Critical illness neuromyopathy (CINM) is a common yet frequently overlooked complication in intensive care units (ICU). CINM often results in prolonged ventilator dependence and persistent limb weakness, significantly impacting patient recovery and long-term quality of life. CINM can be categorized into two primary subtypes: critical illness polyneuropathy (CIP) and critical illness myopathy (CIM). These conditions frequently arise in the context of severe sepsis, multiple organ failure, or as adverse effects of certain medications used in the ICU. This review aims to provide a concise overview of CINM, focusing on its pathophysiology, diagnostic approaches, and current clinical management strategies.

Valosin-containing protein (VCP)-related multisystem proteinopathy (MSP1) is a rare genetic disorder marked by abnormal protein accumulation. This study presents the case of a 52-year-old woman with MSP1, showing progressive weakness, gait disturbances, and respiratory muscle weakness over five years. The clinical examination revealed diverse presentations, including neurogenic changes in electrophysiologic study, multifocal fatty changes of muscle, and cognitive impairment with a confirmed VCP gene mutation through genetic testing. Notably, we identified lobulated myofibers in the muscle biopsy, an unusual finding in MSP1. This is the first report of lobulated myofibers in MSP1 with multisystem involvement. Identifying unique muscle biopsy results in suspected MSP1 patients through careful neurological examinations and timely genetic testing may help in early diagnosis and appropriate management.

Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (anti-HMGCR) antibody related immune-mediated necrotizing myopathy (IMNM) are usually associated with statin use. The disease has features of persistent muscle weakness and creatine kinase (CK) elevation after statin discontinuation. This report describes a 65-year-old female taking atorvastatin, presenting with both proximal lower extremity weakness. IMNM feature were detected on muscle biopsy and high anti-HMGCR autoantibody titer on enzyme-linked immunosorbent assay (ELISA). This patient was treated with corticosteroid. Muscle weakness and CK are improved after immunosuppressive therapy.

Anti-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (anti-HMGCR) myopathy is a subtype of immune-mediated necrotizing myopathy regardless of exposure to statins. Necrotizing myopathy is distinguished by necrotic muscle fibers with a relative lack of inflammation. It is frequently associated with a high risk of permanent muscle damage and disability. Recent studies have suggested a slightly increased risk of cancer in patients with anti-HMGCR myopathy. This report describes a case of statin-naïve paraneoplastic anti-HMGCR myopathy, with rapidly progressive muscle weakness leading to respiratory failure.

Congenital myasthenic syndromes (CMSs) are rare genetic disorders characterized by weakness and fatigue resulting from impaired neuromuscular transmission. Genetic testing can confirm the diagnosis for some types of CMS; however, variations in genotype, clinical phenotypes, age at disease onset, and responses to treatment make diagnosis very difficult. Here we present two adult patients who had significant decremental responses in repetitive nerve stimulation testing and multi-minicore pathology, and who responded to treatment with a cholinesterase inhibitor.

Critical illness neuromyopathy (CINM) is a common but frequently underdiagnosed condition in critically ill patients that contributes to ventilator weaning failure and limb weakness in intensive care unit (ICU). CINM is subdivided into critical illness polyneuropathy and critical illness myopathy, and the occurrence of these conditions in the ICU is associated with multiple organ failure due to sepsis or certain medications. CINM survivors might have persistent functional disabilities and a poor quality of life. This situation demonstrates the need for efforts to minimize or prevent CINM in critically ill patients. This article provides a current overview of CINM and the associated clinical strategies.

Muscle pathology findings may guide the diagnosis of neuromuscular disorders since they are helpful for understanding the pathological processes causing muscle weakness and also provide significant clues for the diagnosis of muscle diseases. Recent advances in molecular genetics mean that a muscle biopsy can be omitted when diagnosing inherited muscle diseases. However, the muscle pathology can still play a role in those cases and its findings are also required when diagnosing inflammatory myopathies.

Citations

• Sarcolemmal Excitability Properties of the Trapezius
  Mitchell J. Lycett, James Lee, Robert Boland‐Freitas, Karl Ng
  Muscle & Nerve.2025; 71(4): 600.     CrossRef
• Redox-active metals and oxidative stress–mediated myopathies in Callinectes amnicola, blue crab populations from impacted sites of the Lagos Lagoon: inferences for adverse ecological outcomes
  Azubuike Victor Chukwuka, Fisayo C. Jerome, Adesola Hassan, Benjamin Ebonwu, Aina O. Adeogun
  Environmental Science and Pollution Research.2023; 30(50): 108565.     CrossRef

A 69-year-old woman presented with a progressive limb weakness. Both clinical and neurophysiological findings were consistent with diagnosis of Guillain-Barré syndrome (GBS). Two days after admission, the patient suffered from an acute coronary syndrome without stenosis at coronary arteriography. Echocardiography revealed left ventricular inferior wall and apical akinesia and decreased ejection fraction. A diagnosis of Takotsubo cardiomyopathy was then made. Left ventricular dysfunction and electrocardiography normalized within one month. Takotsubo cardiomyopathy can be developed as a complication of GBS.

