7- Neuroleptic Malignant Syndrome and Catatonia

Source: https://app.lecturio.com/#/lecture/c/7526/9050/33030

Correct answer: B. Fever and muscle rigidity

Explanation:
The two hallmark features of NMS are hyperthermia (fever) and lead-pipe muscle rigidity. Autonomic instability and altered mental status support the diagnosis, while findings like tremor or leukocytosis are secondary.

Core features of NMS

A 25-year-old man treated with haloperidol develops a temperature of 40°C, severe muscle stiffness, diaphoresis, and fluctuating blood pressure. Which TWO findings are the most characteristic hallmarks of neuroleptic malignant syndrome?

A. Tremor and leukocytosis
B. Fever and muscle rigidity
C. Akathisia and agitation
D. Mutism and posturing
E. Hyperreflexia and clonus

Correct answer: C. It is more common in males and younger patients

Explanation:
NMS shows a male predominance and is more commonly seen in younger individuals, especially with high-potency antipsychotics or rapid dose escalation. Catatonia may precede NMS but is not required, and NMS is not a drug allergy.

Risk factors and epidemiology

Which of the following statements regarding neuroleptic malignant syndrome is MOST accurate?

A. It occurs equally in males and females
B. It is most common in elderly patients
C. It is more common in males and younger patients
D. It requires prior catatonia to occur
E. It represents a true drug allergy

Correct answer: D. Catatonia may precede NMS but is not required

Explanation:
Catatonia can occur before NMS in some psychiatric patients, but many cases of NMS develop without any preceding catatonic state.

Preceding catatonia

Which statement best describes the relationship between catatonia and neuroleptic malignant syndrome?

A. Catatonia is required for the diagnosis of NMS
B. NMS and catatonia are the same condition
C. Catatonia often follows NMS
D. Catatonia may precede NMS but is not required
E. Catatonia excludes the diagnosis of NMS

Correct answer: C. Elevated creatine phosphokinase

Explanation:
NMS causes severe muscle rigidity, leading to rhabdomyolysis, which results in markedly elevated CPK, often accompanied by hyperkalemia and leukocytosis.

Laboratory findings

Which laboratory abnormality is MOST characteristic of neuroleptic malignant syndrome?

A. Decreased creatine phosphokinase
B. Hypokalemia
C. Elevated creatine phosphokinase
D. Thrombocytopenia
E. Hypoglycemia

Correct answer: C. Immediately discontinue the antipsychotic

Explanation:
The first and most critical step is to stop the offending antipsychotic. Supportive care (IV fluids, cooling), benzodiazepines, and dantrolene are mainstays. Beta blockers may be used symptomatically but are not first-line.

Treatment priorities

A patient is diagnosed with neuroleptic malignant syndrome. What is the MOST appropriate initial management?

A. Increase antipsychotic dose gradually
B. Administer beta blockers as first-line therapy
C. Immediately discontinue the antipsychotic
D. Begin long-term dopamine agonist therapy
E. Treat with anticholinergics only

Correct answer: D. Dantrolene

Explanation:
Dantrolene acts peripherally on skeletal muscle and is used in severe NMS to reduce rigidity and hyperthermia.

Medications used in NMS

Which medication directly reduces muscle rigidity by inhibiting calcium release from the sarcoplasmic reticulum?

A. Haloperidol
B. Propranolol
C. Bromocriptine
D. Dantrolene
E. Benztropine

Correct answer: C. Antipsychotics may be restarted cautiously after recovery

Explanation:
NMS is not an allergy. After full recovery, patients may be slowly re-challenged, typically with a different or atypical antipsychotic, under close monitoring.

Future antipsychotic use

Which statement regarding future antipsychotic use after neuroleptic malignant syndrome is TRUE?

A. Antipsychotics are permanently contraindicated
B. NMS represents a lifelong allergy
C. Antipsychotics may be restarted cautiously after recovery
D. Only typical antipsychotics may be used
E. Antipsychotics must be restarted immediately

Correct answer: B. Mutism, waxy flexibility, posturing

Explanation:
Catatonia requires at least three characteristic symptoms, including mutism, waxy flexibility, posturing, stupor, negativism, stereotypy, echolalia, or echopraxia.

