The incidence of FHCS has been reported to range from 4% to 27% in patients with PID.10
In the present study, we identified 82 female patients diagnosed with FHCS during a four year period in an urban ED. The incidence of FHCS was 6.0% in adult (≥15 years) patients with PID in this study. The diagnosis rate of FHCS has increased perhaps due to the development of CT technology and availability. The pathogenesis of FHCS remains uncertain; however, several possible mechanisms have been proposed, including direct, hematogenous, and lymphatic spread. Exudative fluid can drain along the paracolic gutters from the pelvis to the diaphragm, causing perihepatitis followed by adhesions. However, because most patients show no evidence of generalized intra-abdominal infection between the pelvis and the liver, hematogenous or lymphatic spread are proposed. Rare cases of FHCS occurring in men also support these hypotheses.11
An exaggerated immune response is also considered as a pathogenesis, because high titers of IgG antibody (1 : 512 to 1 : 1024) to C. trachomatis
were found in all of the FHCS patients of a previous study.12
Even though clinical manifestations vary, RUQ abdominal pain is the main symptom of FHCS and becomes more severe in response to deep breathing. It develops as a result of congestion of hepatic capsules and fibrous exudates. RUQ pain may follow lower abdominal pain in a matter of days, or the two symptoms may occur simultaneously. Rarely, does RUQ pain present as a symptom without lower abdominal pain.13
As it is difficult to suspect FHCS upon first impression, the initial diagnoses of FHCS patients often include: gall bladder stones, acute cholecystitis, duodenal ulcer, liver abscess, subphrenic abscess, herpes zoster infection, and acute pyelonephritis.
Upon physical examination, tenderness and rebound tenderness are observed not only in the RUQ, but also in other parts of the abdomen. One case report reported pain in the left upper abdomen by perisplenitis as the main symptom of FHCS.14
Although the results of pelvic examination are subjective and somewhat dependent on a physician's expertise, cervical motion tenderness and adnexal tenderness may suggest underlying PID. In this study, however, cervical motion tenderness and adnexal tenderness were reported as negative in 38% and 65% of patients, respectively. This lack of symptomatic presentation may be the result of visiting the ED during or after the recovery phase of PID. A previous study found that symptoms of acute and subacute PID such as fever, abdomen pain, and vaginal discharge are almost always present in patients with FHCS.15
However, in this study, only 15% of patients presented with a fever, and 41% of patients presented with vaginal discharge.
For many years, N. gonorrhoeae
was thought to be the sole causative agent of FHCS. However, most experts now believe that C. trachomatis
is the more common causative pathogen.4,7,8
In this study, using the PCR technique, C. trachomatis
was found to be the main causative pathogen and was detected in 89% of patients. This was comparable to another study which reported that C. trachomatis
was discovered in 82% of the FHCS patients.16
Culture studies are not useful in the ED because of time constraints and the need for special media for C. trachomatis
. PCR for C. trachomatis
may also not be available in most EDs, and the result of PCR cannot be confirmed on the spot. Accordingly, empirical antibiotics sensitive to C. trachomatis
should be considered first in the ED.
Chlamydial infections may increase vulnerability to infection by other microbes, such as gram positive cocci and anaerobes. Therefore, even though the results of culture study are critical for diagnosing FHCS, cases in which expected pathogens are not identified still cannot be ruled out as indeed having the disease. Other causes such as genital imtuberculosis17
and laparoscopic surgery18
have recently been reported to be associated with FHCS.
