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Concept: Differential diagnosis


A growing number of progressive heredodegenerative conditions mimic the presentation of Huntington’s disease (HD). Differentiating among these HD-like syndromes is necessary when a patient with a combination of movement disorders, cognitive decline, behavioural abnormalities and progressive disease course proves negative to the genetic testing for HD causative mutations, that is, IT15 gene trinucleotide-repeat expansion. The differential diagnosis of HD-like syndromes is complex and may lead to unnecessary and costly investigations. We propose here a guide to this differential diagnosis focusing on a limited number of clinical features (‘red flags’) that can be identified through accurate clinical examination, collection of historical data and a few routine ancillary investigations. These features include the ethnic background of the patient, the involvement of the facio-bucco-lingual and cervical district by the movement disorder, the co-occurrence of cerebellar features and seizures, the presence of peculiar gait patterns and eye movement abnormalities, and an atypical progression of illness. Additional help may derive from the cognitive-behavioural presentation of the patient, as well as by a restricted number of ancillary investigations, mainly MRI and routine blood tests. These red flags should be constantly updated as the phenotypic characterisation and identification of more reliable diagnostic markers for HD-like syndromes progress over the following years.

Concepts: Gene, Genetic disorder, Medical terms, Medical diagnosis, Huntington's disease, Presentation of Mary, Differential diagnosis, Huntingtin


BACKGROUND: Among a variety of more common differential diagnoses, the aetiology of acute respiratory failure includes Lyme neuroborreliosis. CASE PRESENTATION: We report an 87-years old huntsman with unilateral phrenic nerve palsy as a consequence of Lyme neuroborreliosis. CONCLUSION: Although Lyme neuroborreliosis is a rare cause of diaphragmatic weakness, it should be considered in the differential workup because of its potentially treatable nature.

Concepts: Medical terms, Lyme disease, Respiratory system, Thoracic diaphragm, Differential diagnosis, Phrenic nerve, Respiratory failure, Neuroborreliosis


In recent years, antisynthetase syndrome has been recognized as an important cause of autoimmune inflammatory myopathy in a subset of patients with polymyositis and dermatomyositis. It is associated with serum antibodies to aminoacyl-transfer RNA synthetases and is characterized by a constellation of manifestations, including fever, myositis, interstitial lung disease, “mechanic’s hands,” Raynaud phenomenon, and polyarthritis. Physicians should be familiar with its variety of clinical presentations and should include it in the differential diagnosis in patients presenting with unexplained interstitial lung disease.

Concepts: Medical terms, Medical diagnosis, Differential diagnosis, Myopathy, Polymyositis


Colonoscopy is a widely used diagnostic and therapeutic modality with a relatively low morbidity. However, given the large volume of procedures performed, awareness of the infrequent complications is essential. Perforation is an established complication of colonoscopy, and can range from 0.2%-3% depending on the series, population and modality of colonoscopy. Acute appendicitis after colonoscopy is an extremely rare event, and a cause-effect relationship between the colonoscopy and the appendicitis is not well documented. In addition, awareness of this condition can aid in prompt diagnosis. Relatively mild symptoms and exclusion of bowel perforation by contrast studies do not exclude appendicitis from the differential diagnosis for post-colonoscopy pain. In addition to the difficult diagnosis inherent to postcolonoscopy appendicitis, treatment strategies have varied greatly. This paper reviews these approaches. We also expand upon prior articles by giving guidance for the role of nonoperative management in these patients. This case and review of the literature will help to create awareness about this complication, and guide optimal treatment of pericolonoscopy appendicitis.

Concepts: Medical terms, Diagnosis, Medical emergencies, Medical diagnosis, Differential diagnosis, Peritonitis, Rectal examination, Vermiform appendix


Ovarian tumors in reptiles are uncommonly reported in the literature and for green iguanas previously reported cases include teratomas, one adenocarcinoma and one papillary cystadenocarcinoma. The present report is the first of a malignant ovarian teratoma in a green iguana. Complete and detailed pathological features, differential diagnosis and surgical management of malignant ovarian teratoma are discussed in this paper.

Concepts: Medical diagnosis, Ovarian cancer, Differential diagnosis, Teratoma, Lizard, Iguanidae, Green Iguana, Iguana


Synopsis The hallmark features of patellar tendinopathy are (1) pain localized to the inferior pole of the patella and (2) load related pain that increases with the demand on the knee extensors, notably in activities that store and release energy in the patellar tendon. While imaging may assist in differential diagnosis, the diagnosis of patellar tendinopathy remains clinical, as asymptomatic tendon pathology may exist in people who have pain from other anterior knee sources. A thorough examination is required to diagnose patellar tendinopathy and contributing factors. Management of patellar tendinopathy should focus on progressively developing load tolerance of the tendon, the musculoskeletal unit, and the kinetic chain as well as addressing key biomechanical and other risk factors. Rehabilitation can be slow and sometimes frustrating. This review aims to assist clinicians with key concepts related to examination, diagnosis, and management of patellar tendinopathy. Difficult clinical presentations (eg, highly irritable tendon, systemic comorbidities) as well as common pitfalls such as unrealistic rehabilitation timeframes and over-reliance on passive treatments are also discussed. J Orthop Sports Phys Ther, Epub 21 Sep 2015. doi:10.2519/jospt.2015.5987.

