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Malaria
Cardiovascular Presentations
Abdominal aortic aneurysm
Acute coronary syndrome (NSTEMI)
Acute coronary syndrome (STEMI)
Acute decompensated heart failure
Acute limb ischemia
Acute mesenteric ischemia
Aortic dissection
Aortic stenosis
Atrial fibrillation and flutter
Bradyarrhythmia and heart block
Cardiac arrest
Deep vein thrombosis
Myocarditis
Pericarditis
Pulmonary embolism
Stable angina
Superficial thrombophlebitis
Superior vena cava syndrome
Supraventricular tachycardia
Syncope (cardiogenic)
Unstable angina
Ventricular tachycardia
Respiratory Presentations
Acute bronchitis
Acute respiratory failure
Aspiration pneumonia
Asthma exacerbation
Bronchiolitis
Community-acquired pneumonia
COVID-19 pneumonia
COPD exacerbation
Croup
Croup (laryngotracheobronchitis)
Epiglottitis
Hemothorax
Hospital-acquired pneumonia
Pleural effusion
Pneumothorax (traumatic)
Pulmonary contusion
Spontaneous pneumothorax
Neurological Presentations
Bell's palsy
Benign paroxysmal positional vertigo
Brain abscess
Cauda equina syndrome
Cervical radiculopathy
Concussion (mild traumatic brain injury)
Encephalitis
Guillain-Barré syndrome
Hemorrhagic stroke (intracerebral)
Ischemic stroke
Lumbar radiculopathy
Malignant spinal cord compression
Migraine
Peripheral neuropathy (acute)
Retropharyngeal abscess
Schizophrenia (acute exacerbation)
Seizure (breakthrough:known epilepsy)
Seizure (first-time)
Spinal cord injury
Status epilepticus
Subarachnoid hemorrhage
Tension headache
Transient ischemic attack
Traumatic brain injury (moderate-severe)
Vestibular neuritis
Viral meningitis
Gastrointestinal Presentations
Acute appendicitis
Acute cholecystitis
Acute diverticulitis
Acute pancreatitis
Anal fissure
Choledocholithiasis and cholangitis
Clostridioides difficile colitis
Gastritis
Gastroenteritis (viral and bacterial)
Gastroesophageal reflux disease
Incarcerated or strangulated hernia
Inflammatory bowel disease flare
Large bowel obstruction
Lower GI hemorrhage
Peptic ulcer disease
Perforated viscus
Small bowel obstruction
Upper GI hemorrhage
Genitourinary and Reproductive Presentations
Acute prostatitis
Acute urinary retention
Ectopic pregnancy
Epididymitis
Orchitis
Ovarian torsion
Paraphimosis
Pelvic inflammatory disease
Priapism
Pyelonephritis
Renal laceration
Ruptured ovarian cyst
Testicular torsion
Tubo-ovarian abscess
Urinary tract infection (uncomplicated)
Urolithiasis (renal colic)
Vaginal bleeding (non-pregnant)
Infectious Disease Presentations
Acute sinusitis
Acute tonsillitis
Acute upper respiratory infection
Animal bite
Bacterial meningitis
Cellulitis
Conjunctivitis (bacterial)
Dental abscess
Endocarditis
Febrile neutropenia
Fournier gangrene
Hand-foot-mouth disease
Hepatitis (acute)
Herpes zoster
HIV-related illness
Human bite
Impetigo
Infected diabetic foot ulcer
Infectious mononucleosis
Influenza
Necrotizing fasciitis
Osteomyelitis
Otitis externa
Parasitic infection
Periorbital cellulitis
Peritonsillar abscess
Scabies
Sepsis
Septic arthritis
Spontaneous bacterial peritonitis
Tick-borne illness (Lyme disease)
Tinea infection
Tuberculosis
Viral exanthem
Wound infection
Trauma Presentations
Achilles tendon rupture
ACL and mceniscus tear
Ankle fracture
Ankle sprain
Burn
Calcaneus fracture
Cervical spine fracture
Clavicle fracture
Dental avulsion
Distal radius fracture
Drowning
Elbow fracture and dislocation
Electrical injury
Facial bone fracture
Facial laceration
Femur fracture
Fingertip amputation
Forearm fracture (radius and ulna)
Frostbite
Hand:finger laceration
Heat exhaustion
Heat stroke
Hip fracture
Humeral shaft fracture
Knee dislocation
Knee sprain
Lightning injury
Mandible fracture
Metacarpal fracture
Metatarsal fracture
Muscle strain
Nasal fracture
Non-accidental trauma
Orbital fracture
Patella fracture
Phalanx fracture (finger)
Proximal humerus fracture
Pulmonary contusion
Rib fracture
Rotator cuff tear (acute traumatic)
Scalp laceration
Scaphoid fracture
Shoulder dislocation
Skull fracture
Splenic laceration
Sternal fracture
Supracondylar pediatric fracture
Tendon laceration (hand:wrist)
Thoracic and lumbar spine fracture
Tibia:fibula fracture
Tibial plateau fracture
Toe fracture
Traumatic epistaxis
Traumatic hyphema
Toxicologic Presentations
Acetaminophen toxicity
Alcohol intoxication
Alcohol withdrawal
Anticholinergic toxicity
Anticoagulant overdose
Benzodiazepine overdose
Benzodiazepine:sedative overdose
Beta-blocker and calcium channel blocker toxicity
Carbon monoxide poisoning
Caustic ingestion
Digoxin toxicity
Drug eruption
Foreign body ingestion
Opioid intoxication
Opioid overdose
Opioid withdrawal
Organophosphate
Salicylate toxicity
Serotonin syndrome
Stimulant intoxication (cocaine, methamphetamine)
Tricyclic antidepressant overdose
Psychiatric Presentations
Acute anxiety
Acute psychosis
Agitation:behavioral emergency
Bipolar disorder
Conversion disorder
Major depressive episode
Neuroleptic malignant syndrome
Suicidal ideation and attempt
Musculoskeletal and Rheumatologic Presentations
Acute low back pain (mechanical)
Bursitis
Cervical radiculopathy
Costochondritis
Gout (acute)
Lumbar radiculopathy
Pseudogout
Tendinitis
Dermatology Presentations
Acute eczema (Eczema acute flare)
