CLINICAL MANIFESTATIONS Most patients with meningitis report fever, lethargy, confusion, headache, vomiting, or stiff neck. The mode of onset may vary. Some patients rapidly develop a headache, confusion, and loss of consciousness within 24 hours; they usually do not have antecedent respiratory symptoms. Others complain of headache, fever, and stiff neck associated with otitis, rhinorrhea, sore throat, or cough for one to seven days prior to the appearance of the full clinical picture. Still, others have symptoms referable to the respiratory tract for several weeks before meningitis sets in.
CLINICAL MANIFESTATIONS Cough is a common symptom in meningococcal and pneumococcal infection; earache often antedates infection with H. influenzae, and a sore throat may precede neisserial meningitis. Other symptoms of bacterial meningitis include backache, weakness, dizziness, ataxia, photophobia, and generalized Inyalgias. Additional clues are a history of alcoholism, a common accompaniment of pneu micrococcal meningitis; previous or recent infection or surgery involving the nose, throat, or sinuses; the patient who has a meningococcal infection.
Physical Findings. Most patients demonstrate the signs of meningeal irritation, i.e. stiff neck and positive Kernig or Brudzinski signs. Patients without these signs are often very young, very old, or severely obtunded. A petechial eruption is rela-tively rare in meningitis owing to bacteria other than meningococci unless ‘bacterial endocarditis is present. There may be physical signs of pneumonia, particularly in patients with pneumococcal meningitis, and evidence of oral infection may also be found.
Often, however, a primary focus (otitis, mastoiditis, sinusitis, pneumonia, or empyema) is not apparent on CLINICAL MANIFESTATIONS physical examination and should be carefully sought by other means because failure to eradicate the primary focus may result in failure of therapy or post-treatment relapse.
Although intracranial pressure is characteristically elevated, papilledema is rare. When it is encountered in the course of acute bacterial meningitis, it should call to mind the possibility of subdural empyema, brain abscess, or venous sinus thrombosis. The level of consciousness in patients with meningitis may vary from mild lethargy to deep coma. Most patients show some degree of confusion. In approximately 50 percent, other signs of neurologic damage develop during the course of infection.
These include major motor seizures, hemipareses, which are often transient and probably post-ictal, signs of diffuse central nervous system damage (bilateral Babinski signs and fixed, mid-stage pupils), or paresis of the second, third, sixth, seventh, and eighth cranial nerves.
Associated Disease. With the exception of epidemics of meningococcal meningitis, which are usually confined to closed environments such as army camps or schools, bacterial meningitis occurs sporadically, usually in a setting of some associated disease. Pharyngitis antedates meningitis in many patients with meningococcal and Hemophilus infection. Otitis with or without mastoiditis, although much rarer nowadays than 20 years ago, remains an important precursor of Hemophilus and pneumococcal meningitis, which is also frequently associated with pneumonia.
Pneumonitis is also often present in meningitis caused by gram-negative pathogens. A number of patients with pneumococcal meningitis have multiple myeloma; patients with this neoplasm are generally prone to recurrent pneumococcal infections. In addition to the common meningeal pathogens, meningitis in patients with diabetes mellitus is likely to be caused by uncommon organisms such as Klebsiella-Enterobacter, and Staphylococcus aureus.
Cranial trauma may pre-cede meningitis by several days and occasionally months or years; in such instances, D. pnrionaraar, hemolytic Staph. aureus or coliform bacteria are usually the offending organisms. Cranial osteomyelitis may intervene between heal trauma and the development of meningitis. Patients undergoing shunt procedures for relief of hydrocephalus tend to have infections with bacteria that are ordinarily not pathogenic such as Staphylococcus epidermidis or micrococci; gram-negative enteric bacteria and Pseudomonas meningitis also com-plicate shunting procedures. Occasionally, sub-cutaneous or mucosal infections such as furunculosis, decubitus ulcers, omphalitis in neonates, and endometritis precede leptomeningitis. Rare Types of Meningitis. Mima polymorpha Meningitis.
Mima polymorpha is a gram-negative pleomorphic bacillus that is easily confused on Gram stain with members of the Neisseria group and. H. influenzae. It can be separated from these organisms, however, by cultural and serologic techniques. Meningitis caused by Mima poly-morph closely resembles meningitis caused by the more common pathogens and cannot be differentiated from them on clinical grounds. Separation of mine from Neisseria is of more than academic importance because the image may be resistant to penicillin and sulfonamides and respond only to the tetracyclines.
Listeria Meningitis. The most common clinical illness caused by Listeria is meningitis, and any patient with clinical and laboratory evidence of meningeal infection said to be caused by a diphtheroid should be assumed to harbor Listeria in the cerebrospinal fluid. Clinically, the illness cannot be distinguished from meningitis caused by other bacteria (see Listeriosis).
Other Organisms. Bacteria that have caused infections usually in patients with antecedent head trauma or neurosurgical procedures include Cl. perfringens and Past. multocida, although any the organism can occasionally produce infection in this setting.