Concepts: Medical terms, Femur, Medical diagnosis, Knee, Differential diagnosis, Tibia, Patella, Patellar ligament


: Digital papillary adenocarcinoma (DPA) is a rare malignant adnexal tumour that occurs almost exclusively in a digital location. Only two case series have been reported previously.

Concepts: Cancer, Oncology, Medical terms, Medical diagnosis, Differential diagnosis, Aggressive digital papillary adenocarcinoma


OBJECTIVES: Molar pregnancies, characterized by hydropic change and trophoblast hyperplasia of chorionic villi, are usually sporadic. Second and third molar pregnancies can occur by chance but may be associated with a rare autosomal recessive condition, familial recurrent hydatidiform mole (FRHM). This condition, in which affected women have a predisposition to complete hydatidiform moles (CHM), is not usually diagnosed until women have experienced several CHM when a differential diagnosis is made by demonstrating the CHM are diploid and biparental (BiCHM) in contrast to sporadic CHM which are androgenetic (AnCHM). Our objective was to investigate whether these genetic differences might be reflected in identifiable phenotypic differences between BiCHM and AnCHM that could enable earlier diagnosis of FRHM. STUDY DESIGN: Histopathological features were compared between 27 AnCHM from 17 individuals and 51 BiCHM from 20 families in whom a diagnosis of FRHM was confirmed by the presence of biallelic NLRP7 mutations or pathological variants. RESULTS: A spectrum of morphological features was observed in BiCHM. As a group they show subtle, but consistent, histological differences from typical sporadic AnCHM, with less marked villous trophoblast hyperplasia, extravillous trophoblast fragments, stromal apoptotic debris, budding architecture, cisterns and trophoblastic inclusions. While there are some BiCHM that individually show atypical histological features, the majority are indistinguishable from typical sporadic AnCHM. CONCLUSION: The majority of cases of FRHM cannot be distinguished from sporadic AnCHM on the basis of histopathological features alone. In a minority of cases CHM may demonstrate ‘atypical’ features that raise the possibility of underlying BiCHM requiring further investigation.

Concepts: Pathology, Obstetrics, Anatomical pathology, Human chorionic gonadotropin, Hydatidiform mole, Trophoblast, Differential diagnosis, Gestational trophoblastic disease


Background: Few studies to date have captured perfusion and vascular permeability changes during a migraineur’s aura. This may be important information to the clinician in the context of the differential diagnosis of migraine with aura versus acute stroke. Summary: We report a case in which magnetic resonance perfusion during a migraine aura showed unilateral hypoperfusion differentially affecting gray and white matter and was associated with a hemispheric increase in permeability. Conclusions: Imaging in this case suggests that migraine aura is associated with oligemia below the threshold for infarction. Increased vascular permeability may be a critical mechanism contributing to perfusion changes observed in migraine with aura.

Concepts: Medical terms, Stroke, Migraine, Epilepsy, Complex partial seizure, Differential diagnosis, Aura, Scintillating scotoma


Study Design: Cross-sectional cohort study.Objective: To further evaluate the diagnostic value of the sedimentation sign by assessing its performance on the differential diagnosis of patients with lumbar spinal stenosis (LSS) and other lumbar conditions with similar clinical presentations.Summary of Background Data: Recently, a new test using MR imaging, the sedimentation sign, was introduced to aid in the diagnosis of LSS. The initial testing demonstrated that the sign was positive in 100% of patients with LSS with decreased walking ability and dural sac cross-sectional areas (CSA) less than 80mm, and negative in 94% of patients with non-specific low back pain, no leg pain or claudication and dural sac CSA greater than 120 mm.Methods: Fifty patients with central or combined LSS, 22 with lateral stenosis only and 43 with posterolateral disc herniation with unilateral radiculopathy were included. Using axial MR images of the lumbar spine, the sedimentation sign was assessed by two observers independently, without knowledge of participant clinical history or diagnosis. Frequencies of a positive sign in each patient group were calculated.Results: The sedimentation sign was positive in 2% of patients with disc herniation, 23% with lateral stenosis and 54% with central or combined stenosis. When the analysis included only LSS patients with dural sac CSA <80mm and walking limitations similar to the original study introducing the sedimentation sign (n = 17), the proportion of patients presenting with a positive sign increased to 82%.Conclusion: The sedimentation sign is more prevalent in patients with the clinical diagnosis of central or combined LSS than in patients with lateral stenosis only or posterolateral disc herniation. Yet, whether it enhances current diagnostic practices remains undetermined.

Concepts: Spinal disc herniation, Low back pain, Back pain, Medical terms, Vertebral column, Medical diagnosis, Spinal stenosis, Differential diagnosis