Allergic contact dermatitis
Erythema multiforme
Henoch-Schönlein purpura
Pressure injury
Psoriasis (acute flare)
Stevens-Johnson syndrome
Toxic epidermal necrolysis
Urticaria (acute)
Environmental and Exposure Presentations
Envenomation (snake, spider, insect)
High-altitude illness
Hypothermia
Hematologic and Oncologic Presentations
Acute chest syndrome
Coagulopathy
Hyperviscosity syndrome
Sickle cell crisis (vaso-occlusive)
Symptomatic anemia
Thrombocytopenia (severe)
Tumor lysis syndrome
Pediatric-Specific Presentations
Bronchiolitis
Croup
Emergency delivery
Febrile seizure
Kawasaki disease
Neonatal jaundice
Neonatal sepsis
Nursemaid's elbow
Pediatric fever 0 to 28 days
Pediatric fever 29 to 60 days
Pediatric fever 61 to 90 days
Pyloric stenosis
Slipped capital femoral epiphysis
Intussusception
Endocrine and Metabolic Presentations
Adrenal crisis
Diabetic ketoacidosis
Hypercalcemia
Hyperosmolar hyperglycemic state
Hypertensive emergency
Hypertensive urgency
Hypoglycemia
Myasthenia gravis crisis
Myxedema coma
Severe hyperkalemia
Severe hyponatremia
Thyroid storm
ENT and Maxillofacial Presentations
Acute laryngitis
Acute otitis media
Acute pharyngitis
Cerumen impaction
Epistaxis (anterior)
Nasal foreign body
Otitis externa
Tympanic membrane perforation
Ophthalmologic Presentations
Acute angle-closure glaucoma
Central retinal artery occlusion
Chemical eye injury
Corneal abrasion
Corneal ulcer
Globe rupture
Ocular foreign body
Orbital cellulitis
Retinal detachment
Obstetric Presentations
Hyperemesis gravidarum
Painful vaginal bleeding in pregnancy
Placenta previa
Placental abruption
Preeclampsia:eclampsia
Preterm labor
Threatened:inevitable:incomplete abortion
Systemic and Miscellaneous Presentations
Anaphylaxis
Angioedema
Cannabis-induced hyperemesis
Malaria
POCUS
Procedures
Calculators
Resuscitation
ECG Guide
Back
Clinical Assessment Checklist
Browse categories and answer follow-up questions to refine your symptom profile.
Approach to the Critical Patient
Immediate priorities
Airway and breathing threats
▶
Respiratory distress triggers
▶
SpO2 <92% on room air
Respiratory rate >30 per minute
Kussmaul breathing pattern indicating acidosis
Altered mental status or seizures
▶
GCS <11 defines cerebral malaria
Seizures more than 2 in 24 hours
If unable to protect airway, immediate airway control
▶
Rapid sequence intubation preparation
Class I recommendation
Circulation and shock assessment
▶
Shock criteria
▶
SBP <80 mmHg in adults
Capillary refill >=3 seconds
Fluid resuscitation caution
▶
Judicious IV fluids to avoid ARDS and pulmonary edema
Avoid aggressive bolusing in severe malaria
Severe anemia triggering transfusion
▶
Hemoglobin <70 g/L in adults
Hemoglobin <50 g/L in children
Severity stratification
Severe malaria criteria — any one qualifies
▶
Impaired consciousness (GCS <11)
▶
Cerebral malaria case fatality approximately 40%
Class I indicator for IV artesunate
Parasitemia thresholds
▶
>=5% by any measure defines severe malaria
>=2% in non-immune travelers defines severe malaria
Metabolic derangements
▶
Lactate >=5 mmol/l
Bicarbonate <15 mmol/l
Glucose <2.2 mmol/l (hypoglycemia)
Organ failures
▶
Acute kidney injury — creatinine >265 micromol/l
ARDS — bilateral infiltrates with refractory hypoxemia
Severe anemia — hemoglobin <70 g/L
Clinical danger signs
▶
Prostration — inability to sit, stand, or walk
Inability to tolerate oral medications
Two or more seizures in 24 hours
Jaundice with high parasitemia
DIC — active bleeding from multiple sites
Monitoring and targets
Monitoring bundle for severe malaria
▶
Continuous pulse oximetry
▶
SpO2 target >=92%
Escalate to HFNC if declining
Serial glucose monitoring
▶
Point-of-care glucose every 4 hours
Quinine and artesunate both cause hypoglycemia
Serial parasitemia
▶
Blood smear every 12 to 24 hours
Confirm declining trend after treatment
Escalation triggers
▶
Worsening GCS or new seizure
▶
ICU escalation
Neurology or infectious disease consult
Rising parasitemia after 24 hours of treatment
▶
Reassess drug resistance
Contact CDC Malaria Hotline 770-488-7788
Respiratory deterioration
▶
Early intubation planning
Caution with aggressive fluids post-intubation
Immediate consults
Consultation triggers
▶
Infectious disease for all confirmed malaria
▶
Treatment guidance especially for severe disease
Post-artemisinin delayed hemolysis monitoring plan
CDC Malaria Hotline available 24 hours a day 7 days a week
▶
770-488-7788 during business hours
770-488-7100 after hours
ICU team for severe malaria
▶
Vasopressor requirements
Dialysis consideration for AKI
History
Travel and exposure history
Travel details — most critical history element
▶
Destination countries and specific regions
▶
Sub-Saharan Africa highest risk for P. falciparum
South and Southeast Asia, Central and South America
Travel dates and duration
▶
Rural versus urban exposure
Nighttime outdoor exposure
Time since return from endemic area
▶
P. falciparum typically within 4 weeks of return
P. vivax and P. ovale can present months to over 1 year later
P. malariae can present years later
Chemoprophylaxis history
▶
Agent used
▶
Atovaquone-proguanil, doxycycline, mefloquine, chloroquine
Same agent used for prophylaxis must not be used for treatment
