Preliminary diagnosis

• Infectious-toxic shock: BP 90/60 mmHg, tachycardia, marked weakness, confusion
• Acute toxic encephalopathy: lethargy, disorientation, delirium
• Hemorrhagic syndrome: epistaxis and petechiae on oral mucosa
• Possible early viral myocarditis or sepsis-associated myocardial depression, given markedly muffled heart sounds

Justification

Important differential diagnoses to exclude urgently

1. Meningococcal sepsis/meningitis: fever, altered mental state, hypotension. Rash may be absent early.
2. Other viral hemorrhagic fever, including hantavirus infection or Crimean-Congo hemorrhagic fever, depending on travel, tick exposure, occupational and epidemiological history.
3. Leptospirosis: fever, myalgia, conjunctival injection and hemorrhagic manifestations.
4. Severe COVID-19 or another respiratory virus.
5. Acute bacterial sepsis, including occult pneumonia.
6. Acute leukemia, immune thrombocytopenia, or disseminated intravascular coagulation, if thrombocytopenia/coagulopathy is found.

Immediate actions

1. ABC assessment, continuous ECG, SpO₂ and blood-pressure monitoring.
2. Two large-bore IV lines.
3. Check capillary glucose immediately.
4. Oxygen if SpO₂ <94%, respiratory distress, shock, or reduced consciousness.
5. Strict input-output charting; insert urinary catheter if shock/critical illness.
6. Frequent neurological assessment, Glasgow Coma Scale, pupils, signs of meningism, seizures.
7. Obtain specimens promptly, but do not delay resuscitation, empiric antibiotics if sepsis is possible, or antiviral therapy.

Examination plan

Bedside and routine investigations

• Full blood count with differential and platelet count
• Peripheral blood smear if cytopenias are present
• CRP, procalcitonin
• Serum electrolytes, glucose, urea, creatinine
• Liver tests: AST, ALT, bilirubin, albumin
• Creatine kinase and LDH
• Serum lactate, arterial or venous blood gas
• Coagulation profile: PT/INR, aPTT, fibrinogen, D-dimer
• Blood group, screen and crossmatch
• Urinalysis, urine output, urine protein and microscopic hematuria
• ECG and cardiac troponin; bedside echocardiography if persistent shock or suspected myocarditis
• Chest radiograph initially, repeated if respiratory status worsens. CT chest only if clinically required and the patient is stable.

Microbiological and virological tests

• Nasopharyngeal swab for influenza A/B RT-PCR, including subtype where available
• SARS-CoV-2 PCR
• Blood cultures from two sites
• Sputum culture/PCR if a lower-respiratory specimen becomes available
• If meningitis/encephalitis is suspected: blood cultures and empiric treatment first; lumbar puncture only after stabilization and after assessing platelet count, coagulation, and possible raised intracranial pressure.
• Epidemiological screening for hantavirus, leptospirosis, dengue, Crimean-Congo hemorrhagic fever, etc., based on residence, travel, rodent contact, tick bites, animal exposure, and sick contacts.

Treatment plan

1. Antiviral treatment

• Oseltamivir 75 mg orally or via nasogastric tube twice daily.
• In severe or progressive disease, treatment is commonly extended beyond 5 days based on clinical course and virological assessment.
• If enteral therapy is impossible, discuss IV antiviral options with infectious-disease specialists, according to local availability.

2. Shock management

• Give a cautious isotonic crystalloid bolus, for example 250-500 mL, then reassess blood pressure, mental status, capillary refill, lung examination, urine output and lactate.
• Continue fluid resuscitation in aliquots, avoiding fluid overload.
• If hypotension persists after adequate fluid assessment, start norepinephrine in an ICU setting to maintain MAP at least 65 mmHg.
• Measure lactate serially and target urine output at least 0.5 mL/kg/hour.
• Consider bedside echocardiography because muffled heart sounds and shock could reflect myocardial dysfunction.

3. Empiric antibacterial therapy

• Ceftriaxone 2 g IV every 12 hours, which covers meningococcal disease and many common severe bacterial infections.

4. Hemorrhagic syndrome

• Avoid IM injections, rectal procedures, unnecessary venipuncture, aspirin, ibuprofen, diclofenac and other NSAIDs.
• Use paracetamol/acetaminophen for fever and pain.
• Local epistaxis care: sit forward, pinch the soft nasal alae continuously, topical vasoconstrictor if appropriate, nasal packing and ENT input if bleeding continues.
• Monitor platelet count and coagulation repeatedly.
• Give platelets, fresh frozen plasma, cryoprecipitate or packed red cells only for clinically significant bleeding or laboratory-guided correction of thrombocytopenia/coagulopathy.

5. Neurological support

• Protect airway if consciousness deteriorates, vomiting occurs, or GCS falls.
• Treat seizures promptly with benzodiazepines and follow the local status-epilepticus protocol.
• Avoid routine sedatives that obscure neurological observation unless needed for safety or airway management.
• Evaluate for meningitis, encephalitis, hypoglycemia, severe electrolyte disturbance and cerebral hypoperfusion.

6. Respiratory surveillance

• Viral pneumonia
• Secondary bacterial pneumonia
• Acute respiratory distress syndrome
• Pulmonary hemorrhage

Working formulation for the chart

• Hemorrhagic syndrome: epistaxis, petechiae on oral mucosa
• Influenza-associated toxic encephalopathy / neurotoxicosis: lethargy, confusion, delirium
• Infectious-toxic shock, at least evolving, manifested by hypotension (90/60 mmHg), tachycardia, muffled heart sounds, altered mental status
• No current clinical evidence of pneumonia, but this must be actively excluded and monitored for.