Citations

• Takotsubo Cardiomyopathy: A Possible Rare Complication of Guillain-Barré Syndrome
  Khalid H Mohamed, Adetola F Oshikoya, Kapil Kumar, Chinyere L Anigbo, Polasu Sri Satya Sai Prashanth , Alaa S Mohamed, Muhammad Haseeb, Hira Nasir
  Cureus.2023;[Epub]     CrossRef
• Takotsubo Cardiomyopathy as a Manifestation of Dysautonomia in Guillain-Barré Syndrome: A Case Series and Review of the Literature
  Dyanet Puentes, Daniela Teijelo, Tamara S Stiep, Sishir Mannava, Jason Margolesky
  Cureus.2021;[Epub]     CrossRef

Primary metabolic myopathy as a type of congenital myopathies was first described by McArdle in 1951. Glycogen storage disease is a disease caused by genetic mutations involved in glycogen synthesis, glycogenolysis or glycolysis. Several types of glycogen storage disease are known to cause metabolic myopathies. We report a case of adult onset metabolic myopathy with glycogen storage.

Background
central core disease is one of the non-progressive benign congenital myopathies characterized by the presence of cores in muscle fibers, which was originally described by Shy and Magee (1956). We describe clinical charcteristics of central core disease in a Korean family manifested by autosomal dominant pattern through three generations.
Methods
Clinical, serologic, and electrophysiologic profiles were evaluated in eleven members among 22 family members through three generations.
Results
Six family members were symptomatic and five were non-symptomatic. Instead of proximal muscle weakness, musculoskeletal manifestations including non-specific joint pain and stiff sense were the most frequent symptoms. Muscle biopsy performed in two symptomatic patients revealed that type Ifiber showed central halo, which is charactreristics of central core disease. No remarkable findings were present in serologic study including CPK level and electromyographic findings suggesting myopathic pattern were only present in two patients among 11 symptomatic group.
Conclusions
In evaluating non-specific musculoskeletal complaints from the familial members showing genetic trait, central core disease should be considered to one of the possible diagnosis.

Ischemic monomelic neuropathy and myopathy are rare complications of peripheral arterial occlusive disease. We reporta case of ischemic monomelic neuropathy of the right sural, common peroneal and posterior tibial nerves and ischemic myopathyof the right tibialis anterior resulting from the occlusion of the right common femoral arteries despite successfulrevascularization. Ischemic monomelic neuropathy and myopathy can occur as a result of occlusion of the specific peripheralartery.

Statin is commonly used for lowering cholesterols and can be myotoxic to cause drug-induced necrotizing myopathy. Statininducedmyopathy ranges from asymptomatic hyperCKemia to lethal rhabdomyolysis but is usually reversed by withdrawalof causative drugs. The patient in this study presented with statin-induced necrotizing myopathy, which was finally improvedwith immunosuppressive therapy, but not just with drug withdrawal. Since statin can induce myopathy through autoimmuneprocesses, we should consider using immunomodulating agents in cases with statin-induced myopathy, which is refractoryto drug withdrawal.

Licorice is widely used as a Chinese(herbal) medicine. The glycyrrhizin, a main ingredient of the natural licorice, has a potent mineralocorticoid effect which may cause severe hypokalemia and muscle paralysis. We present a 60-year-old woman, who had been ingesting one or two spoonful of licorice powder daily for about one year, developed acute flaccied quadriparesis with high levels of serum muscle enzymes and the typical features of mineralocorticoid excess such as severe hypokalemia and metabolic alkalosis. Both plasma renin activity and serum aldosterone level were below the normal values. This case indicates that licorice-induced hypokalemic myopathy should be considered in the differential diagnosis of a patient with acute quadriparesis and hypokalemia.

