Mastoiditis and otogenic complications — formative SAQs

SAQ 1 (10 marks)

A 14-month-old child presents to the emergency department with three days of fever, coryza and ear-pulling. Oral amoxicillin was started yesterday by the family doctor for acute otitis media. Today the child is more unsettled, the temperature is 39.2 degrees Celsius, and behind the right ear the skin is erythematous, swollen and tender with loss of the postauricular crease and the pinna sitting lower and jutting further out than the left. The right tympanic membrane is bulging and erythematous. [4]

Question: Outline the diagnosis, the immediate investigations and the stepwise management of this child, including the myringotomy and the surgical decision. (10 marks) [4]

Model answer

Diagnosis and recognition (2 marks). The diagnosis is acute mastoiditis. The fever with postauricular erythema, swelling and tenderness, the lost postauricular crease, and the pinna displaced downward and outward, in a child with a bulging erythematous tympanic membrane, are the hallmark postauricular signs. The mastoid air cells are inflamed and obstructed, reached from the middle ear through the aditus ad antrum as a complication of the acute otitis media. This is a suppurative complication that demands admission and intravenous antibiotics with urgent ear-nose-and-throat review. [4] [5]

Immediate investigations (2 marks). Take a full blood count, C-reactive protein and blood cultures before antibiotics as a baseline against the 48-hour response. Send any ear discharge, and middle-ear fluid from a myringotomy, for Gram stain, culture and susceptibility. The tympanic membrane is intact and there are no neurological signs, so contrast temporal-bone CT is not mandatory at presentation but is obtained if the child fails to improve or deteriorates, or if a subperiosteal abscess or intracranial complication is suspected. Imaging must never delay intravenous antibiotics. [9] [4]

Immediate management and intravenous antibiotics (2 marks). Admit, establish intravenous access, and start broad-spectrum intravenous antibiotics after blood cultures. Give ceftriaxone 50 mg per kilogram (maximum 2 g) once daily intravenously plus flucloxacillin 50 mg per kilogram (maximum 2 g) every six hours intravenously, covering Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and non-typeable Haemophilus influenzae. Give analgesia and antipyretics. Refer urgently to ear-nose-and-throat surgery. [8] [4]

Myringotomy and the surgical decision (2 marks). Because the tympanic membrane is intact, perform a myringotomy to relieve the middle-ear pressure, sample the organism, and aid drainage. The systematic review confirms that most children with uncomplicated acute mastoiditis respond to intravenous antibiotics with or without myringotomy. A cortical mastoidectomy is indicated if the child fails to improve after 48 hours of intravenous antibiotics, if a subperiosteal or Bezold abscess develops, or if any intracranial complication appears. Reassess the clinical state and the inflammatory markers at 48 hours to decide. [8] [9]

Disposition and safety-netting (2 marks). Admit to a monitored bed under combined paediatric and ENT care. Continue intravenous antibiotics and observe closely, watching the inflammatory markers, the postauricular signs and the temperature. Transition to oral antibiotics on clinical improvement to complete a total course of three to four weeks guided by severity and culture results. At discharge, arrange audiology follow-up to document and monitor the hearing, and give a clear safety-net for recurrent fever, postauricular swelling, headache or any neurological symptom. Most children recover fully with prompt treatment. [5] [4]

SAQ 2 (10 marks)

Question: A 6-year-old with acute mastoiditis develops spiking picket-fence fevers, headache, vomiting and papilloedema while on intravenous antibiotics. (a) What complication has developed, and which imaging confirms it? (b) Outline the medical and surgical management. (c) Name the organisms to cover and the antibiotic regimen. (10 marks) [11]

Model answer

(a) The complication and its imaging (4 marks). The child has developed lateral (sigmoid) sinus thrombosis complicated by otitic hydrocephalus. Mastoid infection eroded the sigmoid plate and inoculated the lateral venous sinus, forming a septic thrombus; the impaired venous outflow raised intracranial pressure, producing the picket-fence spiking fever, headache, vomiting and papilloedema. Contrast-enhanced computed tomography of the temporal bone and brain may show the empty-delta sign of the lateral sinus clot, but magnetic resonance imaging with venography is the modality of choice, defining the thrombus, the venous anatomy and any parenchymal lesion or raised-pressure effect. [11] [9]

(b) Medical and surgical management (3 marks). Admit to a high-dependency or intensive care setting. Give prolonged broad-spectrum intravenous antibiotics. Proceed to a cortical mastoidectomy with evacuation of the infected clot and granulations to achieve source control, which is the mainstay of surgical treatment. Involve neurosurgery and haematology. Anticoagulation is controversial and individualised, reserved for selected cases with clot propagation or persisting raised pressure; sinus decompression or thrombectomy is rarely required. Monitor the intracranial pressure, the vision and the conscious state. [11] [8]

(c) Organisms and antibiotic regimen (3 marks). Cover the streptococci and staphylococci of acute otitis media — Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus — together with anaerobes given the intracranial extension. Give intravenous ceftriaxone 50 mg per kilogram (maximum 2 g) once daily plus flucloxacillin 50 mg per kilogram (maximum 2 g) every six hours, adding metronidazole 7.5 mg per kilogram (maximum 500 mg) every eight hours for anaerobic cover; add vancomycin if MRSA is suspected or the child is critically ill. De-escalate when culture and susceptibility results return, and complete a prolonged course guided by the clinical response and imaging. [8] [11]