Adherence and timing
▶
Started before, during, after travel
Duration after return
Symptom characterization
Core fever syndrome
▶
Fever pattern
▶
Often paroxysmal — chills, rigor, sweat, defervescence cycle
Classic cyclical fevers variable and not reliable for diagnosis
q48h cycle for P. falciparum, P. vivax, P. ovale
q72h cycle for P. malariae
Associated systemic symptoms
▶
Headache
Myalgias and arthralgias
Malaise and fatigue
GI symptoms
▶
Nausea and vomiting
Diarrhea
Abdominal pain mimicking gastroenteritis
Alarm symptoms requiring urgent assessment
▶
Altered mental status or confusion
▶
Cerebral malaria concern
GCS estimation
Seizures
▶
Number in past 24 hours
Focal versus generalized
Respiratory distress
▶
Dyspnea
ARDS risk in severe malaria — can develop after treatment initiation
Dark urine
▶
Blackwater fever — massive hemolysis
Hemoglobinuria
Inability to tolerate oral intake
▶
Vomiting medications
Prostration
Important negatives and alternative diagnosis clues
Features suggesting alternative diagnosis
▶
Rash — uncommon in malaria; suggests dengue or meningococcemia
▶
Petechiae suggests dengue or meningococcal disease
Rose spots suggests typhoid fever
Neck stiffness — suggests meningitis rather than cerebral malaria
Prominent hemorrhagic features — suggests viral hemorrhagic fever
Epidemiologic clues
▶
Aedes mosquito exposure — dengue versus Anopheles for malaria
Tick exposure in northeastern US — babesiosis
Water exposure and conjunctival suffusion — leptospirosis
Risk factors
Host risk factors for severe malaria
▶
Non-immune travelers
▶
No prior malaria exposure
Visiting friends and relatives — often skip prophylaxis
Immunocompromise
▶
HIV increases parasitemia and severity
Splenectomy or functional asplenia
Age extremes
▶
Children under 5 in endemic areas
Elderly travelers
Pregnancy — especially primigravidas
▶
Increased hypoglycemia risk
Severe anemia risk
Placental malaria
Protective genetic factors
▶
Sickle cell trait (HbAS) — 85 to 90% protection against severe P. falciparum
Duffy-negative blood type — near-total protection against P. vivax in sub-Saharan Africans
G6PD deficiency — must be identified before primaquine or tafenoquine use
Past medical and medication history
Relevant past history
▶
Prior malaria episodes — species, treatment, complications
G6PD status — critical before prescribing radical cure
Sickle cell disease or trait
Chronic kidney or liver disease — affects drug dosing
Blood transfusion or organ transplant — rare non-mosquito transmission
Physical Exam
Vitals and general appearance
Vital sign assessment
▶
Temperature
▶
Often >39 degrees Celsius
May be absent between paroxysms — do not rely on afebrile state
Blood pressure
▶
SBP <80 mmHg in adults defines shock in severe malaria
Persistent hypotension requires ICU escalation
Respiratory rate
▶
>30 per minute as severity marker
Kussmaul breathing indicates metabolic acidosis
Oxygen saturation
▶
<92% is a WHO severe malaria criterion
General appearance
▶
Diaphoresis and rigors
▶
Paroxysmal pattern
Post-rigor soaking diaphoresis
Pallor and jaundice
▶
Hemolytic anemia findings
Scleral icterus
Prostration assessment
▶
Inability to sit, stand, or walk unassisted
Neurological assessment
GCS assessment — critical for cerebral malaria
▶
GCS <11 defines impaired consciousness in severe malaria
▶
WHO definition
Case fatality approximately 40%
Posturing assessment
▶
Abnormal flexion or extension
Poor prognostic sign
Seizure activity
▶
Generalized tonic-clonic most common
Subtle focal signs
Meningismus screening
▶
Neck stiffness absent in malaria
▶
If present, lumbar puncture for meningitis
Cerebral malaria is a clinical diagnosis
Fundoscopy if available
▶
Malarial retinopathy — retinal whitening, vessel changes
Specific for cerebral malaria
Abdominal exam
Organomegaly assessment
▶
Splenomegaly
▶
Often tender in acute malaria
Splenic rupture risk with trauma or vigorous palpation
Hepatomegaly
▶
Right upper quadrant tenderness
Liver dysfunction marker
Splenic rupture assessment
▶
Left shoulder tip pain (Kehr sign)
▶
Abdominal guarding
Peritoneal signs
Skin and peripheral exam
Skin findings
▶
No rash expected in malaria
▶
Rash suggests alternative diagnosis
Petechiae suggests dengue, meningococcemia, or DIC
Jaundice severity
▶
Scleral icterus
Skin yellowing in severe hemolysis
Peripheral perfusion
▶
Capillary refill time
▶
>=3 seconds indicates compensated shock
Cool peripheries
Volume status
▶
Dry mucous membranes
Peripheral edema suggests fluid overload in severe malaria
Respiratory exam
Lung auscultation
▶
Crackles suggesting pulmonary edema or ARDS
▶
Can develop after treatment initiation
Bilateral findings more concerning
Kussmaul breathing pattern
▶
Deep labored breathing
Indicates severe metabolic acidosis
Differential Diagnosis
Life-threatening mimics
Infectious emergencies presenting with fever and altered mental status
▶
Bacterial meningitis
▶
ICD-10 G00.9
Neck stiffness and photophobia more prominent
Lumbar puncture if meningismus present
Bacterial sepsis
▶
ICD-10 A41.9
Identifiable source common
No travel history required
Viral hemorrhagic fever (Ebola, Lassa, Marburg)
▶
ICD-10 A98.4 (Ebola)
Hemorrhagic features prominent
High-risk exposure history — contact isolation immediately
