and an important, well established association with squamous cell carcinoma of the bladder.
Chronic intestinal and hepatic schistosomiasis (S. mansoni, S. japonicum) presents with abdominal pain, diarrhea (sometimes bloody), and, over years, hepatosplenomegaly and progressive periportal fibrosis leading to portal hypertension, with, notably, relatively preserved hepatocellular synthetic function compared to cirrhosis of other causes, since the fibrosis is presinusoidal rather than reflecting diffuse parenchymal injury.
Female genital schistosomiasis, an under-recognized manifestation of S. haematobium infection, causes genital lesions and is associated with increased susceptibility to HIV acquisition, an important public health consideration in co-endemic regions.

Microscopy for ova in urine (for S. haematobium, ideally on a terminal, concentrated urine sample, sometimes collected around midday when egg excretion peaks) or stool (for S. mansoni and S. japonicum) is the traditional diagnostic method, though sensitivity is imperfect, particularly in light infection.
Serology can support diagnosis, particularly useful in travelers or in acute Katayama fever presentation before eggs become detectable, though it cannot reliably distinguish active from past, treated infection.
Eosinophilia is a common and useful supportive finding, particularly prominent in acute Katayama fever.
Urinary tract ultrasound assesses for bladder wall thickening, hydronephrosis, and other structural sequelae in chronic S. haematobium infection. Abdominal ultrasound assesses hepatic periportal fibrosis and splenic size in intestinal and hepatic disease, with characteristic imaging patterns described for hepatic involvement.
Cystoscopy with biopsy may be needed to assess bladder pathology or investigate for malignant transformation in longstanding urinary schistosomiasis.

Differentials include other causes of hematuria, other causes of chronic diarrhea, and other causes of hepatosplenomegaly and portal hypertension, particularly cirrhosis of other etiology.

Praziquantel is the treatment of choice across all schistosome species, typically given as a single day's treatment (often split into two doses a few hours apart), highly effective against adult worms though notably less effective against immature, migrating schistosomula, which is relevant in acute Katayama fever, where a repeat dose some weeks later is often given to treat any worms that have since matured.
Acute Katayama fever may additionally benefit from a short course of corticosteroids to dampen the acute immune reaction, alongside praziquantel, particularly in more severe presentations.
Established chronic complications, such as periportal fibrosis with portal hypertension or urinary tract structural damage, are managed according to their own specific principles, since praziquantel treats the active infection but does not reverse established fibrotic damage.
Prevention centers on avoiding contact with potentially infected fresh water in endemic areas, alongside broader public health measures including snail control, improved sanitation, and mass drug administration programs in highly endemic communities.

Referral: infectious disease or tropical medicine for diagnostic confirmation and treatment guidance, particularly in returning travelers; urology for structural urinary tract complications; gastroenterology or hepatology for portal hypertension and its complications.

Gonococcal Arthritis

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management