Intestinal malrotation as a misdiagnosis of pediatric colchicine resistant familial Mediterranean fever

Background Familial Mediterranean fever (FMF) is a disorder characterized by recurrent attacks of fever and serosal inflammation, particularly abdominal pain. Other disease processes, including medical and surgical emergencies, may mimic FMF, especially in atypical cases. Case Presentation We present a case of an adolescent male, referred to us with a diagnosis of colchicine resistant FMF, ultimately diagnosed with intestinal malrotation and recurrent volvulus. Conclusions In atypical presentations of FMF with potential “red flags”, a thorough patient history is extremely important and should result in prompt referral for the appropriate diagnostic tests.


Background
Familial Mediterranean Fever (FMF), the most common monogenic autoinflammatory syndrome, is characterized by recurrent episodes of fever and serosal inflammation, including abdominal pain and vomiting. Intestinal malrotation which occurs as a result of an arrest of normal rotation of the embryonic gut, has a varied clinical presentation from infancy through adolescence and adulthood [1,2]. We present a case of an adolescent male, referred to us with recurrent vomiting and abdominal pain, initially diagnosed with FMF that was resistant to colchicine, ultimately diagnosed with intestinal malrotation.

Case presentation
A 14 year old male of mixed Sephardic-Ashkenazi Jewish ancestry was referred to our Pediatric Rheumatology Clinic with "colchicine resistant FMF". From early infancy he suffered from recurrent afebrile episodes of yellowishgreenish vomiting with abdominal pain. Episodes occurred every 1 to 2 weeks, lasting for 1-3 days. Exercise, stress and infections were precipitants of episodes. The patient did not develop rashes, joint/muscle or chest pain. He was hospitalized during several episodes due to dehydration, easily corrected by intravenous fluids. His school attendance was severely impaired, missing about 2 days every week. His father was diagnosed with FMF, after years of recurrent fever, abdominal pain and vomiting, with compound heterozygous mutations on the MEFV gene (M694V/E148Q). Following father's diagnosis, our patient underwent genetic analysis at age 11 years and a heterozygote E148Q mutation was found. Colchicine was initiated and he received up to 1.5 mg/d for 2 years prior to his referral, with no clinical improvement. He underwent investigations by multiple pediatric gastroenterologists and metabolic diseases specialists, and his laboratory evaluation was normal including: acute phase reactants (even during episodes), blood counts, liver and muscle enzymes, fibrinogen, celiac profile, amino-acids, organic acids, acyl-carnitine and E3 mutation. Abdominal radiographs and ultrasound were normal. His physical examination was unremarkable except for low weight (7 th percentile). Due to the history of bilious vomiting since his neonatal period he was referred by us for an upper gastrointestinal series (UGI). This demonstrated malposition of the ligament of Treitz and a corkscrew appearance of the duodenum, consistent with malrotation ( Fig. 1). After a successful Ladd procedure with classical findings of malrotation but no intestinal ischemia, the patient is feeling well, with no further vomiting episodes, a rapid catch up in the growth curves and full school attendance.

Discussion and conclusion
We present a patient with intestinal malrotation who was initially diagnosed with FMF and treated for 2 years with an adequate dose of colchicine with no response. Fortunately, he did not develop bowel damage after years of recurrent attacks of midgut volvulus.
While the patient fulfilled clinical diagnostic criteria for FMF (Table 1) according to the long-(but not short) version of the Tel-Hashomer criteria [3] (one minor and six supportive criteria), and the Yalcinkaya pediatric criteria [4], several "red-flags" led us to consider an alternative diagnosis. [5][6][7].

Neonatal onset of FMF is uncommon
About 31 % percent of patients with FMF present by age 2 years (mean 1.1 years) [8], 80 % by 10 years and 90 % by 20 years, but only about 5 % by 2 months of age. The most common presentation in the infants is just "fussiness". In almost all others fever is part of the presentation [7,8], thus isolated vomiting in patients under 1 year of age is very uncommon. 2. Bilious vomiting is not characteristic in FMF. 3. The lack of fever and other symptoms characteristic of FMF. These would be expected in a patient with  severe FMF based on the frequency of attacks, age of onset and lack of response to colchicine [6,9]. 4. Normal acute phase reactants during attacks.
Besides clinical criteria, the diagnosis of our patient and treatment with colchicine was initially supported by finding a heterozygous E148Q mutation on the MEFV gene. Genetic testing in FMF is only considered supportive and not diagnostic, particularly in atypical cases. When two mutations are found, FMF diagnosis is confirmed. In atypical cases where only one mutation is found a trial of colchicine is often offered. Indeed up to 30 % of FMF have only a heterozygote exon ten mutation [10]. However, controversy exists regarding the role of some MEFV variations (Table 2), particularly for the exon 2 E148Q glutamic acid to glutamine substitution [11]. Initially, this sequence variation was described as a disease causing mutation with low penetrance and mild symptoms. However, recent studies showed a similar frequency of E148Q among FMF patients and controls, and those findings support the hypothesis that E148Q is a benign polymorphism and not a disease causing mutation [12][13][14]. E148Q may be a disease modifier in other rheumatologic conditions [15][16][17]. E148Q may also modify the severity of FMF when found on the same allele with other mutations. FMF patients who are homozygous for the complex allele (E148Q-V726A/ E148Q-V726A), or compound heterozygotes (E148Q-V726A/V726A), have a more severe disease compared to patients homozygous for V726A [14]. In our patient the E148Q substitution is likely to be only a polymorphism, unlike his father who had a compound heterozygote M694V/E148Q mutation.
Multiple other disease processes may closely resemble FMF and must be excluded in atypical cases, such as surgical emergencies, metabolic diseases and other periodic fever syndromes (Table 3) [18,19]. Both FMF diagnostic criteria have excellent but not 100 % specificity for the population in whom it was developed (99 % for adults with the Tel-Hashomer criteria [3], 92 % for children with the Yalcinkaya criteria [4]). However, the Tel-Hashomer criteria developed for adults had a lower specificity (54 %) in children [4]. Therefore, in atypical cases with potential "red flags" a thorough patient history is extremely important and should result in prompt referral for the appropriate diagnostic tests.
Malrotation is an incomplete rotation of the intestine during fetal development. The mesentery, including the   Includes urea cycle defects, organic acidemias, fatty acid oxidation defects, disorders of gluconeogenesis in infancy, and porphyria in childhood/adolescence GERD gastroesophageal reflux, IBD inflammatory bowel disease, PUD peptic ulcer disease The common causes in each age are marked in bold. Functional gastrointestinal disorders are a common cause of recurrent abdominal pain but without vomiting superior mesenteric artery, is tethered by a narrow stalk, which can twist around itself, and produce life threatening midgut volvulus, with an acute presentation of small bowel obstruction. Traditionally, intestinal malrotation is considered primarily a disease of infancy with infrequent occurrence beyond the first year of life. However, recent studies demonstrate that the prevalence of malrotation in older children and adults appears to be higher than previously thought [1,2]. Upper gastrointestinal series is the gold standard imaging test for diagnosis. Surgical intervention is recommended regardless of age, and presentation of volvulus requires an emergency procedure.
In summary, alterative diagnoses to FMF should be considered in cases of atypical attacks as in our patient, even if fulfilling diagnostic criteria and supported partially by a heterozygous mutation in the MEFV gene. In some cases, as we described, the correct diagnosis may represent a surgical or medical emergency requiring prompt treatment.

Consent
Written informed consent was obtained from the patient's parents for publication of this Case Report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.