Malaria itself — ICD-10 classification
▶
P. falciparum malaria — ICD-10 B50
▶
Most dangerous species
Responsible for most severe disease and deaths
P. vivax malaria — ICD-10 B51
▶
Relapsing potential
Hypnozoites persist in liver
P. ovale malaria — ICD-10 B53.0
▶
Similar to P. vivax
Relapsing
P. malariae malaria — ICD-10 B52
▶
Chronic low-grade parasitemia
Nephrotic syndrome complication
P. knowlesi malaria — ICD-10 B53.1
▶
Zoonotic — Southeast Asia
Rapid parasite multiplication
Travel-related fever differentials
Dengue fever
▶
ICD-10 A90
Aedes mosquito vector — urban areas
Severe myalgia "breakbone fever"
Leukopenia and thrombocytopenia
Rash common
Typhoid fever
▶
ICD-10 A01.0
Insidious onset over days
Relative bradycardia
Rose spots on trunk
Abdominal pain and constipation
Leptospirosis
▶
ICD-10 A27.9
Water or animal exposure
Conjunctival suffusion
Weil disease — jaundice and AKI
Babesiosis
▶
ICD-10 B60.0
Tick exposure in northeastern US
Ring forms on blood smear similar to P. falciparum
No malaria pigment on smear
Tetrad "Maltese cross" form diagnostic
Influenza or COVID-19
▶
Respiratory predominance
13% of US malaria cases initially misdiagnosed as viral illness
Laboratory Tests
Blood smear — gold standard
Thick and thin blood smear (Giemsa-stained)
▶
Indication
▶
Required for all suspected malaria
Provides species identification and parasitemia quantification
Technique
▶
Thick smear — higher sensitivity for detection
Thin smear — species morphology and parasitemia percentage
Interpretation
▶
Parasitemia expressed as percentage of infected RBCs
>=2% in non-immune or >=5% overall defines severe malaria
Serial smears
▶
Repeat every 12 to 24 hours times 3 if initial negative
Repeat every 12 to 24 hours after treatment to confirm decline
Limitations
▶
Operator-dependent expertise required
Low-density parasitemia may be missed on single smear
Rapid diagnostic test
BinaxNOW malaria RDT
▶
Performance characteristics
▶
Results in 2 to 15 minutes
Sensitivity 99.7% for P. falciparum at >5,000 parasites per microliter
Lower sensitivity for non-falciparum species
Clinical role
▶
Rapid bedside detection
Must always be confirmed by microscopy
Negative RDT does not rule out malaria with low parasitemia
Complete blood count and metabolic panel
CBC findings in malaria
▶
Anemia
▶
Hemolytic pattern
Severity guides transfusion decision
Thrombocytopenia
▶
Common and helps differentiate from viral illness
Platelet count <50 x 10^9/L common
Leukocyte count variable
▶
Leukocytosis or leukopenia both possible
Metabolic and organ function
▶
Creatinine for AKI detection
▶
Creatinine >265 micromol/l defines severe malaria AKI
Dialysis may be required
Glucose
▶
Glucose <2.2 mmol/l defines hypoglycemia — severe malaria criterion
Monitor serially — quinine causes hypoglycemia as side effect
Bilirubin and transaminases
▶
Total bilirubin >50 micromol/l in severe hemolysis
Elevated AST and ALT
Lactate
▶
>=5 mmol/l defines severe malaria
Point-of-care lactate for rapid severity assessment
Coagulation and hemolysis markers
DIC screen
▶
Prothrombin time and INR
▶
Prolonged in severe malaria with DIC
Bleeding from multiple sites
Fibrinogen
▶
Low in DIC
Hemolysis markers
▶
LDH — elevated in intravascular hemolysis
Haptoglobin — decreased with hemolysis
Reticulocyte count — elevated in recovering hemolytic anemia
Post-artemisinin delayed hemolysis monitoring
▶
Check CBC, LDH, haptoglobin at 1, 2, 3, and 4 weeks after IV artesunate
Affects approximately 4.8% of patients treated with IV artesunate
Ancillary labs
G6PD level
▶
Required before prescribing primaquine or tafenoquine
▶
G6PD deficiency causes life-threatening hemolysis with these drugs
Contraindicated in G6PD deficiency
Test before any radical cure prescription for P. vivax or P. ovale
Blood cultures
▶
Rule out concurrent bacteremia
▶
Especially in children with severe malaria
Nontyphoidal Salmonella co-infection risk in Africa
Arterial blood gas
▶
Base deficit >8 mEq/L or bicarbonate <15 mmol/l defines severe acidosis
PaO2 and PaCO2 for ventilation assessment
Type and screen
▶
Anticipate transfusion in severe anemia
Diagnostic Tests
Scoring Systems
WHO severe malaria criteria — primary severity tool
▶
Individual criteria each define severe disease
▶
Impaired consciousness GCS <11
Prostration
Multiple convulsions >2 in 24 hours
Respiratory distress — SpO2 <92%
Pulmonary edema on imaging
Abnormal bleeding or DIC
Jaundice with evidence of vital organ dysfunction
Hemoglobin <70 g/L severe anemia
Hypoglycemia glucose <2.2 mmol/l
AKI creatinine >265 micromol/l
Circulatory collapse SBP <80 mmHg
Parasitemia >=5% or >=2% in non-immune patients
Lactate >=5 mmol/l
Prognosis
▶
Multiple complications increase mortality dramatically
Single complication mortality approximately 6%
Multiple complications mortality approximately 43%
Severity scoring context
▶
Clinical severity stratification drives treatment pathway
▶
Severe malaria — IV artesunate mandatory
Uncomplicated malaria — oral artemisinin-based combination therapy
Parasitemia percentage combined with clinical features most informative
▶
ACEP Level B recommendation for combined clinical and parasitemia assessment
MRI
MRI brain in cerebral malaria
▶
Indications