Rationale

Immediate actions

1. Admit directly to an infectious-disease ICU or resuscitation area.
2. Droplet precautions and standard infection-control measures.
3. ABCDE assessment:
   • Continuous ECG, pulse oximetry, respiratory rate, blood pressure, temperature, mental-status monitoring.
   • Two large-bore IV lines.
   • Oxygen if SpO₂ <94%, respiratory distress, or shock.
   • Strict fluid balance and hourly urine output. Insert urinary catheter in shock.
4. Call ICU/anesthesiology and infectious-disease specialists. Do not manage this patient as an outpatient.

Examination plan

Urgent laboratory tests

• CBC with differential and platelet count
• Peripheral blood smear if thrombocytopenia/hemolysis is suspected
• Coagulation profile: PT/INR, aPTT, fibrinogen, D-dimer, thrombin time if available
• Blood group and cross-match
• Serum glucose, electrolytes, urea, creatinine
• Liver panel: AST, ALT, bilirubin, albumin
• LDH, creatine kinase
• Arterial or venous blood gas, lactate
• CRP and procalcitonin
• Urinalysis and urine output monitoring
• Two sets of blood cultures before antibiotics, if this causes no material delay

Etiologic testing

• Nasopharyngeal swab for influenza A/B RT-PCR, with influenza A subtype testing according to local public-health procedures.
• SARS-CoV-2 PCR or multiplex respiratory viral PCR, depending on local availability.
• Sputum Gram stain/culture if productive cough develops.

Instrumental studies

• Portable chest radiograph now, even if auscultation is normal. Repeat if hypoxemia, tachypnea, focal chest signs, or worsening cough occur.
• ECG and troponin because marked tachycardia, hypotension, and muffled heart sounds can reflect myocarditis or shock.
• Bedside echocardiography if persistent hypotension, elevated troponin, or concern for myocardial dysfunction.
• CT brain only after initial stabilization if there is focal neurology, seizure, papilledema, severe persistent reduction in consciousness, or concern for intracranial bleeding.

Lumbar puncture

Important differential diagnoses

• Meningococcal sepsis or meningitis: fever, shock, altered consciousness, mucosal hemorrhages may precede a typical rash.
• Severe bacterial sepsis, including pneumococcal or staphylococcal infection complicating influenza.
• Viral hemorrhagic fever, depending on travel, occupational and contact history.
• Hantavirus infection with hemorrhagic fever and renal syndrome: ask about rodent exposure; monitor creatinine, urinalysis, and thrombocytopenia.
• Leptospirosis, dengue, malaria, and acute leukemia/thrombocytopenia when epidemiologically relevant.

Treatment plan

1. Start antiviral treatment immediately

• Oseltamivir 75 mg orally or via nasogastric tube twice daily, started now.
• Adjust dose for renal impairment.
• Use an extended course, commonly 10 days, if the illness is severe/prolonged or viral replication persists, based on local protocol and specialist advice.

2. Treat shock as sepsis while evaluation is ongoing

• Give a cautious initial bolus of balanced crystalloid, for example 500 mL, then reassess perfusion, lungs, blood pressure, urine output, lactate, and bedside ultrasound where available.
• In true septic shock, total initial fluid resuscitation may approach 30 mL/kg, but should be individualized because excessive fluid can worsen pulmonary edema.
• If hypotension persists after appropriate fluid resuscitation, start norepinephrine in ICU, titrated to maintain MAP ≥65 mmHg.
• Measure and trend serum lactate.

3. Empiric antibacterial treatment

• Ceftriaxone 2 g IV every 12 hours, particularly appropriate if meningitis/meningococcemia is possible.
• Add vancomycin if resistant pneumococcal meningitis or severe post-influenza MRSA pneumonia is a substantial local concern.
• Modify or stop antibiotics once microbiology, imaging, and clinical course clarify the diagnosis.

4. Hemorrhagic-syndrome management

• Avoid intramuscular injections, rectal procedures, aspirin, ibuprofen, ketorolac, and anticoagulants unless there is a compelling indication.
• Use paracetamol/acetaminophen for fever and pain, provided hepatic function permits.
• Control epistaxis with direct pressure, topical vasoconstrictor if appropriate, and ENT assessment or anterior nasal packing if bleeding continues.
• Give platelets, fresh frozen plasma, cryoprecipitate, or red cells only according to platelet count, active bleeding, fibrinogen, coagulation results, and transfusion protocol. Do not give these empirically without evidence of a correctable deficit.

5. Neurologic support

• Frequent Glasgow Coma Scale assessments and pupil checks.
• Check glucose immediately and correct hypoglycemia.
• Elevate head of bed about 30 degrees, avoid hypoxemia and hypercapnia.
• Manage seizures if present, for example with IV benzodiazepine followed by an antiepileptic as indicated.
• If consciousness worsens, arrange airway protection and mechanical ventilation.

6. Ongoing surveillance for complications

• Acute hypoxemic respiratory failure and viral/bacterial pneumonia
• ARDS
• DIC and progressive thrombocytopenia
• Acute kidney injury
• Myocarditis
• Encephalitis/meningitis
• Multiorgan dysfunction