Decoding 揼uitar pick sign� in COVID-19朼ssociated mucormycosis: A case series

揋uitar pick sign,� also referred to as posterior globe tenting, is a radiological surrogate marker of tense orbit and profound vision loss. It is seen commonly in traumatic retrobulbar hemorrhage and carotico-cavernous fistula and less frequently in orbital cellulitis, subperiosteal abscess, and invasive fungal infections. We report a case series of Coronavirus disease-19朼ssociated rhino-orbito-cerebral mucormycosis with guitar pick sign, of which none survived, and discuss the causative pathomechanisms, severity grade, and the clinical relevance of this unique radiological finding.

Diagnosis of mitochondrial diseases: clinical and histological study of sixty patients with ragged red fibers.

BACKGROUND: Mitochondrial diseases are caused by mutations in mitochondrial or nuclear genes, or both and most patients do not present with easily recognizable disorders. The characteristic morphologic change in muscle biopsy, ragged-red fibers (RRFs) provides an important clue to the diagnosis. MATERIALS AND METHODS: Demographic data, presenting symptoms, neurological features, and investigative findings in 60 patients with ragged-red fibers (RRFs) on muscle biopsy, seen between January 1990 and December 2002, were analyzed. The authors applied the modified respiratory chain (RC) diagnostic criteria retrospectively to determine the number of cases fulfilling the diagnostic criteria of mitochondrial disease. RESULTS: The most common clinical syndrome associated with RRFs on muscle biopsy was progressive external ophthalmoplegia (PEO) with or without other signs, in 38 (63%) patients. Twenty-six patients (43%) had only external ophthalmoplegia, 5 (8%) patients presented with encephalomyopathy. Specific syndromes were the presenting feature in 8 (13%), Kearns-Sayre syndrome (KSS) in 4 and myoclonus epilepsy with ragged-red fibers (MERRF) in 4. Myopathy was the presenting feature in 5 (8%) and 4 presented with infantile myopathy. Of the 60 patients, 18 (30%) had proximal muscle weakness. Two patients with KSS and one patient with myopathy had complete heart block necessitating pace making. When the modified RC diagnostic criteria were applied, only 26 (43%) patients had one other major criterion in addition to RRFs for the diagnosis of mitochondrial diseases. The remaining 34 (57%) patients with RRFs on muscle biopsy had only some clinical features suggestive of RC disorder but did not fulfill the clinical criteria (of the modified diagnostic criteria) for the diagnosis of mitochondrial diseases. CONCLUSION: In patients with clinical features suggestive of RC disorder, demonstration of RRFs on muscle biopsy helps in confirming the diagnosis of mitochondrial disease in only a subgroup of patients.

Utility of dystrophin and utrophin staining in childhood muscular dystrophy.

To determine the utility of dystrophin and utrophin staining in the differential diagnosis of childhood muscular dystrophy. Fifty muscle biopsies of histologically confirmed cases of childhood muscular dystrophy, below 16 years of age, were stained immunohistochemically for dystrophin and utrophin. All the 30 muscle biopsies of patients with Duchenne muscular dystrophy (DMD) showed all or majority of muscle fibers deficient for dystrophin and positive for utrophin. In the 4 female DMD carriers there was mosaic pattern of staining for dystrophin and reciprocal positivity for utrophin. All the muscle biopsies of patients with other childhood onset muscular dystrophies were positive for dystrophin and negative for utrophin. This study shows that dystrophin staining differentiates DMD and DMD carriers from other childhood muscular dystrophies and utrophin staining is of no added value. Utrophin up-regulation may compensate for structural deficiency in dystrophic muscle.