▶
Unexplained coma with negative CT
Complex neurological syndrome
Research setting for pathological correlation
Findings
▶
Diffuse white matter signal changes
Cerebral edema pattern
Not routinely required for clinical diagnosis
Limitations
▶
Availability constraints in acute setting
Unstable patients — impractical
Cerebral malaria remains a clinical diagnosis
MRI abdomen
▶
Not routinely indicated
▶
Ultrasound preferred for organomegaly assessment
Reserve for complex cases with atypical features
CT
CT head for altered mental status
▶
Indications
▶
Rule out alternative intracranial pathology
Before lumbar puncture if meningitis suspected
Cerebral malaria itself is clinical diagnosis — CT is to rule out mimics
Expected findings in cerebral malaria
▶
CT often normal or shows diffuse edema
Focal lesion suggests alternative diagnosis
Contraindications and considerations
▶
Radiation exposure relative to clinical yield
Renal function for IV contrast
CT chest for respiratory complications
▶
Indications
▶
ARDS confirmation and characterization
Bilateral infiltrates with hypoxemia
Pulmonary edema versus pneumonia distinction
Findings in severe malaria
▶
Bilateral alveolar infiltrates in ARDS pattern
Pleural effusions
Interstitial edema
Ultrasound
Abdominal ultrasound
▶
Organomegaly assessment
▶
Splenomegaly — size and texture
Hepatomegaly — degree and parenchymal echotexture
Splenic rupture screening when acute left-sided pain
Ascites detection
▶
Free peritoneal fluid
Splenic rupture free fluid
Cardiac POCUS
▶
Hemodynamic shock assessment
▶
Left ventricular function estimation
Pericardial effusion screen
Volume status
▶
IVC collapsibility assessment
Integrate with clinical examination
Lung ultrasound
▶
B-lines for pulmonary edema
▶
Bilateral B-lines support ARDS or pulmonary edema
Guides fluid management decisions
Consolidation pattern
▶
Tissue-like echotexture with air bronchograms
Co-existing pneumonia assessment
PCR testing note
▶
Nucleic acid amplification testing
▶
More sensitive than microscopy for low parasitemia
Useful for species confirmation and mixed infections
Results not immediately available — not for initial management decisions
Disposition
ICU admission indications
Severe malaria — ICU mandatory
▶
WHO severe criteria met
▶
Any single criterion qualifies
IV artesunate initiated in emergency department before transfer
Specific ICU triggers
▶
GCS <11 or deteriorating mental status
Parasitemia >=5% or >=2% in non-immune
Respiratory support requirement — HFNC, intubation
Vasopressor requirement for shock
AKI requiring dialysis
DIC with bleeding
Special high-risk groups requiring ICU consideration
▶
Pregnant patients
▶
All trimesters — increased maternal and fetal risk
Immunocompromised patients
▶
HIV-positive patients with severe immunosuppression
Asplenic patients
Children
▶
All severe criteria apply with pediatric thresholds
General ward admission indications
Uncomplicated malaria requiring admission
▶
P. falciparum with any degree of parasitemia in non-immune patient
▶
Inability to guarantee reliable follow-up
Risk of rapid progression
Inability to tolerate oral medications
▶
Persistent vomiting
First doses monitored in hospital
Uncertain species identification with clinical concern
Pregnancy — all pregnant patients
Pediatric patients without prior immunity
Discharge criteria
Copy
Outpatient management only when all criteria met
▶
Confirmed uncomplicated non-falciparum malaria
▶
P. vivax, P. ovale, or P. malariae with low parasitemia
No severe criteria
Able to tolerate oral medications
▶
First dose observed and tolerated in department
No vomiting
Reliable follow-up arranged
▶
Next day parasitemia check
Infectious disease or tropical medicine follow-up
Responsible adult at home
▶
Return precautions clearly understood
Mandatory outpatient follow-up components
▶
Blood smears until two consecutive negative results
Post-artemisinin delayed hemolysis monitoring for 4 weeks after IV artesunate
State health department reporting
▶
All confirmed malaria cases reportable by law
Treatment
Severe malaria — IV artesunate
IV artesunate — first-line for severe malaria worldwide
▶
Dosing
▶
Adults and children >=20 kg — 2.4 mg/kg IV at 0, 12, and 24 hours
Children <20 kg — 3.0 mg/kg IV at 0, 12, and 24 hours
Then 2.4 mg/kg every 24 hours until PO tolerated
Transition criteria
▶
Parasitemia <=1%
Patient able to tolerate oral medications
Minimum 24 hours IV therapy
Transition regimen after IV artesunate
▶
Complete a full course of oral ACT — artemether-lumefantrine preferred
Total treatment duration includes IV and PO phases
Evidence level
▶
Class I recommendation — superior to IV quinine in multiple RCTs
SEQUAMAT trial demonstrated reduced mortality
Post-artemisinin delayed hemolysis monitoring
▶
Incidence approximately 4.8% in US patients receiving IV artesunate
▶
Occurs 1 to 3 weeks after treatment
Monitor CBC, LDH, haptoglobin at weeks 1, 2, 3, and 4
Alternatives when artesunate unavailable
IV quinine plus doxycycline
▶
Quinine dihydrochloride IV — loading dose 20 mg/kg over 4 hours
▶
Maintenance 10 mg/kg every 8 hours
Maximum 1800 mg per day
IV quinidine no longer available in the US
Doxycycline IV or PO
▶
100 mg every 12 hours for 7 days total
