Malignant rigidity caused

Inpus erythematosus A chronic inflammatory disease of connective tissue, affecting the skin and internal organs, lymphoma A malignant tumor of the lymph nodes, multiple sclerosis A disease of the nervous system, myelodysplasia Abnormal or defective formation of the bone marrow. Mycoplasma Minute primitive bacteria without a rigid cell wall. Mycoplasma pneumoniae causes atypical pneumonia in humans, myeloma cells Malignant tumor cells. 

Antipsychotic drugs include the older phenothiazines and butyrophenones, as well as newer atypical drugs. All of these can cause CNS depression, seizures, and hypotension. Some can cause QT prolongation. The potent dopamine D2 blockers are also associated with parkinsonian-like movement disorders (dystonic reactions) and in rare cases with the neuroleptic malignant syndrome, characterized by "lead-pipe" rigidity, hyperthermia, and autonomic instability (see Chapter 29 Antipsychotic Agents Lithium). 

Among the complications of neuroleptic chemotherapy, the most serious and potentially fatal complication is malignant syndrome, which is characterized by extreme hyperthermia lead pipe skeletal muscle rigidity that causes dyspnea, dysphagia, and rhabdomyolysis autonomic instability fluctuating consciousness leukeocytosis and elevated creatine phosphokinase levels. 

Malignant hyperthermia is an inherited disorder that causes severe hyperthermia, metaboiic acidosis, and rigidity after certain anesthetic agents (most commoniy haiothane and succinyichoiine) are used. 

Rigidity may also be seen with a number of toxins and may be caused by CNS effects or spinal cord stimulation. Neuroleptic malignant syndrome and serotonin syndrome (see p 22) are characterized by rigidity, hyperthermia, metabolic acidosis, and an tered mental status. Rigidity seen with malignant hyperthermia (see p 22) is caused by a defect at the muscle cell level and may not reverse with neuromuscular blockade. 

Dantrolene is not likely to be effective for hyperthennia caused by conditions other than muscular hyperactivity, such as increased metabolic rate (eg, salicylate or dinitrophenol poisoning), neuroleptic malignant syndrome (NMS), impaired heat dissipation (eg, anticholinergic syndrome), or environment exposure (heat stroke). However, there is anecdotal evidence (case reports or case-control studies) of benefit for the management of NMS, MAO inhibitor (phenelzine poisoning)-induced hyperthermia, muscle rigidity from baclofen withdrawal, hypertonicity from carbon monoxide poisoning, tetanus, and black widow spider envenomation. 

Musculoskeletal Malignant syndrome, a disorder thought to be caused by dopamine receptor blockade, causes fever, rigidity, and altered mental status. This disorder is typically caused by antipsychotic medications or abrupt withdrawal of dopamine agonists. It could be rather difficult to decrease the dose at an appropriate pace to avoid malignant s5mdrome. 

---