We observed contrast enhancement of the hepatic capsules suggestive of perihepatitis on the arterial phase of dynamic CT scans from all patients of this study. Capsular enhancement on the arterial phase of CT imaging may reflect increased blood flow at the inflamed hepatic capsule, which is consistent with the laparoscopic findings of moist inflammation with injection of the vessels and exudate formations on the anterior surface of the liver. While enhancement on the portal or delayed phase images may reflect early events in capsular fibrosis, the most commonly enhanced area is the anterior surface of the right lobe, and the depth of enhancement is usually linear or less than 0.5 cm.9
The perihepatic enhancement can be shown as string, broadband, or mixed appearance.19
The inter-observer agreement for perihepatic enhancement is reported as substantial (weighted kappa=0.719) on the arterial phase image set.8
However, perihepatic capsular enhancement can be shown not only in FHCS but also in various other conditions such as peritonitis, liver abscess, acute cholecystitis, and carcinomatosis. However, most of these can be differentiated correctly from FHCS using other CT image findings. For example, thickening of the gall bladder is observable in acute cholecystitis and the location of perihepatic capsular enhancement is adjacent to the inflamed gall bladder. Peritoneal carcinomatosis is frequently accompanied by nodular peritoneal thickening, while FHCS is usually seen as a thin enhancing line along the hepatic capsule. Severe fatty livers can also be differentiated from FHCS by reviewing non-contrast CT images which show pericapsular high attenuating lines.20
Therefore, it is important to search the entire abdominal CT image for other causes that can result in perihepatitis. It is helpful to also review the associated findings of PID, such as pelvic ascites, oophoritis, endometritis, cervicitis and tubo-ovarian abscess, for the diagnosis of FHCS.9
Perihepatitis is also a rarely diagnosed complication of systemic lupus erythematosus (SLE), requiring consideration in SLE patients with RUQ pain.21
First of all, the onset of symptoms is not always consistent with the onset of perihepatitis. Perihepatic capsular enhancement in the early phase may completely disappear in FHCS after improvement of symptoms with antibiotic treatment.4
Even though biphasic CT may not reveal intra-abdominal pathologic findings, such as perihepatitis, and pelvis inflammatory disease, FHCS in the early or recovery phase should be considered as a differential diagnosis for female patients of childbearing age with right upper abdominal pain.
Considering the risks of radiation exposure, the benefit of CT scan should be weighed against the potential risks. Abdominal CT scan of child bearing aged women should be performed cautiously after confirming the status of non-pregnancy. Ultrasonography may be a better approach to evaluate common etiologies such as acute cholecystitis in women with RUQ pain. There have been attempts to study the diagnosis of FHCS by ultrasonography; however this approach has limited utility even though FHCS can be diagnosed by detection of ascites and adhesions between the liver capsule and the abdominal wall.10,22
The detection of subtle thickening of the hepatic capsule is also subjective, and may be affected by the perceptions of the reviewer. In the present study, only one patient out of eight who underwent ultrasonography displayed subtle thickening of the hepatic capsule. Another 7 patients showed unremarkable findings. Magnetic resonance imaging may also be considered to detect perihepatitis, despite its high cost.19
Antibiotic treatment is usually recommended for the treatment of FHCS. Intravenous or oral regimens can be used according to the guidelines for treating PID.10
In the present study, patients were treated with various combinations of antibiotics, including cephalosporin, aminoglycoside, metronidazole, and macrolides. Interestingly, clinical improvement was observed in patients treated with empirical antibiotics which are not effective for chlamydial infection. In the present study, macrolide was prescribed after several days to patients whose PCR results indicated chlamydial infection. Yang, et al.23
postulated that either chlamydial infection often resolves by itself or that it could not be the causative pathogen in FHCS, with other unknown microbes, such as several types of gram positive cocci or anaerobes, that cause pelvic inflammatory disease the more likely causes.
This study has several limitations. First, as a retrospective study, it may be affected by selection bias. Clinically diagnosed PID patients who underwent abdominal CT to evaluate abdominal pain were enrolled in this study. Second, even though laparoscopic examination is known as the gold standard for diagnosis of FHCS,3,4
this study was conducted for patients who were confirmed by clinical features, disease courses and typical findings of FHCS on biphasic CT. So, none of the patients underwent laparoscopic examination to confirm FHCS, nor was a follow-up CT scan performed to evaluate the correlation between clinical improvement and the absence of perihepatitis.
In conclusion, FHCS should be considered as a differential diagnosis for female patients of childbearing age with right upper abdominal pain. Timely diagnosis using biphasic CT with arterial and portal phases may help ensure adequate medical treatment as well as avoid invasive procedures.