Avoid in pregnancy and children under 8 years
QT prolongation monitoring required
▶
ECG before and during quinine infusion
Cardiac monitoring mandatory
IM artemether when IV access unavailable
▶
3.2 mg/kg IM loading dose
▶
Then 1.6 mg/kg IM daily
Less reliable absorption than IV artesunate
Transition to oral ACT as soon as tolerated
Uncomplicated malaria — chloroquine-resistant or unknown resistance
Artemether-lumefantrine (Coartem) — first-line
▶
Adult dosing (>=35 kg)
▶
4 tablets per dose (each tablet contains 20 mg artemether and 120 mg lumefantrine)
Twice daily for 3 days — first two doses 8 hours apart
Must administer with fatty food or full-fat milk to optimize absorption
Pediatric dosing weight-based
▶
5 to 14 kg — 1 tablet per dose twice daily times 3 days
15 to 24 kg — 2 tablets per dose twice daily times 3 days
25 to 34 kg — 3 tablets per dose twice daily times 3 days
Evidence and safety
▶
Class I recommendation for uncomplicated P. falciparum
Safe in second and third trimester of pregnancy
Atovaquone-proguanil (Malarone) — alternative
▶
Adult dosing — 4 adult tablets once daily for 3 days
▶
Take with food or milky drink
Contraindicated in pregnancy
Contraindicated in infants <5 kg
Avoid in severe renal impairment
Pediatric dosing by weight
▶
5 to 8 kg — 2 pediatric tablets daily times 3 days
9 to 10 kg — 3 pediatric tablets daily times 3 days
11 to 20 kg — 1 adult tablet daily times 3 days
Quinine plus doxycycline or tetracycline or clindamycin
▶
Quinine sulfate 542 mg base (650 mg salt) PO three times daily for 3 or 7 days
▶
3 days if used with doxycycline or tetracycline
7 days if used with clindamycin or alone
Doxycycline 100 mg PO twice daily for 7 days
▶
Avoid in pregnancy and children under 8
Clindamycin 20 mg/kg/day PO divided three times daily for 7 days
▶
Alternative when doxycycline contraindicated
Uncomplicated malaria — chloroquine-sensitive species
Chloroquine phosphate
▶
Dosing
▶
600 mg base (1000 mg salt) initially
Then 300 mg base (500 mg salt) at 6 hours
Then 300 mg base at 24 hours and 48 hours
Total dose 1500 mg base
Chloroquine-sensitive species
▶
P. vivax — in most areas except Papua New Guinea and Indonesia
P. ovale — globally sensitive
P. malariae — globally sensitive
P. knowlesi — sensitive
P. falciparum in Central America (west of Panama Canal), Haiti, Dominican Republic, and Middle East
Monitoring
▶
QT prolongation risk — ECG recommended with higher doses
Retinal toxicity with prolonged use (not an acute concern)
Radical cure — relapse prevention
Primaquine — P. vivax and P. ovale hypnozoite eradication
▶
Dosing
▶
30 mg base once daily for 14 days (standard)
15 mg base once daily for 14 days (alternative, lower dose)
G6PD-deficient patients — weekly dosing under expert guidance only
Mandatory G6PD testing before prescribing
▶
G6PD deficiency causes severe life-threatening hemolysis
Contraindicated in pregnancy
Evidence level
▶
Class I recommendation for relapse prevention in P. vivax and P. ovale
Tafenoquine — single-dose alternative
▶
300 mg single dose for adults >=16 years
▶
Must be administered with a meal
G6PD testing mandatory before use
Contraindicated in G6PD deficiency (any degree)
Contraindicated in pregnancy and breastfeeding
Supportive care
Hypoglycemia management
▶
Point-of-care glucose every 4 hours in severe malaria
▶
IV dextrose 50% for glucose <2.2 mmol/l
Quinine and severe infection both cause hypoglycemia
Fever control
▶
Acetaminophen (paracetamol) preferred
▶
1 g PO or IV every 6 hours as needed
Avoid NSAIDs in dengue overlap concern
Fluid management
▶
Judicious IV normal saline for dehydration
▶
Avoid aggressive bolusing — ARDS and pulmonary edema risk in severe malaria
Furosemide for pulmonary edema
▶
40 to 80 mg IV as needed
Blood transfusion for severe anemia
▶
Hemoglobin <70 g/L in adults — transfuse packed red cells
Hemoglobin <50 g/L in children — transfuse
Exchange transfusion no longer recommended — insufficient evidence
Special Populations
Pregnancy
Malaria in pregnancy — high-risk emergency
▶
Increased severity risk
▶
Primigravidas at highest risk
Placental malaria — parasites sequester in placenta
Hypoglycemia more severe and more frequent
Severe anemia more common
Fetal and neonatal risks
▶
Preterm delivery
Intrauterine growth restriction
Congenital malaria — rare but possible
Treatment in pregnancy
▶
First trimester — severe malaria
▶
IV artesunate is recommended despite limited first trimester data
Risk of untreated severe malaria exceeds theoretical teratogenicity risk
Chloroquine if chloroquine-sensitive species and uncomplicated
Second and third trimester — severe malaria
▶
IV artesunate first-line — safe and effective
Second and third trimester — uncomplicated malaria
▶
Artemether-lumefantrine preferred — safety data support use
Atovaquone-proguanil — contraindicated
Radical cure — contraindications
▶
Primaquine and tafenoquine contraindicated in pregnancy and breastfeeding
G6PD testing of infant required before primaquine use in breastfeeding mother
Monitoring in pregnancy
▶
Fetal heart rate monitoring when viable gestation
▶
Non-stress test consideration in third trimester
Maternal SpO2 target >=95%
Glucose monitoring every 4 hours minimum
Geriatric
Older adult considerations