The field of critical care medicine has flourished, but an unfortunate result of improved patient survival in the intensive care unit is the occurrence of certain acquired neuromuscular disorders. During the lase two decades, various neuromuscular disorders were recognized as common cause of weakness occurring in critically ill patients. The two most common disorders are an acute quadriplegic myopathy predominantly associated with the use of intravenous corticosteroids and neuromuscular junction blocking agents and severe systemic illness termed critical illness myopathy(CIM), and an axonal sensorimotor polyneuropathy termed critical illness polyneuropathy. I will review briefly about general components of the CIM.

Patients of chronic alcoholism may show many kinds of complications such as myopathy, nutritional problems,peripheral neuropathy, withdrawal seizure and encephalopathies. We report an unusual case of alcoholic myopathy diagnosed with typical laboratory and pathological findings initially manifested as acute reversible encephalopathy showing transient abnormalities on brain MRI.

Nemaline myopathy is one of the congenital myopathy, which is characterized by histological findings of nemaline bodies (rods) and type 1 fiber hypotrophy and predominance. It can be classified into three forms according to the age of onset and clinical features: congenital form, childhood-onset form, and adult-onset form. We report an 18-year-old patient with generalized muscle weakness and dysmorphic features who was diagnosed as typical childhood-onset nemaline myopathy.

Critical illness polyneuropathy (CIP) and critical illness myopathy (CIM) occur commonly in the patients who havebeen on mechanical ventilation for more than 1 week. Even in some patients diagnosed with CIP, an underlyingmyopathy may be the primary cause of the muscle weakness. The cormorbid status of CIP and CIM is called as criticalillness polyneuropathy and critical illness myopathy (CIPNM). We describe a 56-year-old man with acute quadriparesisand areflexia after systemic inflammatory response syndrome. The diagnosis of CIPNM is important to avoid unnecessaryinvestigations and unreasonably pessimistic prognosis. Electrophysiologic studies are essential for the diagnosis and forplanning further clinical management.

Colchicine is a drug used for the treatment of acute gouty arthritis or various autoimmune diseases. Gastrointestinaladverse effects such as abdominal pain and vomiting are the common side effects of the drug, but rarely myopathy hasbeen reported to occur particularly in renal recipients who were treated concomitantly with immunosuppressants. Herein,we report a case who presented with acute myopathy after treated with colchicine for acute gouty arthritis.

Among drug-induced myopathy, steroids are probably the most common cause. The risk of steroid myopathy(SM)increases with the dose and duration of use. It is typically a proximal myopathy, preferentially affecting the hip girdlemuscles. Motor and sensory nerve conduction studies are normal. The needle EMG is usually within the normal rangeor may be minimally abnormal. Occasionally, low-amplitude, short-duration MUAPs may be seen in the proximal muscles.Of note, abnormal spontaneous activity is not seen. This point is often very useful in differentiatingpolymyositis(PM) from SM. It is common for patients with PM to be treated with steroids, respond well, and then havethe steroids tapered. If muscle weakness then returns, it may be very difficult to differentiate recurrent PM from SM onclinical grounds. The presence of abundant abnormal spontaneous activity strongly suggests PM rather than SM.

Miyoshi myopathy (MM) is caused by the mutations of dysferlin gene (DYSF), which impairs the function of dysferlin protein causing muscle membrane dysfunction. We report a patient showing the MM phenotype who has a sister with LGMD 2B phenotype, along with the results of the immunohistochemical and molecular analyses of the DYSF gene. Immunohistochemical analysis noted negative immunoreactivity against dysferlin. Direct DNA sequencing of whole exons of DYSF gene revealed heterozygous nonsense mutations (c.610C>T + c.2494C>T). To our knowledge, this is the first reported MM case with this very combination of heterozygous mutations.

A 73-year-old man with progressive quadriparesis was diagnosed as Guillain-Barré syndrome. On the 6th hospital day, thepatient complained of sudden chest discomfort. The blood test and echocardiography suggested myocardial injury, and acutemyocardial infarction was considered. However, coronary angiography displayed no vascular lesion, and the electrocardiographyand echocardiogram showed marked improvement 14 days later. We concluded the patient had a reversible cardiomyopathywhich is a rare complication of Guillain-Barré syndrome.

Nephrogenic systemic fibrosis (NSF) is a systemic disease that affects the skin and other tissues in patients with renalinsufficiency and exposure to gadolinium-containing contrast. A 55-year-old woman with end-stage renal disease on hemodialysiswas consulted for progressive general weakness. After she had undergone multiple MRIs with gadolinium-containing contrastmedia, muscle weakness and skin lesions were developed. Her skin and muscle biopsy specimens showed CD34+ fibroblastentrapping collagen bundles. There are few reports of NSF with myopathy.