Management of Hyperpyrexia

Lt Dhirendra

Hyperpyrexia

• Also called Fever

• represents an elevation in the body's set thermoregulatory point

• Core temperature is regulated by the anterior hypothalamus

• Fever is caused by increased prostaglandin E2

(PGE2) synthesis in the hypothalamus

• Autonomic discharge from hypothalamus raises core temperature through shivering and dermal vasoconstriction

• Normal circadian variation in core temperature occurs with nadir in early morning and peak in late afternoon

• Normal Body Temperature

– Upto 98.9 at 6 am

– Upto 99.9 at 4 pm

Etiology

• infectious process • Drugs

– Antiarrhythmics (procainamide, quinidine)– Antibiotics (penicillins, sulfonamides, erythromycin, isoniazid,

nitrofurantoin)– Anticonvulsants (barbiturates, carbamazepine, phenytoin)– Antidepressants (TCAs, monoamine oxidase inhibitors)– Antihistamines (H1 and H2 antagonists)– Antihypertensives (nifedipine, hydralazine, methyldopa, captopril,

hydrochlorothiazide)– Drugs of abuse (cocaine, amphetamines)– NSAIDs– Others (allopurinol, heparin, meperidine)

• Systemic inflammatory– Collagen vascular diseases– Rheumatic fever– Rheumatoid arthritis– Systemic lupus erythematosus– Vasculitis– Polymyalgia rheumatica– Temporal arteritis– Granulomatous diseases– Sarcoidosis– Inflammatory bowel disease– Sickle cell disease– Hemolytic anemia

• Neoplastic disease– Lymphomas and leukemias– Hepatoma– Metastatic carcinomas– Atrial myxomas

• Endocrine– Lymphomas and leukemias– Hepatoma– Metastatic carcinomas– Atrial myxomas

• Pulmonary embolus• Familial Mediterranean fever• CNS lesions

Signs and Symptoms

• Chills, shivering, and rigors

– Mechanisms to raise body core temperature

• Fatigue

• Malaise

• Myalgias

• Night sweats

• Anorexia

• Specific fever patterns– Relapsing fevers: febrile episode with alternating

afebrile intervals

– Seen in malaria, Borrelia infections, rat-bite fever, and lymphoma (Pel Ebstein fevers)

– Remittent fever: temperature falls daily but does not return to normal

– Seen in TB and viral diseases

– Intermittent fevers: exaggerated circadian rhythm

– Seen in systemic infections, malignancy, and drug fever

– Reversal of normal circadian patterns

– Sometimes seen in typhoid fever and disseminated TB

• Differential Diagnosis

– Core temperatures >41°C more common in these states

– Neuroleptic malignant syndrome

– Malignant hyperthermia

– Serotonin syndrome

– Heat stroke

Treatment

• Monitoring and IV access should be obtained in the field for unstable patients or patients with altered mental status

• Immediate treatment rarely required

• Airway control, breathing and circulatory support for unstable patients

• Initiate broad-spectrum antibiotic treatment immediately for immunocompromised patients and patients with unstable vital signs or profound mental status changes

• Antipyretics– Acetaminophen, NSAIDs, or salicylates

• Glucocorticoids– Most febrile patients do not require antipyretic medication

other than for comfort.– Selected patients require more aggressive antipyretic

interventions• Pregnant women• Patients with history of seizure disorders• Patients with significant cardiac disease• Hemodynamically unstable patients• Patients with altered mental status

• Empiric antibiotics for unstable or immunocompromised patients

• External cooling mechanism rarely indicated