▶
Atypical presentation risk
▶
Fever may be blunted or absent
Confusion or delirium as primary presentation
Falls related to prostration
Comorbidity burden
▶
Renal impairment — dose adjustment for renally cleared medications
Cardiac disease — increased QT prolongation risk with quinine and chloroquine
Polypharmacy and drug interactions
Treatment modifications
▶
Renal dosing adjustments
▶
Quinine — reduce dose in severe renal impairment
Atovaquone-proguanil — avoid in severe renal impairment (eGFR <30)
IV artesunate — no dose adjustment required
Cardiac monitoring
▶
Baseline ECG before quinine or chloroquine
Continuous monitoring during IV quinine infusion
Hypoglycemia vigilance
▶
More frequent glucose monitoring in elderly patients
Reduced glycogen reserves
Disposition bias
▶
Lower threshold for admission
▶
Frailty and limited home supports
Rapid deterioration potential
Pediatrics
Severe malaria in African children
▶
Leading infectious disease cause of childhood mortality globally
▶
Sub-Saharan Africa bears highest burden
Children under 5 most vulnerable
Specific pediatric severe malaria features
▶
Severe anemia proportionally more common than in adults — hemoglobin <50 g/L
Cerebral malaria with seizures very common
Respiratory distress from acidosis
Impaired consciousness
Hypoglycemia — especially with quinine treatment
Pediatric treatment dosing
▶
IV artesunate for severe malaria
▶
<20 kg — 3.0 mg/kg IV at 0, 12, and 24 hours then daily
>=20 kg — 2.4 mg/kg IV at same intervals
Artemether-lumefantrine by weight for uncomplicated malaria
▶
5 to 14 kg — 1 tablet per dose twice daily times 3 days
15 to 24 kg — 2 tablets per dose twice daily times 3 days
25 to 34 kg — 3 tablets per dose twice daily times 3 days
Atovaquone-proguanil — avoid in <5 kg
▶
Weight-based pediatric tablet dosing
Clindamycin replaces doxycycline in children under 8 years
▶
20 mg/kg/day divided every 8 hours for 7 days
Pediatric-specific monitoring
▶
Blood glucose every 4 hours in severe malaria
▶
Hypoglycemia threshold — glucose <2.2 mmol/l
Seizure management
▶
IV or rectal diazepam for acute seizure
Phenobarbital or phenytoin for recurrent seizures
Blood transfusion threshold
▶
Hemoglobin <50 g/L or clinical signs of circulatory compromise
Background
Epidemiology
Global burden
▶
WHO 2023 estimate — 249 million cases annually worldwide
▶
608,000 deaths annually — approximately 75% in children under 5 in Africa
Sub-Saharan Africa accounts for over 90% of global malaria deaths
United States imported malaria
▶
Approximately 2,000 cases annually diagnosed in the US
Predominantly returning travelers and visiting friends and relatives
P. falciparum accounts for approximately 70% of US cases
Species distribution
▶
Plasmodium falciparum
▶
Most virulent species — responsible for nearly all malaria deaths
Dominant in sub-Saharan Africa
Growing artemisinin resistance emerging in Southeast Asia
Plasmodium vivax
▶
Most geographically widespread — Central and South America, Asia
Relapsing — hypnozoites persist in liver for months to years
Duffy-negative blood type protective in West Africans
Plasmodium ovale
▶
Two subspecies — wallikeri and curtisi
West and Central Africa, Southeast Asia
Relapsing species
Plasmodium malariae
▶
Low-density chronic parasitemia
Nephrotic syndrome complication
Plasmodium knowlesi
▶
Zoonotic — Southeast Asia (Malaysia, Philippines, Indonesia)
Rapid parasite doubling — potentially severe
Risk populations
▶
Non-immune travelers — highest per capita risk in US
Pregnant women — immunological susceptibility to placental malaria
Children under 5 in endemic areas — lack acquired immunity
HIV-positive individuals — impaired malaria control
Asplenic patients — uncontrolled parasitemia risk
Pathophysiology
Parasite life cycle
▶
Mosquito to human transmission
▶
Anopheles mosquito injects sporozoites during blood meal at night
Sporozoites travel to liver within minutes
Hepatic stage (exoerythrocytic phase)
▶
Sporozoites invade hepatocytes
Silent incubation — 7 to 30 days depending on species
P. vivax and P. ovale form dormant hypnozoites — source of relapse
Blood stage (erythrocytic phase)
▶
Merozoites invade red blood cells
Synchronized rupture causes fever paroxysms
Hemolytic anemia from RBC destruction
Parasite sequestration in microvasculature for P. falciparum
Cerebral malaria mechanism
▶
Sequestration of parasitized RBCs in cerebral microvasculature
▶
P. falciparum PfEMP1 protein binds to ICAM-1 on endothelium
Obstruction of cerebral blood flow
Inflammatory cytokine release
Blood-brain barrier disruption
▶
Cerebral edema
Neuronal injury
Severe malaria organ injury mechanisms
▶
Hypoglycemia
▶
Parasite consumption of glucose
Impaired hepatic gluconeogenesis
Quinine and quinidine stimulate insulin release
ARDS and pulmonary edema
▶
Endothelial injury and capillary leak
Can occur after treatment starts — fluid overload exacerbates
AKI
▶
Microvascular obstruction in renal vasculature
Hemoglobinuria from massive hemolysis — tubular injury
Anemia
▶
Direct RBC destruction by parasite
Immune-mediated bystander hemolysis
Dyserythropoiesis in bone marrow
Therapeutic Considerations
Artemisinin-based combination therapy rationale
▶
Artemisinins — most rapidly acting antimalarials