Catatonia diagnosis

Which of the following combinations meets the diagnostic criteria for catatonia?

A. Fever, rigidity, leukocytosis
B. Mutism, waxy flexibility, posturing
C. Tremor, hyperreflexia, clonus
D. Akathisia, dystonia, dyskinesia
E. Hallucinations, delusions, paranoia

Correct answer: C. Lead-pipe muscle rigidity

Explanation:
NMS causes uniform, sustained muscle rigidity, described as lead-pipe rigidity, distinguishing it from dyskinetic or hyperreflexive syndromes.

Movement patterns

Which movement abnormality is MOST characteristic of neuroleptic malignant syndrome?

A. Choreiform movements
B. Orofacial dyskinesia
C. Lead-pipe muscle rigidity
D. Hyperreflexia with clonus
E. Ballismus

Correct answer: C. Severe hyperthermia and rigidity

Explanation:
The combination of high fever + severe rigidity + autonomic instability is classic for NMS and signals a medical emergency.

Key exam distinction

Which feature best distinguishes neuroleptic malignant syndrome from other antipsychotic side effects?

A. Presence of hallucinations
B. Onset after long-term use only
C. Severe hyperthermia and rigidity
D. Reversible dystonic movements
E. Sedation without autonomic instability

Correct answer: B. Diaphoresis and labile blood pressure

Explanation:
Autonomic dysfunction in NMS includes tachycardia, labile blood pressure, diaphoresis, and temperature instability. Hyperreflexia and clonus are more typical of serotonin syndrome.

Autonomic instability

Which of the following findings BEST represents autonomic dysfunction seen in neuroleptic malignant syndrome?

A. Hyperreflexia and clonus
B. Diaphoresis and labile blood pressure
C. Waxy flexibility and posturing
D. Orofacial dyskinesia
E. Delusions and hallucinations

Correct answer: C. Severe skeletal muscle rigidity

Explanation:
Dysphagia in NMS results from severe rigidity and muscle spasms, increasing the risk of aspiration and respiratory complications.

Dysphagia and muscle complications – Swallowing difficulty

A patient with suspected neuroleptic malignant syndrome develops difficulty swallowing. This symptom is MOST directly related to:

A. Autonomic instability
B. Anticholinergic toxicity
C. Severe skeletal muscle rigidity
D. Central serotonin excess
E. Tardive dyskinesia

Correct answer: C. Stress and muscle breakdown response

Explanation:
Leukocytosis in NMS is reactive, related to severe physiologic stress and rhabdomyolysis, not infection or allergy.

Leukocytosis interpretation – White blood cell elevation

Leukocytosis in neuroleptic malignant syndrome is BEST explained by which mechanism?

A. Bone marrow suppression
B. Infection from immunosuppression
C. Stress and muscle breakdown response
D. Autoimmune hypersensitivity reaction
E. Chronic inflammation

Correct answer: C. A behavioral syndrome associated with medical or psychiatric illness

Explanation:
Catatonia is a behavioral syndrome, not a disease itself. It occurs in the context of psychiatric disorders or general medical conditions and is diagnosed based on characteristic motor and behavioral signs.

Catatonia as a syndrome (conceptual) – Nature of catatonia

Which statement BEST describes catatonia?

A. A medication-induced movement disorder
B. A standalone psychiatric diagnosis
C. A behavioral syndrome associated with medical or psychiatric illness
D. A subtype of schizophrenia only
E. A form of extrapyramidal side effect

Correct answer: B. Autonomic nervous system dysregulation

Explanation:
Diaphoresis in NMS reflects autonomic instability, a core feature of the syndrome along with fever and cardiovascular instability.

Profuse sweating (diaphoresis emphasis) – Diaphoresis significance

Profuse sweating in neuroleptic malignant syndrome is MOST closely associated with which underlying process?

A. Peripheral neuropathy
B. Autonomic nervous system dysregulation
C. Dopamine hypersensitivity
D. Allergic drug reaction
E. Cholinergic excess