▶
Reduce parasitemia faster than any other drug class
Kill all blood stages including young gametocytes
Partner drugs extend elimination of remaining parasites
▶
Lumefantrine, amodiaquine, piperaquine
Prevent selection of artemisinin-resistant parasites
Resistance concern
▶
Artemisinin partial resistance emerging in Southeast Asia and East Africa
Kelch13 gene mutations associated
WHO recommends triple ACT in high-resistance areas
Drug resistance patterns
▶
Chloroquine resistance
▶
P. falciparum resistant in most endemic regions except limited areas
P. vivax chloroquine resistance in Papua New Guinea, Indonesia, parts of South America
Sulfadoxine-pyrimethamine resistance widespread
▶
Not used for uncomplicated treatment
Still used for intermittent preventive treatment in pregnancy in some regions
Mefloquine resistance in Southeast Asia border regions
Drug interaction and safety considerations
▶
QT prolongation drugs — quinine, chloroquine, hydroxychloroquine
▶
Avoid concurrent QT-prolonging medications
Baseline ECG before initiating
CYP enzyme interactions
▶
Artemether-lumefantrine metabolized by CYP3A4
HIV antiretroviral interactions common
Fatty food requirement for artemether-lumefantrine
▶
Bioavailability reduced by 70% without fat
Whole milk or full-fat dairy meal acceptable
Malaria prevention for future travel
▶
Chemoprophylaxis options
▶
Atovaquone-proguanil — daily, start 1 to 2 days before travel
Doxycycline — daily, start 1 to 2 days before travel
Mefloquine — weekly, start 2 to 3 weeks before travel
Chloroquine — weekly, for sensitive regions only
Mosquito avoidance measures
▶
DEET-based repellents
Permethrin-treated clothing
Insecticide-treated bed nets
Patient Discharge Instructions
copy discharge instructions
Copy
Malaria home care instructions
▶
Take all antimalarial medications exactly as prescribed
▶
Complete the full course even if feeling better
Take artemether-lumefantrine with a fatty meal or full-fat milk — this is essential
Do not skip doses
Activity and diet
▶
Rest while febrile
Stay well hydrated
Eat regular meals to prevent low blood sugar
Fever management at home
▶
Acetaminophen (paracetamol) for fever and pain
Avoid aspirin and ibuprofen unless advised by your doctor
Return to emergency department immediately for
▶
Confusion, extreme sleepiness, or seizures
▶
These are signs of cerebral malaria
Inability to keep medications or fluids down
▶
Vomiting medications within 30 minutes of taking them
Shortness of breath at rest or worsening breathing
Dark brown or red-colored urine
▶
Sign of dangerous hemolysis (blackwater fever)
Recurrent fever after initially feeling better
▶
Could indicate treatment failure or new complication
Jaundice — yellow skin or eyes
Signs of bleeding — unusual bruising, blood in stool or vomit
Extreme weakness — unable to stand or walk
Follow-up appointments
▶
Blood tests to confirm malaria parasites have cleared
▶
Typically within 24 to 72 hours after starting treatment
If you received IV artesunate in hospital
▶
Return for blood tests at 1, 2, 3, and 4 weeks
Delayed anemia can develop weeks after treatment
If you have P. vivax or P. ovale malaria and are prescribed primaquine
▶
Complete the 14-day course
This prevents relapse — malaria can come back months later without it
Prevention for future travel
▶
Take prescribed malaria prevention medications if travelling to endemic areas
▶
Start before departure and complete full course after return
Use DEET insect repellent — reapply every few hours
Sleep under insecticide-treated mosquito nets
Wear long sleeves and pants in evenings and at night
References
Guidelines and key sources
Primary evidence sources
▶
Daily JP, Minuti A, Khan N — Diagnosis, Treatment, and Prevention of Malaria in the US, JAMA 2022
▶
Comprehensive US-focused review
Treatment algorithms and prophylaxis guidance
Daily JP, Parikh S — Malaria, New England Journal of Medicine 2025
▶
Most current comprehensive review
Post-artemisinin delayed hemolysis incidence data
Poespoprodjo JR, Douglas NM, Ansong D, Kho S, Anstey NM — Malaria, Lancet 2023
▶
Global epidemiology and pathophysiology
Long B, MacDonald A, Liang SY et al — Malaria: A Focused Review for the Emergency Medicine Clinician, American Journal of Emergency Medicine 2024
▶
Emergency medicine clinical focus
Shahbodaghi SD, Rathjen NA — Malaria: Prevention, Diagnosis, and Treatment, American Family Physician 2022
▶
Treatment dosing tables
Institutional guidelines
▶
CDC Yellow Book 2025 — Ridpath AD, Wallender E — Malaria chapter
▶
Chemoprophylaxis guidance
Treatment recommendations by region and species
WHO Guidelines for the Treatment of Malaria (current edition)
▶
Severe malaria WHO criteria definitions
IV artesunate dosing protocols
CDC Malaria Hotline — 770-488-7788 (business hours)
▶
770-488-7100 (after hours and weekends)
Available for diagnostic and treatment guidance
ICD-10 coding reference
▶
B50 — Plasmodium falciparum malaria
B51 — Plasmodium vivax malaria
B52 — Plasmodium malariae malaria
B53.0 — Plasmodium ovale malaria
B53.1 — Plasmodium knowlesi malaria
B54 — Unspecified malaria
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.
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